James' RV-7A Project

Left Tank sealing - Part 1

admin — Tue, 31 Aug 2010 09:39:44 +0000

Here is a summary of my first lot of tank sealing work. This represents 4 ’sessions’ each about 3 hours long. You get about an hour to work with the sealant once mixed, add an hour for setup and and hour for clean up each time.

First I backriveted the stiffeners to the botton of the tank skin. Everything was given a good scrub down with a scotch brite pad then cleaned with MEK and masked to make clean up easier. The sealand is mixed 10:1 by weight and then applied to the skin, rivets inserted from the outside and taped in place. Then the stiffeners are backriveted in place. Last job is to clean away excess sealant making a nice fillet alone the tank to stiffener seams and covering each rivet shop head with sealant to ensure no leaks.

I also got the filler neck and drain valve sealed and riveted into place.

The ribs were done two at a time. That’s all I could manage within the 1 hour working time of the sealant.

Here you can see inside the inboard-most bay of the tank. Once this rib was installed I installed the vent tube, capacitance fuel sender plates ans wiring and another anti-hang-up guide for the flop tube.

Tanks misc prep

admin — Thu, 15 Jul 2010 09:17:57 +0000

Tank attach bracket drilled for flop tube attach point.

The skin is machine countersunk (not dimpled) along the row of rivets that joing the skin to the baffle. this makes inserting the baffle easier during assembly/sealing.

Made anti-hang-up guides to stop the flop tubes catching on the inspection cover nutplates when I'm upsidedown. I deviated from the plans slightly here to make a more robust and failsafe solution.

Fuel tank inspection holes

admin — Sat, 19 Jun 2010 09:15:58 +0000

Bought this circle cutter (fly cutter) to cut the large inspection panel holes in the tank root ribs. Unfortunately it was too big to mount in my drill press so I decided to have a crack with the handheld electric drill….

It actually worked really well. I used plenty of cutting oil and nice slow rpm.

One down one to go.

Next job was to fit the reinforcing rings around the holes i had just cut, and install the nutplates.

More left tank…

admin — Sun, 13 Jun 2010 23:55:10 +0000

Work continued on the left tank today. I matchdrilled the capacitance fuel sender plates to the appropriate ribs and attached 3 nutplates to each sender plate.

I also drilled the tank nose reinforcing plates and attach brackets to the end ribs.

Finally I deburred all the holes in the ribs, skin and misc parts. I need to cut the big (5″) hole in the root end rib for the inspection cover but I don’t have a circle cutter. Off to borrow one - and failing that I’ll try and pick one up online.

Left Tank work

admin — Sat, 12 Jun 2010 23:42:10 +0000

Big day on the left tank today.

Made these tank attach/alignment brackets from some angle stock. Did the right one at the same time. They still need a little finishing work but mostly there.

Positioned and drilled the fuel cap flange....Â

...and the fuel drain mounting flange.

I also made the trap doors that go on the second most inboard rib in each tank. These are used with the flop tubes to cover one of the holes in the rib that fuel flows through. The idea is that when doing aeros and rolling iverted, the door will slow the fuel from rushing out of the inboard bay preventing the engine from surging or stopping. I needed one for each tank so made them both today. I had to deviate from the plans a bit - the top half od the hinge needs to be longer to provide room for a rivet to attach to the flat part of the rib web. Also, not shown here is a small .020″ packer I had to make to go under the top half of the hinge. That was necessary to allow the door to sit closed nice and flat against the rib

Here is the left tank trap door riveted to the rib, and the right one ready to go when I get to that point.

Tank bits from Vans!

admin — Sun, 06 Jun 2010 23:39:05 +0000

Received my flop tubes and delux fuel caps from Vans today.

I’m putting flop tubes in both tanks so I can fly upsidedown from either. Also, these delux fuel caps are a work of art! Much better than the standard Vans caps which I should have deleted from my wing order. They are very nicely finished and easy to operate without needing tools or a stick to open.

Left Tank Ribs

admin — Sat, 05 Jun 2010 23:34:03 +0000

Deburred, fluted and straightened the flanges on the ribs for the left fuel tank. Cleco’d them to the baffle which was bolted to the spar and fitted the skin. The whole assembly was then removed and matchdrilled on the bench.

Looking like a wing with the tank in place.

Tank assembly ready for match-drilling.

Matchdrilled tank stiffeners

admin — Sun, 16 May 2010 00:41:38 +0000

Matchdrilled all the tank stiffeners to the tank skins.

Alex doing what he does best....supervising!

Tank stiffeners

admin — Fri, 14 May 2010 00:37:00 +0000

TodayÂ I cut and deburred all the stiffeners for both tanks. Glad that’s done!Â

Process was, mark out with a sharpie, cut on bandsaw, deburr on scotchbrite wheel.

Tank attach Z-brackets

admin — Mon, 03 May 2010 00:31:40 +0000

Quite a lot of work here although it doesn’t look like much!

The tank Z-brackets are measured, drilled, fitted, drilled again, drilled for nutplates, countersunk, primed, nutplates riveted on. Doesn’t sound like 5 hours of work!!!

Z-Brackets ready for priming