Subject: Flight Model Question

Newsgroups: warbirds.general

In a previous existence, I had the opportunity to learn to fly around in sailplanes (A wonderful way to spend a day). In this previous life, I learned that when I applied ailerons, no matter what the wing angle to the horizontal, I had to apply a little rudder in the same direction because of aileron-induced drag. In other words, suppose I am in a right turn, wings banked right, etc. If I want to resume level flight, I apply a little opposite aileron (in this case, left) and also a little opposite rudder to counteract the ailerons induced drag (which in this case would be a bit of left rudder). Do this, and you resume level flight in a nice, aerodymanically clean matter with no slipping. Don't apply that little bit of left rudder, and you resume level flight, but that little bit of yarn tied to the pitot tube in front of the windscreen would indicate that you were slipping a bit as you did so.

Now the question. When I do this in my nice, powerful Warbirds machine, I find that applying opposite aileron doesn't give me aileron-induced drag. In fact, I find that I don't even need rudder until I am in the bank and starting the turn, at least that is what the ball and the little green pip over my sight claim. Now, I haven't got much experience in the flying of real world powered aircraft (let alone overpowered WWII fighter planes), so maybe they really do handle this way, but if so, would someone with more experience than I tell me that is the case and let get some sleep at night? Or is this a minor defect in the flight model as we currently have it?

Thanks,

Doug Hansen

"warmut"

From: "BD"

Newsgroups: warbirds.general

I also am a sailplane pilot, with some power time as well.

The effect you describe is known as adverse yaw. It is especially pronounced in sailplanes because of the length of the wings, which give them a longer moment arm (more leverage) Also, the ailerons are frequently proportionally larger on a sailplane.

The effect does occur in power planes, but is often almost unnoticeable, especially at higher speeds. When flying power, I have a tendency to overuse the rudder. I find myself having to watch the rudder input carefully, since too much rudder in a slow turn can cause the inside wing to stall, resulting in a spin. Airline pilots will tell you that they almost never use the rudder in a turn, even with the yaw damper turned off.

Adverse yaw is modelled in WB, but I have no idea how accurately, since I am still waiting for my P-51 to be delivered.

From: "Finn"

Newsgroups: warbirds.general

I just got my solo student glider permit this summer. Starting powered flight training this week.

It seems to take more rudder in general in gliders. My very small experience agrees with yours. :)

Finn

From: Wells Sullivan

Newsgroups: warbirds.general

I think that because sailplanes have really long wings and the ailerons are WAY out there...you get the effect more. It is modelled in WB. Fly a Fw-190 and you should notice it. It may not be as noticeable on a computer screen, cause you can't really feel anything and your perspective isn't the same either (the screen is much smaller than your view in real life, so any small changes in heading are less noticeable).

From: "Bjornar Svingen"

Newsgroups: warbirds.general

Another thing is that most planes (at least GA planes) have measures to reduce adverse yaw. It can be unequal throw on the up and down movement, for the same input the aileron that goes up goes let say 10 degrees while the one that goes down only goes 2 degrees (just examples). Since only down deflection will increase drag (higher effective aoa) you don't want all that drag producing adverse yaw. Another commonly used measure is to make the aileron and hinges so that a small part of the aileron that go up, also goes down. The part that goes down only produces drag, so that the drag will be more or less equal on both sides. And you can combine some of them.

I really don't know how it was done on the WWII birds, but I would guess they had some of the same things as GA planes have today??

On gliders you will reduce drag as much as possible, so drag producing devices is not used (I would think), and the long wings certainly doesn't help.

From: Wells Sullivan <general6@iaw.com>

Newsgroups: warbirds.general

Most fighters do use the techniques that you mention. The Spitfire has 'frise' type ailerons, where the hinge line is back a bit, so that when an aileron goes up, the leading edge of it goes down a little. The ailerons also went up more than down.