"H" jig is used to square wing & check for washout.

Skins are clecoed in place for match drilling

The wing construction is where I began my customizing of this aircraft. I wanted to be able to hold all my auxiliary fuel in the wings instead of the cargo space which is more common.

I wanted to achieve this without changing the structural or aerodynamic design of the wings. I spent several weeks studying the plans before I decided how to do it.

In the end I decided that simply building the outboard leading edge in the same manner as the inboard leading edge was the simplest & strongest way. I wasn't breaking any new ground with the wingtips as this option has been available from Jon Johanson thru Van's for several years now. The new "sheared" style of wingtip isn't yet available, but at the price of these, I would have done it myself anyways.

The wing is pretty much unchanged when empty. Each OB leading edge tank added 4.5 pounds empty, and the wingtip tanks also added 4.5 pounds empty. So we can call it 20 extra pounds. I can live with that.

The aircraft will hold 505 pounds of useable fuel, plus reserve in the header tank. My calculations show improved span loading on the wings. This should also improve stability, however any spins would be very hard to stop once started. 

Normal use of these auxiliary tanks should not include landings, however I've calculated that the wings should easily withstand a 3G landing with full fuel. More than that and structural damage could occur, however this is an extremely hard landing (sometimes called a crash). In any crash I would prefer the wings come off anyways, taking that fuel with them.

Access Plates

The plans call for an access plate to be installed on the inboard end of the tanks. It is through this access plate that the fuel level sensor units are mounted. These access plates seem to be a source of leakage, judging from experiences of other builders. When using the capacitive probe fuel sensor plates, they are located within the baffled section of the tank and cannot be accessed through this hole once tank is finished. So I couldn't see any reason to have these access plates. Even if the fuel outlet becomes plugged, the first option would be to back-flush the line & remove the drain valves to empty any possible debris. If it ever becomes necessary to get inside these tanks, a circle cutter can open them up faster than removing the access plates. Closing them up again would obviously require installation of the plates, but it wouldn't be any more difficult to do then than now.

Outboard Leading Edge Tanks

I will compose a written procedure for building the outboard leading edge tanks, for those that would like to try this. It will be posted here when I finish it.

The rest of the wings were built as per the plans.

Back to Front Page -  C-FSTB

July 23, 2002

Fuel tank construction begins with inboard tanks.

Outboard tanks under construction. One bay is left open for landing light & access to fuel plumbing.

Inside of tank is left unprimed, while light bay is primed.

Adjustable landing light holder on bench.

Light holder riveted in place.

Outboard tank complete

Both tanks being mounted

Joint strip being fitted

Fuel plumbing passing through spar to outboard tank.

Fuel plumbing to wingtip tank.

That's me bucking rivets for the top skin.

It's always easier to teach an assistant to operate the rivet gun than the bucking bar.

Aileron bellcrank

Hinge for slotted flaps.

Flaps are built in a cradle first, then final riveting is done on a flat jig with sandbags for weight to ensure they are straight.

One down, 1/2 to go.

Both wings complete, except for bottom skins, which don't get riveted until inspection is passed