P40 Slinky Wings?

[Chilli]

I am very interested in what causes my cartoon P40's wing act like a slinky    I intentionally fly without the stall limiter, so it is obvious that at slow speeds I would stall.  What I am asking, is when I am recovering from a stall, would the wings actually rock back and forth violently, or would it tend to stay in a spin or tilt to one side?  After many adjustments to my joystick input I still get the feeling that response from my controller is "sluggish" or at least appears to be.

[SectorNine50]

The E has a pretty nasty stall characteristic, however I'm not really sure what you mean by "slinky..."  Have any film of it by chance?

[Chilli]

Let me know if the link works.  This is the first attempt at using the widget.   

This is not a severe example but at the end of film and whenever speed is about 100 mph or less, and in a stall the wings rock back and forth like I am over correcting, and then the result is loss of altitude.

http://gruppeoutlaws.50megs.com/box_widget.html  From the link click on AboveSlinky.afh and download While there feel free to checkout the site and blog... some good photos of past and present Outlaws, WW2 aces, and a cool film of WW2 footage in the blog area.

This is NOT a whine, rather a question as to whether or not it is my controller input settings, or just by design of the in game stall characteristic?  Obviously, if I kept my speed above 100 mph I can avoid it.  However, I often have to chop throttle and do sharp maneuvers to try and shake enemies in pursuit.

Also, an opportunity here, for anyone to chime in with some good advice on P40 maneuvers to reverse someone on your 6.

Thanks all. 

[SectorNine50]

Yeah, I've had that happen to me in the P-40E before, can be pretty hard to control.  The video makes it look like you use your rudder a LOT.  I'm not sure what your set-up is (pedals, twisty-stick, keyboard) but try to minimize your rudder in turns as the sliding can cause your wings to lose lift in certain situations; make you rudder movements smooth and deliberate.

Also, was it just the film being weird, or were you flying around at full flaps the entire film?

[Chilli]

I will take a look at the film again but yes, I was using an extraordinary amount of flaps to recreate a stall condition.  Also, yes I do use a lot of rudder and use a twisty stick.  I will take your advise and try to dial that back.


  Thank you very much 

[dtango]

You're experiencing a slow speed alternating assymetric stall.  The wing rock is probably caused by your attempt to recover by pulling back on the stick in trying to arrest the nose down pitching (as evidenced by your accelerameter).  Pulling back is causing the other wing to stall and to stall more than first wing causing the aircraft to roll the other direction.

Stalls occur when you exceed the wings critical angle of attack.  Particularly in the stalls you induced to the right you're stalling the right wing but not the left.  When you try to correct by pulling back on the stick you increase aoa which causes the left wing to exceed critical angle of attack and stall.  The stall is more pronounced than the right wing and thus you're airplane rolls to the left.  The rock back and forth occurs with you trying various ways to arrest the motion by elevator input which makes the situation unpredictable because of the aoa you're introducing with elevator.  Because you're flying at slow speeds and already at th e ragged edge of flight and near critical aoa, any elevator input can put you beyond aoa for normal flight and thus stall.

Hope that explains it.

Tango, XO
412th FS Braunco Mustangs

[Chilli]

(edit)  The rock back and forth occurs with you trying various ways to arrest the motion by elevator input which makes the situation unpredictable because of the aoa you're introducing with elevator.  Because you're flying at slow speeds and already at th e ragged edge of flight and near critical aoa, any elevator input can put you beyond aoa for normal flight and thus stall.

Hope that explains it.

Tango, XO
412th FS Braunco Mustangs

Yes it does explain it very well.  Thank you very much.  I picked the P40 as the example even though I also get a similar reaction in other planes as well, but P40 seems to loose altitude in those situations a bit faster.  I guess I need to really pay attention to that stall buzzer (smacks forehead).

Thank you both for really good information and advice.  All in all the P40 is a fun plane to fly.

[Shifty]

Chilli,

Burn the main tank off first and fight on the fuselage tank. It helps cut down on the wing rock for me. YMMV.

[Chilli]

Thanks Shifty,

That's a good one.  I used to pay attention to fuel tanks, but didn't realize that the main tank I assume makes the wings heavier. 

I used to burn the tanks in ponies, etc. that were labeled LW and RW hoping for better stability.

[caldera]

Yesterday was my first day flying without the stall limiter on and my p-40 had the wing rock big time. A very helpful pilot named Avaro gave up a couple hours of his time to spar with me in the duelling arena. He said you've got to go much lighter on the stick and scaling your stick might be a good idea too.

[Geophro]

For some reason I could not see the cockpit view, nor any control surfaces moving in the entire film.
Still, I can see two things.
First, that was definitely PIO, not a natural tendency of the airframe.  Tango explained that part well.
Also, the amount of nose wobble went beyond just roll induced yaw.  Back in my twisty stick days, I had to put a reasonably large deadband into the rudder so that in the heat of battle, I wasn't unintentionally giving rudder inputs.  Someone suggested that at every opportunity, I should release the stick.  When I did so, the nose would invariably slew some back to neutral.  That got better with the larger deadband and more practice.  It (almost) went away completely with pedals.  Remember, yaw-roll coupling works in both directions.

Now a little more on the stall characteristics of the P-40E.  It definitely has a vicious accel stall, but it's low speed stall characteristics are relatively benign.  It will give you a little wing wobble and buffet telling you that you have gone too far before it actually departs.  Simply release a little back pressure on the stick, and everything is fine.  If you have the stick planted in your belly, you will go from controlled flight into the beginning of stall, right through the buffet/wobble and straight into departure faster than you can pucker.  Also, do not stand on the rudder to try to catch and hold the nose.  That works for many AH aircraft, but the P-40 doesn't have the power to weight ratio to pull that off.  When you are riding the stall, you MUST ease forward on the stick before adding any aileron or rudder, otherwise you leave your energy-maneuver envelope and get what Tango described.  Once in the stall, the recovery is like any other aircraft.  The only cure is airpeed over the wings.  So, unload, unload, unload.  The stick should be no farther back than neutral, and get off the ailerons and rudder.  You can't just snatch the P-40 out of trouble like a spit or zero. You either have the altitude to recover, or you don't.  And it does not matter what your opponent is doing, at that point your only enemies are Mean Mr. Gravity and Hard Mr. Ground.  The sooner you unload, the better your chances become.  Once you start getting some speed, you can ease in some control inputs to start to arrest whatever flavor of stall you happen to be in.  In the P-40, that means eventually you will learn how to fly under trees to complete the recovery.  Watch out for the squirrels.

When heavy on fuel, the already poor power to weight obviously gets worse.  I used to fly the P-40 a lot, and 100% fuel was simply too difficult.  I'm sure people with better skills can manage that heavy, and I used to practice at 100%, but I never even bothered trying to fight at 100%.  At 50% fuel, the P-40 actually comes to life, and at 25% and a notch of flaps you can surprise the crap out of a bunch of people.  So try 50% + DT and you get 100% fuel range if needed and a 50% fighting weight.

So in summary: larger rudder deadband, smoother on the controls, and less fuel.  Good luck.