GarySS

My Feedback: (13)

Hello,
I'm looking for some ideas for control horns to link the upper and lower ailerons on a bipe of about 60 inch wing span total. I've reviewed the GP Skybolt ARF manual and they say to just chop a standard plastic control horn down to one hole and then use a wire pushrod. Is there another control horn that is more substantial/ elegant/ scale-like that I can use 4-40 hardware and maybe cover the rod with aerodynamic brass tubing? I'm looking for a solid connection as well as a scale appearance.
Thanks!!!!!!
GarySS

jetmech05

that is the same set up on many bipes...the Goldberg Ultimate for one.....I put my pushrod for the upper and lower ailerons right behind the wing struts.....never have had my come loose and believe it or not it doesn't look bad...
Good Flyin

da Rock

Skybolt, you say?

I wouldn't put much faith in the GP Skybolt ARF manual on how to rig paired biplane ailerons.

Any time you have staggered wings on a biplane you run the risk of having screwed up throws on the slave aileron. This setup solves that problem on mine.

A 60" span biplane is a decent sized model. That might be a good reason to go with 4 servos.

Why cover the rod? Why not use shaped tube? There is shaped aluminum tubing available in LHSs already. You want to keep the weight down for sure. Surfaces are usually balanced with weight AHEAD of the hinge line to counteract flutter. Putting more weight aft of the hinge line is just the opposite. Don't think I'd use brass or an extra part (cover) or such. Go lighter and use less hardware. I'd really look harder at 4 servos.


BTW, I made the horns on my Skybolt out of the supplied horns. Cut off the base and epoxied the horn part into the aileron. Lighter, stronger, less slop, no differential throw introduced. (Elegant?)

GarySS

My Feedback: (13)

Thanks DaRock........have you had flutter with interplane connections before? I do like your smoother way of installing the Skybolt horns. They look like they are in the same postion as in the instructions????.....

Stickbuilder

Look in the Vintage and Antique Forum under Waco YMF. In the almost 300 pages, you can see several of them.

Bill, AMA 4720
WACO Brotherhood #1

da Rock

Flutter?
Nope, but I've never used more hardware than you see in the picture above. Less hardware means less weight. And fewer points where slop can happen. Slop is most often the cause of flutter. Heavier surfaces isn't usually a major cause, but no reason to push the issue.

Smoother way of installing? I like the lighter weight, stronger attachment, and reduction in number of places where slop can happen.

What I really like, after having flown a couple of other modeler's Skybolts that were built as the ARF mfg suggested, is the way mine flies.

Same position as in the instructions? Look at the instructions for where the connecting rod will attach for both bottom and top ailerons. Where is the top attached? Underneath the aileron. Where is the attachment in the picture? Above the top aileron. The attachment here shows the layout for two different riggings. Notice that both show where right angles at each connect point wind up going. The accepted direction is for the right angle to go directly to the hinge line of the surface. When the right angle doesn't, the surface does not move uniformly. It will move less or more than the servo tries to move it. That happens to be how experienced modelers rig to get differential ailerons (where one move appreciably more than the other in one direction and the opposite difference in movement in the other direction). The 2nd picture shows the different amounts the ailerons move on a Skybolt with the OEM rigging. With the rigging shown in that earlier attachment, all 4 ailerons move the exact same amount up or down. With the OEM, when both lowers move 20degrees, one upper moves 23degrees while the other moves 26. That's 3 different aileron deflections at the same time.

GarySS

My Feedback: (13)

Thanks Da Rock! You should be a senior professor in the University of Biplanes!!! This is planted in my references.
Best Regards, GarySS

da Rock

Thanks, and you're welcome..........

Keep in mind that our models will fly with some really horrendous rigging, balance, alignments, and such. It's truly amazing how awful some models are that fly "perfectly" in their owner's eyes. And there usually is really no way to prove any difference in performance between one model and the other. A bunch of our smaller biplanes like the Skybolt and WM's Ultimate and such prove it every day. Their owners are happy as flies on a pig's lips with the models and rigging. And I'm almost that happy with mine. (pig's lips ain't my preference)

There is a guy at one field I fly at with a Skybolt rigged by the mfg's book. He is positive that our two Skybolts fly the same, neither better than the other. He also believes you have to watch out or "Skybolts" will snap out of some maneuvers and landings are just a bit touchy. I don't. Could be the aileron rigging or better trimming. We'll never know for sure.