I miss the Propwash effect in CoD!

[TUCKIE_JG52]

There's an important effect that is missing in CoD I think: the propwash. Or if it's present, it's barely noticeable.

The propeller blows a stream of air into the tail surfaces, even when the plane is stopped. This is why in a taildragger plane, the usual procedure to taxi on the ground is to have always the stick pulled backwards to prevent propeller strike, so the propwash blowing into the horizontal stab makes a downward force that glows the tail into the ground.

This is perfectly noticeable in other simulators like Rise of Flight, and I expected this one here.


Well I know, the developer team is very busy by now. No problem, but please, it would be really nice that you model this feature, CoD will reach a next stage of flight model realism... please consider it for future patches!

Thank you! :)

[RAF74_Winger]

I agree. The tail forces are almost non-existent at low speeds, it's quite safe to put in forward elevator with take-off power at the moment.

Hope the devs find time amongst their other tasks to fix it.

W.

[Viper2000]

There's an important effect that is missing in CoD I think: the propwash. Or if it's present, it's barely noticeable.


I think that there is a propwash effect.

Take a Blenheim and try adding power without locking the tail wheel.

It doesn't have wash over the rudder, and so it's essentially impossible to hold it straight until it's going quite fast.

Since this turning effect happens even when the aeroplane is stationary, I would submit that it can't be P-factor, and I don't see how it can be torque.

So I therefore conclude that the swirling propwash is probably responsible.

OTOH, interaction between propwash and the ground may well be absent, since this is only a factor for a very small % of any given sortie, so it's easy to understand how it might be ignored.

I would caution that the degree to which the wash gets under the tail vs simply flowing around it varies quite a lot from type to type and also depends upon configuration, wind conditions and the ground attitude of the aeroplane. So it's not obvious what the correct behaviour should be.

I've operated 3 tailwheel types, and they varied considerably. The CAP10B seemed most likely to nose over, the Citabria felt somewhat more stable, and the Stearman didn't seem at any risk of nosing over at all. OTOH, it was extremely hard work to taxi on concrete because it combined yaw instability with a huge amount of lag in yaw. So by the time the nose started to move one way you already needed to be feeding in opposite rudder...

The other point worth making is that some types will actually auto-lock their tail wheel with full back stick, so you can't really taxi them properly with the stick all the way back.

IME the best policy is to be gentle, think ahead, and above all, fly the aeroplane from the moment you switch on to the moment you switch off. Getting too tangled up in type specific details puts you at risk of reverting to the wrong procedure under pressure. The classic warbird example would be applying takeoff rudder trim the wrong way when switching between Merlin and Griffon Spitfires. But I digress...

[RAF74_Winger]

I think that there is a propwash effect.

Yes, I agree it's there, but not nearly enough of it. The tail doesn't come up anywhere near soon enough on take-off; and try my standard demonstration (in the original IL2) of applying full power against the brakes with the spitfire and putting in full forward elevator. There's a reason why RAF fitters used to hang onto the tailplane while conducting engine runs on the ground. I notice that the aircraft will nose over with full power applied in CoD, but not without a significant amount of forward elevator.

The CAP10B seemed most likely to nose over, the Citabria felt somewhat more stable, and the Stearman didn't seem at any risk of nosing over at all.

Would you dare apply full power with the brakes on and put in forward stick with any of those though?

I suspect this is why the aircraft handle so sluggishly in the post stall regime, though I can't be certain of course.

W.

[Viper2000]

Would you dare apply full power with the brakes on and put in forward stick with any of those though?

Now you're getting into sim vs reality stuff.

IRL there's an awful lot of things I wouldn't do because I can't afford to make mistakes. New propellers and overhauling shock loaded engines costs money I don't have.

However, I suspect that if you were careful you'd be able to gently lift the tail with the brakes and power and suffer no ill effects in probably both the Citabria and the Stearman. Of course, that doesn't mean full forward stick.

The serious STOL guys do this sort of thing quite frequently. But they also end up bending their aeroplanes from time to time:

http://www.youtube.com/watch?v=YuE2cW8NMx8&feature=related