Debra
04-27-2007, 04:31 PM
I am fairly new to flying R/C and just recently I outgrew my high-wing trainer. I just bough a Tower Hobbies ARF low wing aerobat and equipped it with a brand new O.S MAX .46LA. After building the model I took it out to the field and broke in the engine as instructed by the manual and put 2 gentle flights on the model afterwards without fail. My problem is that there is a slow drip of fuel coming from the carb when the motor is not being ran after the tank is filled. Is this normal for inverted 2-strokes? Seems like if it is leaking like this it would cause a miss-adjustment or issues during flight. Please explain.
Thanks in advance,
B.
Dear B.,
Any fuel in the fuel tank that is higher than the needlevalve is going to run out. Where is the centerline of your fuel tank in relation to the needlevalve? The centerline of the fuel tank should be even with, or preferably, 1/4 - 3/8" lower. With the inverted engine installation, yours is probably higher?
With an upright engine the fuel would run into the carburetor flooding the engine, so it is common procedure to either pinch the fuel line after filling the tank with a pair of hemostats or just leave the fuel line disconnected with the end higher than the top of the tank until ready to start the engine. With a trike-gear ship, just throw a rag over the tail and let the ship set on it's tail.
As for the effect on performance - this is why engines tend to run leaner towards the end of a tank, i.e., you have gravity feed for the first half,
and suction feed the second half. Muffler pressure helps, but not completely.
Good flying
Clarence Lee
Thanks in advance,
B.
Dear B.,
Any fuel in the fuel tank that is higher than the needlevalve is going to run out. Where is the centerline of your fuel tank in relation to the needlevalve? The centerline of the fuel tank should be even with, or preferably, 1/4 - 3/8" lower. With the inverted engine installation, yours is probably higher?
With an upright engine the fuel would run into the carburetor flooding the engine, so it is common procedure to either pinch the fuel line after filling the tank with a pair of hemostats or just leave the fuel line disconnected with the end higher than the top of the tank until ready to start the engine. With a trike-gear ship, just throw a rag over the tail and let the ship set on it's tail.
As for the effect on performance - this is why engines tend to run leaner towards the end of a tank, i.e., you have gravity feed for the first half,
and suction feed the second half. Muffler pressure helps, but not completely.
Good flying
Clarence Lee