stunthanger.com
Engine basics => Engine set up tips => Topic started by: Matt Colan on June 17, 2011, 09:27:57 PM
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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?
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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
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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.
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There are two types of plastic tanks. Those that leak and those that are going to leak..... LL~
That is a quote from Mr. Smith.
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Derek,
As usual, J. Randall is correct again!
I never met a plastic tank I liked!
W.
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There are two types of plastic tanks. Those that leak and those that are going to leak..... LL~
That is a quote from Mr. Smith.
LL~ LL~
Windy told me that quote last year at Brodak's when I was trying to get it shimmed right. It still wasn't right on my official flights but was a lot better than it was before I shimmed it.
The only plane that we have where the plastic tank works beautifully is my grandfather's F-14. He has an LA 46 in it with a 4 ounce (i think it's a 4 ounce) plastic tank in it. He has it jammed up with foam and a 2nd part of the cowling which he cut from the plane to make, and that hasn't had an issue and runs the same upright and inverted.
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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.
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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.
Hi Dwayne,
That's what we did, I just used the term shim to make it easy for other people to know what I was talking about. And no matter how much I moved it, it engine was still running rich on outside maneuvers.
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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.
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I've used plastic tanks periodically. My only real gripe has been that they don't tend stay static (plumbing can move around) and you can't do a cut off loop with a clunk. They work fine and I've had good luck with them generally. But I've also had fine luck with metal tanks so there you are.