Rudder effects

[Tony Oliver]

Here is a question which always provokes more questions than provides a definitive answer. I ask it because despite many years of using the procedure, I'm still not sure what the answer will be in all situations :-

If a rudder/elevator thermal soarer is in strong lift and you want to bring it down safely without excessive speed, or overstressing the wing, it is a simple matter to fly the model down INVERTED. When you do this, why does the rudder work almost invariably the same way as when it's the right way up? ie even inverted, left rudder on the stick will turn the model left, and vice-versa.

Most people don't believe it, so why not try it? There's often a slight opposite turn , hesitation, then reversion to the direction of the stick movement.

I'll be very interested to hear opinions and the result of tests.
Please do it at a safe height, and don't bend your model doing it!


Cheers

Tony

[shoe]

I'm gonna guess that this would only happen on a model that had a significant amount of polyhedral. The rudder causes a yaw and then the inverted polyhedral creates a roll in the opposite direction that's why the delay. A very uncoordinated turn at best but I imagine the roll eventually overcomes the yaw.

[Tony Oliver]

That's my guess too Andy - which is why I specified rudder/elevator models. However it still works so long as there's even a slight amount of dihedral. It's a little wierd to say the least.
Tony

[ramair]

i agree with the last two posts,the glider with poly etc naturally wants to go threw the air with the least amount of resistance,which is right side up.here is something to try;;;go inverted,,hit the rudder left,,as soon as you see a reaction hit full right rudder,,,,you can almost flip it over in a very strange manner!
on a differant topic,my [over powered] glow plane,if i want to climb better,i go inverted because it produces more lift[[and drag] inverted,i have enough power to over come any extra drag but i can take advantage of the extra climb rate,,,,,who knows maybe [with enough power]a fridge would climb well????

ramair p.s. i said climb well,,not fly well!!