Length of Bending Brake For A Scratch Build?

[Charles1954]

Is my 48" bending brake long enough if I want to scratch-build a Sonex? Is the rear wing spar channel one long 10' piece or can it be spliced from two pieces?

[Area 51%]

The good news...My Legacy plans show a splice in the rear spar even though the supplied spar in my kit is full length.

The bad news...(maybe) The splice is not at mid-point but greatly favors the inboard section of the spar. 96in for the inboard section and only 13in at the outboard. .

[BobDz]

What is the thickness of the material for the Spar?

An aluminum siding brake will bend 032.
Would that work?

[kmacht]

A 4’ brake is big enough if you buy the channel kit from sonex (it they still offer it). If you don’t buy the pieces of C channel from them you will need a longer brake. Off the top of my head I think the c channel that runs down the underside of the turtledeck is the longest piece that would need to be bent. Check out the zenith 601 builders website as well as Mike smiths sonex build log. They both show how to make a long enough brake out of some angle iron and hinges.

Keith #554

[peter anson]

The only parts that are too big for 4' brake are the flaps and rear spar. However, the control surfaces are pretty tricky to get right. I recommend you buy them from Sonex and if you do that you may as well buy the rear spars too.

Peter

[karmarepair]

An aluminum siding brake will bend 032.
Would that work?

In my experience, no, siding brakes are rated to bend nearly dead soft annealed 1000 or 5000 series aluminum, and not the fairly stiff 6061-t6. You'll get a bow in the middle of a long bend

[karmarepair]

If you're a hard case, use this method: http://www.youtube.com/watch?v=y9kR-OnoJgM

Use more clamps than Mattias uses here (the siding he's bending is pretty soft), and if you can, clamp with a piece of square steel tubing.

I have seen, but now can't find, a video of the designer of the Thatcher CX-4 beating out the MAIN SPARS at Sun'N'Fun using a folding table, a long, straight 2 x 4, and a dead blow hammer as a demo. I've made some fairly long bends myself. Go SLOW, only a few degrees of plastic deformation each pass, or you'll get ripples in the flanges due to stretching.

[mike.smith]

I built one long enough to bend the rear spars without a splice. As it turned out, I MIS-CUT the channels, and ended up with the splice anyway. Oh, well!

https://www.cannedhamtrailers.com/pdfs/ ... eplans.pdf