Quote:
Originally Posted by 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.
|
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...