Aux fuel tank width (A Model 4-place QB)

[Dpearson]

Well I tried to test-fit my aux tank from the top side of the wing, before cutting the hole in the bottom skin. Unfortunately the tanks (including the welded fittings) seem to be wider than the spacing between the ribs.
The Beartracks article from 1996 says the tank should be 13-1/4" wide. The ones I have are ~13-1/2" "wall-to-wall", and the welded fittings add another 1/2" or so, giving a total of 14". The spacing between the rib flanges is ~13-3/4", so the welded fittings can't make it past the rib flange.

Has anyone else encountered this? I'm wondering if these tanks (which I believe were manufactured back in 2006) are out of spec...

 

[alaskabearhawk]

Mine were the same. I had to insert them through the access hole (it's tight), when almost in, hold it against the rib on the non-fitting side and the bung will just barely clear. Fittings go in after the tank is in. The space under those flanges is usable. It's tight, but it will work.

 

[Dpearson]

Thanks for the encouragement. I will summon all my courage and cut the opening.

 

[alaskabearhawk]

It's always hard to make these commitments,...you're cutting a hole in THE WING for goodness sake! But, it really is a non-event. Just have a plan and go for it. I suffer terribly from from "the paralysis of analysis", but it is getting better!

FWIW, I did measure my tanks.. They are between 13 1/4 - 13 3/8ths inches wide at each end and about 13 1/2 wide in the middle.

 

[Gerhard Rieger]

Mine was also a tight fit, once in they are good

 

[Dpearson]

All went well - it was a bit of an "Interference" fit but there's enough flex in the ribs that it just barely squeezes in. Hooray!

 

[Gerhard Rieger]

They are a very tight fit, glad you got them in.