I have a friend (shall remain namesless) who installed his 13 gallon tanks with metal covers due to the fact that "you might want to get them out sometime to fix a leak" which makes sense to me. He also made a neat hinged setup for his wing fairings that eliminates some of the screws going down the sides of the wing to prevent the problem of constant tightening of loose screws Everything fits tight and it sort of snaps into place, if I remember correctly. Very handy with the mtal work. Maybe he has 337's on the improvments, I never asked .
It is too bad that simple improvements can't be made without going through a bunch of hassle on these older planes. Granted you wouldn't want the metal tank covers to blow off in flight, but there are places where common sense prevails.
My thought for the day!
Mike
"If God had intended man to fly He would have given us more money"
Looking at the tank cover on your photo, the only change I would make is to tuck the cover under the wing fairings. The tank cover certainly makes sense (as my friend said) should you have a leak (they do pop up from time to time) or need to reposition something at a later date due to rubbing, etc. I can't imagine cutting a brand new fabric job to correct a leak..............I know, test , test, test......... .
Mike
"If God had intended man to fly He would have given us more money"
I agree completely Mike! You would think common sence would carry a little weight now days, but it seems to be just the oposite.
In a hypothetical situation, IF I needed wing tanks and IF my covering and paint were really good, I MIGHT consider using metal covers. Plus, what if they needed to be removed.
There is an Aeronca drawing for the installation of metal wing tank covers. It looked pretty straight forward. Let me dig around to find the number for you.
The drawing number is 7-10002. The drawing calls for a couple extra stiffners , a top brace directly behind the rear spar to attach the metal cover with screws and some felt strips on top of the tank straps.
It's not an Airknocker but my 7EC/FC manual has the metal cover drawings. I decided against it, as you really can't get the tank out of the wing even with removable covers. The drag wires and fittings are pretty much inaccessable without cutting the fabric, or perhaps even removing the wing from the aircraft.
The smaller tanks may be a whole 'nuther matter, though; I have 13-gallon tanks.
With the removable cover, you can get in to make minor adjustments and/or repairs, though. I tested my tanks several times before covering the wings. Each time was with gasoline, as it seems to find holes that water can't.
Jon B: I've built several tanks and what works best is 1-1.5 psi of air in the tank and soap and water brushed on the outside welds to check for seapers and leaks.
Ron
Before you believe anything I say, check with two more people. If they agree, I must be right.