Fuel tank and Carb alignment
06-09-2002, 03:27 AM
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Fuel tank and Carb alignment
I'm currently building a H9 Aresti and I'm not happy with the fuel tank alignment. Actually, I'm building my second Aresti. I only got 5 minutes and three touch and gos before the first one crashed. Right after taking off the third time the engine died and I met a fence while trying to land dead stick. I'm not sure if this matters or not but the fuel tank was exactly half empty. The engine is well broken in and flew great in my Ultra Stick. I never had a problem with it dying in flight.
Considering the engine is mounted upside down, should the carb/needle valve still be aligned with 1/4-3/8" down from the top of the tank? I think the fact the engine is in upside down shouldn't matter. If I mount the tank so the fuel lines are lined up with the predrilled holes in the firewall, the bottom of the tank will line up with the carb/needle valve.
I've attached a picture of the plane right side up showing the stock alignment and where I think the tank should be mounted. Any suggestions?
Considering the engine is mounted upside down, should the carb/needle valve still be aligned with 1/4-3/8" down from the top of the tank? I think the fact the engine is in upside down shouldn't matter. If I mount the tank so the fuel lines are lined up with the predrilled holes in the firewall, the bottom of the tank will line up with the carb/needle valve.
I've attached a picture of the plane right side up showing the stock alignment and where I think the tank should be mounted. Any suggestions?
06-09-2002, 04:09 AM
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Fuel tank and Carb alignment
I have often wondered about that particular setup/plane myself.
My suggestion would be to go bubbleless. Tetra or Jett Engineering fuel tanks would eliminate that possiblity.
My suggestion would be to go bubbleless. Tetra or Jett Engineering fuel tanks would eliminate that possiblity.
06-09-2002, 04:48 AM
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Fuel tank and Carb alignment
Daniel:
It is not as critical as upright engine,since the high tank can flood
the lower crankcase making the rich running. I would place tank
just under mfg. location.
What I have found best for inverted engines is using the old idle
bar glow plugs. That bar tends to burn the excess fuel left sitting
down in the cylinder head.
Randy
It is not as critical as upright engine,since the high tank can flood
the lower crankcase making the rich running. I would place tank
just under mfg. location.
What I have found best for inverted engines is using the old idle
bar glow plugs. That bar tends to burn the excess fuel left sitting
down in the cylinder head.
Randy
06-09-2002, 10:12 AM
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Fuel tank and Carb alignment
In any engine position the spraybar should be aligned with the centreline of the tank, viewed from the side.
In your photograph you will need to raise the tank to achieve this.
Ed s
In your photograph you will need to raise the tank to achieve this.
Ed s
06-09-2002, 02:14 PM
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Fuel tank and Carb alignment
I got the 1/4-3/8" from the top of the tank directly from the OS manual for my engine. Is it standard practice to align the center of the tank?
06-09-2002, 06:29 PM
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Fuel tank and Carb alignment
The general rule is for the center line of the tank to be in line with the spray bar as Ed mentioned. As far as your engine
quiting, several things could have caused this. Always check that
your high speed needle is set right by holding the plane vertical with the engine at full throttle and make sure that the engine doesn't sag or slow down from to lean of a mixture. A dirty or old
glow plug can cause a engine to quit in the air after a short run.
Bad fuel, many things to sort out.
quiting, several things could have caused this. Always check that
your high speed needle is set right by holding the plane vertical with the engine at full throttle and make sure that the engine doesn't sag or slow down from to lean of a mixture. A dirty or old
glow plug can cause a engine to quit in the air after a short run.
Bad fuel, many things to sort out.
06-09-2002, 09:40 PM
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Fuel tank and Carb alignment
I would tend to agree with Ted, in that I doubt if the tank location caused your engine to die. The location can and does affect how well the engine runs, but it usually results in being hard or impossible to get a good needle setting that will hold, not the engine quitting at full throttle unless it goes way lean. With the high tank location in your old plane, it would come nearer running better half empty than full, I would think. Try to get the tank lower, but I don't think you should assume that is your main problem. First thing I try in such a situation is a new glow plug.
