dmax64

I'm Building a Weeks Solution X Biplane. I want to set it up to do 3D. My question is, on the tail surfaces should I put a 45 degree bevel on the control surfaces only l< or should I bevel both the control and the fixed surfaces. >< . I've seen it done both ways, what are the pros and cons.

Chris300s

My Feedback: (1)

Pros - cons, more work - less work. It's generally accepted that you don't need more than 45deg. of throw for 3D. That is unless you're flying gliders....
My personal experience has been with +/- 60deg. of throw, I backed off and now run the standard +/- 45deg on rudder, +/- 40 deg. on elevator, +/- 25deg. on ailerons.
I'd only bevel one side and save the strength of the trailing edges.
Chris

Giant Scale

The bevel angle that you use on the LE and TE will depend to some extent on the thickness of the wood you are using. I like to bevel the LE of the surface a full 45 degrees and then bevel the TE between 10-15 degrees. This will give you plenty of throw. On the rudder on my 35% Giles 202 I had to add an extra 1/2" plank to the LE of the rudder in order to get a 45 degree bevel,since the rudder is narrower at the top and wider at the bottom. You need to place a protractor on the end of the LE plank you are using and see how much bevel you can get. I try to leave a flat spot along the hinge line of 1/16-1/8 inch and then taper the the bevel to a sharp edge where it meets the surface.

Rcpilot

My Feedback: (78)

You should only bevel the control surfaces. By working the trailing edge of the wing, rudder or elevator; you might be asking for trouble.

Beveling the trailing edged of the surfaces can create a funny "vortex" of air going over the hinge line. This has caused flutter and even a few hinge separations.

If you want a really slick bevel on those ailerons, just glue a piece of triangle stock on them and then use a planer to knock a flat spot on the hinge line. Works AWESOME and a lot less hassle than trying to sand those control surfaces.

If your worried that this process will make the control surface "grow" and make it stick out too far; just plane a little off the surface before glueing on the triangle stock.

Good luck.

MinnFlyer

My Feedback: (4)

Last year I built a GP Extra 330L. They recommended a double bevel on the tail feathers if you want to do 3D.

Motowncali

My Feedback: (3)

I bevel both. Even if you only want 30deg. of throw it is stronger to bevel both surface 15 deg rather than 30 on one surface. Just make sure your hinges move freely and you seal the gap between the two surfaces. I am flying an Aeroworks 31% 300L and get 50deg on elev. 30 deg on ail and haven maxed my rudder yet but is around 45 deg. All surfaces are double bevel per the plans.