Sealing the Fuel Tanks – Part I

Today I started to seal the left wing fuel tank.  I decided to follow the method laid out by Rick Galati at Van’s Air Force.

The method involves fay sealing surfaces and allowing the sealant to partially cure before riveting.  It is supposed to be less messy, and after handling the sealant for a while, I can imagine that trying to shoot rivets with this wet material everywhere would be quite frustrating and sloppy.  I masked off the area around the stiffeners to allow for easier clean-up after a partial cure.  We’ll see how that works out tomorrow.

As it was, the method is (so far) not terribly messy, as long as you’re willing to sacrifice a ton of nitrile gloves to prevent spreading the sealant around too much.

Today I prepped and sealed the left wing tank inboard rib hardware (fuel flange and anti-rotation plates) and five of the fourteen tank skin stiffeners.  I could have done more, but had only mixed 55g of the sealant (50g Part A : 5g Part B).  That was just exactly enough for the pieces I worked on today.  Perhaps I could have been a little less generous at first and got another stiffener or maybe two, but it looks like you need about 10-11g of sealant for each stiffener, including losses to the pot and gloves, etc.

When I opened the can, my first thought was:  “Wow, that’s a polysulfide!”  And sure enough, it is, according to the manufacturer.  It has a rather rich aroma.

Here’s what I accomplished today.  More tomorrow.

The inboard rib hardware:

The stiffeners:

Easy Peasy Rivet Squeezy

I finished replacing the rivets in the inboard aileron bracket on the left wing that I mentioned in my last post.  They look much better now, and I will not be worrying about them anymore.  It is amazing how thinking about these has actually slowed me down for a while, until I finally just got up the nerve to drill them out and replace them.  I have replaced other rivets before, but I was nervous that in drilling these out, I would damage the aileron bracket and have to build it all over again.  I just jumped in and did it this evening with no issues.  Glad that is behind me!

After that, I clecoed the top skins to the left wing and prepped it all to begin riveting as soon as I can get a helper.

Right wing leading edge complete and shop cleanup

Yesterday I completed the right wing leading edge, cleaned up some shop area, moved the tail cone to a better storage location, and then made a test fit of the left wing leading edge to the main spar. The fit looked good.

I have one rivet I need to drill out and re-set on the left wing rear spar, and then I will begin the top skin riveting process.

Left Wing Outboard Leading Edge Complete

Long time, no update.  Rest assured, work has been progressing!

Today, after a long preparation period that involved tons of part finishing and priming (and receiving and inventorying the fuselage kit), I began final construction of the major sub-assemblies of the wings.  8 hours of work later, I completed assembly of the left wing leading edge assembly.  Tomorrow I plan to complete the right wing leading edge assembly, and possibly begin main wing top skin riveting.  Or maybe fuel tanks.

Hole cut for the stall warning system access cover.
Access cover plate doubler pre-priming
Test fit of access plate cover and doubler.
Left wing leading edge stall warning system access/inspection doubler and cover installed 6/9/2018
Left wing leading edge stall warning system access/inspection doubler and cover installed 6/9/2018
Left wing leading edge assembly and riveting in progress 6/9/2018
Left wing leading edge assembly and riveting in progress 6/9/2018
Left wing leading edge assembly and riveting in progress 6/9/2018
Completed Left Wing Outboard Leading Edge 6/9/2018
Completed Left Wing Outboard Leading Edge 6/9/2018
Completed Left Wing Outboard Leading Edge 6/9/2018
Completed Left Wing Outboard Leading Edge 6/9/2018

Right Wing Tank Work

Today I spent a lot of time deburring and dimpling the right wing tank skin, stiffeners, and associated parts. I also found that the DRDT-2 works better for screw hole dimpling than the pneumatic squeezer did, so I ran the left wing tank skin back through the screw hole dimpling process, and the holes now look much crisper.

I also got a very nice surprise when Mom and Tim showed up unannounced for a visit and gave me a great little chest that Tim made for me in his wood shop. I’m going to come up with a good use for it that will not damage it. Tim said I should keep it in the workshop but I want to make sure I don’t get it dirty or scratched or damaged in other ways. It really is a nice piece of craftsmanship!

It is made of wormy chestnut, which is really pretty. I think it is finished only with linseed oil. The aroma is very nice, and I like the natural finish.

He even signed and dedicated it!

Update

Well, I haven’t updated this blog for a very long while, but I have been working, albeit slowly, on completing the wings. My work rate has picked up significantly in the last couple of weeks. We took a couple of trips in the Warrior (to the beach and to Vermont) and it got me back into the spirit of building.

The left fuel tank is nearly complete–needs only priming of some external parts and then final assembly with sealant. Right hand tank is nearly there too. Once I get the the point I need to prime, I will be priming many wing parts prior to final assmebly.

Below is a picture of the inboard left hand fuel tank rear rib. I have added a fitting for a fuel return line. The engine I bought has an Airflow Performance fuel injection system which benefits from a fuel return to the tank for starting. Also, I will do this for both tanks so that if in the future I decide to switch to a fuel injection system that requires a fuel return, I will have it available. I’ll cap off the return that is unused with a cap fitting.

A picture of the right wing tank during a test assembly. Left wing tank is almost ready to assemble and seal up.

Finished Deburring the Wing Ribs!

I finally finished deburring all of the remaining leading edge and fuel tank ribs for both wings.  This incredibly tedious job was made much quicker by the use of some small abrasive wheels that had been recommended on VAF.  I had seen these months ago but never got around to buying any until last week.  They enabled me to cut down the time to finish deburring a rib from close to an hour to more like 10 minutes.  Unbelievable!

I primarily used the 3M wheels for finishing and polishing and the Brite Rite wheels for roughing work.  I only used about 3 Brite Rite wheels (they are very durable, but remove a lot of material) and about 10 3M wheels.

It is such a relief to be done with this part of the build!  When I have to deburr ribs in the fuselage, I will definitely be using this technique.  It should work for all kinds of other parts as well.  I’m going to order lots more of these wheels.