I hope you will not find this question too 'Jumbo' to answer.

[JonnyBoy12]

Many of you on here may recall the advent of the Space Shuttle programme which in the early 1980s took up all the news at the time. In some rare cases the Space Shuttle had to land at a far away site like White Sands missile testing range (correct me if I am wrong about this as can not swear to it). In this case the Space Shuttle had to ride home 'piggy back' on the top of a converted Boeing 747 or Jumbo Jet. As a biplane or triplane has more wing area than a monoplane (plane with only one set of wings) would the wings of the Space Shuttle give it more lift and make it more efficient and save fuel compared to a 'normal' Jumbo Jet?

I will understand if you can not answer this strange question but it has been bugging me for weeks. I have looked at the main NASA site but can not see where to ask this.

I thank you all for your understanding and kind and helpful answers.

[boxtops]

I don't know, but I would have thought that the extra weight of the shuttle would be a hindrance, rather than providing more lift?

[237SJ]

Do you mean would it give the 747 more lift? I`m no expert but I would think the answer would be no. The wings of the 747 wouldn`t have been designed to be perfectly aligned to the wings of another aircraft riding piggy-back. I would think the aerodynamcs of the 747 would have been compromised by a bulky space shuttle on it`s back.

[Jonathan-Joe]

Flying with the additional drag and weight of the Orbiter imposes significant fuel and altitude penalties according to http://en.wikipedia.o...ttle_Carrier_Aircraft

[Calibax]

I don't know the answer but I would guess that as the wings of the shuttle were designed only to provide a stable glide back to earth rather than gererating lift, then as boxtops says, the extra mass would more than compensate for any extra lift so it would be less efficient.

[jomifl]

No, if it did they would build all jumbo jets with a space shuttle stuck on top. But seriously, the extra frontal area and surface area that produces far more drag than lift equivalent to a normal jumbo would make it a lot less efficient. The additional weight would also have had large energy costs. If it made it more efficient they could have put it on a smaller plane as it is I suspect that the jumbo jet was pushed to it's carrying limits and could only carry the space shuttle at relatively low altitude.

[dundurn]

This question has been coming up practically as long as the 747 has been in use for ferry flights. For the approach and landing test flights where the shuttle was air-launched from the back of the 747 the shuttle was mounted with a nose-up attitude, about 7 degrees I think. The 747 dived immediately prior to release and thanks to the shuttle's nose-up it was generating enough lift to pull away from the 747. Note this wasn't enough lift to "fly", just to fall more slowly than the 747. For the ferry flights the shuttle is mounted differently and provides almost no lift at all. I've seen an estimate of c1000 lb but don't know how accurate that is. The 747 is empty apart from fuel and crew and has a comfortable margin of power to carry the empty shuttle. It does require additional vertical tail surfaces, however, and suffers significant penalties in its range and altitude performance.

[JonnyBoy12]

Yes, that does answer my question very well. I did not seriously think that it would pay for itself with the very small amount of lift the stubby wings would give. Did not know the penalties in fuel and performance were that severe.

Range only 1,000 miles.
Flight ceiling only 15,000 feet.
Maximum speed only Mach 0.6.

Remind me not to take my Space Shuttle on holiday with me this year. Do not think that they will let me do this even if I pay the excess weight charge.

[Jumbo747]

I wonder.....................

[237SJ]

To get an answer about ferrying the shuttle on a 747 you need to find out the weight of the shuttle versus the weight of the jumbo. Bearing in mind that the jumbo will be a lot lighter than a commercial one. The insides will have been stripped out and it will be a lot lighter. Presumably it will not be doing a long range flight so won`t be that heavy with fuel. I can get a few details for you about the weight of a jumbo (with passenger, bags, fuel etc but might take a little while) but I still think the 747 will be compromised by the reduced aerodynamics of the shuttle on it`s back.