Discussion:
Jeff Bezos' secretive rocket company just revealed its plans to tower over SpaceX
(too old to reply)
d***@hotmail.com
2016-09-12 17:14:21 UTC
Permalink
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust — about half as powerful as NASA's Saturn V launcher.

Unlike the Saturn V, however, Blue Origin plans to build on its rocket-recycling
experience and reuse the giant first-stage booster of each launcher — saving
untold cash over multiple launches, since rocket boosters are normally trashed in
the ocean."


"Named in honor of John Glenn, the first American to orbit Earth, New Glenn is 23
feet in diameter and lifts off with 3.85 million pounds of thrust from seven BE-4
engines. Burning liquefied natural gas and liquid oxygen, these are the same BE-4
engines that will power United Launch Alliance's new Vulcan rocket."

See:

http://www.techinsider.io/blue-origin-new-glenn-rockets-2016-9
Rob
2016-09-12 17:16:53 UTC
Permalink
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust — about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
Rick Jones
2016-09-12 20:11:12 UTC
Permalink
Post by Rob
Size in feet and weight in pounds? Is it designed in the 19th
century?
http://www.space.com/34034-blue-origin-new-glenn-rocket-for-satellites-people.html

Includes both sets of units. I'm guessing the actual measurements are
SI and the feet and pounds are just for the US readers.

rick jones
--
No need to believe in either side, or any side. There is no cause.
There's only yourself. The belief is in your own precision. - Joubert
these opinions are mine, all mine; HPE might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hpe.com but NOT BOTH...
Fred J. McCall
2016-09-12 22:40:17 UTC
Permalink
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust — about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
Jeff Findley
2016-09-14 10:14:37 UTC
Permalink
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
William Mook
2016-09-16 04:16:11 UTC
Permalink
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!


Fred J. McCall
2016-09-17 02:03:14 UTC
Permalink
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
William Mook
2016-09-17 05:34:51 UTC
Permalink
Post by Fred J. McCall
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
Outside the US SI units are generally used (kg, meters, kilometers)
Fred J. McCall
2016-09-18 17:57:22 UTC
Permalink
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
Outside the US SI units are generally used (kg, meters, kilometers)
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
JF Mezei
2016-09-18 22:16:05 UTC
Permalink
Post by Fred J. McCall
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
And nautical mile is actually an SI measure (exactly 1852metres in the
currect definition, while originally was the distance for a second of
latitude. ( the km was originally defined as 1/10,000 the distance
between equator and the pole, now defined relative to speed of light, so
the nautical mile is also based on speed of light).

From:
http://www.bipm.org/en/measurement-units/base-units.html

The metre is the length of the path travelled by light in vacuum during
a time interval of 1/299 792 458 of a second.


With regards to air traffic control, the standard practice is for ATC to
be able to handle american pilots in english, feet, pounds etc. However,
local pilots are able to speak local language and use local units (such
as ordering fuel in litres instead of pounds). However, local pilots
needs to be able to speak eaglish and understand US units when they
travel abroad.


Note: aircraft measure how full their tanks are by volume, not weight,
so easier to reconciliate fuel loaded in litres with what the aircraft
tank gauges show. But you still need to convert to a weight measurememnt
for aircraft performance and take-off limits purposes.
Alain Fournier
2016-09-19 00:17:34 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
And nautical mile is actually an SI measure (exactly 1852metres in the
currect definition, while originally was the distance for a second of
latitude. ( the km was originally defined as 1/10,000 the distance
between equator and the pole, now defined relative to speed of light, so
the nautical mile is also based on speed of light).
No the nautical mile is not an SI measure. Pretty much all are units
currently in use would be SI measures by that standard. The definition
of an inch in the US (the place still using inches) is 2.54 cm. The
definition of a pound-mass 0.45359237 kg. The pound-force is defined
as the gravitational force exerted on a mass of one pound-mass in one
standard gravity, which is 9.80665 m/s^2. Etc.


Alain Fournier
Rob
2016-09-19 08:28:08 UTC
Permalink
Post by JF Mezei
Note: aircraft measure how full their tanks are by volume, not weight,
Maybe on some small or older aircraft, where you can also find car-style
fuel gauges that only indicate E-1/4-1/2-3/4-F indication.

On modern jetliners, the fuel gauges indicate weight of fuel.
Fred J. McCall
2016-09-19 15:11:37 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
And nautical mile is actually an SI measure
Poppycock.
Post by JF Mezei
... (exactly 1852metres in the
currect definition, while originally was the distance for a second of
latitude. ( the km was originally defined as 1/10,000 the distance
between equator and the pole, now defined relative to speed of light, so
the nautical mile is also based on speed of light).
http://www.bipm.org/en/measurement-units/base-units.html
Read your own cite. Do you see 'nautical mile' as one of the seven
base SI units? No. So which POWERS of the base units can you
multiply together to get 'nautical miles'? By your reasoning above,
almost any unit is an 'SI unit' since you can convert from an SI unit.
Post by JF Mezei
With regards to air traffic control, the standard practice is for ATC to
be able to handle american pilots in english, feet, pounds etc. However,
local pilots are able to speak local language and use local units (such
as ordering fuel in litres instead of pounds). However, local pilots
needs to be able to speak eaglish and understand US units when they
travel abroad.
Silly notion. Again, STANDARD (as in International Standard) aviation
units are as I stated. I've never heard of anything other than GA
aircraft order fuel in VOLUME measures like litres. You care about
the WEIGHT of fuel because all your fuel consumption figures are by
weight.
Post by JF Mezei
Note: aircraft measure how full their tanks are by volume, not weight,
so easier to reconciliate fuel loaded in litres with what the aircraft
tank gauges show. But you still need to convert to a weight measurememnt
for aircraft performance and take-off limits purposes.
Who gives a shit what the guage measures? You better be thinking
about fuel in weight, because that's how you determine if the thing
stops and falls out of the sky or not.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
JF Mezei
2016-09-19 21:52:44 UTC
Permalink
Post by Fred J. McCall
multiply together to get 'nautical miles'? By your reasoning above,
almost any unit is an 'SI unit' since you can convert from an SI unit.
The nautical mile used to be defined as 1/60s of a degree of latitude.
( 90 * 60 nautical miles gave you distance from equator to a pole).

(I used to think it was longitude (circumference at equator = nm * 60 *
360 but apparently it never was).


However, its current official definition of a nautical mile is 1852
metres. 1852 is no longer a conversion factor it is the actual definition.

It may not be an SI unit, but its definition is fixed to one.


Note that from a GPS point of view, distance is measured in radians
(angle) and then converted to human distances using the radius of the
earth (which depends oh which model you use eg WGS84 where
equatorial=6378.137km and polar=6356.752km for radius

Not sure how pre-GPS rockets/satellites worked to express their position
above earth (and thus do the math).
Post by Fred J. McCall
Who gives a shit what the guage measures? You better be thinking
about fuel in weight, because that's how you determine if the thing
stops and falls out of the sky or not.
If the plane measures how full its tanks are by having a scale under the
tank, then yeah, it measures weight. But if it measures by how high the
fuel gets in the tank, then it measures volume.

And this is why when you get fuel by the pound, they also give you the
current density of fuel so you (or plane's computer) do the conversion
from volume to pounds to verify this is what you have in the tanks.

Note: in the case of the Gimli glider, the fiuel gaues were inop, so the
pilots did math to calculate how many litres they needed, and could not
check that that quantity fulled the tanks to expected level.
Fred J. McCall
2016-09-20 17:30:17 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
multiply together to get 'nautical miles'? By your reasoning above,
almost any unit is an 'SI unit' since you can convert from an SI unit.
The nautical mile used to be defined as 1/60s of a degree of latitude.
( 90 * 60 nautical miles gave you distance from equator to a pole).
(I used to think it was longitude (circumference at equator = nm * 60 *
360 but apparently it never was).
However, its current official definition of a nautical mile is 1852
metres. 1852 is no longer a conversion factor it is the actual definition.
It may not be an SI unit, but its definition is fixed to one.
Still a conversion factor. And still not an SI unit.
Post by JF Mezei
Note that from a GPS point of view, distance is measured in radians
(angle) and then converted to human distances using the radius of the
earth (which depends oh which model you use eg WGS84 where
equatorial=6378.137km and polar=6356.752km for radius
Note that that's not at all how GPS distances are measured. GPS
positions are in meters from an ECEF reference point.
Post by JF Mezei
Not sure how pre-GPS rockets/satellites worked to express their position
above earth (and thus do the math).
Geodetic coordinates.
Post by JF Mezei
Post by Fred J. McCall
Who gives a shit what the guage measures? You better be thinking
about fuel in weight, because that's how you determine if the thing
stops and falls out of the sky or not.
If the plane measures how full its tanks are by having a scale under the
tank, then yeah, it measures weight. But if it measures by how high the
fuel gets in the tank, then it measures volume.
Wrong. If it measures how high the fuel gets in the tank it measures
DEPTH. This is then converted to 'volume' before it hits the gauge
based on the meter knowing the shape of the tank to get volume or to
pounds by knowing the volume and density between the sensor(s) in the
tank and the gauge.
Post by JF Mezei
And this is why when you get fuel by the pound, they also give you the
current density of fuel so you (or plane's computer) do the conversion
from volume to pounds to verify this is what you have in the tanks.
No, they give you the 'current density' as a measure of the quality of
the fuel and so they can correct to a 'standard temperature density'
for performance calculations.
Post by JF Mezei
Note: in the case of the Gimli glider, the fiuel gaues were inop, so the
pilots did math to calculate how many litres they needed, and could not
check that that quantity fulled the tanks to expected level.
Uh, they were only doing volume calculations because the fuel gauges
were INOP.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
JF Mezei
2016-09-20 19:36:39 UTC
Permalink
Post by Fred J. McCall
Still a conversion factor. And still not an SI unit.
farenheight is defined by freezing and boiling points of water. You can
get a farenheit temperature wiothout needing to refer to another scale.

Nautical Mile is defined in terms of metres, a SI meaure. You cannot
get a nm without refering to the metre because it is defined as 1852 metres.
Post by Fred J. McCall
Note that that's not at all how GPS distances are measured. GPS
positions are in meters from an ECEF reference point.
http://williams.best.vwh.net/avform.htm#Dist

latitude and longitudes are all about angles when you compare 2 locations.

(how the GPS calculates lat and lon from satellite signals propagation
delays and dopler is a different story)
Post by Fred J. McCall
Wrong. If it measures how high the fuel gets in the tank it measures
DEPTH. This is then converted to 'volume' before it hits the gauge
At least you agree that plane's tank doesn't measure the weight of the fuel.
Post by Fred J. McCall
No, they give you the 'current density' as a measure of the quality of
the fuel and so they can correct to a 'standard temperature density'
for performance calculations.
The thing is that truck that feed the fuel to the plane would measure it
in volume as it passes through the pump and gauge. So the density would
be entered at the truck to convert the volume to weight.

When fuel is delivered in litres, then the conversion to weight is done
in the plans based on the density provided by the fueling crews.
Post by Fred J. McCall
Uh, they were only doing volume calculations because the fuel gauges
were INOP.
The inop fuel gauges prevented them from verifying they had ordered
enough fuel and that enough fuel was loaded. The original mistake was in
their math in calculating how much fuel to order. The fueling folks put
into the plane the amount requested by pilots.

Had the fuel gauges worked, pilots would have realised that the amount
they ordered only half filled the tanks which should have been nearly
full and detected the original mistake.

Note: for water: 1litre = 1kg = 2.2 US pounds. Fuel is lighter than
water but not that much. So pilots should have had a rough sanity check
when they ordered their fuel or did the conversion from pounds to litres
that something was amiss.
Fred J. McCall
2016-09-20 21:37:05 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
Still a conversion factor. And still not an SI unit.
farenheight is defined by freezing and boiling points of water. You can
get a farenheit temperature wiothout needing to refer to another scale.
Nautical Mile is defined in terms of metres, a SI meaure. You cannot
get a nm without refering to the metre because it is defined as 1852 metres.
Still a conversion factor. And still not an SI unit.
Post by JF Mezei
Post by Fred J. McCall
Note that that's not at all how GPS distances are measured. GPS
positions are in meters from an ECEF reference point.
http://williams.best.vwh.net/avform.htm#Dist
latitude and longitudes are all about angles when you compare 2 locations.
No, they aren't.
Post by JF Mezei
(how the GPS calculates lat and lon from satellite signals propagation
delays and dopler is a different story)
GPS only bothers to calculate lat/lon/alt for the convenience of the
humans.
Post by JF Mezei
Post by Fred J. McCall
Wrong. If it measures how high the fuel gets in the tank it measures
DEPTH. This is then converted to 'volume' before it hits the gauge
At least you agree that plane's tank doesn't measure the weight of the fuel.
But the gauge very well may (actually mass, since an aircraft is an
accelerated frame).
Post by JF Mezei
Post by Fred J. McCall
No, they give you the 'current density' as a measure of the quality of
the fuel and so they can correct to a 'standard temperature density'
for performance calculations.
The thing is that truck that feed the fuel to the plane would measure it
in volume as it passes through the pump and gauge. So the density would
be entered at the truck to convert the volume to weight.
Fuel is priced in volume but jets buy it by weight.
Post by JF Mezei
When fuel is delivered in litres, then the conversion to weight is done
in the plans based on the density provided by the fueling crews.
No.
Post by JF Mezei
Post by Fred J. McCall
Uh, they were only doing volume calculations because the fuel gauges
were INOP.
The inop fuel gauges prevented them from verifying they had ordered
enough fuel and that enough fuel was loaded. The original mistake was in
their math in calculating how much fuel to order. The fueling folks put
into the plane the amount requested by pilots.
Had the fuel gauges worked, pilots would have realised that the amount
they ordered only half filled the tanks which should have been nearly
full and detected the original mistake.
Note: for water: 1litre = 1kg = 2.2 US pounds. Fuel is lighter than
water but not that much. So pilots should have had a rough sanity check
when they ordered their fuel or did the conversion from pounds to litres
that something was amiss.
The gauge in the aircraft would have shown POUNDS of fuel.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
JF Mezei
2016-09-20 21:51:36 UTC
Permalink
Post by Fred J. McCall
Fuel is priced in volume but jets buy it by weight.
In metric countries, airlines can buy it in litres (volume).
Post by Fred J. McCall
The gauge in the aircraft would have shown POUNDS of fuel.
The planes are able to display tank status in litres or pounds or I
assume in other measurements.

In the case of the Air Canada 767, it was configured to display metric
units.
Rob
2016-09-21 08:11:03 UTC
Permalink
Post by JF Mezei
In the case of the Air Canada 767, it was configured to display metric
units.
Well that story was a bit more complicated, as usual when accidents occur:
there rarely is just one single cause.

The fuel gauges were inoperative as a result of a single unit failure
in a redundant system, followed by a diagnostic action by an engineer
that was interrupted, resulting in no fuel gauge display at all.
(instead of just using the remaining unit of the redundant pair)

The pilots misunderstood the remarks about the fuel gauge problems, and
decided to fly the aircraft even though that was not authorized with a
completely inoperative fuel gauge display.

They then went on to just calculate the weight of fuel required, and
have that converted to volume by the fuel supplier, and that is where an
error crept in because Canada had just switched from imperial to metric
and the imperial conversion factor from weight to volume was used,
then the outcome was used as a metric volume.

It was not noticed because there was no fuel gauge display that could have
alerted them to the relatively small amount of fuel in the tanks, or could
have early-warned them during the flight that it would be depleted soon.
So they only noticed the problem when one tank was completely empty,
soon followed by the others.

While I understand that weight of fuel is more significant to performance
of the aircraft than volume, I find it confusing that the two are being
used in parallel, and manual conversions are being made by pilots and
ground personnel. Apparently it is normal to calculate required fuel as
weight, subtract tank contents, then order extra fuel as weight knowing
that it can only be measured by the tanker in volume. To me this seems
"asking for trouble". Using imperial vs SI units is only part of that.

Well, most likely the tanker personnel now have better tools available
to do this conversion...
JF Mezei
2016-09-21 17:43:54 UTC
Permalink
Post by Rob
While I understand that weight of fuel is more significant to performance
of the aircraft than volume,
Needed to determine how much luggage/cargo can be loaded on aircraft,
calculate centre of gravity and the V1/V2 speeds during takeoff.

For flight length, either will work because computer can display "pounds
per hour" or "litres per hour" for fuel consumption. But for takeoff,
the plane's specs are in weight.
Post by Rob
I find it confusing that the two are being
used in parallel, and manual conversions are being made by pilots and
ground personnel.
In the case of the Gimli glider, pilots *should* have known that if they
want 22 pounds of fuel, the rough equivalent would have been 10 litres.
And since fuel is lighter than water, the number of litres should have
been north of 10. So if their math yielded 5 litres they *should* have
seen a problem.
Rob
2016-09-21 18:42:29 UTC
Permalink
Post by JF Mezei
Post by Rob
While I understand that weight of fuel is more significant to performance
of the aircraft than volume,
Needed to determine how much luggage/cargo can be loaded on aircraft,
calculate centre of gravity and the V1/V2 speeds during takeoff.
For flight length, either will work because computer can display "pounds
per hour" or "litres per hour" for fuel consumption. But for takeoff,
the plane's specs are in weight.
I understood that it is weight of fuel that matters because the weight
determines the amount of energy you get from it, and the volume varies
by temperature. However, I have a hard time believing that the volume
change for a liquid is significant in aviation fuel calculations, as
there always has to be sufficient extra fuel to do some waiting, a go
around, and a deviation to the nearest airport. That extra is always
going to be significantly more than the variation in density, I think.

Of course, for rocketry it is all different.
Post by JF Mezei
Post by Rob
I find it confusing that the two are being
used in parallel, and manual conversions are being made by pilots and
ground personnel.
In the case of the Gimli glider, pilots *should* have known that if they
want 22 pounds of fuel, the rough equivalent would have been 10 litres.
And since fuel is lighter than water, the number of litres should have
been north of 10. So if their math yielded 5 litres they *should* have
seen a problem.
The problem is that they were new to the conversion factor and so they
would not immediately notice that. I can understand this, as we
went through the process of getting a new currency with a factor 2.2
different value to what I had always worked with, and it means that
you suddenly have to calculate things that you used to be able to
estimate and compare without thinking about it.

Both the pilots and ground crew found themselves in a new situation.
And in hindsight there are often many places where it would have been
possible to avoid the accident.
JF Mezei
2016-09-21 19:04:23 UTC
Permalink
Post by Rob
I understood that it is weight of fuel that matters because the weight
determines the amount of energy you get from it, and the volume varies
by temperature.
Airplanes have limits on how heavy they can be at takeoff and landing.
Fuel represent a huge percentage of total weight. Every kilogram of
fuel you load means one less kilogram of cargo you can load.

They have centre of gravity limits, and the pilots calculate limits

And at takeoff, pilots calculate 2 critical speeds (when they can lift
off, and speed beyond which they can no longer stop without going beyond
the end of that particular runway). Both speeds are highly dependent on
weight of aircraft, as well as wind, temperature and altitude.

And because carrying fuel during flight costs fuel, airlines don't want
to carry more fuel than they have to. So tanks are not always 100% full
at time of departure.

The density of fuel is needed because fuel pumps work with volume, and
the tanks on a plane measure volume. So they need the density to get
more accurate evaluation of it weight.

To get somewhat back on topic, SpaceX has made strides in getting
"supercooled" kerosene and I assume LOX in order to get more fuel loaded
in the same space.

Anyone know the rought weight difference between a normal launch and one
with super cooled fuel ?
Rob
2016-09-21 19:15:11 UTC
Permalink
Post by JF Mezei
Post by Rob
I understood that it is weight of fuel that matters because the weight
determines the amount of energy you get from it, and the volume varies
by temperature.
Airplanes have limits on how heavy they can be at takeoff and landing.
Fuel represent a huge percentage of total weight. Every kilogram of
fuel you load means one less kilogram of cargo you can load.
I understand that the total weight of the aircraft is important, but
my understanding is that the weight of fuel is calculated for the trip
because the aircraft requires a specified weight of fuel to cover some
distance.
(this cannot be a linear function, though, because taking on more fuel
means the plane will become heavier and consume more fuel, requiring
even more fuel to make up for that)

So they know they need "10000 kg of fuel" (say 21000 pounds for americans)
for the trip, then they order that from the supplier and somewhere along
the line it has to be converted to liters or gallons. Error-prone.

I would say, make the fuel trucks deliver in kilograms, and all trouble
is over. Maybe wasn's to easy with an old mechanical counter, but
should be peanuts on a modern microcontroller based counter.
Post by JF Mezei
The density of fuel is needed because fuel pumps work with volume, and
the tanks on a plane measure volume. So they need the density to get
more accurate evaluation of it weight.
What I wonder about is how significant the varying density of fuel
will be relative to the total volume. When the density of the fuel
varies by 3% and then you add 10% at the end for safety margin, most
or all of the trouble to include density is wasted and you introduce
a new risk of introducing an error.
Post by JF Mezei
To get somewhat back on topic, SpaceX has made strides in getting
"supercooled" kerosene and I assume LOX in order to get more fuel loaded
in the same space.
Anyone know the rought weight difference between a normal launch and one
with super cooled fuel ?
Yes that is interesting, and in a space launch it is more interesting
because much more prediction, calculation and checking can be done on
a space launce than on an airliner trip.
JF Mezei
2016-09-22 07:06:23 UTC
Permalink
Post by Rob
I understand that the total weight of the aircraft is important, but
my understanding is that the weight of fuel is calculated for the trip
because the aircraft requires a specified weight of fuel to cover some
distance.
It requires a certain "amount" of view to cover the distance with
current weaither predictions as well as contigencies (more infavourable
wind, delays at airport and diversion to airport). The rules on how much
surplus you need are very clear although you can cheat.
Post by Rob
So they know they need "10000 kg of fuel" (say 21000 pounds for americans)
for the trip, then they order that from the supplier and somewhere along
the line it has to be converted to liters or gallons. Error-prone.
In the case of Gimli, their ordered in litres. Pilots made error
converting from whatever they had calculated they needed into litres.
BTWm the Flight did Montreal-Ottawa-Edmonton, and at the stop in Ottawa,
they made the exact same mistake, ran out of fiew before reaching winnipeg.
Post by Rob
I would say, make the fuel trucks deliver in kilograms,
I am not sure there are any pumps that calculate how much they pump in
weight. I think they are all in volume and calibrated very precisely.
Post by Rob
What I wonder about is how significant the varying density of fuel
will be relative to the total volume. When the density of the fuel
varies by 3% and then you add 10% at the end for safety margin,
Safety marging is extremely precisely calculated based on rules, and
airlines have learned tricks to minimize this.

if FAA says you need 10% extra in case of unfavourable winds, then the
airline will brake a New York to London trip in say 5 legs. They only
carry the excess based on length of 1 leg. After first leg, if they
have not consumed any of that surplus, they carry that surplus over to
"secure" the second leg. If at end of second leg, they still haven't
consumer that surplus, they carry over to 3rd leg etc. (each leg has a
designated airport, and if at the end of a leg, they end up with
insufficient fuiel to make the next one with the legally mandated
reservesm then they have to land and refuel).

So fuel variations of 3% when you are managing your required 10% to bare
minumum is a huge "error" and I suspect they are very careful about that.
Fred J. McCall
2016-09-23 22:31:06 UTC
Permalink
Post by JF Mezei
In the case of Gimli, their ordered in litres. Pilots made error
converting from whatever they had calculated they needed into litres.
BTWm the Flight did Montreal-Ottawa-Edmonton, and at the stop in Ottawa,
they made the exact same mistake, ran out of fiew before reaching winnipeg.
No, they didn't. They ordered in KILOGRAMS. The GROUND CREW used the
wrong conversion factor to calculate the number of litres of fuel
required.
Post by JF Mezei
So fuel variations of 3% when you are managing your required 10% to bare
minumum is a huge "error" and I suspect they are very careful about that.
To get a 3% swing in fuel volume you would need a preposterous
temperature swing. Coefficient of expansion of kerosene is something
like 0.00099 per degree Celsius, so a 3% change in volume would
require a temperature swing of some 30+ degrees Celsius from
'standard'.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
Rob
2016-09-24 07:47:12 UTC
Permalink
Post by Fred J. McCall
Post by JF Mezei
So fuel variations of 3% when you are managing your required 10% to bare
minumum is a huge "error" and I suspect they are very careful about that.
To get a 3% swing in fuel volume you would need a preposterous
temperature swing. Coefficient of expansion of kerosene is something
like 0.00099 per degree Celsius, so a 3% change in volume would
require a temperature swing of some 30+ degrees Celsius from
'standard'.
That is why I question the reasoning that fuel has to be calculated
in weight and then converted to volume "because of variations in the
fuel density". There will be some difference but it will be very
small. Important for space flight, but probably not for aviation.
Fred J. McCall
2016-09-21 19:20:01 UTC
Permalink
Post by JF Mezei
Post by Rob
While I understand that weight of fuel is more significant to performance
of the aircraft than volume,
Needed to determine how much luggage/cargo can be loaded on aircraft,
calculate centre of gravity and the V1/V2 speeds during takeoff.
Not just that. Fuel consumption is usually given in pounds of fuel in
the performance manuals.
Post by JF Mezei
For flight length, either will work because computer can display "pounds
per hour" or "litres per hour" for fuel consumption. But for takeoff,
the plane's specs are in weight.
You don't just say 'fill er up' and go fly. The quantity of fuel
required for the flight (and diverts) is calculated before fueling.
Performance figures are in MASS of fuel required. It doesn't matter
what the airplane can display in.
Post by JF Mezei
Post by Rob
I find it confusing that the two are being
used in parallel, and manual conversions are being made by pilots and
ground personnel.
In the case of the Gimli glider, pilots *should* have known that if they
want 22 pounds of fuel, the rough equivalent would have been 10 litres.
It's 12.5 litres, not 10 litres.
Post by JF Mezei
And since fuel is lighter than water, the number of litres should have
been north of 10. So if their math yielded 5 litres they *should* have
seen a problem.
Except we're not talking about little numbers like 5-10 litres here...
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
JF Mezei
2016-09-22 07:12:06 UTC
Permalink
Post by Fred J. McCall
You don't just say 'fill er up' and go fly.
Suggest you want a documentary called "Octopussy" where a british secret
agent does just that after running out of fuel and landing near a gas
station :-)
Post by Fred J. McCall
Post by JF Mezei
want 22 pounds of fuel, the rough equivalent would have been 10 litres.
It's 12.5 litres, not 10 litres.
1 litre of H2O = 1kg = 2.2 lbs. so 22 pounds is 10 litres.
Post by Fred J. McCall
Except we're not talking about little numbers like 5-10 litres here...
They loaded about half the needed fuel on the plane. The the order of
maginture of their error is far greater than the density difference
between water and fuel. And less dense fuel would have taken more
litres than if they had ordered the same weight of water.

If you take pounds of fuel needed and divide by 2.2, you get litres of
water to match those pounds. In fuel, the numbe rof litres would be
somewhat higher.

If your calculated number is half of what you need for water instead of
being slightly higher, then you shoudl spot a mistake has been made.
Fred J. McCall
2016-09-23 22:36:52 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
You don't just say 'fill er up' and go fly.
Suggest you want a documentary called "Octopussy" where a british secret
agent does just that after running out of fuel and landing near a gas
station :-)
Suggest you're enough of an idiot without trying to make jokes.
Post by JF Mezei
Post by Fred J. McCall
Post by JF Mezei
want 22 pounds of fuel, the rough equivalent would have been 10 litres.
It's 12.5 litres, not 10 litres.
1 litre of H2O = 1kg = 2.2 lbs. so 22 pounds is 10 litres.
We don't fuel jets with H2O. We fuel them with Jet-A or similar,
which has a density of around 0.8 kg per litre. Do the math. You'll
get 12.5 litres for 22 pounds.
Post by JF Mezei
Post by Fred J. McCall
Except we're not talking about little numbers like 5-10 litres here...
They loaded about half the needed fuel on the plane. The the order of
maginture of their error is far greater than the density difference
between water and fuel. And less dense fuel would have taken more
litres than if they had ordered the same weight of water.
If you take pounds of fuel needed and divide by 2.2, you get litres of
water to match those pounds. In fuel, the numbe rof litres would be
somewhat higher.
If your calculated number is half of what you need for water instead of
being slightly higher, then you shoudl spot a mistake has been made.
Except nobody checked after the fact to see what they had. This is
normally the duty of the flight engineer. B767 has a 2-person cockpit
crew (no flight engineer) and the duty of checking the fuel level was
never reallocated by Air Canada for this type of aircraft. So it
didn't matter what they used, since they didn't look.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
Fred J. McCall
2016-09-21 18:05:23 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
Fuel is priced in volume but jets buy it by weight.
In metric countries, airlines can buy it in litres (volume).
Post by Fred J. McCall
The gauge in the aircraft would have shown POUNDS of fuel.
The planes are able to display tank status in litres or pounds or I
assume in other measurements.
In the case of the Air Canada 767, it was configured to display metric
units.
Got a RELIABLE cite for the configuration of the aircraft?
--
"It's always different. It's always complex. But at some point,
somebody has to draw the line. And that somebody is always me....
I am the law."
-- Buffy, The Vampire Slayer
Alain Fournier
2016-09-20 23:16:07 UTC
Permalink
Post by Fred J. McCall
Post by JF Mezei
Post by Fred J. McCall
Still a conversion factor. And still not an SI unit.
farenheight is defined by freezing and boiling points of water. You can
get a farenheit temperature wiothout needing to refer to another scale.
Nautical Mile is defined in terms of metres, a SI meaure. You cannot
get a nm without refering to the metre because it is defined as 1852 metres.
Still a conversion factor. And still not an SI unit.
No it isn't a conversion factor. It is the definition. Nautical miles,
inches, pounds etc. are defined based on SI units.


Alain Fournier
Fred J. McCall
2016-09-21 18:08:37 UTC
Permalink
Post by Alain Fournier
Post by Fred J. McCall
Post by JF Mezei
Post by Fred J. McCall
Still a conversion factor. And still not an SI unit.
farenheight is defined by freezing and boiling points of water. You can
get a farenheit temperature wiothout needing to refer to another scale.
Nautical Mile is defined in terms of metres, a SI meaure. You cannot
get a nm without refering to the metre because it is defined as 1852 metres.
Still a conversion factor. And still not an SI unit.
No it isn't a conversion factor. It is the definition. Nautical miles,
inches, pounds etc. are defined based on SI units.
Coming to an agreement to REDEFINE something in terms of something
else based on what the required conversion factor was does not make
the new ratio magically into something new. Still a conversion
factor.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
Alain Fournier
2016-09-21 23:31:43 UTC
Permalink
Post by Fred J. McCall
Post by Alain Fournier
Post by Fred J. McCall
Post by JF Mezei
Post by Fred J. McCall
Still a conversion factor. And still not an SI unit.
farenheight is defined by freezing and boiling points of water. You can
get a farenheit temperature wiothout needing to refer to another scale.
Nautical Mile is defined in terms of metres, a SI meaure. You cannot
get a nm without refering to the metre because it is defined as 1852 metres.
Still a conversion factor. And still not an SI unit.
No it isn't a conversion factor. It is the definition. Nautical miles,
inches, pounds etc. are defined based on SI units.
Coming to an agreement to REDEFINE something in terms of something
else based on what the required conversion factor was does not make
the new ratio magically into something new. Still a conversion
factor.
No it is not just a conversion factor. There is a conversion rule to
go from Fahrenheit to Celsius degrees. If the definition of a Celsius
degree was to be changed, you would have to change the conversion rule.
Because it is a conversion rule not a definition.

Not so for the pound-mass versus the kg. If the definition of a kg
was to change, which will likely happen in the not too distant future,
you don't have to change to conversion rule to go from kg to pounds.
It is the value of a pound that would change, because a pound is
defined to be 0.45359237 kg, whatever a kg is. Same for inches vs
meters. The inch is defined as 2.54 cm, if the cm changes, not likely
to ever happen again, then the inch changes, not the conversion rule.


Alain Fournier
William Mook
2016-09-21 02:59:38 UTC
Permalink
Fred has obviously never flown an aircraft privately in another country.


Post by Fred J. McCall
Post by JF Mezei
Post by Fred J. McCall
multiply together to get 'nautical miles'? By your reasoning above,
almost any unit is an 'SI unit' since you can convert from an SI unit.
The nautical mile used to be defined as 1/60s of a degree of latitude.
( 90 * 60 nautical miles gave you distance from equator to a pole).
(I used to think it was longitude (circumference at equator = nm * 60 *
360 but apparently it never was).
However, its current official definition of a nautical mile is 1852
metres. 1852 is no longer a conversion factor it is the actual definition.
It may not be an SI unit, but its definition is fixed to one.
Still a conversion factor. And still not an SI unit.
Post by JF Mezei
Note that from a GPS point of view, distance is measured in radians
(angle) and then converted to human distances using the radius of the
earth (which depends oh which model you use eg WGS84 where
equatorial=6378.137km and polar=6356.752km for radius
Note that that's not at all how GPS distances are measured. GPS
positions are in meters from an ECEF reference point.
Post by JF Mezei
Not sure how pre-GPS rockets/satellites worked to express their position
above earth (and thus do the math).
Geodetic coordinates.
Post by JF Mezei
Post by Fred J. McCall
Who gives a shit what the guage measures? You better be thinking
about fuel in weight, because that's how you determine if the thing
stops and falls out of the sky or not.
If the plane measures how full its tanks are by having a scale under the
tank, then yeah, it measures weight. But if it measures by how high the
fuel gets in the tank, then it measures volume.
Wrong. If it measures how high the fuel gets in the tank it measures
DEPTH. This is then converted to 'volume' before it hits the gauge
based on the meter knowing the shape of the tank to get volume or to
pounds by knowing the volume and density between the sensor(s) in the
tank and the gauge.
Post by JF Mezei
And this is why when you get fuel by the pound, they also give you the
current density of fuel so you (or plane's computer) do the conversion
from volume to pounds to verify this is what you have in the tanks.
No, they give you the 'current density' as a measure of the quality of
the fuel and so they can correct to a 'standard temperature density'
for performance calculations.
Post by JF Mezei
Note: in the case of the Gimli glider, the fiuel gaues were inop, so the
pilots did math to calculate how many litres they needed, and could not
check that that quantity fulled the tanks to expected level.
Uh, they were only doing volume calculations because the fuel gauges
were INOP.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
Fred J. McCall
2016-09-21 18:16:14 UTC
Permalink
Mook has obviously never seen a standard aeronautical chart or
approach plate.
Post by William Mook
Fred has obviously never flown an aircraft privately in another country.
http://youtu.be/9YucR-A3lKA
Post by Fred J. McCall
Post by JF Mezei
Post by Fred J. McCall
multiply together to get 'nautical miles'? By your reasoning above,
almost any unit is an 'SI unit' since you can convert from an SI unit.
The nautical mile used to be defined as 1/60s of a degree of latitude.
( 90 * 60 nautical miles gave you distance from equator to a pole).
(I used to think it was longitude (circumference at equator = nm * 60 *
360 but apparently it never was).
However, its current official definition of a nautical mile is 1852
metres. 1852 is no longer a conversion factor it is the actual definition.
It may not be an SI unit, but its definition is fixed to one.
Still a conversion factor. And still not an SI unit.
Post by JF Mezei
Note that from a GPS point of view, distance is measured in radians
(angle) and then converted to human distances using the radius of the
earth (which depends oh which model you use eg WGS84 where
equatorial=6378.137km and polar=6356.752km for radius
Note that that's not at all how GPS distances are measured. GPS
positions are in meters from an ECEF reference point.
Post by JF Mezei
Not sure how pre-GPS rockets/satellites worked to express their position
above earth (and thus do the math).
Geodetic coordinates.
Post by JF Mezei
Post by Fred J. McCall
Who gives a shit what the guage measures? You better be thinking
about fuel in weight, because that's how you determine if the thing
stops and falls out of the sky or not.
If the plane measures how full its tanks are by having a scale under the
tank, then yeah, it measures weight. But if it measures by how high the
fuel gets in the tank, then it measures volume.
Wrong. If it measures how high the fuel gets in the tank it measures
DEPTH. This is then converted to 'volume' before it hits the gauge
based on the meter knowing the shape of the tank to get volume or to
pounds by knowing the volume and density between the sensor(s) in the
tank and the gauge.
Post by JF Mezei
And this is why when you get fuel by the pound, they also give you the
current density of fuel so you (or plane's computer) do the conversion
from volume to pounds to verify this is what you have in the tanks.
No, they give you the 'current density' as a measure of the quality of
the fuel and so they can correct to a 'standard temperature density'
for performance calculations.
Post by JF Mezei
Note: in the case of the Gimli glider, the fiuel gaues were inop, so the
pilots did math to calculate how many litres they needed, and could not
check that that quantity fulled the tanks to expected level.
Uh, they were only doing volume calculations because the fuel gauges
were INOP.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
William Mook
2016-09-20 00:43:19 UTC
Permalink
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
Outside the US SI units are generally used (kg, meters, kilometers)
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
http://aerosavvy.com/metric-imperial/

One of the challenges of international flying is handling different units of measure in different countries. In aviation, the battle between imperial and metric units continues
Fred J. McCall
2016-09-20 17:35:36 UTC
Permalink
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
Outside the US SI units are generally used (kg, meters, kilometers)
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
http://aerosavvy.com/metric-imperial/
One of the challenges of international flying is handling different units of measure in different countries. In aviation, the battle between imperial and metric units continues
"International pilots are extremely well versed in all the aviation
units discussed in my article below. We use these units daily and can
juggle them in our sleep. The AirAsia 8501 flight crew was on their
own turf, flying a familiar route. To blindly speculate that they
became confused about units of measure is absurd."

Note that your cite agrees exactly with what I already said. Also
note that Russia (and the old Soviet Bloc), the big player using
metric (China and North Korea use metric because ... guess where they
got their aircraft from?) is channging to a flight level system based
on feet for altitude.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
William Mook
2016-09-21 03:06:53 UTC
Permalink
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
Outside the US SI units are generally used (kg, meters, kilometers)
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
http://aerosavvy.com/metric-imperial/
One of the challenges of international flying is handling different units of measure in different countries. In aviation, the battle between imperial and metric units continues
"International pilots are extremely well versed in all the aviation
units discussed in my article below. We use these units daily and can
juggle them in our sleep. The AirAsia 8501 flight crew was on their
own turf, flying a familiar route. To blindly speculate that they
became confused about units of measure is absurd."
Note that your cite agrees exactly with what I already said. Also
note that Russia (and the old Soviet Bloc), the big player using
metric (China and North Korea use metric because ... guess where they
got their aircraft from?) is channging to a flight level system based
on feet for altitude.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
If you actually got out of your mom's basement and actually flew aircraft in places outside the USA, you would see immediately just how full of shit you are.

http://www.smartcockpit.com/docs/b737ng-flight-instruments

See page 22 item 4. -- ALL MODERN AIRCRAFT ALLOW THE PILOT TO SELECT THE UNITS OF MEASURE THEY FEEL MOST COMFORTABLE USING.

Most pilots outside the USA choose 'metric'.

Just saying.

You can measure fuel in kg or pounds, speed in mph or km/hr, altitude in feet or meters.
Fred J. McCall
2016-09-21 18:36:44 UTC
Permalink
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
Outside the US SI units are generally used (kg, meters, kilometers)
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
http://aerosavvy.com/metric-imperial/
One of the challenges of international flying is handling different units of measure in different countries. In aviation, the battle between imperial and metric units continues
"International pilots are extremely well versed in all the aviation
units discussed in my article below. We use these units daily and can
juggle them in our sleep. The AirAsia 8501 flight crew was on their
own turf, flying a familiar route. To blindly speculate that they
became confused about units of measure is absurd."
Note that your cite agrees exactly with what I already said. Also
note that Russia (and the old Soviet Bloc), the big player using
metric (China and North Korea use metric because ... guess where they
got their aircraft from?) is channging to a flight level system based
on feet for altitude.
If you actually got out of your mom's basement and actually flew aircraft in places outside the USA, you would see immediately just how full of shit you are.
Ah, the usual Mookie fact filled and cogent rebuttal.
Post by William Mook
http://www.smartcockpit.com/docs/b737ng-flight-instruments
See page 22 item 4. -- ALL MODERN AIRCRAFT ALLOW THE PILOT TO SELECT THE UNITS OF MEASURE THEY FEEL MOST COMFORTABLE USING.
No, Mookie. Commercial aircraft allow you to set some things BECAUSE
THERE ARE PLACES LIKE RUSSIA AND CHINA that run their ATC in meters.
Post by William Mook
Most pilots outside the USA choose 'metric'.
Then they're pretty stupid because most ATC in the world is going to
give you 'feet' for commanded altitudes.
Post by William Mook
Just saying.
You can measure fuel in kg or pounds,
Nothing in the reference manual YOU cited indicates that those units
can be changed.
Post by William Mook
speed in mph or km/hr,
Speed is in KNOTS CALIBRATED AIRSPEED and MACH, you ignorant twat.
This isn't settable according to YOUR cite. See page 7-8.
Post by William Mook
altitude in feet or meters.
Because China and Russia.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
William Mook
2016-09-21 03:19:43 UTC
Permalink
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
Outside the US SI units are generally used (kg, meters, kilometers)
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
http://aerosavvy.com/metric-imperial/
One of the challenges of international flying is handling different units of measure in different countries. In aviation, the battle between imperial and metric units continues
"International pilots are extremely well versed in all the aviation
units discussed in my article below. We use these units daily and can
juggle them in our sleep. The AirAsia 8501 flight crew was on their
own turf, flying a familiar route. To blindly speculate that they
became confused about units of measure is absurd."
Note that your cite agrees exactly with what I already said. Also
note that Russia (and the old Soviet Bloc), the big player using
metric (China and North Korea use metric because ... guess where they
got their aircraft from?) is channging to a flight level system based
on feet for altitude.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
http://www.smartcockpit.com/aircraft-ressources/B767_Flightdeck_and_Avionics.html

Page 112 shows how to get the fuel flow to display in kilograms per hour and oil quantity to display in litres. There's also a note that ALL the instrumentation can be made to display in metric units.

Page 135 shows how to engage the metric unit option on the istrumentatoin display units and the navigation systems.

The point is, while it all makes sense to your gut based on your extensive reading of US based aviation literature available to you, it has no basis in reality for those who actually fly overseas on a regular basis.

Loading Image...
Fred J. McCall
2016-09-21 19:00:14 UTC
Permalink
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Fred J. McCall
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
Outside the US SI units are generally used (kg, meters, kilometers)
Not for aviation. The INTERNATIONAL STANDARD is pounds, feet,
nautical miles.
http://aerosavvy.com/metric-imperial/
One of the challenges of international flying is handling different units of measure in different countries. In aviation, the battle between imperial and metric units continues
"International pilots are extremely well versed in all the aviation
units discussed in my article below. We use these units daily and can
juggle them in our sleep. The AirAsia 8501 flight crew was on their
own turf, flying a familiar route. To blindly speculate that they
became confused about units of measure is absurd."
Note that your cite agrees exactly with what I already said. Also
note that Russia (and the old Soviet Bloc), the big player using
metric (China and North Korea use metric because ... guess where they
got their aircraft from?) is channging to a flight level system based
on feet for altitude.
http://www.smartcockpit.com/aircraft-ressources/B767_Flightdeck_and_Avionics.html
Page 112 shows how to get the fuel flow to display in kilograms per hour and oil quantity to display in litres. There's also a note that ALL the instrumentation can be made to display in metric units.
Page 135 shows how to engage the metric unit option on the istrumentatoin display units and the navigation systems.
The point is, while it all makes sense to your gut based on your extensive reading of US based aviation literature available to you, it has no basis in reality for those who actually fly overseas on a regular basis.
No, Mookie. The POINT is that what I've said is CORRECT. ATC doesn't
request your unit preferences.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
Rob
2016-09-17 08:07:55 UTC
Permalink
Post by Fred J. McCall
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
That is not correct. Outside the US, jet fuel is widely measured
in kilograms. A wellknown near-accident in Canada was caused by
the fact that the crew ordered a number of kilograms of fuel and
got delivered that number of pounds, as the switchover from pounds
to kilograms had been made shortly before.
Sylvia Else
2016-09-18 09:17:14 UTC
Permalink
Post by Fred J. McCall
Post by William Mook
Post by Jeff Findley
Post by Fred J. McCall
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust ? about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It's designed someplace that's actually capable of doing it. Real
aeronautical engineers work in feet, pounds, and Rankine.
LOL. I'll take working in SI units over imperial units any day.
Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
SI Rules!
Then you should avoid airplanes entirely. Fuel is measured in pounds,
altitude is measured in feet, and distance is measured in nautical
miles. The only place that did it differently was the old Soviet
Bloc.
And visibility is measure in statute miles.

Oh, and cloud cover is measured in eighths of the sky.

Sylvia.
Brian T.
2016-09-13 02:41:09 UTC
Permalink
Post by Rob
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust — about half as powerful as NASA's Saturn V launcher.
Size in feet and weight in pounds? Is it designed in the 19th century?
It is designed in the 21st, in a nation where SpaceX and Blue Origin
are about to make every other space launch provider in the world very,
very obsolete.

The paradigm shift accelerates.

Now with at least *two* Super Heavy (50+ tons to LEO) commercial
launch vehicles planned for entry into service after 2020, the comsat
industry is going to start working on much, much bigger satellites.
And Ariane 6/Angara/Vulcan/GSLV will be left behind.

Brian
JF Mezei
2016-09-12 21:26:25 UTC
Permalink
Post by d***@hotmail.com
http://www.techinsider.io/blue-origin-new-glenn-rockets-2016-9
Is there commercial demand for such a heavy lifter? Or are its hopes
pinned on governmentds funding the assembly of a large mars expedition
ship, at which point a heavy lifter can be of use to bring the large
modules with fewer flights?

Secondly, what is the advantage of having a 3rd stage as oppposed to
making a bigger tank for 2nd stage for longer burn with same delta-V ?

Since both second and 3rd stages are single engine, I don't see much of
an advantage of having 3 stages since you end up pushing one extra
engine and all extra weight to orbit.

If LOX/LH2 is so much more efficient than LOX/LNG, why not make second
stage LOX/LH2 ?

Seems to me like they could produce their 2 variants by simply making
one with larger tanks for second stage. (or even 2 tanks of each on
second stage if having smaller tanks has advantages over single very
large tank).
Brian T.
2016-09-13 02:52:25 UTC
Permalink
On Mon, 12 Sep 2016 17:26:25 -0400, JF Mezei
Post by JF Mezei
Post by d***@hotmail.com
http://www.techinsider.io/blue-origin-new-glenn-rockets-2016-9
Is there commercial demand for such a heavy lifter?
There will be, now that there are two (maybe three, but I suspect
Falcon Heavy will eventually be replaced by variants of SpaceX's BFR.)
Comsats are about to get a lot bigger.
Post by JF Mezei
Or are its hopes
pinned on governmentds funding the assembly of a large mars expedition
ship, at which point a heavy lifter can be of use to bring the large
modules with fewer flights?
It looks like SpaceX (Mars) and Blue Origin (Orbital Tourism, strong
hints about Lunar Tourism with their talk of New Armstrong) will be
their own core customers. They'll pick up commercial contracts along
the way just due to their price points, and will likely establish new
markets. Space Solar Power just became much more realistic (although
it will still need oil to spike again.)
Post by JF Mezei
Secondly, what is the advantage of having a 3rd stage as oppposed to
making a bigger tank for 2nd stage for longer burn with same delta-V ?
You don't lug the extra drymass of the larger stage on missions that
don't need it. The third stage might also have other uses in the
future (lunar tug? orbital tanker?) He might plan on recovering Stage
2 in New Glenn Mk.II.
Post by JF Mezei
Since both second and 3rd stages are single engine, I don't see much of
an advantage of having 3 stages since you end up pushing one extra
engine and all extra weight to orbit.
If LOX/LH2 is so much more efficient than LOX/LNG, why not make second
stage LOX/LH2 ?
It would have to be bigger/heavier. Bezos might (probably does?) also
have Stage 2 reusability in mind for down the road, so he's saving
mass for that application.

Brian
JF Mezei
2016-09-13 04:04:31 UTC
Permalink
Post by Brian T.
You don't lug the extra drymass of the larger stage on missions that
don't need it.
How feasable is it to make 2 versions of the second stage ? One with
elongated tanks, and one with normal tanks ?

Considering current plans are for a BE-4 engines for stages 1 and 2, and
BE-3 engines and different fuel for 3rd stage, eliminating 3rd stage
would greatly simplify things.

Would building longer tanks be the equivalent of boeing building 787s of
different lengths? Just add "plugs" that make the fuselage longer and
styrenghten a few stringers in strategic places ?

It seems to me that buidling 2 versions of stage 2 with just more fuel
capacity as the difference would be far more simpler and cost effective
than building 2 totally different stages with different engines, fuel,
tank designs etc.


And finally, this "Glen-3" project. How much of a pipe dreamn is it ?
does it have credibility or is this just a press release for vapourware
that has little chance of being built ?
Fred J. McCall
2016-09-13 08:29:09 UTC
Permalink
Post by JF Mezei
Post by Brian T.
You don't lug the extra drymass of the larger stage on missions that
don't need it.
How feasable is it to make 2 versions of the second stage ? One with
elongated tanks, and one with normal tanks ?
It's feasible but you'd lose performance.
Post by JF Mezei
Would building longer tanks be the equivalent of boeing building 787s of
different lengths? Just add "plugs" that make the fuselage longer and
styrenghten a few stringers in strategic places ?
No, it's not the same. More stages means less parasitic mass carried
along. Why do you think we don't just build them with one really big
stage?
Post by JF Mezei
It seems to me that buidling 2 versions of stage 2 with just more fuel
capacity as the difference would be far more simpler and cost effective
than building 2 totally different stages with different engines, fuel,
tank designs etc.
Big performance hit.
Post by JF Mezei
And finally, this "Glen-3" project. How much of a pipe dreamn is it ?
does it have credibility or is this just a press release for vapourware
that has little chance of being built ?
So far it's ALL a pipe dream, since they don't have engines yet.

I'm not sure what niche they're aiming at with these, given that they
won't be flying until after Falcon Heavy is available. Unless they
are significantly cheaper, I don't see how they compete wedging
themselves between Falcon 9 and Falcon Heavy.
--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
William Mook
2016-09-13 08:38:51 UTC
Permalink
Post by Brian T.
On Mon, 12 Sep 2016 17:26:25 -0400, JF Mezei
Post by JF Mezei
Post by d***@hotmail.com
http://www.techinsider.io/blue-origin-new-glenn-rockets-2016-9
Is there commercial demand for such a heavy lifter?
There will be, now that there are two (maybe three, but I suspect
Falcon Heavy will eventually be replaced by variants of SpaceX's BFR.)
Comsats are about to get a lot bigger.
More powerful and greater numbers.
Post by Brian T.
Post by JF Mezei
Or are its hopes
pinned on governmentds funding the assembly of a large mars expedition
ship, at which point a heavy lifter can be of use to bring the large
modules with fewer flights?
It looks like SpaceX (Mars) and Blue Origin (Orbital Tourism, strong
hints about Lunar Tourism with their talk of New Armstrong) will be
their own core customers. They'll pick up commercial contracts along
the way just due to their price points, and will likely establish new
markets. Space Solar Power just became much more realistic (although
it will still need oil to spike again.)
Space tourism is doable with highly reusable vehicles. The history of comsats are one to one (telstar) then one to many (Sirius satellite radio, satellite TV) and many to many (wireless global hotspot). Teledesic and Iridium were the first forays into that field. Limitations and cost of access to space limited their success. SpaceX and Blue Origin changes that. At stake? $1.7 trillion per year telecom market.

Thin film concentrating optics with high intensity highly efficient thin disk lasers, in conjunction with holographic laser tracking - make 22 megawatt per ton power satellites possible. At $10 million per ton, 50 to 60 ton satellites attain over 1 GW at a cost LESS than coal fired power. This gives access to $5 trillion + primary energy markets. This is the big enchilada.
Post by Brian T.
Post by JF Mezei
Secondly, what is the advantage of having a 3rd stage as oppposed to
making a bigger tank for 2nd stage for longer burn with same delta-V ?
Let's say you have a 3.5 km/sec exhaust speed and a total delta vee requirement of 9.2 km/sec when you include gravity and air drag losses. Then you need to have 92.78% propellant on take off. With a 4.22% structure fraction you're left with 3.00% payload. So, for a given payload on orbit, say 60 tonnes, you need a rocket that's 60 tonnes divided by 0.03 or 2,000 tonnes take off weight!

Now let's say you have the same 3.5 km/sec exhaust speed, but you divide the rocket into two stages that achieve 4.6 km/sec each stage for the same total 9.2 km/sec. Then you need to have 73.14% propellant on take off in each stage. With a 4.22% structure fraction, you're left with 22.64% payload on each stage. 5.12% of the take off weight ends up on orbit. So, dividing into 0.0512 60 tonnes obtains 1,170 tonnes take off weight. A SMALLER VEHICLE!

Now, let's say you have the same 3.5 km/sec exhaust speed, but you divide the rocket into three stages that achieve 3.1 km/sec each stage for the same total 9.2 km/sec Then you need to have 58.76% propellant on each stage. With 4.22% structure fraction this leaves 37.02% payload fraction for each stage. Over three stages that's 5.23% of take off weight ends up on orbit. 1,145 tonnes take off weight - a yet smaller vehicle.

Looked at differently, if the 1,170 tonne 2 stage vehicle is equipped with a third stage, it puts up 61.1 tonnes instead of 60.0 tonnes - details count - slight improvements in propellant density, thrust, and so forth - can eke out 2, 3, 4 or 5 extra metric tons to LEO - structure fractions drop slightly - propellant increase slightly, acceleration is adjusted slightly, thrust increased slightly, etc.
Post by Brian T.
You don't lug the extra drymass of the larger stage on missions that
don't need it.
The more stages the more of the take off mass ends up in orbit as shown.
Post by Brian T.
The third stage might also have other uses in the
future (lunar tug? orbital tanker?) He might plan on recovering Stage
2 in New Glenn Mk.II.
The BE-3 is a LOX LH2 engine - that is ideally suited for a fourth kick stage for lunar operations as described in another post.
Post by Brian T.
Post by JF Mezei
Since both second and 3rd stages are single engine, I don't see much of
an advantage of having 3 stages since you end up pushing one extra
engine and all extra weight to orbit.
The more stages the more fraction of take off weight ends up in orbit. This is basic rocket science. Displacing a portion of the 60 tonnes with propellant mass - extends range dramatically.
Post by Brian T.
Post by JF Mezei
If LOX/LH2 is so much more efficient than LOX/LNG, why not make second
stage LOX/LH2 ?
Because of the cost of LOX/LH2 versus LOX/LNG. Because of the logistics. Because of the complexity. Best used in a fourth kick stage to push 20 tonnes beyond LEO to the moon or Mars.
Post by Brian T.
It would have to be bigger/heavier.
Not really. The more stages the better, especially if structure fraction is high.

To show this lets do a calculation with a really big structure fraction. Consider a two stage and three stage rocket with a 10% structure fraction and a 3.5 km/sec exhaust speed.

TWO STAGE

Ve = 3.5 km/sec, Vf = 9.2 / 2 = 4.6 km/sec
u = 1 - 1 / exp(4.6/3.5) = 0.74133
p= 1 - 0.74133 - 0.1 = 0.16867 per stage -->
0.16867^2 = 0.02448 -->
60/ 0.02448 = 2,109.1 tonnes

take off weight.

THREE STAGE

Ve = 3.5 km/sec, Vf = 9.2 / 3 = 3.067 km/sec
u = 1 - 1 / exp(3.067/3.5) = 0.58364
p = 1 - 0.58364 - 0.1 = 0.31636 per stage --->
0.31635^3 = 0.10008

A 60 ton to orbit three stage vehicle masses only 600 tonnes at take off. A two stage to orbit vehicle masses 2,109.1 tonnes. A one stage vehicle can't make it to orbit - with this huge structure fraction!

Now the interesting detail is this - 2,109.1 tonnes take off weight translates to 210.9 tonnes payload on orbit - BECAUSE OF THE THIRD STAGE! See?
Post by Brian T.
Bezos might (probably does?) also
have Stage 2 reusability in mind for down the road, so he's saving
mass for that application.
FULL REUSABILITY is the goal- that's a definite.
Post by Brian T.
Brian
Seven BE-4 engines have 3.85 million pounds of thrust. Taking off at 1.28 gees - the same as the Saturn V - actual calculations involve calculus of variations solution - but 1.28 gees is a good first approximation of optimal take off acceleration - 1.28 gees means that the weight of the vehicle at take off is 3.00 million pounds of weight. A TWO stage version of this vehicle lifts 2.45% of its take off weight into LEO - which is 73,500 pounds! A THREE stage version of this vehicle lifts 10.00% of its take off weight into LEO - which is 300,000 pounds!

You start with one stage - and fly it. Then you go to two stage and fly it. Then you add a third stage.
Fred J. McCall
2016-09-13 08:09:42 UTC
Permalink
Post by JF Mezei
Post by d***@hotmail.com
http://www.techinsider.io/blue-origin-new-glenn-rockets-2016-9
Is there commercial demand for such a heavy lifter?
It only lifts 70% of what Falcon Heavy will lift.
Post by JF Mezei
Or are its hopes
pinned on governmentds funding the assembly of a large mars expedition
ship, at which point a heavy lifter can be of use to bring the large
modules with fewer flights?
It's physically big, but it doesn't have the lift capacity for that
sort of thing.
Post by JF Mezei
Secondly, what is the advantage of having a 3rd stage as oppposed to
making a bigger tank for 2nd stage for longer burn with same delta-V ?
More stages means you're lifting less parasitic structure weight.
Post by JF Mezei
Since both second and 3rd stages are single engine, I don't see much of
an advantage of having 3 stages since you end up pushing one extra
engine and all extra weight to orbit.
You shed the parasitic mass of the second stage on the way up. By
your logic, we could just build one big stage. Why have a second one?
Post by JF Mezei
If LOX/LH2 is so much more efficient than LOX/LNG, why not make second
stage LOX/LH2 ?
LOX/LNG is only mildly cryogenic and thus easier to handle. Note that
the SpaceX Raptor engine currently in development will also be a
LOX/methane engine.
Post by JF Mezei
Seems to me like they could produce their 2 variants by simply making
one with larger tanks for second stage. (or even 2 tanks of each on
second stage if having smaller tanks has advantages over single very
large tank).
Ask yourself why we don't just build single stage rockets. The
reasoning is the same.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
Brian T.
2016-09-13 15:23:06 UTC
Permalink
On Tue, 13 Sep 2016 01:09:42 -0700, Fred J. McCall
Post by Fred J. McCall
It only lifts 70% of what Falcon Heavy will lift.
70% of what? FH Fully Expendable or FH outboards to LZ-1 and core to
barge?

And really, that 70% is based on extrapolation from the sizes/thrust
given. We're not that sure of them yet. BO probably isn't yet, either.
I've seen 40 tons, 50 tons, and even 60 tons estimates in just the
last 24 hours.

We're not really sure what FH will truly be capable of, either.

Brian
Fred J. McCall
2016-09-13 16:46:23 UTC
Permalink
Post by Brian T.
On Tue, 13 Sep 2016 01:09:42 -0700, Fred J. McCall
Post by Fred J. McCall
It only lifts 70% of what Falcon Heavy will lift.
70% of what? FH Fully Expendable or FH outboards to LZ-1 and core to
barge?
Whichever you like IF you assume the same mode of operation for both
rockets. They're speculative numbers at best.
Post by Brian T.
And really, that 70% is based on extrapolation from the sizes/thrust
given. We're not that sure of them yet. BO probably isn't yet, either.
I've seen 40 tons, 50 tons, and even 60 tons estimates in just the
last 24 hours.
Fair enough, but you've got a rocket with significantly bigger
structure (and thus significantly higher parasitic mass) and
significantly less thrust.

Yes, performance for these is speculative, since they don't even have
the engines through testing yet. It's still three years out. However,
we know that a rocket using LNG for fuel needs about 20% more tankage
to get the same total impulse when compared to RP-1 because the bulk
density of LNG/LOX is only around 80% that of RP-1/LOX. And we've got
pretty reliable thrust numbers at this point.

So they're sort of stuck with the bigger structure if they want
equivalent burn times. And they're stuck with lifting that bigger
second stage as well.
Post by Brian T.
We're not really sure what FH will truly be capable of, either.
Uh, we're pretty sure of those numbers, since SpaceX has published
them and development of Falcon Heavy is pretty far along. The engines
are existing engines with lots of flight experience. We even know
pricing for Falcon Heavy.
--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
JF Mezei
2016-09-13 23:33:26 UTC
Permalink
Post by Fred J. McCall
More stages means you're lifting less parasitic structure weight.
You shed the parasitic mass of the second stage on the way up. By
your logic, we could just build one big stage. Why have a second one?
First stage: many heavy engines and lots of fuel needed to get the thing
going.

I can understand if stage 1 had sayd 9 engines, stage two had 3 and
stage 3 had 1.

With each release of a stage, you reduce the number of engine mass you
need to accelerate for the next step.

But for Glen-3, both stages 2 and 3 have 1 engine.

Lets assume tanks for stage 2 and 3 each weight 1 tonne for sake of
discussion.

So you have stage 2 with 1 engine and tanks weighting 1 tonne, and stage
3 with 1 engine and tanks weighting 1 tonne.

Combining this into single stage 2, you have 1 engine and a tank weight
2 tonnes. You save on the weight of an engine and greatly simplify your
design because you no longer have a stage 3 that ises different engine
and propellant.

And if you are able to create a stage 2 with a 1 tonne tank and a
version with a longer 2 tonne tank, you then have your 2 variants
depending on cargo/destination with far simpler differences than if you
have a single variant of stage 2 and a totally differeht stage 3.

With the 3 stage approach, stage3 is totally dead weight from ground to
the point where its engine fires. And dead weight to get from ground to
near-orbit means a LOT more fuel is needed.
William Mook
2016-09-14 04:16:46 UTC
Permalink
This is a preliminary estimate of stage weights - based on what has been publicly released

Stage Total------- Stage Wgt- Propellant
1------ 3,080,000.0 2,002,000.0 1,767,920.0
2------ 1,078,000.0 700,700.0 618,772.0
3------ 377,300.0 245,245.0 216,570.2
Payload 132,055.0 132,055.0

Here's the acceleration with 7 engines on the first stage, 1 engine on the second stage, and 1 engine on the third stage, all at full blast (but recall they can be throttled back from 550,000 lbf to 20,000 lbf!)

G-start G-end
1.250 3.571
0.510 1.458
1.458 4.165

Here's the radial acceleration due to centripetal force of a rocket moving at the terminal velocities each is capable of;

Speed Loss Net--- Gee- Net
2.800 0.865 1.935 0.063 0.937
6.000 1.295 4.705 0.371 0.629
9.200 1.295 7.905 1.048 -0.048

So, the acceleration of the first stage starts at 1.25 gees straight up and ends up at 3.571 gees largely horizontal! Of course these can be throttled back to maintain a reasonable maximum - say 2.000 gees. At first stage burn out the ship is moving at 1.9 km/sec and centripetal acceleration is 0.63 gees and 0.937 gees is pulling back. The second stage starts out at 0.5 gees but rises to 1.458 gees at second stage burn out. At that time the ship is moving at 4.7 km/sec and centripetal acceleration reduces gee loading to 0.63 gees! Now, to counteract that gravity pull, the rocket is pointed up 25.5 degrees - as it continues to accelerate horizontally at altitude. The third stage fires horizontally, and if its not throttled back itends up at over four gees! However, throttling again saves the day, limiting the load to two gee.

So, these engines are perfectly well suited for this mission. A second engine might be useful in the second stage, but isn't strictly necessary, since the ascent trajectory is chosen to allow for the turning of the rocket in such a way as to minimise gravity losses. This is the gravity turn trajectory all space launch vehicles follow - for minimum propellant use and maximum efficiency.

Loading Image...
Fred J. McCall
2016-09-19 14:58:31 UTC
Permalink
Post by William Mook
This is a preliminary estimate of stage weights - based on what has been publicly released
Stage Total------- Stage Wgt- Propellant
1------ 3,080,000.0 2,002,000.0 1,767,920.0
2------ 1,078,000.0 700,700.0 618,772.0
3------ 377,300.0 245,245.0 216,570.2
Payload 132,055.0 132,055.0
Just what "publicly released" numbers are you using to arrive at the
preceding? Please provide a cite.
Post by William Mook
Here's the acceleration with 7 engines on the first stage, 1 engine on the second stage, and 1 engine on the third stage, all at full blast (but recall they can be throttled back from 550,000 lbf to 20,000 lbf!)
G-start G-end
1.250 3.571
0.510 1.458
1.458 4.165
Here's the radial acceleration due to centripetal force of a rocket moving at the terminal velocities each is capable of;
Speed Loss Net--- Gee- Net
2.800 0.865 1.935 0.063 0.937
6.000 1.295 4.705 0.371 0.629
9.200 1.295 7.905 1.048 -0.048
So, the acceleration of the first stage starts at 1.25 gees straight up and ends up at 3.571 gees largely horizontal! Of course these can be throttled back to maintain a reasonable maximum - say 2.000 gees. At first stage burn out the ship is moving at 1.9 km/sec and centripetal acceleration is 0.63 gees and 0.937 gees is pulling back. The second stage starts out at 0.5 gees but rises to 1.458 gees at second stage burn out. At that time the ship is moving at 4.7 km/sec and centripetal acceleration reduces gee loading to 0.63 gees! Now, to counteract that gravity pull, the rocket is pointed up 25.5 degrees - as it continues to accelerate horizontally at altitude. The third stage fires horizontally, and if its not throttled back itends up at over four gees! However, throttling again saves the day, limiting the load to two gee.
It looks like you're saying that it doesn't make orbit without the
third stage. That's not right. The mission profile for this thing is
like the old Saturn V mission profile, where the third stage is in LEO
before it fires and is used for deep space missions.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
Fred J. McCall
2016-09-14 04:20:53 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
More stages means you're lifting less parasitic structure weight.
You shed the parasitic mass of the second stage on the way up. By
your logic, we could just build one big stage. Why have a second one?
First stage: many heavy engines and lots of fuel needed to get the thing
going.
I can understand if stage 1 had sayd 9 engines, stage two had 3 and
stage 3 had 1.
Well, no, you apparently don't understand it at all. The number of
engines per stage is essentially irrelevant and has nothing to do with
whether staging makes sense or not. The relevant numbers are dry mass
dropped with a stage (all structure, including tanks and engines) plus
the additional mass to 'stretch' the tanks vs the additional mass
required to make the new stage (engines, tanks). Plus you need to
take into account optimization of an engine for specific altitudes;
stage 1 engines will be less efficient at the altitude range where
stage 2 will burn, etc.

Saturn V Stage 1 and Stage 2 both had 5 engines.
Post by JF Mezei
With each release of a stage, you reduce the number of engine mass you
need to accelerate for the next step.
You're also dropping tank and structure weight that you no longer need
to carry along.
Post by JF Mezei
But for Glen-3, both stages 2 and 3 have 1 engine.
But they are not the same engine and do not burn the same fuel. Stage
3 has the same purpose as the third stage on a Saturn V and doesn't
increase payload to LEO at all. It's intended for longer range
missions.

<remove silly assumptions>

Engineers don't design staging schemes in ways to make them fail. Your
assumed numbers indicate your stages are designed by someone who is
not very bright.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
JF Mezei
2016-09-14 05:12:08 UTC
Permalink
Post by Fred J. McCall
whether staging makes sense or not. The relevant numbers are dry mass
dropped with a stage (all structure, including tanks and engines) plus
the additional mass to 'stretch' the tanks vs the additional mass
required to make the new stage (engines, tanks).
You are conveniently forgetting dry mass that needs to be
lifted/accelerated from ground to the point where a stage's engines are
started.

So Stage 3 is dead weight from liftoff until its engine is lighted up.


If Stage 2 with bigger tanks ends up weighting less than normal Stage 2
+ Stage 3, then you gain much efficiency between liftoff and the spot
where Stage 3 would have separated.

Yeah, the Stage3 with big (half empty) tanks may not be as light and
efficient as stage 3, but this cost MAY be less than the advantages of
carryting less mass from the ground.

Since both stage 2 and 3 will operate in vacuum, I am somewhat perplexed
that one would consider one engine to be better suited for the job in
vaccuum than the other.

If the LH2/LOX BE3 engine is better in vacuum, then logically shouldn't
it also be used on stage 2 ?


I am always weary of announcements that appear more as PR exercises than
something which was conceived by engineers after having played with the
numbers to optimize a design. This smells more of Blue Origins wanting
to keep a foot in each BE-4 and BE-3 doors by announcing this virtual
design. In other words, a design that is more driven by business
relationships than by engineering optimizations.
Fred J. McCall
2016-09-14 05:43:14 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
whether staging makes sense or not. The relevant numbers are dry mass
dropped with a stage (all structure, including tanks and engines) plus
the additional mass to 'stretch' the tanks vs the additional mass
required to make the new stage (engines, tanks).
You are conveniently forgetting dry mass that needs to be
lifted/accelerated from ground to the point where a stage's engines are
started.
You are conveniently making shit up, since I'm doing no such thing.
Post by JF Mezei
So Stage 3 is dead weight from liftoff until its engine is lighted up.
True, but what's your point?
Post by JF Mezei
If Stage 2 with bigger tanks ends up weighting less than normal Stage 2
+ Stage 3, then you gain much efficiency between liftoff and the spot
where Stage 3 would have separated.
Yes, if an idiot designs the staging scheme this can certainly happen.
Post by JF Mezei
Yeah, the Stage3 with big (half empty) tanks may not be as light and
efficient as stage 3, but this cost MAY be less than the advantages of
carryting less mass from the ground.
It MAY be, but only if an idiot designs the staging scheme.
Post by JF Mezei
Since both stage 2 and 3 will operate in vacuum, I am somewhat perplexed
that one would consider one engine to be better suited for the job in
vaccuum than the other.
Look up the specific impulse of LOX/LH2 vs LOX/LNG.
Post by JF Mezei
If the LH2/LOX BE3 engine is better in vacuum, then logically shouldn't
it also be used on stage 2 ?
Not necessarily. Remember, we're talking about TWO launchers here;
one is a two stage and the other adds a third 'deep space' stage.
Specific impulse and weight both matter and they tend to matter more
for upper stages.
Post by JF Mezei
I am always weary of announcements that appear more as PR exercises than
something which was conceived by engineers after having played with the
numbers to optimize a design. This smells more of Blue Origins wanting
to keep a foot in each BE-4 and BE-3 doors by announcing this virtual
design. In other words, a design that is more driven by business
relationships than by engineering optimizations.
I'm sorry, but I don't think you'd recognize "engineering
optimizations" if they bit you on the ass. Saturn V was two LOX/RP-1
stages and a third 'deep space' stage with LOX/LH2. They didn't need
to maximize ISP for the two lower stages that got them to LEO. They
did need to maximize ISP for that 'deep space' stage because otherwise
it would be too heavy to get the total impulse they needed. Your
position here seems to be that everyone starting with Werner von Braun
got it wrong and that you know better.

You don't.
--
"Ignorance is preferable to error, and he is less remote from the
truth who believes nothing than he who believes what is wrong."
-- Thomas Jefferson
JF Mezei
2016-09-14 17:20:39 UTC
Permalink
Post by Fred J. McCall
Look up the specific impulse of LOX/LH2 vs LOX/LNG.
Maybe then someone can explain to me why LNG is better than LH2 for the
second stage.

Since both stages operate in Vacuum, if LH2 performs better in vacuum
than LNG, then why not use LH2 for both Stage 2 and 3 ?


In what way is the second stage different from 3rd ? Dont they both
operate in what is , for all practical purposes, vacuum ?
Post by Fred J. McCall
Not necessarily. Remember, we're talking about TWO launchers here;
one is a two stage and the other adds a third 'deep space' stage.
Specific impulse and weight both matter and they tend to matter more
for upper stages.
You brought up von Braun. His Saturn 5 used LH2 for stages 2 and 3.
Post by Fred J. McCall
Loading Image...
This contradicts your statement that Saturn 5 was 2 RP-1 stages and LH2
for 3rd stage.

One big difference is that for Apollo, they had to make it work at
whatever cost in a very limited amount of time and with little past
experience.

When you look at SpaceX, it is clear that as a business they optimized
the design to have lower costs and mass produce engines. They learned
from previous rockets in history. SpaceX started small and scaled up
instead of making one hunking big rocket from the get go.

This is why I am a bit weary of some company with little experience in
rockets starting off with a very large rocket.
Fred J. McCall
2016-09-14 18:15:44 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
Look up the specific impulse of LOX/LH2 vs LOX/LNG.
Maybe then someone can explain to me why LNG is better than LH2 for the
second stage.
Any number of reasons. It's easier to handle because it's only mildly
cryogenic. For the stage to have the same performance it would have
to be physically bigger if it was LH2 due to the low density of LH2,
which impacts what the first stage has to lift and LNG is sufficient
to the purpose of the stage. There are no doubt many others.
Post by JF Mezei
Since both stages operate in Vacuum, if LH2 performs better in vacuum
than LNG, then why not use LH2 for both Stage 2 and 3 ?
It's got nothing to do with "operating in vacuum". LH2 *always* has a
higher ISP than LNG.
Post by JF Mezei
In what way is the second stage different from 3rd ? Dont they both
operate in what is , for all practical purposes, vacuum ?
They have different purposes.
Post by JF Mezei
Post by Fred J. McCall
Not necessarily. Remember, we're talking about TWO launchers here;
one is a two stage and the other adds a third 'deep space' stage.
Specific impulse and weight both matter and they tend to matter more
for upper stages.
You brought up von Braun. His Saturn 5 used LH2 for stages 2 and 3.
Post by Fred J. McCall
https://upload.wikimedia.org/wikipedia/commons/b/b2/Saturn_v_schematic.jpg
This contradicts your statement that Saturn 5 was 2 RP-1 stages and LH2
for 3rd stage.
Right. My bad. However, they both had 5 engines, just like the 2nd
and 3rd stage of New Glenn both have one engine. You thought the
latter circumstance just made no sense, so why did the Saturn V make
sense?
Post by JF Mezei
One big difference is that for Apollo, they had to make it work at
whatever cost in a very limited amount of time and with little past
experience.
When you look at SpaceX, it is clear that as a business they optimized
the design to have lower costs and mass produce engines. They learned
from previous rockets in history. SpaceX started small and scaled up
instead of making one hunking big rocket from the get go.
SpaceX started 'bigger' than Blue Origin did.
Post by JF Mezei
This is why I am a bit weary of some company with little experience in
rockets starting off with a very large rocket.
Uh, where did you get the idea that Blue Origin has "little experience
in rockets"? They succeeded in having a first stage (of their New
Shepard launcher) land before SpaceX did and have reused such a stage
where (so far) SpaceX has not.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
JF Mezei
2016-09-14 20:39:52 UTC
Permalink
Post by Fred J. McCall
Uh, where did you get the idea that Blue Origin has "little experience
in rockets"? They succeeded in having a first stage (of their New
Shepard launcher) land before SpaceX did and have reused such a stage
where (so far) SpaceX has not.
As I understand, New Sheperd is in the same class as Branson's joy rides
in Virgin Galactic. It goes up and falls back down.

OK, so I read up a little. BE-3 is an engine they have already designed,
but they need to make the vacuum version. If they mass produce BE-3 for
the joy-ride business, I guess it isn't so bad if they use them for 3rd
stage now and then (and apparently being considered for the ULA Vulcan
upper stage).

But then, why not use BE-3 on second stage and make bigger tanks when
needed ? Or better yet, could they attach extra tanks to Stage 2, and
stage 2 could ditch them once empty to reduce weight ?


Also, with current materials technology, do LOX / LH2 tanks weight
considerably less than in Saturn 5 days or still roughly the same ?

I recall I think DC-X experimenting with composite tanks but as with
most nasa projects, got cancelled before they could get it to work. I
note that SpaceX uses Aluminium-Lithium compiosite for its
structures/tanks. I take it that composite tanks aren't ready for prime
time yet?
Fred J. McCall
2016-09-15 01:54:54 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
Uh, where did you get the idea that Blue Origin has "little experience
in rockets"? They succeeded in having a first stage (of their New
Shepard launcher) land before SpaceX did and have reused such a stage
where (so far) SpaceX has not.
As I understand, New Sheperd is in the same class as Branson's joy rides
in Virgin Galactic. It goes up and falls back down.
It's a rocket, is it not? It's smaller than Falcon 1, is it not?
First you complain that Blue Origin didn't 'start small' like SpaceX
and now you're complaining that they started TOO small?
Post by JF Mezei
OK, so I read up a little.
You know, it would be really nice if you did that BEFORE you started
posting...
Post by JF Mezei
BE-3 is an engine they have already designed,
but they need to make the vacuum version. If they mass produce BE-3 for
the joy-ride business, I guess it isn't so bad if they use them for 3rd
stage now and then (and apparently being considered for the ULA Vulcan
upper stage).
You should recognize that Vulcan with new engines is even more of a
paper rocket than New Glenn. You should also note that it uses BE-4
on its first stage and BE-3 on its third stage, very like New Glenn.
Post by JF Mezei
But then, why not use BE-3 on second stage and make bigger tanks when
needed ?
You mean other than the small detail that you'd need something like 5
BE-3 engines to replace that single BE-4 on the second stage? And
you'd need much larger tanks just to get the same performance (which
screws up New Glenn 2-stage)? And now you're carrying all that excess
tankage and engines you didn't need if you'd actually staged onto your
deep space mission?

BE-3 thrust - 110,000 lbf
BE-4 thrust - 540,000 lbf
Post by JF Mezei
Or better yet, could they attach extra tanks to Stage 2, and
stage 2 could ditch them once empty to reduce weight ?
That's almost always a losing proposition. You almost always get
better performance if you ditch all the structure (including the
engine package) and use a smaller, lighter engine package on the upper
stage. Note that there are rockets (vague recollection) that cut the
middle ground and ditch tanks plus SOME of the engines when they
'stage' (which just seems unnecessarily complicated to me).
Post by JF Mezei
Also, with current materials technology, do LOX / LH2 tanks weight
considerably less than in Saturn 5 days or still roughly the same ?
They CAN be lighter, but aren't necessarily. Lighter tanks are more
expensive. The idea these days is to cut cost rather than go for
performance over all.
Post by JF Mezei
I recall I think DC-X experimenting with composite tanks but as with
most nasa projects, got cancelled before they could get it to work. I
note that SpaceX uses Aluminium-Lithium compiosite for its
structures/tanks. I take it that composite tanks aren't ready for prime
time yet?
DC-X needed that sort of thing because it was developing SSTO
technology and if you wanted ANY payload you needed to pretty
aggressively cut weight, no matter what it cost.
--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
JF Mezei
2016-09-15 05:13:05 UTC
Permalink
Post by Fred J. McCall
BE-3 thrust - 110,000 lbf
BE-4 thrust - 540,000 lbf
Ok thanks. I had not seen those numbers, puts things in perspective.

What is the weight of each engine ? is there a massive difference of
same order of magnitude as their thrust ?
Post by Fred J. McCall
They CAN be lighter, but aren't necessarily. Lighter tanks are more
expensive. The idea these days is to cut cost rather than go for
performance over all.
OK, so basically, if I read correctly, since the Saturn 5 days,
advancements in materials have not made significant dents in tank weights.

Do LNG, RP-1 and LH2 tanks all have similar weight for same volume or
does LH2 need thicker/heavier walls for instance ?

Is it correct to state that LH2 needs more volume, but weights less than
RP1 to get same delta-V ? I asusme the "weights less" really means that
the fuel weights much less, but since it needs bigger tank, the combo of
fuel/tank weights just "less" ?
Fred J. McCall
2016-09-15 11:54:12 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
BE-3 thrust - 110,000 lbf
BE-4 thrust - 540,000 lbf
Ok thanks. I had not seen those numbers, puts things in perspective.
What is the weight of each engine ? is there a massive difference of
same order of magnitude as their thrust ?
Looking around, I don't find anyone giving weights of the engines. You
know, you could look as easily as anyone else and pretty much everyone
is going to have to try to look it up.

It is of interest, though, that the Blue Origin BE-4 looks very like a
SpaceX Raptor engine. Same fuel/oxidizer and very close to the same
thrust.
Post by JF Mezei
Post by Fred J. McCall
They CAN be lighter, but aren't necessarily. Lighter tanks are more
expensive. The idea these days is to cut cost rather than go for
performance over all.
OK, so basically, if I read correctly, since the Saturn 5 days,
advancements in materials have not made significant dents in tank weights.
Unless you're willing to pay for it.
Post by JF Mezei
Do LNG, RP-1 and LH2 tanks all have similar weight for same volume or
does LH2 need thicker/heavier walls for instance ?
I would assume that the more cryogenic the fuel is the heavier the
tank structure has to be, both for insulation and pressure containment
purposes.
Post by JF Mezei
Is it correct to state that LH2 needs more volume, but weights less than
RP1 to get same delta-V ? I asusme the "weights less" really means that
the fuel weights much less, but since it needs bigger tank, the combo of
fuel/tank weights just "less" ?
You need to look at what is called the bulk density of the
fuel/oxidizer mix and the ISP both to get an idea of just what the
difference in tank size needs to be to get equivalent total
performance. Values in the following table should let you figure it
out.

http://yarchive.net/space/rocket/fuels/fuel_table.html

ISP for RP-1 and LNG are about the same, but the bulk density of
LNG/LOG is only about 80% that of RP-1. So LNG rockets need tanks
over 20% larger than an RP-1 rocket. Based on bulk density, LH2/LOX
bulk density is like 35% that of RP-1, so if they had the same ISP I'd
need almost 3x as much tankage for an LH2 stage. However, LH2 has a
large ISP advantage, so to get the same total performance the LH2
rocket really only needs tanks about 2.3 times as large as RP-1.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
JF Mezei
2016-09-15 18:22:35 UTC
Permalink
Post by Fred J. McCall
need almost 3x as much tankage for an LH2 stage. However, LH2 has a
large ISP advantage, so to get the same total performance the LH2
rocket really only needs tanks about 2.3 times as large as RP-1.
Assuming for sake of discussion that engines are the same weight:

Is it correct to assume that for same delta-V, the weight of LH2+
bigger tank will still be less than weight of RP-1+tank ?

(aka: weight of lighter fuel more than compensates for heavier tank?)
Alain Fournier
2016-09-16 01:06:09 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
need almost 3x as much tankage for an LH2 stage. However, LH2 has a
large ISP advantage, so to get the same total performance the LH2
rocket really only needs tanks about 2.3 times as large as RP-1.
Is it correct to assume that for same delta-V, the weight of LH2+
bigger tank will still be less than weight of RP-1+tank ?
(aka: weight of lighter fuel more than compensates for heavier tank?)
Yes that that is correct.

The assumption that the engines are the same weight isn't too bad once
you are in orbit or nearly in orbit (for upper stages) because you can
use smaller engines and let them burn longer. But for the for the first
stage, since you need much more thrust, that assumption does not hold.


Alain Fournier
Fred J. McCall
2016-09-17 02:00:42 UTC
Permalink
Post by JF Mezei
Post by Fred J. McCall
need almost 3x as much tankage for an LH2 stage. However, LH2 has a
large ISP advantage, so to get the same total performance the LH2
rocket really only needs tanks about 2.3 times as large as RP-1.
Is it correct to assume that for same delta-V, the weight of LH2+
bigger tank will still be less than weight of RP-1+tank ?
(aka: weight of lighter fuel more than compensates for heavier tank?)
Rocket performance is based on MASS of fuel, not volume.
--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn
Fred J. McCall
2016-09-12 22:37:57 UTC
Permalink
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust — about half as powerful as NASA's Saturn V launcher.
And about 70% as powerful as Falcon Heavy, which will be available
before it is.
Post by d***@hotmail.com
Unlike the Saturn V, however, Blue Origin plans to build on its rocket-recycling
experience and reuse the giant first-stage booster of each launcher — saving
untold cash over multiple launches, since rocket boosters are normally trashed in
the ocean."
We'll see how long it takes them to successfully land one after they
actually get them built.
--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw
Brian T.
2016-09-13 03:01:28 UTC
Permalink
On Mon, 12 Sep 2016 15:37:57 -0700, Fred J. McCall
Post by Fred J. McCall
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust — about half as powerful as NASA's Saturn V launcher.
And about 70% as powerful as Falcon Heavy, which will be available
before it is.
Yes, but maybe by not all that much time. I think FH just took another
year's hit due to the Amos-6 disaster. And SpaceX has a lot on their
plate with Commercial Crew and a big backlog of Falcon 9FT payloads
still waiting their turn to fly. I can easily see FH being
backburnered to 2018-19.

Frankly, given Musk's hints about BFR in 2021 or so and Falcon 9FT
getting ever more powerful, I wouldn't be shocked if he reaches the
conclusion that FH is a dead end and abandons it.
Post by Fred J. McCall
We'll see how long it takes them to successfully land one after they
actually get them built.
Flight 1 almost certainly will be a short Stage 1-only hop over to
LZ-1 or wherever their landing site is, with progressively longer
flights out to the barge and eventually "out and back", then moving on
to flights with Stage 2. Really, how else can he test the thing? It is
being built at KSC and launched at CCAFS and is too big to overland to
Van Horn. So no Grasshopper equivalent operations seem possible.

Brian
William Mook
2016-09-13 00:10:56 UTC
Permalink
Post by d***@hotmail.com
"The largest of the two new rockets, called the "New Glenn 3-stage," is an
enormous 23 feet in diameter (about half the length of a school bus), 313 feet
tall (close to the height of the Apollo moon rockets), and will spew out 3.85
million pounds of thrust — about half as powerful as NASA's Saturn V launcher.
Unlike the Saturn V, however, Blue Origin plans to build on its rocket-recycling
experience and reuse the giant first-stage booster of each launcher — saving
untold cash over multiple launches, since rocket boosters are normally trashed in
the ocean."
"Named in honor of John Glenn, the first American to orbit Earth, New Glenn is 23
feet in diameter and lifts off with 3.85 million pounds of thrust from seven BE-4
engines. Burning liquefied natural gas and liquid oxygen, these are the same BE-4
engines that will power United Launch Alliance's new Vulcan rocket."
http://www.techinsider.io/blue-origin-new-glenn-rockets-2016-9
haha - the timing is right! Let the games begin!

The inline staging has much to recommend it, providing you have common engines, avionics and propellants throughout;

Amazing how much can be inferred from this. LOX/LNG - has a O/F ratio of 3.85 to 1.00 - and an exhaust speed of 3.4 km/sec at sea level and 3.7 km/sec in vacuo. 23 ft (7 meter) diameter stage is a little smaller in diameter than the External Tank. Instead of having seven or eight similar air-frames cross-feeding, Bezos has chosen to use tanks in line in three stages. Using common engines, and keeping a common cross section achieves many of the same goals as having common flight elements. Though you do have to light engines in flight, which means they're dead weight until you light them and you have the probability they may not light properly. Still a workable design!

LNG and LOX are about $150 per ton - so that's good to know. They're both easily handled compared to LOX LH2. Less costly too.

3.85 kg LOX 1.14 kg/litre 3.38 litres
1.00 kg LNG 0.47 kg/litre 2.12 litres

4.85 kg TOT 0.88 kg/litre 5.50 litres

Now, 3.85 million pounds of thrust translates to 1.75 million kg of thrust (17.16 megaNewtons). With the same acceleration as the Saturn V at lift off (1.28 gees) we have a take off weight of 1,400,000 kg.

Now, with a 3.4 km/sec in the first stage and a 3.7 km/sec in the upper stages which can afford higher expansion, we have a propellant fraction of 0.57334 for each stage to achieve orbit in three stages. With the first stage attaining 2.90 km/sec, the second and third stages adding 3.15 km/sec each - for a total ideal delta vee of 9.20 km/sec. After gravity losses and air drag - the payload achieves 7.91 km/sec - orbital velocity.

Structure fraction for the Bezos is low compared to legacy systems. Around 7.5% with all the recovery gear added. This leaves 1-0.574 - 0.076 = 0.35 payload fraction per stage.

So, starting with a 1.4 million kg take off weight (3,080,000 lbs) we can see that the three stage vehicle puts 60 metric tons (132,000 lbs) into LEO - slightly more than the Falcon Heavy! The length of tanks of constant diameter and cross section is 252 ft to carry 2,958.3 cubic meters of propellant in three stages. Add three interstage lengths of 16 ft each for the engines, and you have 300 ft length precisely before adding the payload!

http://read.bi/2cn8eiQ


Item................. Wgt (pounds) Weight (kg) Vol(m3) Len(m) Len( f)t

Thrust............. 3,850,000.0 1,750,000.0
Take Off Weight 3,080,000.0 1,400,000.0

Propellant......... 1,767,920.0 803,600.0 2,009.0 52.2 171.2
LNG................... 364,519.6 165,690.7
LOX................... 1,403,400.4 637,909.3
Structure.......... 234,080.0 106,400.0

Balance............ 1,078,000.0 490,000.0

Propellant......... 618,772.0 281,260.0 703.2 18.3 59.9
LNG................... 127,581.9 57,991.8
LOX................... 491,190.1 223,268.2
Structure.......... 81,928.0 37,240.0

Balance............. 377,300.0 171,500.0

Propellant.......... 216,570.2 98,441.0 246.1 6.4 21.0
LNG................... 44,653.6 20,297.1
LOX................... 171,916.6 78,143.9
Structure........... 28,674.8 13,034.0

Payload.............. 132,055.0 60,025.0

So, how did we do? How close is this to the Glenn 3 - three stage rocket?

https://www.nasaspaceflight.com/2016/09/blue-origin-new-glenn-orbital-lv/

While the first stage is slated for recovery to gain the biggest bang for the buck, there's no reason not to look at the second and third stages as well. The second stage doesn't need to be recovered down range. Its flying fast enough to skip around the world and land at its launch point, similar to the way a Sanger bomber was designed to do back in the 1930s. The orbital stage ditto - it can be deorbited and land directly at the launch point when its released its payload. Throwing away the aeroshell is the last thing to be reused.

The BE-4 can be throttled back to 20,000 lbs thrust from 550,000 lbs thrust. This means that a single BE-4 in the second and third stages simplify operations logistics and support - with the seven engines in the first stage.

The BE-3 is an interesting engine as well. Its a 110,000 lbf LOX/LH2 engine and is well suited, with ZBO composite cryogenic tanks, and MEMS based solar powered cryo-coolers on board, for deep space operations. Deeply throttable as well to 3,500 lbf, its ideally suited to take 132,000 lb payload from LEO to LLO or to Mars or the Asteroids. Capable of 4.6 km/sec exhaust speeds in vacuo, it projects the most mass most conveniently at lowest technical risk.

A delta vee from LEO to LLO and back again is 4.4 km/sec. 0.6158 propellant fraction and with a 0.0742 propellant fraction leaves 0.3100 payload fraction. So, 132,000 lbs in LEO -equipped with a BE-3 powered kick stage, can carry 40,920 lbs (18,600 kg) to Low Lunar Orbit (LLO) and back to Earth - to be recovered and reused!

https://www.wired.com/2013/07/lunar-flying-units-1969/





The astronaut tourists on this trip will wear mechcanical counter pressure biosuits with MEMS based life support and MEMS based bipropellant engine arrays that will operate as a rocket belt with the biosuit creating a space wingsuit - that allows an astronaut to jump down from LLO to the Lunar Surface and back to orbit again - spending up to 16 hours on the lunar surface and up to 24 hours in the suit. Over the course of an 8 day stay in LLO each astronaut tourist will visit the moon three times and return - from three different locations.

Each astronaut and crew person will have 400 lbs of consumables on board and 2,500 lbs of payload and structure allocated to them. This allows 1,500 lbs of this is LOX/LH2 propellant - used for the three lunar landings and take offs via rocket belt.

16 passengers and 4 crew members may be transported with this system.

1,183.3 metric tons (2.6 million lbs) of propellant at $150 per metric ton costs $177,495.20 per launch! The lunar stage contains 12,510.7 lbs of LH2 at $0.45 per lb and 68,808.8 lbs of LOX at $0.07 per lb. That's another $10,446.50 per trip.

Propellant is $200,000 per trip for 16 people - $12,500 per person. A vehicle that is reliably captured and reused 150 times and costs $60 million to build - costs another $400,000 per trip - for 16 people this adds $37,500 per person. A total out of pocket cost of $50,000!

The value is far more obviously! At $500,000 profit per passenger and 16 passengers per flight - each flight earns $8 million. At 104 flights per year this is $832 million per year. With four launchers and four moonships, this flight rate is easily sustained - and 1,664 people can visit the moon 4,992 times per year - transforming out understanding and relationship to the cosmos.

A 60 tonne payload carrying 0.9 tonne satellites puts up 66 satellites per launch and in 11 launches 722 satellite network is deployed capturing a large segment of the world's $1.6 trillion telecom market - by providing a discoverable legal signal that lets anyone with a laptop, tablet or handset communicate at 70 MB/sec to anyone anywhere in the world - while at the same time providing very secure cloud based services and live Google Earth images - that are searchable over time and space.

This provides a revenue 1000x greater, and sets the stage for whomever achieves this to have the capital needed to transform life on Earth and humanity's relationship to the cosmos.

Power satellites are next! At 60 metric tons and 22 megawatts of power per metric ton - 1.32 gigawatt power stations may be orbited. At $10 million per ton - for the satellite - the $600 million cost is less than that of a coal fired plant! Zero fuel costs once deployed. Selling power at $0.11 per kWh - which is highly competitive, and making it available anywhere its needed on Earth - which is highly sought after - all at no pollution - is a win/win for everyone! 1.32 million kilowatts - times 8766 hours per year 11.571 billion kWh per year - and at $0.11 per kWh earns $1.27 billion per year - over 30 years at sizeable discount rates this is worth $13.6 billion the day it starts paying. This is $12.0 billion net for the investors - and $0.6 billion for the build and another $1.0 billion incentive to Bezos per launch. He takes a $2.0 billion stake and donates the launch, liquidates half that stake the first year, and holds on to the balance. The investment group - organised by Bezos - reinvests most of their money to expand the programme.

Humanity requires on the order of 10,000 billion watts to sustain high living standards world wide- and at 1.36 billion watts per satellite requires 7300 satellites of this size. Launching one per day takes 20 years to meet this demand. Over 30 years the launcher infrastructure sustains a 50% growth from today's figures. Very large return, very small investment. $87.6 trillion assets earning 100x more money than the comsat network.
William Mook
2016-09-13 00:59:16 UTC
Permalink





First stage empty is 234,000 lbs,
Second stage empty is 82,000 lbs
Third stage empty is 30,000 lbs.

So, a quad rotor type arrangement - but with throttling rocket engines - and gimbals - on each corner - with BE-4s with a range of thrust from 550,000 lbs to 20,000 lbs - we have 2.2 million lbs to 80,000 lbs.

With a propellant fraction of 0.6 and structure fraction of 0.2 - and payload up to 0.2 we have a vehicle that is capable of two gee acceleration - fully fuelled - 1,170,000 lbs not to exceed weight 234,000 lbs vehicle structure - 234,000 lbs payload weight - 702,000 lbs propellant. This has a five minute hover time. Now terminal velocity of a largely empty tank is about half sound speed. About 384 mph (620 kph, 172 m/sec) So, two minutes at this speed covers 20.6 km (12.8 miles).

A GPS transponder on the vehicle, tracks the vehicle until it is 12 miles above the landing threshold. A platform launches and meets the descending booster mid flight, clamps the hold down clamps at the base of the rocket, and lands the rocket and platform gently - all in a space of four minutes. The cost? Less than $48,000 in propellants!

This greatly simplifies recovery and minimises mass on board the rocket and maximises payload to orbit!

Though this is rather cool! I must admit.




A 110,000 lbf engine - throttable back to 4,000 lbf - is more scalable

From four of the large engines to twenty of the smaller engines - for the recovery of the big booster. Eight engines in a smaller platform to recover the second stage. Four engines to recover the third stage. Or merely reuse the smaller platform for the third stage as well.

Given the advanced development of the first stage recovery - its probably best not to change it at this point. However, a smaller platform using eight of the 110,000 lbf engines - two on each corner - to zoom up and recover the second and third stages - might be something to consider as a continuing development programme.

It could also recover capsules - and payloads from orbit - or returning from a failed launch.
William Mook
2016-09-14 04:48:45 UTC
Permalink
The first stage of the Glenn 3

2,002,000.0 pounds - stage weight
234,080.0 pounds - structure
1,767,920.0 pounds - propellant
1,403,400.4 pounds - LOX
364,519.6 pounds - LNG

Could be clusted into a three element launcher, or a seven element launcher.

A three element launcher, with the second stage of the Glenn 3

700,700.0 pounds - stage weight
618,772.0 pounds - propellant weight
81,928.0 pounds - structure

This Glenn 3 heavy can put up 278,000 pounds into LEO! It masses 7.02 million pounds at lift off and produces 11.55 million pounds of thrust!

The Glenn 3 Super is a seven element system puts 555,000 lbs into LEO. It masses 14.65 million pounds at lift off and produces 26.95 million pounds of thrust at lift off!

This lifts 4.16x the payload of the original inline Glenn 3 and puts 67 passengers and 13 crew members into Low Lunar Orbit and returns them to Earth. The passengers and crew use rocket belts to land on the moon and return to the orbiting ship - landing and taking off three times each - providing a really compelling lunar exploration adventure!
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