Arnaldo Posted August 14 Report Share Posted August 14 Hi. How long the fuel pump last according to Rotax manuals ? Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted August 14 Report Share Posted August 14 For the mechanical pump on the carbureted engine Rotax calls for replacement every 5 years. Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted August 14 Report Share Posted August 14 Rotax would like the pump changed every five years, but many go 8-10. Your choice. It’s extremely rare they fully fail and if one did they fail open. In a high wing you can still get fuel and fly around 5K rpm. If a pump does start to have an issue 98% of the time they just start to leak. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted August 15 Report Share Posted August 15 4 hours ago, Roger Lee said: In a high wing you can still get fuel and fly around 5K rpm. That is assuming that the fuel tanks are in the wings with enough head pressure for gravity feed. Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted August 15 Report Share Posted August 15 I do lots of off the books research to test certain limits. One of them was with the pump. I pulled the inlet and outlet hoses and joined them together. You could run full throttle with head pressure only in our CT. The fuel is high enough over the engine to supply it by gravity feed. Then I put the hoses back on the pump and removed the pump with the hoses on and let it dangle. I placed a blind ver the pump hole. So this would duplicate a totally failed pump. When our pumps fail they fail open. The engine would see 5K rpm, but getting up higher in rpm would make it stumble some. I told Rotax people and no one there ever knew what the real low pressure setting was below it’s recommended 2.2 psi minimum. So in a high wing head pressure alone will run the engine. Low wing aircraft will not do this since the fuel is usually lower than the engine and lacks any head pressure to the engine. I rarely publish my research / testing because it may go against recommendations, but I usually tell the Mfg’s. Mfg limits they publish usually have a liability and safety spec published and rarely the real numbers. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted August 15 Report Share Posted August 15 Roger, you missed my point entirely. Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted August 15 Report Share Posted August 15 9 hours ago, Tom Baker said: Roger, you missed my point entirely. Hi Tom, I do agree. You need a high wing for head pressure. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted August 16 Report Share Posted August 16 My point was not all high wing LSA have fuel in the wings. Some have fuselage tanks. Quote Link to comment Share on other sites More sharing options...
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