Last Update-03/13/2010 01:40 AM
After many hours of scratching my head as to what to do in regards to bending the almost 8 foot pieces of aluminum for the stab and elevator spars, I decided to put pencil to paper and steel to grindstone. I will build the brake I have been developing in my head. The idea for this brake came from several different sources. Most of us who have investigated this problem have seen the wooden brake another zenith builder developed. I figured if this could be done with a few simple door hinges, then I should be able to come up with something similar utilizing the 4 x 4 x .250 angle iron I had laying around for another project. The key to this type of brake is that the hinge centerline doesn't really have to be right at the bend line. All we need is something stiff enough to "push" the metal around the radius bending bar clamped to the top.
Here they are all attached. I counter-sunk the 10-32 machine screws so the leaf would fold down against the body.
To the right are the countersunk holes for the handle.
Handle being bolted to the leaf on the right.
(yes, I realize its very obvious what is happening in these pictures, but I have to fill this space with something !)
I used 5/16" counter sunk stove bolts to attach the handle.
I picked up this 4' x 12' piece of .025 6061 today from Airparts Inc. I love living right down the street from them. This will be cut into an 8 foot section and the pieces cut out of it for the elevator and stab spar.
I cut the radius bar from a piece of white pine. I routed an 1/8" radius on one edge and then ran it through the table saw to bevel the front 30 degrees back from the leading edge.
Whooo hooo! This thing actually works! The only thing I had to do to finish up was give the flanges a little tap along their length with a dead blow hammer to get the flanges to the proper angle. The banana effect was only about an 1/8 in the middle while laying on its back. Not bad for 100 bucks worth of steel and hinges.! Give it a shot. The only thing I would recommend is the best possible clamps to hold down the radius bar. Cheap ones that bend won't cut it.
Now I can get on with building the rest of the tail components.