747 and Shuttle
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747 and Shuttle
Is there a change in the amount of lift generated when the 747 piggybacks the Shuttle, or does the added weight somehow canx things out? Would there be a need for higher AoA during certain flight phases for example. I don't believe the weight factor comes into play concerning lift, but does it effect other qualities? If the lift is increased, would a shorter take-off run be used?
LJ.
LJ.
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Good question. And the answer? No idea, but I wait with interest.
The thing is, all these questions, and many more, (fuel consumption, VNE etc.) would have to be answered before they even began modifying the 747 to do the job. And all those answers would have to be correct - first time.
There are some very clever people around.
Sometimes, I feel very humble.
The thing is, all these questions, and many more, (fuel consumption, VNE etc.) would have to be answered before they even began modifying the 747 to do the job. And all those answers would have to be correct - first time.
There are some very clever people around.
Sometimes, I feel very humble.
I can't post the link to this, since it's on a restricted access website (but any SETP members will find it without trouble), but...
Quotes from a paper called:-
SHUTTLE CARRIER AIRCRAFT FLIGHT TESTS
by FITZHUGH L. FULTON, JR. (F)
NASA, DRYDEN FLIGHT RESEARCH CENTER
Published by Society of Experimental Test Pilots, 1977
All a bit vague I'm afraid, and a distinct lack of hard numbers comparing the performance between the two - but I'd read between the lines and say that implies that the lift available was significantly increased.
G
Quotes from a paper called:-
SHUTTLE CARRIER AIRCRAFT FLIGHT TESTS
by FITZHUGH L. FULTON, JR. (F)
NASA, DRYDEN FLIGHT RESEARCH CENTER
Published by Society of Experimental Test Pilots, 1977
Takeoffs
Takeoffs were conducted at gross weights from 554,000 pounds to 626,000 pounds. The simulator-developed technique of gradually increasing thrust to takeoff power by the time the airplane reached a speed of 60 KCAS was confirmed as a desirable standard technique. However, it was found that a more rapid thrust increase (with takeoff power set by 30 KCAS) could be tolerated. Under these circumstances, nose strut extension
was enough to cause a momentary loss of nose wheel steering. However, the steering loss was of short duration and caused no problems. The rapid thrust increase technique would be useful for reducing ground roll when taking off on a short runway. Rotating to a pitch attitude of approximately 7 degrees for liftoff gave a tip fin clearance of about I O feet. The rotation technique causod the takeoff speed t o be 5 or 6 KCAS higher than for an
unmodified aircraft and added slightly to the takeoff distance, but it was satisfactory for this special purpose airplane. The ground roll distance at a gross weight of 554,000 pounds was about 5000 feet; this represented the launch mission takeoff weight.
MATED SCA TESTS IN FERRY CONFIGURATION
When the ALT program is completed, the SCA is to be used to ferry orbiters wherever they are needed. The tail cone will be on; the primary difference between the previously tested mated inert configuration and the ferry configuration will be a change in the angle of incidence of the orbiter on the SCA. The forward attachment pylon will be shortened to give a 3-degree angle of incidence, which will reduce the drag due to the orbiter
considerably.
Three flights with takeoffs a t gross weights up t o 710,000 pounds are planned to recheck flutter clearances, obtain stability and control data, confirm configuration airworthiness, and compile the necessary performance data for the ferry missions.
CONCLUSIONS
The modified Boeing 747 has proven to be a satisfactory carrier for the orbiter. With the orbiter attached, the shuttle carrier aircraft’s handling qualities, performance, and stability and control were good or better through-out the envelope tested. And finally, the launches of the orbiter with the tail cone on have been satisfactorily completed.
Takeoffs were conducted at gross weights from 554,000 pounds to 626,000 pounds. The simulator-developed technique of gradually increasing thrust to takeoff power by the time the airplane reached a speed of 60 KCAS was confirmed as a desirable standard technique. However, it was found that a more rapid thrust increase (with takeoff power set by 30 KCAS) could be tolerated. Under these circumstances, nose strut extension
was enough to cause a momentary loss of nose wheel steering. However, the steering loss was of short duration and caused no problems. The rapid thrust increase technique would be useful for reducing ground roll when taking off on a short runway. Rotating to a pitch attitude of approximately 7 degrees for liftoff gave a tip fin clearance of about I O feet. The rotation technique causod the takeoff speed t o be 5 or 6 KCAS higher than for an
unmodified aircraft and added slightly to the takeoff distance, but it was satisfactory for this special purpose airplane. The ground roll distance at a gross weight of 554,000 pounds was about 5000 feet; this represented the launch mission takeoff weight.
MATED SCA TESTS IN FERRY CONFIGURATION
When the ALT program is completed, the SCA is to be used to ferry orbiters wherever they are needed. The tail cone will be on; the primary difference between the previously tested mated inert configuration and the ferry configuration will be a change in the angle of incidence of the orbiter on the SCA. The forward attachment pylon will be shortened to give a 3-degree angle of incidence, which will reduce the drag due to the orbiter
considerably.
Three flights with takeoffs a t gross weights up t o 710,000 pounds are planned to recheck flutter clearances, obtain stability and control data, confirm configuration airworthiness, and compile the necessary performance data for the ferry missions.
CONCLUSIONS
The modified Boeing 747 has proven to be a satisfactory carrier for the orbiter. With the orbiter attached, the shuttle carrier aircraft’s handling qualities, performance, and stability and control were good or better through-out the envelope tested. And finally, the launches of the orbiter with the tail cone on have been satisfactorily completed.
G
The one visible change apart from the obvious attachment equipment is the supplementary fins attached to the ends of the tailplane on either side. Why were these necessary ?
I've also wondered if the orbiter generates enough lift to offset its own weight. I believe the radome on top of the Boeing AWACS does so.
Also believe the 747 cannot do a transcontinental trip with the orbiter aboard, so Edwards to the Cape has to stop midway for fuel. Wonder if this is a fuel consumption increase or a MTOW restriction.
I've also wondered if the orbiter generates enough lift to offset its own weight. I believe the radome on top of the Boeing AWACS does so.
Also believe the 747 cannot do a transcontinental trip with the orbiter aboard, so Edwards to the Cape has to stop midway for fuel. Wonder if this is a fuel consumption increase or a MTOW restriction.
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Some googling later...
The supplementary fins are probably for additional stabilization as the vortex/coverage from the Shuttle will significantly influence the flow around the vertical stabilizer (guess based on memory of aerodynamics classes way back when)
from http://www.astronautix.com/stages/nasa747.htm
Note speed and range
SCA Descriptions
Dimensions
Wingspan: 195 ft. 8 in.
Length: 231 ft. 10 in.
Height: Top of vertical stabilizer, 63 ft. 5 in.; To top of cockpit area, 32 ft. 1 in.
Weight: Basic weight, NASA 905, 318,053 lbs- NASA 911, 323,034 lbs; Maximum gross taxi weight, 713,000 lbs; maximum gross brake release weight, 710,000 lbs; maximum gross landing weight, 600,000 lbs
Engines
Four Pratt and Whitney JT9D-7J gas turbine engines, each producing 50,000 lbs of thrust
Performance
Airspeed limits with, and without an orbiter: 250 knots or Mach 0.6
Altitude: Typical cruise with orbiter, 13,000-15,000 ft MSL; typical cruise unmated, 24,000-26,000 ft MSL. Minimum temperature at altitude 15 degrees (F) (-9 degrees C) or 8 psi ambient pressure
Range : Typical mated, 1000 nautical miles (with reserves); maximum unmated, 5500 nautical miles
Fuel Capacity
47,210 gallons (316,307 lbs) jet fuel
from http://www.astronautix.com/stages/nasa747.htm
Note speed and range
SCA Descriptions
Dimensions
Wingspan: 195 ft. 8 in.
Length: 231 ft. 10 in.
Height: Top of vertical stabilizer, 63 ft. 5 in.; To top of cockpit area, 32 ft. 1 in.
Weight: Basic weight, NASA 905, 318,053 lbs- NASA 911, 323,034 lbs; Maximum gross taxi weight, 713,000 lbs; maximum gross brake release weight, 710,000 lbs; maximum gross landing weight, 600,000 lbs
Engines
Four Pratt and Whitney JT9D-7J gas turbine engines, each producing 50,000 lbs of thrust
Performance
Airspeed limits with, and without an orbiter: 250 knots or Mach 0.6
Altitude: Typical cruise with orbiter, 13,000-15,000 ft MSL; typical cruise unmated, 24,000-26,000 ft MSL. Minimum temperature at altitude 15 degrees (F) (-9 degrees C) or 8 psi ambient pressure
Range : Typical mated, 1000 nautical miles (with reserves); maximum unmated, 5500 nautical miles
Fuel Capacity
47,210 gallons (316,307 lbs) jet fuel
The supplementary fins are probably for additional stabilization as the vortex/coverage from the Shuttle .....
Interesting to read that! I hadn't thought much about the difference between the Air launch tests and a ferry flight. Obviously for the first you want the orbiter to be at a positive angle of attack at launch, otherwise you would just be throwing it straight away, hoping it would bounce of the top of the 747 
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What happens in icing conditions? I would imagine the accrual on the shuttle could be pretty large - but without obvious anti or deicing kit. Especially since the speeds are lower than a normal 747 flight and down in the weeds.
Is the shuttle plugged in and electrically powered, or is it "off". Does anyone ride in the shuttle during ferry? I would imagine not, but can see a few times when someone might.
Is the shuttle plugged in and electrically powered, or is it "off". Does anyone ride in the shuttle during ferry? I would imagine not, but can see a few times when someone might.
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055166k,
Thanks for that. And the only digital computers they had at the time were the ones on the ends of their arms, with help from a slide rule.
I believe the Germans had their own version of a composite - there must have been some kind of competition going on at the time.
Farmer.
Thanks for that. And the only digital computers they had at the time were the ones on the ends of their arms, with help from a slide rule.
I believe the Germans had their own version of a composite - there must have been some kind of competition going on at the time.
Farmer.
Last edited by Farmer 1; 10th Sep 2005 at 16:12.
