building question

[az_gila]

Originally Posted by rbibb

The -4 is different. There is a single 0.063 plate that the angle has to overlap. So milling (IIRC correctly the plans state "file away material as required" or something like that. Since the angle is 0.125 thick you remove half (or in practice a bit less to get the angle to lay flat against the plate piece of the bulkhead assembly and the fuselage skin.

That must be the lower angle (longeron) at 0.125 then.

I was comparing the upper angle in your first picture which seems to be 0.063 thick. Is that correct?

[rbibb]

The lower angle (which you can't really see in the pictures well) is a 1x1x0.125 that is actually opened up a bit in a brake such that its sides don't meet at a 90 angle (something like 100 degrees IIRC and Van's supplies the raw stock pre-bent). The upper angle (the one what angles from the lower firewall weldement to the wing spar bulkhead about 6" from the floor) is a 3/4 x 3/4 x 0.125 angle. Both pieces get "milled" or filed such that they can lay flat against the outside fuselage skin while overlaying the reinforcement plate (0.063) that is part of the wing bulkhead assembly.

With parts in hand it starts to make sense. Similar to the RV-6 drawing you showed but just a bit different in the details.

[rv4dude17]

thanks for all the posts and pictures. it really helped...