I was wondering if anyone has heard of adding a heatsink to the 912UL fuel pump. The purpose would be to cool the fuel somewhat maybe heading off vapor lock. On the legacy -12 the pump sets just inside the right air intake hole slightly to the left so a heatsink extending off the end of the pump would catch the fresh air entering the cowl. After a flight I measured the gearbox temp at 190f and the fuel pump temp at 160f. The pump mounting insulator is helping stop some of the heat transfer but I would think a cooler pump couldn't hurt things.
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heatsink on fuel pump
- Thread starter seagull
- Start date
Piper J3
Well Known Member
You are correct to be concerned about vapor lock with 912ULS…. it happened to me on climb out several years ago. Engine shook so violently I thought it would come loose from the mount.
Cooling the mechanical fuel pump is not the solution. The 912ULS has fuel lines routed on top the engine which get “heat-soaked” when engine is shut off and/or during ground ops. The RV-12 has a very tightly-cowled engine with only two small air inlets. Taxiing downwind doesn’t permit much cooling. This is what caused my vapor lock when doing repeated take-offs with long taxi back to departure end of runway.
Van’s issued a SL-00078 May 10, 2023 specifically addressing vapor lock when using winter-blend auto fuel. Van’s also made a video titled Mogas in Aviation
Both the Service Letter and video should be required reading, with complete understanding and acceptance, for anyone operating Rotax 912ULS.
You might also be interested in this thread…. https://vansairforce.net/threads/vapor-lock-rv-12-rotax-912uls.194385/
Cooling the mechanical fuel pump is not the solution. The 912ULS has fuel lines routed on top the engine which get “heat-soaked” when engine is shut off and/or during ground ops. The RV-12 has a very tightly-cowled engine with only two small air inlets. Taxiing downwind doesn’t permit much cooling. This is what caused my vapor lock when doing repeated take-offs with long taxi back to departure end of runway.
Van’s issued a SL-00078 May 10, 2023 specifically addressing vapor lock when using winter-blend auto fuel. Van’s also made a video titled Mogas in Aviation
Both the Service Letter and video should be required reading, with complete understanding and acceptance, for anyone operating Rotax 912ULS.
You might also be interested in this thread…. https://vansairforce.net/threads/vapor-lock-rv-12-rotax-912uls.194385/
