F-8 Crusader Quiz Question

[PRB]

So, when in flight and the wing is "raised up", in aerodynamic terms, have you raised the wing or lowered the fuselage? I'm not sure. This question was raised (as it were) on our VA-94 face book page, by a rather senior A-7 pilot, so he probably knows the answer. I'm "cheating" on the quiz right now...

[MenendezDiego]

You're increasing the AoA, so I'd say you've raised the wing, as the engine is still in the same place.

[SkippyBing]

You've changed the rigging angle which means you can either fly at the same speed with the fuselage lowered down (wing at same angle of attack so same lift) or slower with the fuselage at the original angle (wing at a higher angle of attack so the same lift at a lower speed).
So I'd imagine initially, as your speed is broadly the same throughout the change, to maintain level flight the pilot will lower the fuselage to keep the wing AoA the same. As the aircraft slows he can increase the AoA of the wing to fly slower with the fuselage returning to the original pitch.
Conversely if the pilot deliberately kept the fuselage angle the same it would increase the wing's AoA and cause the aircraft to start climbing.

[PRB]

You've changed the rigging angle which means you can either fly at the same speed with the fuselage lowered down (wing at same angle of attack so same lift) or slower with the fuselage at the original angle (wing at a higher angle of attack so the same lift at a lower speed).
So I'd imagine initially, as your speed is broadly the same throughout the change, to maintain level flight the pilot will lower the fuselage to keep the wing AoA the same. As the aircraft slows he can increase the AoA of the wing to fly slower with the fuselage returning to the original pitch.
Conversely if the pilot deliberately kept the fuselage angle the same it would increase the wing's AoA and cause the aircraft to start climbing.

I like this answer. Basically, it depends on your point of view. Sort of. Assuming constant speed (AOA), the answer is you've lowered the fuselage. But the point of the device is to slow down and land, so you've raised the wing. It's a trick question! :icon_lol:

[Navy Chief]

So, when in flight and the wing is "raised up", in aerodynamic terms, have you raised the wing or lowered the fuselage? I'm not sure. This question was raised (as it were) on our VA-94 face book page, by a rather senior A-7 pilot, so he probably knows the answer. I'm "cheating" on the quiz right now...

Seems like I used to hear that old question many years ago when I actually worked on Crusaders. My vote would be the wing gets raised. And, of course, the story about a pilot that somehow managed to take off in afterburner, and actually land the plane with wings folded. Apparently that happened more than once too....

NC

[Sundog]

Well, from an Aeronautical Engineering viewpoint, there is a longitudinal line running down the fuselage that is usually the physical reference. By raising the wing, you're changing the angle of incidence of the wing. This wasn't something new either. The XB-51 was able to change the angle of incidence of it's wing as well and there were other designs that explored this as well, before the F-8 came along. Such as the original design of the Grumman Jaguar, before they switched the design to a swing wing.

So the short answer is, you're neither raising the wing or lowering the fuselage. You're changing the angle of incidence of the wing, allowing the wing to have a higher alpha without raising the nose as high as would be required if it were fixed. This allows the pilot to maintain good visibility on approach and also allows a shorter landing gear due to having a lower tail scrape angle, which also reduces weight and improves performance.
Of course, the weight of the system that changes the angle of incidence adds weight, which lowers all up performance. But, as with everything in aircraft design, there's always a trade-off.

[johndetrick]

Seems like I used to hear that old question many years ago when I actually worked on Crusaders. My vote would be the wing gets raised. And, of course, the story about a pilot that somehow managed to take off in afterburner, and actually land the plane with wings folded. Apparently that happened more than once too....

NC


Proof that the above statement is true.

[Ian Warren]

Proof that the above statement is true.
Pleased you posted that John , that is puts that rumor the bed once and for all , now i wonder how the plane was allowed to take off like that or was it a actual "Let Try This Out" flight ... whatever still impressive :cool:

Edit: The photo dose show evidence that it has been doctored between the aircraft and the ground ... ?


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[TARPSBird]

The "Raise the wing or lower the fuselage?" topic was kicked around on the F-8 List a couple months ago, it went pretty much same as the comments here and that list is almost entirely retired USN/USMC F-8 drivers. :icon_lol: As for taking off with the wings folded, the above pic can be seen on Lt. Col. Don "Mofack" Cathcart's website and it's the real deal...
http://www.mofack.com/Night_Infamy.htm
If you can leave Mofack's site without reading several of his TINS (This Is No Sh*t) stories you have more discipline than I have.