The P-40 hates me (mysterious stalling behavior)

[Demetrious]

Hello all,

Recently I've taken quite a shine to the P-40 in all it's iterations- the speed is somewhat lacking but it's roll rate is excellent and it seems capable of handling pretty much anything well (as long as you can sucker that FW-190 into a turn fight, that is.) There's just one little thing that has been driving me absolutely nuts.

The P-40 has an alarming tenancy to flip over and faceplant right into terra firma for no reason at all. This happens generally as I'm making a rather smooth (and not hard) turn, at around 150 MPH, or as I'm pulling out of a loop, at speeds of up to 200 MPH. She seems to want to roll left and stall, making me think it's an effect of torque, but sometimes she's okay with jerking around to the right, too. For reference, the P-40's stall speed is 90 MPH, and this phenomena is constantly observed at modest angles of attack- or no angle at all.

Naturally, this likes to strike just as I've won the rolling scissors or the like, and will unceremoniously flip my bird over and SLAM it into the earth just as I try to gently and smoothly take up a leisurely lag pursuit. As you may imagine, this makes me so mad I can barely breathe sometimes. Now, I've noticed this behavior consistently in both Aces High and IL-2 Sturmovik, so clearly I'm doing something wrong. I just can't imagine what. Do I need to give her some rudder opposite the direction of torque when undertaking maneuvers? Is torque in this bird worse then normal?

[Anaxogoras]

I was practicing in the P-40 last week for FSO, and I can confirm that it will snap roll if your angle of attack is too great.  The best thing you can do is simply not pull back so hard on the stick.

[Demetrious]

I was practicing in the P-40 last week for FSO, and I can confirm that it will snap roll if your angle of attack is too great.  The best thing you can do is simply not pull back so hard on the stick.

It's snap rolling with very low, gentle control input and very modest angle of attack- sometimes with no angle of attack. This starts around 150 MPH, which doesn't make much sense to me, because the P-40 stalls out near 90 and has always been described (in Real Life and in AH) as a good handler at low speeds.

[Anaxogoras]

It's snap rolling with very low, gentle control input and very modest angle of attack- sometimes with no angle of attack.

You're grossly exaggerating here.

[Demetrious]

You're grossly exaggerating here.

Not at all. This exact situation strikes, usually, when I'm coming out at the bottom of a short dive (having gone perfectly straight,) and the instant she feels control input, she snap-rolls. The other common scenario is just after I've won the rolling scissors, and my foe is trying to turn away. At about 130-50 MPH, just hanging there in the sky, having held her steady for at least two seconds with no AoA at all, as soon as I try to roll left/right and pull into a gentle lag pursuit (and I do mean gentle,) she rolls. Not a snap roll in that situation, but a nasty little lurch to the left (it's almost always the left, no matter which way I turn,) that requires heavy rudder and time to address, which lets my enemy slip away. The constant leftwards tendency is what makes me think it's some kind of torque effect.

[jerkins]

Film?

[Demetrious]

Film?

I'll see what I can do, though it might not tell you much. Obviously the ship shouldn't be quite so prone to rolling, so I was expecting somebody to tell me that my joystick scaling is out of whack or the like. Or perhaps I need a bit of rudder in my turns.

As I said, this phenomena also appears in IL-2 Sturmikov, which has a flight model reasonably close to AH, so the fault clearly lies with something I'm doing.

Nobody minds mediafire for the hosting, I hope?

EDIT: Nevermind, I think I've solved it. I went to play with my joystick scaling and lo and behold, the X-axis didn't have scaling enabled for some funny reason.  Just an idiot, nothing to see here, move along...

[Krusty]

If it dipped one wing then flipped to the other, it sounds like maybe an accelerated stall (because you mention pulling out of a dive)


Keep in mind the P-40 will spin out pretty easily (not as bad as the P-39), so you have to watch her in rolling scissors, loops, and I don't recomment hammerhead manuvers at all. By the time you recover your enemy has killed you.

[Anaxogoras]

EDIT: Nevermind, I think I've solved it. I went to play with my joystick scaling and lo and behold, the X-axis didn't have scaling enabled for some funny reason.  Just an idiot, nothing to see here, move along...

You must mean the Y-axis.

[CAP1]

Hello all,

Recently I've taken quite a shine to the P-40 in all it's iterations- the speed is somewhat lacking but it's roll rate is excellent and it seems capable of handling pretty much anything well (as long as you can sucker that FW-190 into a turn fight, that is.) There's just one little thing that has been driving me absolutely nuts.

The P-40 has an alarming tenancy to flip over and faceplant right into terra firma for no reason at all. This happens generally as I'm making a rather smooth (and not hard) turn, at around 150 MPH,as the angle of bank increases, so does your stall speed. almost sounds like you're getting a departure stall. or as I'm pulling out of a loop, at speeds of up to 200 MPH.this one, you may be exceeding the critical angle of attack, and stalling the wing. She seems to want to roll left and stall, making me think it's an effect of torque, but sometimes she's okay with jerking around to the right, too. For reference, the P-40's stall speed is 90 MPH, and this phenomena is constantly observed at modest angles of attack- or no angle at all. don't forget.....the angle of attack as far as your airplane is concerned is to the oncomming wind. thus, if you're in a 40 degree dive, and yank the plane to a 20 degree dive suddenly, you've just exceeded the wings angle of attack.

Naturally, this likes to strike just as I've won the rolling scissors or the like, and will unceremoniously flip my bird over and SLAM it into the earth just as I try to gently and smoothly take up a leisurely lag pursuit. As you may imagine, this makes me so mad I can barely breathe sometimes. Now, I've noticed this behavior consistently in both Aces High and IL-2 Sturmovik, so clearly I'm doing something wrong. I just can't imagine what. Do I need to give her some rudder opposite the direction of torque when undertaking maneuvers? Is torque in this bird worse then normal?

[CAP1]

It's snap rolling with very low, gentle control input and very modest angle of attack- sometimes with no angle of attack. This starts around 150 MPH, which doesn't make much sense to me, because the P-40 stalls out near 90 and has always been described (in Real Life and in AH) as a good handler at low speeds.

also.....is that 90 mph stall speed clean, or dirty?

[Saxman]

IL-2 Sturmikov, which has a flight model reasonably close to AH

 

[Rebel]

What flight controller are you using? 

Wings level, if you pull back on the stick hard enough, it'll snaproll neat as you please.  But only if you pull back hard- or have a spike.....

[CAP1]

What flight controller are you using? 

Wings level, if you pull back on the stick hard enough, it'll snaproll neat as you please.  But only if you pull back hard- or have a spike.....

yes...that is creating the departure stall. the wing is at that point exceeding the critical angle of attack.

[Traveler]

The P-40 has an alarming tenancy to flip over and faceplant right into terra firma for no reason at all. This happens generally as I'm making a rather smooth (and not hard) turn, at around 150 MPH, or as I'm pulling out of a loop, at speeds of up to 200 MPH. She seems to want to roll left and stall, making me think it's an effect of torque, but sometimes she's okay with jerking around to the right, too. For reference, the P-40's stall speed is 90 MPH, and this phenomena is constantly observed at modest angles of attack- or no angle at all.

As everyone so far has eluded to, but not yet stated in the clear, It’s not the airspeed, a stall is totally dependent on the Angle of Attack (AOA) of the Relative Wind (RA) and not the speed of the aircraft.