Loop in an Extra

I'll do that, Lance. Thanks for the tip! I have one more question, which I'll post in this thread just to keep everything together.

If a Cessna 182 had a couple parts (elevator, aileron) clipped off in flight from impact with another plane, would it fall to earth nose up or nose down?
 
Toby said:
I'll do that, Lance. Thanks for the tip! I have one more question, which I'll post in this thread just to keep everything together.

If a Cessna 182 had a couple parts (elevator, aileron) clipped off in flight from impact with another plane, would it fall to earth nose up or nose down?
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Toby, it could be either. If you lost the elevator but not the horizontal stabilizer, I think the answer would lie with how the airplane was trimmed before the impact. Now if you lost the whole h.stab and elevator the nose would fall down because the h.stab elevator combo exerts downward pressure on the tail, and without that, (and with a suddenly lighter tail) the nose would go down.

Now there are many exceptions to "the tail pushes down". But for a 182 which is nose heavy to begin with, the tail will push down unless the CG is at the extreme back end of the envelope. If it were that far back, maybe up maybe down. You will get some comments on this and please listen to those with more experience than I.

-Skip
 
Toby said:
I'll do that, Lance. Thanks for the tip! I have one more question, which I'll post in this thread just to keep everything together.

If a Cessna 182 had a couple parts (elevator, aileron) clipped off in flight from impact with another plane, would it fall to earth nose up or nose down?
Click to expand...

If an aileron fell off without any other damage to the wing and the control linkage wasn't jammed, the loss of aileron wouldn't seriously affect the planes ability to fly. Losing one side of the elevator would also have the potential to leave the plane relatively controllable, albeit with less pitch authority, and the reduced weight at the tail would shift the CG forward. Together that might create problems during landing where the pilot might not be able to hold the nose up prior to touchdown, and that would be exacerbated by an already forward CG (e.g. two folks in the front seats, nothing in back). If the both sides of the elevator departed the tail the result would almost surely be a sudden pitch down and likely very high negative g force which could easily fold the wings (down). With or without wing failure the plane would be doomed unless the CG had originally been far enough aft of the aft limit that it was nearly in balance with the elevator's weight gone (since the elevator has a very long arm it's relatively light weight would still have a big effect on the CG). After the initial pitch down (nose drop) it's hard to say which end would be up at the time it hit the ground.

That said, it's hard to imagine how an elevator or aileron could be knocked off without some serious collateral damage which would have unpredictable effects on controllability. For instance if the collision also bent the horizontal stabilizer's leading edge downward the plane would likely pitch up violently.
 
gismo said:
If the both sides of the elevator departed the tail the result would almost surely be a sudden pitch down and likely very high negative g force which could easily fold the wings (down). With or without wing failure the plane would be doomed
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Excellent. :)
 
Toby said:
If a Cessna 182 had a couple parts (elevator, aileron) clipped off in flight from impact with another plane, would it fall to earth nose up or nose down?
Click to expand...

gismo said:
If an aileron fell off without any other damage to the wing and the control linkage wasn't jammed, the loss of aileron wouldn't seriously affect the planes ability to fly.
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Yup - And this has been proven on the 182 via Alan Klapmeier's mid-air collision. They lost the right aileron and about 4 feet of the right wing and were able to land it, albeit with nearly full left aileron - So losing an aileron and 4 feet of a wing is about the limit.

WRT the elevator: What Lance said.
 
Skip Miller said:
If you lost the elevator but not the horizontal stabilizer, I think the answer would lie with how the airplane was trimmed before the impact.
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I don't think that would have any impact, considering that on the 182 the trim tab is connected to the back of the elevator. Lose the elevator, you lose trim too. That's true of most small airplanes, the exception being Mooneys which trim via moving the entire horizontal stabilizer slightly. (This is different from the Pipers, which have a stabilator and an anti-servo tab - The Mooney still has a separate H-stab and elevator.)

Now there are many exceptions to "the tail pushes down". But for a 182 which is nose heavy to begin with, the tail will push down unless the CG is at the extreme back end of the envelope. If it were that far back, maybe up maybe down.
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Nope - The tail *always* pushes down when inside W&B limits, even with the CG at the extreme aft end of the envelope. If the CG were far enough aft that the tail were not pushing down, the airplane would lose its stability and likely begin to oscillate, soon breaking apart without any outside influence such as a mid-air.

So, I'm gonna say that if the entire elevator is chopped off along with one aileron, it's gonna be nose down but probably still level in roll.
 
Toby said:
gismo said:
If the both sides of the elevator departed the tail the result would almost surely be a sudden pitch down and likely very high negative g force which could easily fold the wings (down). With or without wing failure the plane would be doomed
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Excellent. :)
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Now Toby, that's a TERRIBLE thing for a pilot to say! ;)
 
flyingcheesehead said:
Nope - The tail *always* pushes down when inside W&B limits, even with the CG at the extreme aft end of the envelope. If the CG were far enough aft that the tail were not pushing down, the airplane would lose its stability and likely begin to oscillate, soon breaking apart without any outside influence such as a mid-air.

So, I'm gonna say that if the entire elevator is chopped off along with one aileron, it's gonna be nose down but probably still level in roll.
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Diverging from Toby's query slightly but I'm told (by experts) that some of the Bonanzas actually allow loading with the CG very slightly behind the center of lift on the wings and that at the aft CG limit the tail actually provides a very slight positive lift. The necessary static stability is there (but about as weak as the FAA allowed under CAR 3) from other aerodynamic influences. That said, losing just the weight of the elevator would push the CG far enough forward that the nose would drop so even if those experts were correct the point is moot WRT Toby's scenario.
 
gismo said:
Diverging from Toby's query slightly but I'm told (by experts) that some of the Bonanzas actually allow loading with the CG very slightly behind the center of lift on the wings and that at the aft CG limit the tail actually provides a very slight positive lift.
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Wouldn't loading it with the CG in such a position that the tail produced zero lift/downforce create the potential for a divergent oscillation, or at least an undamped one?

The necessary static stability is there (but about as weak as the FAA allowed under CAR 3) from other aerodynamic influences.
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Hmmm. What would those other aerodynamic influences be?

(Maybe that big antenna on top of the cabin? ;) :rofl:)
 
flyingcheesehead said:
Wouldn't loading it with the CG in such a position that the tail produced zero lift/downforce create the potential for a divergent oscillation, or at least an undamped one?



Hmmm. What would those other aerodynamic influences be?

(Maybe that big antenna on top of the cabin? ;) :rofl:)
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I believe it's the "torque" of the wing when generating lift but I'm not even certain the whole statement is true.
 
Don't know about a 182, although there have been several survivable loss of aileron incidents in them, but the 172 can literally lose an engine and make a walk away landing.

http://www.aircraftone.com/aircraft/accidents/20001212X23999.asp




Toby said:
I'll do that, Lance. Thanks for the tip! I have one more question, which I'll post in this thread just to keep everything together.

If a Cessna 182 had a couple parts (elevator, aileron) clipped off in flight from impact with another plane, would it fall to earth nose up or nose down?
Click to expand...
 
Just out of curiosity, what happens if the vertical stabilizer were to depart the aircraft?
 
well lets see......
the horizontal and elevator control the pitch of the main wing who's pitching moment changes with angle of attack. So theoretically the main wing will have a 0 pitching moment at some angle of attack. That means that at some magic angle the wing will slip through the air without pitching either direction. In reality however its much more likely to pitch nose down with the loss of the horizontal and or the elevator. In some cases the plane would tumble though the airfoil on a 182 (2300 series) is fairly stable so it would probably just pitch nose down til it hit.

On the other hand, the loss of the vertical fin and rudder wouldn't necessarily cause a crash. It would reduce the controlability quite a lot but the fin is there to insure yaw stability, some of which comes from the fuselage. I remember a B52 that lost almost the entire fin when doing low altitude flying in the rocky's. It hit some extreme turbulance and tore off the fin. The plane continued flying for quite some time to a safe landing. I think it was scrapped due to other damage caused by the turbulance but no landing issues. There are also some good examples of bombers coming back to england in WWII with fins missing and having safe though not picturesque landgings.

The loss of the ailerons is not necessarily a trip to the briny deep but depending on how they are removed it could cause some other serious damage that would be grounds for rapid grounding. Tearing off a wingtip might leave an aileron flapping in the breeze for a bit while it shreds the aft side of the wing and flap....? I've seen that happen on drones and RPV's where the initial damage would be survivable but the departing parts finished off the vehicle.

I think if you are going to lose some parts the fin is the way to go. Scary and suspenseful but not a show stopper. It would probably induce some nasty dutch roll tendencies but not kill the plane.

Frank
 
Late to this thread, but I have a friend who had a mid-air - 152 v. Pitts. Both survived. They both owned the planes. They switched and were flying each others plane. The Pitts pilot in this flight decided to spook the 152 driver, by coming up from underneath, and going vert. right in front of the 152. There would be wake turb. as well to startle the 152 driver. Really, really dumb move. Anyway, the Pitts pilot cut it too close, and the 152's prop. cut the top half of the vert. stab. in half on the Pitts. Both planes remained flying. Pitts had control and told 152 pilot to land first, because he (Pitts) was wanting the emergency crews ready for his landing. 152 landed uneventful. News crews arrived by the time the Pitts landed. No problem. Both landed safely. Lucky and after a brief vacation from their flying privledges, they're flying again.
 
Also, there's a guy who flies a cub or something similar, in airshows, that at one pint drops an aileron. His routine is close to the ground, and acts as if he is out of control, the whole time. He flew at Reno this year. Name escapes me, but there's video of him on Youtube.
 
ActiveAir said:
Also, there's a guy who flies a cub or something similar, in airshows, that at one pint drops an aileron. His routine is close to the ground, and acts as if he is out of control, the whole time. He flew at Reno this year. Name escapes me, but there's video of him on Youtube.
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I don't think he actually drops an aileron - I think he's got a double aileron on one side, and he drops it, but the rest of it's still there.
 
ActiveAir said:
Also, there's a guy who flies a cub or something similar, in airshows, that at one pint drops an aileron. His routine is close to the ground, and acts as if he is out of control, the whole time. He flew at Reno this year. Name escapes me, but there's video of him on Youtube.
Click to expand...

Here is a video from Reno:

http://www.youtube.com/watch?v=Tbp4I2Diyhs

Here is another one where you can see the wing better after the aileron drops off:

http://www.youtube.com/watch?v=NWtkEDY9V2k

Here is his website.
 
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