Originally Posted by Jon Clements (Post 466797)

Thanks all for the kind words. Genuinely appreciated.

Pierre -

I modified the outboard leading edges to become Long Range Tanks with the assistance of a mate of mine who is an AME (structures). The middle bay between the main tank and the outboard tank is open and provides access to the plumbing (via the opening for the landing light in the leading edge). To improve the structure we installed skin doublers to the underside and the outboard tanks are stiffened with lateral angles in the same way as the main tanks. The outer tanks have their own filler caps and all four tanks are plumbed separately to a four way Andair fuel selector. The vent lines are split via a "T" to provide direct venting to both the inboard and outboard tanks. We made a sacrificial test tank as part of the process, filled it with water and tested it to 7.5G's before it showed signs of deflection.
Main tanks hold 80 Litres per side (approx 20 gallons) and the outboard tanks hold 70 Litres (approx 18 gallons) per side.
Stating the obvious - I have included operating limitations in my POH for the aux fuel tanks.....no landings with fuel in outboard tanks (except in emergency) and no aerobatics with fuel in outboard tanks.

I elected to rivet the outboard tanks in place rather than install plate nuts/screws essentially because I did not want to modify the spar design. If they ever leak and I have to remove them it will be a case of drilling out the rivets and I suspect my paint job won't like that much !

The CoG is relatively unaffected by the additional fuel in the leading edge so my C of A has a higher Max weight (2020lbs) than Vans recommends to accommodate long range operations when necessary. On a day to day basis the aircraft is operated to the standard weight limits recommended by Vans and it is ALWAYS operated within the C of G range recommended by Vans (including Long Range Operations).

Cheers

Jon