Strange P-39 stall - finally caught on film.

[Boozeman]

From time to time when flying the P-39, there is this weird stall that is almost unrecoverable - maybe some of you have also experienced it. Problem is, when i want to recreate it on purpose, I can't. I just can get the usual stalls like on most other aircraft, short and violent, but easy to recover. THis stall is different though. When in it, all controls are dead - pretty much like those stalls on the Mossie and 152, when they tumble down like a leave with zero airspeed. However, in this case the plane has enough airspeed, close to 200, but still dead controls.

So here is it, in all it's dreaded beauty:

http://www.netcologne.de/~nc-vreckova/p39stall.ahf

As you can see at 0:43, the stall sets on at about 200 mph, flips the plane a little, and then it drops like a stone all the way to the ground. Normally at this dive angle and speed, you can easily pull out... but not with this one - no reaction to elevator, rudder or aileron inputs.

Here is a another film:

http://www.netcologne.de/~nc-vreckova/p39stall2.ahf

Pretty similar to the first film. Wing flips at about 210 mph, controls go dead for about 2 seconds. As suddenly as they dissappeared, as suddenly they were back though. But one still think why did they go out in the first place?

Any comments on this matter or the films?




   

[ShrkBite]

It looked like when you hit 200, you started to get lit up. is it possible you could of lost your stab or tail even? otherwise, i got no idea.

[Soulyss]

Historically the P-39 was considered by many to a very tricky and demanding plane to fly, the pilot had to be really careful and deliberate on the controls or enter an accelerated stall.  There are certainly parts of Aces High's P-39 flight envelope that will bite you if you're not very very smooth and careful on the controls

It also had the somewhat controversial reputation to tumble, combat pilots certainly felt that it would and could however Bell test pilots apparently could never replicate it under test conditions. 

Charles King of the 39th Fighter Squadron flew P-39's and P-400's in New Guinea and had the following to say.

The P-39's handling characteristics have also come in for some criticism too.  However, I am convinced that the fighter did not "tumble", as been widely reported.  All tests to record a tumble were unsuccessful. It was easy to stall the airplane on it's back, with a resultant flat inverted spin.  In that situation, retarding the throttle would allow the aeroplane to drop into an easily recoverable normal spin.  Loss of altitude was minimal, but to a disoriented pilot with a control stick that seemed useless, this was not apparent.  The aeroplane oscillated slowly and horizontally as the noes dipped below the horizon and then rose above it.  To some pilots this was interpreted as a tumble.

Looking at the film but without the benefit of all the information (stall horn, control inputs, etc.) I would say that you just got into an accelerated stall.  It's happened to me more times than I'd care to admit to, and I think if you had more room a normal stall recovery would have worked.  Get the nose down, built some speed and pull out. 

[warphoenix]

From time to time when flying the P-39, there is this weird stall that is almost unrecoverable - maybe some of you have also experienced it. Problem is, when i want to recreate it on purpose, I can't. I just can get the usual stalls like on most other aircraft, short and violent, but easy to recover. THis stall is different though. When in it, all controls are dead - pretty much like those stalls on the Mossie and 152, when they tumble down like a leave with zero airspeed. However, in this case the plane has enough airspeed, close to 200, but still dead controls.

So here is it, in all it's dreaded beauty:

http://www.netcologne.de/~nc-vreckova/p39stall.ahf

As you can see at 0:43, the stall sets on at about 200 mph, flips the plane a little, and then it drops like a stone all the way to the ground. Normally at this dive angle and speed, you can easily pull out... but not with this one - no reaction to elevator, rudder or aileron inputs.

Here is a another film:

http://www.netcologne.de/~nc-vreckova/p39stall2.ahf

Pretty similar to the first film. Wing flips at about 210 mph, controls go dead for about 2 seconds. As suddenly as they dissappeared, as suddenly they were back though. But one still think why did they go out in the first place?

Any comments on this matter or the films?




   

acually the 152 goes into permeabillity which mean it aproaches mach 1 and the aircraft of ww2 controle surfaces weren't designed for such speeds

[Masherbrum]

acually the 152 goes into permeabillity which mean it aproaches mach 1 and the aircraft of ww2 controle surfaces weren't designed for such speeds

 

[Banshee7]

acually the 152 goes into permeabillity which mean it aproaches mach 1 and the aircraft of ww2 controle surfaces weren't designed for such speeds

 

[warphoenix]

after the plane  stalls

[Yossarian]

Do you mean compression?  That's what happens when your plane's controls seem to 'lock up' at high speeds.

[Ack-Ack]

acually the 152 goes into permeabillity which mean it aproaches mach 1 and the aircraft of ww2 controle surfaces weren't designed for such speeds

You're talking about 'compressability', as permeability isn't a word to the best of my knowledge and no, the Ta 152 didn't suffer from compressability like the P-38 or the P-47 did.


ack-ack

[mtnman]

Permeability is a word, but I'm not sure how it would be applicable here.

We measure the permeability of the food packaging we make at work.  In other words, we measure how much, and of what, can pass through our film.  A film could be semi-permeable, for example, and allow air or gasses to pass through it, but not water.   

[Spikes]

acually the 152 goes into permeabillity which mean it aproaches mach 1 and the aircraft of ww2 controle surfaces weren't designed for such speeds

[rabbidrabbit]

acually the 152 goes into permeabillity which mean it aproaches mach 1 and the aircraft of ww2 controle surfaces weren't designed for such speeds

Not only are you wrong but WTF does it have to do with the p-39?

P.S. spelling... it's just a click away.

[Captain Virgil Hilts]

acually the 152 goes into permeabillity which mean it aproaches mach 1 and the aircraft of ww2 controle surfaces weren't designed for such speeds

 

[Widewing]

acually the 152 goes into permeabillity which mean it aproaches mach 1 and the aircraft of ww2 controle surfaces weren't designed for such speeds

I suggest a Google search on Permeability.... Or, even a check of Wiki: http://en.wikipedia.org/wiki/Permeability


My regards,

Widewing

[Motherland]

You'd better listen to him guys, his uncle taught him all about the permeability of the Heinkel Do 152, and he knows his stuff. He was a P82 pilot over Japan, after all.