flyingcheesehead
Touchdown! Greaser!
Twice this weekend, I had something odd happen - I landed for fuel, heard a gurgling noise coming from the fuel vent (I have a single vent on the left tank with a crossover to the right) and when I took off the fuel cap I got a whooshing sucking noise.
At first, I suspected a blocked fuel vent (nothing visible blocking it though). The engine seemed to run fine, though, and I fueled both sides equally (close, anyway: 30 gallons left, 33 right). So, I suspected some sort of one-way valve in the fuel vent, but nobody I talked to had ever heard of such a thing and neither have I.
Then, when it happened again, I got another surprise: It wasn't sucking, it was blowing! So now the mystery expands: Where the heck is high-pressure air coming from???
This happened twice over the weekend, but not every flight. Here are the details:
Happened:
1) Short flight, KOSH-KCLI (37nm), 4500 feet. Fairly low tanks - 79 useable, added 63.
2) Longer flight, KCAD-MBL-MTW-63C, 12,000 feet over the lake. Fairly low again, ended up putting in 52 gallons (again, very close between tanks - 25.7 left, 26.3 right).
Didn't happen:
1) KCLI-KMDW. Started with full tanks, flew about 1.5 at a max altitude of 7500. No gurgling noise. Wasn't present for the 10 gallons that were added.
2) KMDW-KCAD. Started nearly full, flew a couple of hours at 7500 feet. Did not add fuel, but no gurgling noise either.
3) 63C-KMSN. Short flight, 3500 feet, no gurgling, did not add fuel.
I fly this plane a LOT and this has not happened before. Any ideas?
At first, I suspected a blocked fuel vent (nothing visible blocking it though). The engine seemed to run fine, though, and I fueled both sides equally (close, anyway: 30 gallons left, 33 right). So, I suspected some sort of one-way valve in the fuel vent, but nobody I talked to had ever heard of such a thing and neither have I.
Then, when it happened again, I got another surprise: It wasn't sucking, it was blowing! So now the mystery expands: Where the heck is high-pressure air coming from???
This happened twice over the weekend, but not every flight. Here are the details:
Happened:
1) Short flight, KOSH-KCLI (37nm), 4500 feet. Fairly low tanks - 79 useable, added 63.
2) Longer flight, KCAD-MBL-MTW-63C, 12,000 feet over the lake. Fairly low again, ended up putting in 52 gallons (again, very close between tanks - 25.7 left, 26.3 right).
Didn't happen:
1) KCLI-KMDW. Started with full tanks, flew about 1.5 at a max altitude of 7500. No gurgling noise. Wasn't present for the 10 gallons that were added.
2) KMDW-KCAD. Started nearly full, flew a couple of hours at 7500 feet. Did not add fuel, but no gurgling noise either.
3) 63C-KMSN. Short flight, 3500 feet, no gurgling, did not add fuel.
I fly this plane a LOT and this has not happened before. Any ideas?