Spiral of Death

[CNY_Dave]

Holy cow, the warnings the guy puts up on this on-board vid...

WWII AT-6 Texan Part II (aka T6 T-6 SNJ Harvard) SPIN

[CNY_Dave]

AOPA on entering a spin in the pattern...

http://www.aopa.org/asf/publications...tall_spin.html

"In short, the average vertical recovery distance was just short of 1200 feet. Pilots allowing a spin to develop at or below traffic pattern altitude are nearly certain to crash, no matter how quick their reflexes or skillful their recovery."

[BBCorvette18]

Well I finally smashed my FMS Giant cub today because of the death spiral. Not to mad about it as I hated the way it flies compared to my FunCub. So more electronics to put on $store scratch builds LOL

[xmech2k]

LOL! I guess this was the beginning of military aviations attitude that fighter planes are supposed to be hard to fly. I think I recently read a snippet that the full size Texan was a handfull to get the students ready for fighters. Even years later, when the T-38 Talon was developed, the military brass almost didn't accept it because a 'fighter is not supposed to be easy to fly!' (Though the 38 had it's quirks too, as I've read.)

Thanks for the insight, CNY Dave.

[Rockin Robbins]

Originally Posted by CNY_Dave

Holy cow, the warnings the guy puts up on this on-board vid...

WWII AT-6 Texan Part II (aka T6 T-6 SNJ Harvard) SPIN

Oh My! It's a "good" trainer because it will kill you to teach you a lesson! All those pilots crashing AT6s in the first videos are experienced, good pilots doing things just about any other plane would let them get away with.

The good news is that the AT-6 is predictable and will bite you exactly the same way for the same reasons every time. By flying with strict discipline you can return alive. Unfortunately with no instrumentation to gage airspeed, G force, or anything else about how the plane is flying strict discipline is totally subjective. You have to leave a large amount of headroom for safe operation, keeping turns way wider than you think is necessary, keeping speed significantly above what you think stall speed is. You might not even want to find out what stall speed is because it could result in immediate departure into the.....all together now.....SPIN....OF DEATH!!!

Wow! The full size video sure drove the point home, didn't it?

[CNY_Dave]

If/when I get mine in the air I'm going to have to practice what *not* to do and do some spins with *significant* altitude.

[Rockin Robbins]

But here's what you can't do with your AT-6. Steve from Killerplanes.com with a crashproofed Dynam Corsair. It's a thing of absolute beauty doing things that would get you killed in an AT-6

YouTube Video

The way he flies it and considering his comments, I'm surprised the Dynam Corsair doesn't have a wider following!

[fhhuber]

Originally Posted by dahawk

First thing I do is chop the throttle if I'm high enough. Had the AT-6 JPowers mini and she was a tip staller, especially, if it was too slow in the turns. Had no rudder. In that case, I would apply power. Never got into the full death spiral mode.

I have 5 models that require power OFF to recover from a spin. The torque of the electric power system and the relatively large props just hold the planes in the spin regardless of other control inputs.

There are a few aircraft that DO NOT EVER recover from a spin. This is usually from a combination of the CG being back (for improved maneuverability) and lack of effective rudder/in area when the aircraft spins.

The F-4-U Corsair (full scale) had this issue. The Navy waived the stall/spin testing requirement for type acceptance because of the aircraft's speed and ability to survive battle damage.
Moving the CG forward will cure the issue... so RC models tend to be able to recover because of CG and "fudging" the vertical tail-surfaces oversize a bit.

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So...

Keep CG forward a bit (25% to 30% "MAC"*) and be ready to kill power in order to recover from a spin.

If CG is far enough forward you can't keep the aircraft in a spin regardless of how hard you try. It will recover and you can force it back into a spin again though.
For some planes when the CG is that far forward they can barely take off at full throttle... if they can take off at all.

*Ajaer explains MAC better than I do (I know him from other forums)... I think he has the explanation in a doc to copy-paste.

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Another thing that can help with spin issues is tweaking the ailerons' centering just a bit to give wash-out (or cure wash-in). I have seen cases where one turn on each aileron clevice (you just about can't see that the aileron center is different) cured bad stall-spin characteristics.

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Finding what is the real issue is 90% of the problem in curing a plane of bad spin "habits".

[mrmike007]

Here is a question. Would any of those gyro's out there help stabilize a death spiral if in one?

[CNY_Dave]

A yaw (rudder) gyro might. Roll (aileron) gyro, probably not.

If the gyros were fast enough (roll or yaw or both) in might just keep it from going into the spiral, but it'd still be stalled and probably plummeting.

[mrmike007]

Yeah I was thinking if it was able to stop the spin before it got serious, you, the controller would be able to pull it out of a dive then only if time was on your side...(altitude). ???

[JetPlaneFlyer]

I've flown with a gyro and in my experience it's not going to help at all, in fact it might make it worse my masking the onset of the stall so you might not get the usual warning signs. Once a wing stalls it's going to drop into a spin and no gyro on earth is going to stop it.

The gyro would also tend to apply up elevator in order to try and lift the nose as it drops, which is the total opposite of what you want for stall/spin recovery

[CNY_Dave]

I still say a nice touch of realism would be a stall horn...