Space Shuttle Carrier Aircraft Projects

Hi,

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A couple of questions for Space Shuttle experts. Is anyone familiar with the emergency procedures for the 747 SCAs? I've always wondered if it was anticipated that some situations would require the crew to jettison the shuttle in order to keep the 747 flyable. Even if the combination were flyable, I'd think that there'd be some emergency landing situations where the prospect of a 75 ton payload above and behind the cockpit would be intimidating. In that case, was there a means for the jettisoned orbiter to glide under autopilot control or would it just be a big lawn dart? Did NASA avoid flying the combination over densely populated areas for this reason? (in routine operation I mean, I know that photo/airshow laps were done over Paris, Washington DC, Sacramento and San Francisco at least)
Also, could the shuttle, as a payload of the SCA, be trimmed in flight? I'd think that that would be useful to improve the combination's flying characteristics and to reduce loads on the airframes.
 
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My understanding is that outside the actual Approach and Landing tests, the SCA usually did not fly with the explosive bolts necessary to jettison the Shuttle installed. So the issue is rather moot.

Also, for most of its life, the Shuttle could not drop the landing gear automatically, so it could not have landed from the back of the SCA without crew on board.
 
I thought the SCA had some kind of escape system, so the answer might have been "let the 747 and orbiter crash after crew escaped via parachute".
 
In regards to SCA crews having parachutes.... I don't believe they did. To quote an old friend, who was an F-16 pilot that was asked how tanker crew egress in an emergency.... "They don't." So, I think the simple answer is they would have rode it in one way or the other. Also, so far as jettisoning the orbiter without crew.... well, that's problematic at best. As mentioned above, they rarely carried the explosive bolts. But lets play Devil's advocate and say they did, as soon as the thing is jettisoned, you're going to have to make a nose dive to avoid having the vertical stabilizer smash into the orbiter. Assuming the SCA is at a point where this would be considered, good luck on it being able to do such a maneuver.
 
TomS said:
Also, for most of its life, the Shuttle could not drop the landing gear automatically, so it could not have landed from the back of the SCA without crew on board.
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By "controlled glide" I didn't mean to suggest that the orbiter might be able to land itself, only that it would glide (until it crashed) in a controlled manner rather than follow an unpredictable trajectory. Releasing a glider that will keep going in the direction that you point it would be a different decision than jettisoning an unpredictable 75t brick with wings.
 
Conroy really looks weird. The siamese C-5 looks more realistic... except the Galaxy first decade was just horrible. No surprise NASA picked a 747 over it. The irony being that Stratolaunch ultimately used a few major pieces from 747s, mostly the engines. In passing, with 250 mt of payload, a Roc could carry three Shuttle orbiters...
 
707LPN said:
But lets play Devil's advocate and say they did, as soon as the thing is jettisoned, you're going to have to make a nose dive to avoid having the vertical stabilizer smash into the orbiter. Assuming the SCA is at a point where this would be considered, good luck on it being able to do such a maneuver.
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That's not quite correct... when an aircraft first goes into a dive the tail actually rises - remember that the elevators (and rudders) force the tail to go in the opposite direction of the desired maneuver, in order to re-align the fuselage in the desired direction.

For the tail to drop the aircraft needs to pitch up - and this maneuver would help by increasing the AOA of the shuttle as well, thus increasing its lift.

The procedure would have been:
1. pull the control wheel back, bringing the nose up
2. immediately activate the explosive bolts
3. as soon as the bolts blow pull the throttles back to slow the B747 (to give more time to separate), and gently push the wheel forward, to bring the aircraft back to level without raising the tail, while allowing the higher AOA of the shuttle to lift it further away and up.
4. once the shuttle is fully clear then you advance the throttles to leave the shuttle behind you.
 
TsrJoe said:
www.nasa.gov

Russ Arasmith Shuttle Artwork - NASA

Russ Arasmith Shuttle Artwork
www.nasa.gov www.nasa.gov
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Considering the many, horrible issues with the C-5A first decade, I was wondering whether they also thought of a "twin 747". The difficulty being the low wing. Would it be possible to build a twin 747 with the wings low, and the central wing high - because it needs to be high to hang the Shuttle orbiter below.
Would look a bit weird... kinda like that. _o-o_
 
Main advantage of these "monstrosities" compared to the 747-SCA that got the job in the end: no need for the "mate/demate device". The big crane used to haul the orbiter on the back of the 747. In stark contrast: just tow the Shuttle Orbiter under the central wing, haul it, hang it to the central wing, fly away. Same for the ALT flight tests: easier and safer to drop Stratolaunch style than flying above the 747 tail...

Funny to think Stratolaunch kinda build such aircraft... only after the Shuttle was retired. No idea if there are 1/144 scale model of Stratolaunch's Roc, might be fun to hang a 1/144 Shuttle orbiter under the central wing.
 
Had a shuttle orbiter sported a steel frame, might Roc and SuperHeavy be able to support them?
 
Archibald said:
Main advantage of these "monstrosities" compared to the 747-SCA that got the job in the end: no need for the "mate/demate device". The big crane used to haul the orbiter on the back of the 747. In stark contrast: just tow the Shuttle Orbiter under the central wing, haul it, hang it to the central wing, fly away. Same for the ALT flight tests: easier and safer to drop Stratolaunch style than flying above the 747 tail...
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How would the orbiter be raise to be hung from the wing?
The issue is the attach points. The SCA attach points mimicked the ET attach points. The orbiter is designed to take launch and aero loads from these points. There are 4 points to lift the orbiter for mating to the ET (and SCA) but these do not have quick releases nor can they take loads more than the weight of the orbiter
 
publiusr said:
Had a shuttle orbiter sported a steel frame, might Roc and SuperHeavy be able to support them?
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no. The shuttle orbiter is incompatible with the superheavy in any configuration.
Orbiter with steel frame couldn't support itself (too heavy for its own wings)
 
Byeman said:
How would the orbiter be raise to be hung from the wing?
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In the case of the Conroy.... thing... it seems that the Orbiter would be supported from underneath by an improbable-looking set of struts. Not saying it's a good solution, but it does at least answer that question.
 
This was in 1972 73 so Orbiter was still in design phase.
There are 4 points to lift the orbiter for mating to the ET (and SCA) but these do not have quick releases nor can they take loads more than the weight of the orbiter
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With the orbiter in the design phase the four points you mention might be adapted. Of course this would impact the orbiter design, construction and costs in many negative ways... the proverbial slippery slope.
Almost importantly the twin aircraft would be eye-watering expensive to built when NASA budget hit rock bottom in FY74.

Boeing and Lockheed were in poor shape circa 1973. C-5 had tons of glitches with the company part corrupt, part bankrupt. The 747 was much less technically troubled than the C-5 but almost bankrupted Boeing too.
Imagine one of these troubled companies building a Roc beast of aircraft under a cost plus contract for a cash strapped NASA. What could possibly go wrong ?
In the end NASA certainly made the right choice: second-hand 747s.
 
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