Thanks for the responses, guys!

Bruce,
Yeah, I admit it. I'm a sucker for a catchy phrase. All of the "tricks" you mention are things that I'm familiar with and have seen "at the races" so to speak. I haven't seen a lot of aluminum wheels lately; most guy use what we call "pizza cutters". These wheels are the min diameter and are made of the same material as bowling balls. When viewed from the edge, they are diamond shaped -- .25" thick at the hub tapering down to about .0625" or less at the outer radius. And the hub countersinks into the wheel! Pretty nice really.

You're also correct about filing an airfoil on the gear. Man, that IS a lot of work! That is the part I dread most about putting together a new racing plane. I am usually content to just round the edges everywhere I can on the gear; getting the aft edge down to a sharp TE for a proper airfoil just takes too much work! Now we have CF gear available that is already shaped. I keep meaning to get a set or two to try but never seem to get around to it.

Ben,
That's a good explanation that I haven't heard before. Thanks! What do you think about wheel pants? I think that when the rules allow, using pants is to the racer's advantage even when you pay the small weight penalty. Of course, since Q40 is supposed to be a scale event, you can't put pants on a plane when the originals didn't have them. Any of the P51s--Foxy Lady, Miss Ashley, Red Barron or planes like the Napier Heston or Caudron or Firecracker for example.

Any thoughts about how to optimize the design of wheel pants?

Some of the other "little" things we do that add up... Yes, all linkages are concealed. "Skin" hinging techniques where there is no visible hinge line on the top surface of a control surface. Sealing the underside of the hinge line on the bottom of the surface. Fudging the wing tip shape to try to minimize the vortex. Area rule fuses etc.

There is another thing that I'm not sure about... The RX on/off switch. What would be the best way to reduce drag for this necessary item? There really are just two popular ways that guys are handling this. First is to have a small piece of music wire that protrudes through the side of the fuse that you can pull for "on" and push for "off". The other thing I've seen is to drill a small hole through the switch knob, thread a fine piece of fishing line through the hole and knot it, then have the line exit both sides of the fuse. Then you pull on one side for on, and pull the other side for off. This requires about 3" of line exit each side so you have something to grab. So you have about six inches total of this fine fishing line flapping in the breeze. This compared to about a half inch of music wire for the other method.

Which of these methods would you say is more advantageous?

Thanks again guys!