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Proper Mounting of a Fuel Tank

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Old 03-07-2013, 09:18 PM
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Propa
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Default Proper Mounting of a Fuel Tank

Guys, I've got a really "dumb" question. I installed a Brodak BH-487 in my Novi and I though I had it installed correctly until today when I tried to get some break-in time on the new Brodak 40 engine. Now this tank is a 3oz tank and after 4 attempts the engine won't burn more than 1.5 oz before the engine dies; leaving 1.5 oz in the tank. My question is: what is the correct positioning for the tank? Looking head on at the plane, the engine is inverted, the feed line is on the left side with the uniflow line and the vent line on the right side (on the top, toward the canopy). Now did I goof on mounting it? Looking at the Brodak picture it looks like the uniflow and vent lines are opposite what I actually have. I'm so frustrated? Did I goof the setup??
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Old 03-07-2013, 10:04 PM
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Default RE: Proper Mounting of a Fuel Tank

Does the engine continue to run if you tilt the outboard wing down? The end of the fuel line inside the tank is at the "fat" end of the tank; halfway down from the top.(Assuming it's a wedge tank). When the plane is flying, fuel is forced to the ouside of the tank. With the plane at rest, the tank will only suppy 1/2 the volume to the engine.
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Old 03-08-2013, 05:12 AM
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Default RE: Proper Mounting of a Fuel Tank

Being a metal wedge tank, the feed line is in the wedge half way up the tank so the engine can only use up half the fuel with the model sitting on the ground. Fill the tank, start the engine and then tip the model vertical on its outboard wingtip and it'll empty the tank. In flight, the wedge is effectively the bottom of the tank.
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Old 03-08-2013, 05:36 AM
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Default RE: Proper Mounting of a Fuel Tank

Guys, Thank you, Thank you, Thank you! You're so right .... I couldn't see the forest for the trees! I had the plane sitting flat on the stand while I timed the engine run. I only lifted it a couple of times per run to set the needle and verify a consistant 2-4 break. I feel so stupid! It's amazing how my logic has deteriorated over the years. Take care!
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Old 03-08-2013, 01:48 PM
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Default RE: Proper Mounting of a Fuel Tank


Quote:
ORIGINAL: Propa

Guys, Thank you, Thank you, Thank you! You're so right .... I couldn't see the forest for the trees! I had the plane sitting flat on the stand while I timed the engine run. I only lifted it a couple of times per run to set the needle and verify a consistant 2-4 break. I feel so stupid! It's amazing how my logic has deteriorated over the years. Take care!

Welcome to that "Logic" thing "CLUB". Lots of us "old-timers" belong there.

A number of CLers are switching to RC Tanks simply because the flow is always there like in an RC model. Scale CL may make touch and go landings, etc. and they don't need the engine quitting as the rules require some taxi where the centrifugal force does not keep the fuel on the side of the tank as in flight.

In addition there are some tanks with a bladder inside where the airpressure compresses the bladder to keep a measure of fuel around the fuel outlet. Have not tried them for CL but probably will soon. For RC aerobatic and racing they are great as designed. As designed they are not good for Touch and Go after the tank is down to half full, or half empty as your optimism/pessimism may determine. For CL that is a flaw but it can be worked out by using a feed line such as in a normal tank, i.e. a longer feed line with a weighted nipple.

Enjoy!
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