"Wiggly" Rudder

I had the pleasure of flying with some of the OKC crew yesterday, and saw a Nobler with an articulated rudder. I think I read someplace that Al Rabe was one of (if not the) first to do this. Anyway, while I understand the principle and the reason, I didn't have the chance to sit and examine how it was done -- the pilot was getting ready to fly and I'd just shown up as a complete stranger. I apologize, but I've forgotten the pilot's name, but all there (Mike and Larry, I think) were very accomodating.

Anyway, it looked very clever -- more clever than I am -- and I was wondering where I might find posts or articles (with drawings) that I could look at to figure out just how it's done. Does anyone have a lead?

Im sure there have been pictures etc in Stunt News but you might start by searching "Rabe rudder "on this forum.That'll keep you busy for a while.Keith V

Yep the wiggle rudder was developed by Al Rabe and often refered to as the Rabe Rudder. Do a search for "Rabe Rudder" and check the all words box. You should come up with plenty of info..

Kewl. I'll exhaust myself on "Rabe Rudder" and, by then, I'll probably know more than is good for me.

Thanks!

They work great. I put them on numerous combat and stunt planes.

No so complicated.

1. Make sure the control horn is on the BOTTOM, OUTSIDE part of the elevator. If not, no problem, just add an extra horn there.

2. Put a ball link on the elevator horn.

3. Connect the ball link to the rudder with a short pushrod.

4. Use trial and error to adjust the system to where there is very little rudder movement on UP and a heck of a lot on DOWN.

Think about how big to make the rudder too. If it looks scale, it is probably too big. Roughly 1x3in. is about right for many ships. I once tried a wiggly rudder on a Twister. Made it full size. It would cock the plane 20 deg. out on the outside square corners.

I added one to my latest and greatest. It worked very well for settling down yaw motions in the sharp maneuvers. Never could get the leadouts and fin trimmed to eliminate yawing. Al's rudder worked first time.(got lucky on the rudder size and movement)

I understand what a Rabe rudder does, but have never understood how to set one up the way everyone else does. I've had them on two Twisters. In the first one I made, I put a strip of wire down the inside edge of the outer elevator, with a space between it and the elevator. I made a roughly U-shaped piece of wire running in the space between the elevator wire and the elevator. The ends of the U were atached to the rudder. The U was formed so as to give about 1/8 inch of out on full up and about 3/16 of out on full down. There was a photo in one of Danny Dirt's columns in Model builder. I can find the issue if anyone cares.

On the second Twister, I stuck a small nail in the trailing edge of the outside elevator, and another in the trailing edge of the elevator. I tied a piece of fine wire between them such that I got movement as described above.

Kim,

The movable rudder is explained in great detail in the 2001 Nov/Dec issue of Stunt News. the article includes a photo which shows all that you need to make the thing work.