Folks I have four wing tanks. Two inner by 30 ltr each side and two outer by 20 ltr. Each tank is separately vented via a tube that exits below the wing and points into the slipstream. You might think this is fine....and it is on the ground...but in flight the two inner vents seem to receive more pressure due I think to the propwash than the two outer. The result is that when both inner and outer are selected together (ie. takeoff on both), fuel gets pushed out of the inner, through the fuel tap into the outers and eventually out under the fuel caps. Loss of fuel is pronounced to the point where the vapour trail is visible from the tower....talk about F111 tail pipe flares!!! The problem is slower to manifest itself as the fuel levels drop and at first I could not understand why it only happened occasionally. I initially thought faulty caps with suction over the top was the cause.
The fix, I think, is to connect all tank vents internally but to only have one vent external. I mention this because it is a heap easier to install these internal connections prior to sealing up and installing your wings.....just something for those of you with wing tanks to be wary of. I will have to cut into my outer wings to get at the tank to effect this solution...bugger. Any other ideas or similiar experiences to discuss would be most welcome. My bird got aileron rolled, barrel rolled, wingovered and spun on Thursday by my test pilot...wish I could do all that stuff...looks so easy!!. Getting 145 knots at 3800rpm with the finer pitch on the 56" by 3 blade Warp Drive with 2700cc Corvair. Those of you with 3100cc engines will really hoot. Regards John and Janet Martindale 29 Jane Circuit TOORMINA NSW 2452 AUSTRALIA ph: 61 2 6658 4767 email: johnj...@chc.net.au
