Flying the rudder in thermal turns

[Steve P]

I was talking with one of our flying friends about how the heck some of us make so many low slow turns working low lift or when lingering at the end of the runway all while flying such large span sailplanes. The answer? The rudder. It’s essential in clean thermal flying. And, cross-control for not snagging a tip down low. ;-)

As a long-term reference for the forum, I'm posting a link here to an old but excellent article by Mark Drella that has lived for years on the CRRC website...

http://www.charlesriverrc.org/articl...rmalFlying.htm

A great read.

[JimD]

Carrying this a bit further...

A) The rudder, in its purest sense, causes rotation around the vertical axis that runs through the center of gravity.

B) An airfoil produces lift by creating a pressure differential as air flows over the differential curves of the top and bottom of a wing.

C) This differential remains when air flows from back to front over the wing.

D) Therefore, the pure application of rudder at low speed can cause the sailplane wings to rotate around the vertical axis much like helicopter blades thus allowing the sailplane to hover!

proof:

If A= B and B = C then A = C

Now let the Fun begin! 🤓

[JimD]

Please read the above with your sense of humor fully engaged! 😉