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- Jul 6, 2016
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Hi Guys
Bit of an unusual problem on first test of my Laser 200 fitted, with an IO-360. It's got a few of us stumped so I'll give you guys all the info and I'm sure the collective knowledge on here will come up with something i haven't thought of.
So flight test 1, usual profile, climb into the overhead, all temps, pressures and fuel flows look good, then after reducing manifold pressure and rpm the engine immediately dies. No reduction in fuel pressure, or any other indication to warn of an issue on the IEFIS.
Dead stick landing back in, not ideal but no big problem. After landing we notice there is fuel pouring out of the inverted fuel vent line... Could these issues be linked?
Before the first flight we had completed all of the usual fuel flow tests. We had also done a good amount of high power ground running (limited by engine break in/temps) including this same throttling back profile that caused the in flight stoppage. We also never saw this overflow and syphon from the inverted vent line. We sent the fuel servo off to be run on a flow bench and it came back normal with a clean bill of health.
We ran a number of tests to confirm that the one way shuttle valves between the main and acro tank operated as expected. We also blocked up all breathers to see how long the electric pump could run for pulling the tank under vacuum. I also tried to optimize the vent line routing to go as high as possible above the tank before heading down to the belly.
After trying all of the above we carried out more ground running before attempting flight two this last weekend. Climbed much higher before reducing the throttle demand but had the exact same engine stoppage, second dead stick landing all ok but sure enough fuel pouring out of the inverted breather....
Only thing i can think of is removing the one way shuttle valves from the tank in case they are somehow not letting fuel into the acro tank and there is some sort of pressure issue created. I still don't understand how that works out that the engine runs ok at high power demand but suddenly quits when the power is brought back??? Or are these two separate issues?
Any ideas?
Bit of an unusual problem on first test of my Laser 200 fitted, with an IO-360. It's got a few of us stumped so I'll give you guys all the info and I'm sure the collective knowledge on here will come up with something i haven't thought of.
So flight test 1, usual profile, climb into the overhead, all temps, pressures and fuel flows look good, then after reducing manifold pressure and rpm the engine immediately dies. No reduction in fuel pressure, or any other indication to warn of an issue on the IEFIS.
Dead stick landing back in, not ideal but no big problem. After landing we notice there is fuel pouring out of the inverted fuel vent line... Could these issues be linked?
Before the first flight we had completed all of the usual fuel flow tests. We had also done a good amount of high power ground running (limited by engine break in/temps) including this same throttling back profile that caused the in flight stoppage. We also never saw this overflow and syphon from the inverted vent line. We sent the fuel servo off to be run on a flow bench and it came back normal with a clean bill of health.
We ran a number of tests to confirm that the one way shuttle valves between the main and acro tank operated as expected. We also blocked up all breathers to see how long the electric pump could run for pulling the tank under vacuum. I also tried to optimize the vent line routing to go as high as possible above the tank before heading down to the belly.
After trying all of the above we carried out more ground running before attempting flight two this last weekend. Climbed much higher before reducing the throttle demand but had the exact same engine stoppage, second dead stick landing all ok but sure enough fuel pouring out of the inverted breather....
Only thing i can think of is removing the one way shuttle valves from the tank in case they are somehow not letting fuel into the acro tank and there is some sort of pressure issue created. I still don't understand how that works out that the engine runs ok at high power demand but suddenly quits when the power is brought back??? Or are these two separate issues?
Any ideas?
