Profiling control surfaces
 

Can anyone advise the best way of profiling a solid piece of balsa to form an elevator/rudder section as per attached sketch - a method for forming the bevel on the front edge and one to create an accurate/consistent tapered profile.

Many thanks.

RE: Profiling control surfaces
 

Two lengths of metal rod or round stock of different diameters. The large diameter should be the same diameter as the trailing edge of the wing. The smaller diameter rod should be whatever thickness you want to make the sharp end of the control surface.
Lay the metal rods on each side of the control surface and use a sanding block to form the angle. The tapered control surface will have an accurate angle if the rods are used to control the sanding block.

Control line flyers use this method to form the tapered "Flaps" on control line stunt models where the elevator and flaps are coupled.

I hope this helps.:D

RE: Profiling control surfaces
 

Big 10-4 to Broken Wings, been doing it that way for many years. I even use a power sander with 80 grit paper and it doesn't take very long to shape it. As far as the LE I have a tool - see picture

RE: Profiling control surfaces
 

That is a good trick.

Great Planes has a sanding block that is designed to bevel trailing and rounding leading edges. I have one and it's the cat's meow.

http://www.greathobbies.com/producti...od_id=GPMR6190

RE: Profiling control surfaces
 

Another way for shaping the leading edge is to glue a length of tri stock to the LE of the control surface and then profiling the edges to suit.

This is actually easy to do and gives you near perfect 45 deg profile. Not good though if you require a different angle:D

RE: Profiling control surfaces
 

You can find a couple of good articles here:

http://charlesriverrc.org/articles_construction.htm

RE: Profiling control surfaces
 

My favorite method is to carve it to shape with a razor plane.

Draw center lines on all the edges all the way around the piece of wood. Then draw the desired bevels on the edge. With a good razor plane held at the right angle, start making passes the full length of the blank. After a few passes with the plane, you will be starting to carve the bevel. Check that the carved bevel in parallel to the line you drew. Continue until you're almost to the line. Then finish with a sanding block. Remember to leave the trailing edge at the desired thickness.

Using this method, with some practice you can make a piece that you would swear was machine shaped. And instead of turning all that balsa into annoying dust it makes pleasant little curly shavings. It also works great for the hinge line bevels.

I find it an absolutely entertaining thing to do. But then again, I'm weird that way.

Dave

RE: Profiling control surfaces
 

^^ what he said.

RE: Profiling control surfaces
 

Bandsaw

RE: Profiling control surfaces
 

RevyMaxx,
I have considered this tool but it appears that the tool requires the use of the adhesive backed sanding paper. How does that work with the many different contoured surfaces on this tool. I would think that the sanding paper would not keep the profile of the tool faces as my experience with the recommended sanding paper from GP is not all that flexible.

Just wondering as I have hand shaped both LE and TE's and this tool looks like a good solution.

RE: Profiling control surfaces
 

The adhesive backed rolls I have form in the groves without much effort, your first placement attempt may not be the best but after that you get the hang of it. Easy on, tear-off. The grits I have are 120, 180, 240, 340. The rolls are not that pricey and they go a loooong way.