Hi,

I have always flown a simple polyhedral sailplane with rudder and elevator (no ailerons). Part of my goal in getting a sim (AFPD) is to try to master ailerons before getting a sailplane that has them. No training help here, I'm on my own.

Everyone talks about coordinating turns with rudder and aileron. Is there a simple rule for how this is done? I find that sometimes I am doing rudder with the turn, sometimes against it. Same with ailerons. Seems to depend on whether the turn is going "too far" and perhaps on the plane.

Also, what sort of bank angle is appropriate? The AFPD planes anyway, seem to want to bank pretty steeply when aileron is applied -- I end up applying aileron, then elevator, then backing off aileron, then adding in rudder (more or less in that order).

Cordially,

Eric

Sounds to me like you know already what to do. It's a really simple setup where you just utilize both to get the specifik bank angle and turn radius that you need from the plane at the time. Like when you're really low with a sailplane you'd want to get a really tight turn so you can get into the bottom of the thermal where it is tight. So in that case most of the time you would be cross controlling so you can get a tight turn but also keep the bank angle at a minimum to get the most of the minimal lift. Experiment with it, but it sounds like you already got it all figured out.

Wish I had it all figured out already!

When you talk about cross-controlling in your post, do you mean with the turn on rudder (to get the tight turn), and opposite the turn on on aileron (to keep the turn flat)?

Thanks,

Eric

p.s Enjoyed your post on "how to" thermal with AFPD

Well yes exactly that. You would turn left on the rudder which is also the primary turn direction. But then use the Aileron to keep the wings at the right angle. Obviously mostly all planes will roll with rudder input. So if you want to keep the rudder in there you will have to compensate a little with opposite aileron. Also keep in mind that keeping the wings absolutely horizontally is not at all the idea. Just a comfortable angle for the model. And well obviously depending on what you are doing. Whether it's catching a low thermal or just plain doing a steep turn.

The thermal thing on AFPD must have helped I got my first spec out with the Electra the other day. A good 40 minute flight (I retired after serious neck strain). And well in actual fact it did spec out, for about 20 seconds we couldn't see or find it. LOL

Congratulations! The first plane I built (never completed) was a Gentle Lady in high school. A beautiful plane.

Here in Vermont, the soaring season (such as it is) is pretty short, we rub our hands together and wait for spring (which comes in June).

Cordially,

Eric

A few thoughts;

I usually think of rudder and aileron as two different and independent control surfaces.

Ailerons. You use ailerons to set the bank angle. When you've reached the desired bank angle, move the stick back to neutral and make small adjustments to keep the bank angle constant. Higher bank angle -> tighter turn. Up elevator is required during the turn to keep altitude constant.

Rudder. Have you flown a real plane? If you have, you have probably noticed that you can feel whether the turn is coordinated or not. In a perfectly coordinated turn, you will feel like your body weight pulls straight down into the seat. Too little rudder, and you will be pulled "into" the turn. Too much rudder, and you will be pushed "out of" the turn. Rudder is used only to keep the nose and tail in the same line during the turn, to avoid skid/slip. Turn rate is not controlled by rudder, but is a secondary effect of the rudder. (Which means that you can make a turn tighter by applying more rudder, but then the turn won't be coordinated).

ehart: I've also gone through my fair share of gentle ladys in my past. I've built a couple and owned a few more also in my high school flying period They are great little planes and used to be very cheap to get in the air. Fortunately for us here in SA we have good weather all year round except for maybe August when the winds start creeping in. But no snow to worry about in winters.

Sandal: You are absolutely right with everything you said. Fact is when I fly power planes I hardly ever mess with rudder for just a normal turn. But ever since I got busy with gliders and 3D flying the rudder started working in some very strange ways. Fact is that the topic at hand relates to gliders and thermal soaring in particular. I have very limited experience with thermal soaring but I shared what I have found up untill now. For me it works very well to cross control in very low altitude lift. Seeing as the thermals are also small in these areas it's helped to get the wings as flat as possible and obviously you need to get the turn radius to a minimum to get anything out of the limited lift. So in these scenarios I most of the time rely on alot of rudder and then some opposite aileron to keep the bank angle low. Some elevator also comes into play obviously to resolve the coupling and get the glide path/ratio right. I know the word coordinated also is mentioned in the topic so this is what I figured up untill now. You are right about the G forces having different impacts on you if the turn is not absolutely perfect. But sometimes we want to juggle those to get the best performance out of the model.

Spacey,

I agree with you. There are quite a lot of situations where we don't want coordinated flight. One example is thermal soaring, but I also thought of side slipping with powered airplanes, to slow down and increase sink rate (landing approach). Real planes without flaps often use this method, and I think it works well for models too.

Ahh yes that's also a good example of utilizing both controls. Funny how we can manipulate the plane in sooooo many different ways to our advantage with simply 4 controls. It really gets interesting when flaps, camfer control and all that funky jazz also gets dropped into the equation.

Thanks folks, this is very good information. Spacey, your comments help me understand why I felt I was losing too much altitude in my turns (banking too much). And Sandal, I was treating ailerons like rudder (where you have to hold the input to keep the turn going), and of course, you're right, I should be *initiating* the bank with ailerons, then returning to neutral (more or less) to keep a steady bank angle.

Thanks to you both, I will practice these suggestions.

- Eric