After having pains with the Oriental Plus and getting a decent engine run for an entire season, I decided I have had enough of plastic tanks.  It leaked like a siv at the end of the flying year last year which made me refinish the nose over the winter, now the shim is off by A LOT and no matter where I move the tank up, down, or rotate it, the shim doesn't change at all.  Also today, I landed and the thing started spitting up fuel through the pickup and now the nose is discolored again (sigh).

So now we decided that, in order for this to be a decent backup ship for the NATS, should anything happen to the TP, I need a good motor run, so starting tomorrow we're going to cut into the airplane, install a tank floor, cut into the wing about a 1/2" to accomodate a 6 ounce magnum tank.  We'll see what happens after that.

Has anybody else had plastic tank issues like what I just described?

There are those that love plastic tanks, those that haven't used one yet, and those that don't like them at all. Same for metal tanks, I suspect.

I'd suggest making your own tank. Make the < biased toward the top, so it's 1/2" from the top side. And make the tank about 1-1/4" to 1-1/2" high, so you won't have to cut into the wing LE for room. The commercial tank I have in my SV-11 is supposed to be 6 oz (it's 6" long), and the way the overflow is installed, it probably only held 5.3 oz. I noticed that when I cut the belly out of it to put the sump on. Should have fixed the overflow then, but didn't, so now I'm going back in for a second tour.  Steve 

Yea, I was one of those who liked plastic tanks, that's why I put one in the Oriental Plus.  But after dealing with it last year, spending half the year trying to get it shimmed right.  Then the tank sprang a huge leak on the last flight of the 2010 flying season where I refinished the nose.  Then this year, after we sealed it, it started leaking again, and the shim wasn't right anymore, it was off by A LOT!  We took the tank out and put fiberglass around the area where it was leaking, and I tried it again.  It didn't leak but I didn't have a motor run worth anything.  I tried to tach it at 10700, and it would tach there, +/- 300RPM!  It ran allright in the air, but the shim was way off, after we moved it quite a bit to get it to run better.  I finally had enough with it.

There is a 6 ounce magnum tank in it now, and I'm going to test that out in a couple days.  I just want to make sure it works so that I have a good motor run for the back up airplane in case something happens to the other one.

Derek,

As usual, J. Randall is correct again!

I never met a plastic tank I liked!


W.

Hey Matt sorry to hear this I've been using plastic for years and have not had a single issue with leaks, I have a Sullivan 4oz. that is 20 years old and still going of course I replace the tubing and rubber stopper every couple of years. Also I don't understand this shim thing I have mine set up uniflow with a solid tube bent towards the outside of the tank so I can simply turn the tube up or down to acheive the desired engine run. Hope everything works out for you.

I have only tried plastic clunks a couple of times. The problem I have is when refueling, I manage to move the pickup tube a little and then it is either to high or to low for upright / inverted. Went back to hard tanks and never looked back. They work fine in my R/C ships.