Re: Worrying power loss on take-off
Some interesting points. Thanks.
I (with an engineer) have been doing some investigative work on her this afternoon. We tried to replicate the situation with no luck and she runs fine which frustrates me somewhat as I was hoping for the same thing to happen when he was there.
We checked the fuel flow which was fine. The fuel filter is clear. The feed to the carb is therefore ok. We did notice that Carb Heat "cold" was giving about 25% hot air deflection which we have corrected. Unless mistaken, I don't think this would have caused the sudden drop. Tomorrow he is going to take the carb off and give it a good inspection and clean out in case it has muck in it.
My only other thought has been inspired from a post above. Before she went in for the top OH she did have a fair bit of MOGAS in her main tanks and wing tanks. We syphoned the three tanks out after the overhaul as the temps at the moment are 34 degrees here. When she went in for work they were around 16 degrees so MOGAS was ok to fly on then. After syphoning out the tanks we put 7 gallons of AVGAS in the main tank and ran her up on that. I flew her for 20 minutes and she was fine. Whilst flying in the afternoon (shortly before the trouble started) I recall turning the tap to drain the remnants of the MOGAS into the main tank that hadn't come out of the wing tanks when we syphoned them. There must have been about 3 gallons of MOGAS (more than I expected) that would have drained on top of approx 6 gallons of AVGAS that remained in the main tank after my 20 minute flight earlier in the day. It was definitely after I did this that the problems at full power started.
The MOGAS in the wing tanks would have been 7 weeks old and the temps have been high recently. My question is whether there is a chance that diluting AVGAS with 1/3 ratio of 7 week old MOGAS might have caused the problem at high power settings?
Ideas (however unusual) welcome?
Some interesting points. Thanks.
I (with an engineer) have been doing some investigative work on her this afternoon. We tried to replicate the situation with no luck and she runs fine which frustrates me somewhat as I was hoping for the same thing to happen when he was there.
We checked the fuel flow which was fine. The fuel filter is clear. The feed to the carb is therefore ok. We did notice that Carb Heat "cold" was giving about 25% hot air deflection which we have corrected. Unless mistaken, I don't think this would have caused the sudden drop. Tomorrow he is going to take the carb off and give it a good inspection and clean out in case it has muck in it.
My only other thought has been inspired from a post above. Before she went in for the top OH she did have a fair bit of MOGAS in her main tanks and wing tanks. We syphoned the three tanks out after the overhaul as the temps at the moment are 34 degrees here. When she went in for work they were around 16 degrees so MOGAS was ok to fly on then. After syphoning out the tanks we put 7 gallons of AVGAS in the main tank and ran her up on that. I flew her for 20 minutes and she was fine. Whilst flying in the afternoon (shortly before the trouble started) I recall turning the tap to drain the remnants of the MOGAS into the main tank that hadn't come out of the wing tanks when we syphoned them. There must have been about 3 gallons of MOGAS (more than I expected) that would have drained on top of approx 6 gallons of AVGAS that remained in the main tank after my 20 minute flight earlier in the day. It was definitely after I did this that the problems at full power started.
The MOGAS in the wing tanks would have been 7 weeks old and the temps have been high recently. My question is whether there is a chance that diluting AVGAS with 1/3 ratio of 7 week old MOGAS might have caused the problem at high power settings?
Ideas (however unusual) welcome?
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