Thorp Air Command - T18.net

I am looking for suggestions as how to put the 1 - 1.5 deg additional angle on my outer wing cap angles. The measured angle is a little less than 90 deg so I have several degs to go. I have tried putting the two sides on a steel plate and using a block of wood and hammer to spread the sides but seems will require a pretty large hammer and won't look pretty. My search criteria on the newsletter did not produce much, however I am sure this has been discussed. Appreciate your suggestions

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thenthorn

Use a 12" or larger floor disc sander and set the table to 1.5 degrees. Some builders elect not to cut the angle, it does leave a little distortion at the spar. Don't ask how I know this.........

Round off the outer corner of the extrusion.

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In theory, theory and practice are the same. In practice, they are not.

Jubal,

I slightly 'flattened' my L-shape spar caps ever so slowly by working them in a vise. A heavy plate against one jaw was used across the open legs as I moved along the length of the extrusion several times. A block of wood helps on the other jaw to keep from putting nicks in it too. It doesn't take much effort but it takes patience. So does the whole airplane-building thing.

C-channel spar caps were done with a file. The folding wing doesn't have much length on the center section so it went pretty quickly.

As Dick says, file off the sharp corners before attaching skins.

Les Krumel

Very Good. I appreciate the suggestions. I'm off to the shop.

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thenthorn

I used a 3 x 21 inch belt sander with an 80 grit followed by a 120 grit belt to round off the outer edge and then polished with a 3M pad. Made quick work of the job.

RB