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Engine basics => Engine set up tips => Topic started by: Allen Eshleman on June 19, 2012, 05:09:05 AM
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My brother tried to start a Super Tigre 51 mounted on a Score last night with much difficulty. It would run rich - we were starting it upside down so the engine would be up. When we flipped the plane over right side up, it would lean out and stop. It is hooked to a Brodak wedge uniflo tank.
We suspect a problem with the NVA and will be checking that out. However, we have some questions.
Do ST 51's start alright with the head down?
Is there a problem with where the spray bar goes into the engine for use in a full bodied plane?
Any ideas from the bit you can garner about the problem?
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Did you line up the fuel pickup with the needle valve? Fuel tank 101 y1
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I've noticed something really strange with the ST 51. Mine is a T&L version mounted inverted in a Legacy. Choking, as usual until it seems "wet", it will never give a "bump". Flipping, it seems quite dead. suddenly, it takes off! There is one other T&L 51 here that seems to act the same way.
Every other engine I've used, mounted inverted, will give a bump, and starting after that is quick and easy.
Something strange is going on in Italy, or wherever they are made.
Floyd
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It is hooked to a Brodak wedge uniflo tank.
Check that the fuel feed line to the engine is connected to the fuel feed pipe on the tank and not to the vent.
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Do ST 51's start alright with the head down?
In a word, yes. As with any engine it's a matter of learning what it likes for a prime but once you've figured that out it should be a one flick starter. The only difficulty I found with mine is that the ground setting bore no relationship to how it runs in the air. That took several flights to find the correct in-air setting but once found it was a matter of flick and fly.
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Starting "on the wheels" should be no problem. Less likely to flood, IMO. If you have a ST glowplug in it, replace it with something hotter, like the Thunderbolt R/C Long or 4-Cycle/Big Bore glowplug.
While some (T&L/Tom Lay, for instance) like to move the spraybar down into the venturi boss in the case, I have run them both ways and not seen any dramatic difference, even in the same plane/tank. Both Al Rabe and Ted Fancher wrote about and did spraybar location tests with venturi extensions and reported no relationship to tank height and upright/inverted lap speeds. Ted theorized that there was some sort of "pumping center" inherent in each engine design. My own minimal testing hints to me that a simple muffler change can require an adjustment of tank height. Well, I seem to remember that being required after changing muffler type! H^^ Steve