Longeron Fit?

Post by **bullojm1** » Sat Jun 30, 2007 8:36 am

Today I fit the longerons to the aft fuselage on my -7. The instructions tell you to align top of the longerons with the top of the side skins - easy enough. However, where the longeron passes over the F-711 bulkhead, the bulkhead interferes and makes the best alignment I can get about 1/32". To illustrate my point better, here are two pictures:

Pic showing the gap:

Pic showing the interference:

Anyone else run into this on their project? The the verdict on the right thing to do?

I appreciate any advice.[/img][/img]

cjensen · Post by **cjensen** » Sat Jun 30, 2007 11:59 am

Hey Mike,

I just went out and looked at mine, and I had a similar, but slightly smaller gap than 1/32. I just left it alone. I don't think 1/32 is going to matter either. Just my .02...

Post by **bullojm1** » Sat Jun 30, 2007 12:04 pm

Chad,
Thanks for taking a look at your fuse. After taking a closer look, my longeron was slightly twisted causing it to creep up. Once I clamped it down, it turned out to be flush.

Sometimes you gotta cry for help before you figure it out 5 seconds later

Post by **Spike** » Sat Jun 30, 2007 12:12 pm

Amen to that. I liken it to teaching. Having to teach someone about some subject is the best way to become familiar with it and to make sure you know it.

Good job !

Spike

cjensen · Post by **cjensen** » Sat Jun 30, 2007 12:52 pm

Glad you figured it out Mike! I know just how you feel...

Post by **bullojm1** » Mon Jul 02, 2007 9:12 am

As a follow up, my original solution of twisting the longeron a little to make it line up wasn't the fix I needed. The twist cause the longerons not to be parallel with each other when a ruler was put between the two. i.e... they looked like they were pigeon-toed. I worried about this propagating to alignment issues with mounting the horizontal stabilizer later on.

To trim down the F-711A/B bulkheads without disassembling anything or marring up the F-711C bars, I used this trick:

I was able to slide a piece of thick plastic between the F-711A/B and the F-711C. This acted as a guard to keep me from scratching the F-711C bar as I filed. After a few minutes, everything fit nice and snug. I supported the aft fuse by resting it on the end of the F-711C bars so that the longerons could hang down. The only disassembly needed was a few clecos holding the side skins on the aft fuselage.