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fuel tank access panel and flop tube

slngsht

Well Known Member
Hi All,
I've finished my left tank and working on the right tank now. Left got the standard pickup, right getting flop tube.
My question is - with the flop tube install, what if I skipped the access panel altogether? What is the down side?
If at a future date I need to get to the flop tube, I would have to cut access through the baffle to get in.
I prosealed the access panel for my left tank - i imagine getting it back open a few years down the road will be a battle anyway. Seems for the right tank, keeping the inboard rib solid would save some weight.
What other downsides?
 
I have a flop tube on the left, standard on the right, and didn't put an access panel on either. If the day ever comes when I need to get to one of them, well, then I'll add an access panel. For the time being, it's one less thing to leak.
 
Search flop tube

There are numerous comments regarding o-ring wear and abrasion to the tank skin suggesting replacement of the o-ring. It appears logical the wing would need to come of then.
 
I think Larry means that this simple o-ring replacement would require you to add an access which you are not going to do while the wing (or at least the tank) is still mounted. I personally would have an access just in case but that is just me. Also, add in an anti rotation bracket for that flop tube, I had to open my access after the tank was done to add this. :mad:
 
I think Larry means that this simple o-ring replacement would require you to add an access which you are not going to do while the wing (or at least the tank) is still mounted. I personally would have an access just in case but that is just me. Also, add in an anti rotation bracket for that flop tube, I had to open my access after the tank was done to add this. :mad:
it would definitely require removing the tank for sure. after searching based on Larry's comment, I may just put in the standard pickup. I will do some acro, but nothing extreme.
 
I am about to close my left wing tank that has the flop tube. The only hole I had to cut into the baffle was to relocate the fuel float sensor. if you go with the capacitative sensor then you don't have to cut into the baffle. If you need to get access to the flop tube in the future, the side panel at the root should be sufficient.
 
If you don't have inverted oil, inverted fuel is worthless. If you don't have fuel injection, it's doubly worthless. And, it brings with it multiple failure modes that don't exist with the 'stock' fuel pickup. Common ones are loosening of the various fittings associated with the flop tube, and flop tube hangup. Both will restrict access to a significant percentage of the fuel in that tank. Both have happened often enough to generate service bulletins in RVs.

FWIW,

Charlie
 
If you don't have inverted oil, inverted fuel is worthless. If you don't have fuel injection, it's doubly worthless. And, it brings with it multiple failure modes that don't exist with the 'stock' fuel pickup. Common ones are loosening of the various fittings associated with the flop tube, and flop tube hangup. Both will restrict access to a significant percentage of the fuel in that tank. Both have happened often enough to generate service bulletins in RVs.

FWIW,

Charlie
I have fuel injection. I also have inverted oil stuff, but was really on the fence about it and would likely not put it on.
 
Then the next question is, do you like bloodshot eyeballs. :) The only time I've ever seen engine stoppage in a carb'd -4 is about 2/3 the way up the upline of hammerheads. I don't do sustained inverted flight or 'outside maneuvers, but I do do all the typical variations on loops, rolls, cuban 8s, etc.

Charlie
 
There are numerous comments regarding o-ring wear and abrasion to the tank skin suggesting replacement of the o-ring. It appears logical the wing would need to come of[f] then.

The tank can be removed without removing the entire wing. I have my left tank off now to repair a leak. The access panel had also developed a leak since the last CI (cork gasket). I didn't build my tanks but the person that did put in the flop tube (left) and return fuel fittings. Easy enough to cap off but and have the option to use them in the future.
 
Tank removal

My bad ! I have assumed removing a tank on a nicely painted wing is a 50/50 chance of undesireable anghst. I hope your mileage varies positively 😊
 
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