I'd always been curious how much (if any) oil would siphon out of a J-3's A-65 oil tank if the oil filler cap was not properly secured before flight. Also, would a pilot notice the condition before the engine lost all of its oil?
Yesterday, I conducted what I thought was a through pre-flight inspection after completion of the Cub's annual inspection. I'd missed the fact that the oil filler cap was loose, though, and I flew for an hour with it that way. Back at the hangar, I noticed what looked to be a considerable amount of fresh engine oil running back on the right side of the fuselage. It took a while to clean up the mess there and in the cowlings and engine compartment. Duh.
Learned: In that hour of flight, the engine did not lose all of it's oil. The amount of oil lost did not even register on the dip stick. What initially looked to be a hell of a mess was actually very little oil at all. Oil did not blow onto the windshield or into the cabin at the forward door seal, so I did not notice the condition while in flight.
Would the results have been different if the cap had been missing altogether? Don't know.
Yesterday, I conducted what I thought was a through pre-flight inspection after completion of the Cub's annual inspection. I'd missed the fact that the oil filler cap was loose, though, and I flew for an hour with it that way. Back at the hangar, I noticed what looked to be a considerable amount of fresh engine oil running back on the right side of the fuselage. It took a while to clean up the mess there and in the cowlings and engine compartment. Duh.
Learned: In that hour of flight, the engine did not lose all of it's oil. The amount of oil lost did not even register on the dip stick. What initially looked to be a hell of a mess was actually very little oil at all. Oil did not blow onto the windshield or into the cabin at the forward door seal, so I did not notice the condition while in flight.
Would the results have been different if the cap had been missing altogether? Don't know.
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