08/12/2026
Hello MCMC members.
Thought I might try and tap your combined knowledge banks on an issue I'm having.
Building Frank Zaic's rubber powered Utility Special from his 1937 plans. I enlarged the plans 25% to a 30" wingspan and I'm converting it to park flyer RC. This is a build just for sport flying.
My issue is how to do the rudder control with the twin rudders. Now that I have it framed up (life size so to speak as opposed to just lines on paper) I've found that there is very little room to install any kind of bell crank or mechanism of whatever type. On top of the minimal fuse space back there, the control rods would also face interference from the elevator movement.
Unless someone has a truly great idea to solve this, I may have to resort to doing a "Connie" on it and add a third rudder in the middle to have a direct control rod connection from the servo.
Question 1a, I'm not an aeronautical engineer. Will I have unintended issues adding a third rudder? Such as should I decrease the size of the exterior rudders? Enlarge the middle rudder? Leave them all the same size? Holy Crap. Can my one issue lead to multiple others!?
I am attaching four photos.
A look at the original bare bones.
A look at my structure to date.
A close up of the empennage.
A look at the empennage, sighting down the stab/elevator.
Any suggestions would be greatly appreciated,
Ted
