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Firewall Fitted

July 16, 2013

I got quite a bit done this weekend.  First off I had to get the longerons completed.  When I left off I only had some of the holes drilled.

I didn't count them, but I am sure there are two hundred.

I didn’t count them, but I am sure there are two hundred.

The ones on the bottom are what I worked on.

The ones on the bottom are what I worked on.

Once this was done I had to do some trimming on the front of the longerons.  There is a 3/4″ measurement and I was off about 1/2″.  So the Dremel and a cutoff wheel came into play.   I then had to fabricate some straps.  These tie in the F-704 bulkhead with the longeron.  It took me more time to find the stock then it did to make the parts and fit them.

Note:  If you are looking for the .063″ aluminum sheet that you are supposed to make the F-704L from….then you’re out of luck.  Just make it from scrap you have laying around.  There is no part that makes up that they sent you to make it.

100_1460 100_1461

Next up is mounting the firewall.  Waaaay back a bunch of months ago I assembled the firewall and then stored it in the attic.  Now it is time to hang it on the front of the fuselage.

100_1462And guess what?  It fits perfectly.  I clamped the firewall to the longerons and then lined up the flanges of the firewall with the side skin and clamped it all together.  Be sure to check the flanges here and make sure they are good and flush with the sides.  Check the bottom too (top in this photo).

Speaking of the bottom it was time to go liberate that part from the attic.  I peeled my blue plastic off, did all my edge prep.

I tried a new technique with the edge prep.  This sheet is really thick.  It is where your feet go while flying.  When they cut the sheet there are these little “nubs” left behind that are about 1/32″ higher than the metal around it.  I’ve eaten up a lot of Scotchbrite wheels trying to clean that stuff up.  This time I decided to start with a file and get rid of as much of those nubs as I can.  This ended up working great.  I used less Scotchbrite at the cost of about 3 extra minutes of elbow grease.  I think I’ll keep doing it this way, even on the thinner sheets.

I mounted the bottom forward-most skin into place and got it cleco’d onto the spar and the firewall.  I then proceeded to drill the hole from the side skin to the firewall.

100_1463And that was pretty much it for the weekend.  Pretty productive session.  During the week, if I can, I am going to try to get the aux longerons in place on the inside of the skin.  I’ve read through those instruction and I am still not sure I understand them.  There is a twist that those longerons need, but I dont know where the twist goes.


From → Build Log, Fuselage

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