rib attach angles (on the patrol in case the 4 place is different)

[sjt]

I am 95% certain that when reading a spec for sheet metal bends, the interpretation is an outside to outside measurement. That being said, the patrol attach angles that connect the spar to the rib are made out of 032 - and as far as I can tell are 1/2 x 1/2.

Quite often I hear that builders are using 5/8 x 5/8 angles. I am not sure if I misunderstand the drawing; or if individual builders are more conservative.

Can anyone tell me where the 5/8 number comes from?

stan timmerman
austin tx

[LukeS]

Some builders use/recommend the 5/8 x 5/8 angles instead of 1/2 x 1/2 to allow more room to work. The 1/2 x 1/2 angles give very little room for the bucking bar, but that is the spec per my 4-place drawings. I'm using 1/2 x 1/2, and wish I had a little more room for the bucking bar.

[N3UW]

Like luke said. It is nice to have a little more room to work with. I made mine 5/8". Getting the bucking bar that close if tough and you have to be dead on to maintain your 1/4" edge margins on both sides. 5/8" or ever 3/4" will give you more wiggle room. The only downside I see is weight.

[sjt]

Thanks for the info. I think I have access to an 8 foot brake and hope to get my spars bent this weekend. Their shear is not long enough for the spar but it might finish off the attach angles faster then doing them by hand.

I will start with the aileron. I think the first bend will be easy. It is getting that second bend that worries me. I will either come home with spars or a life time supply of attach angles.

Bob's patrol manual gives a formula for the blanks. The more detailed sheet metal calculations show his formula to be a little bigger then the more complicated calculation.

stan