SkyCaptain109 Posted December 6, 2014 Share Posted December 6, 2014 I have a few questions about the electrical fuel pump: In the manual it says the electrical fuel pump must not be run for more than 30 seconds, so do I have to turn it off after T/O? When I do this the fuel pressure drops and the engine quits which I don't understand because P1+P2 fuel pumps are running? And also what is the winter start handle all about? I know it's used for cold weather start up but what does it do? How does it work? Link to comment Share on other sites More sharing options...
SkyCaptain109 Posted December 7, 2014 Author Share Posted December 7, 2014 In the original manual it says that you have to turn on the electric fuel pump when the fuel pressure at high altitudes drops below a certain pressure, so this means the electric fuel doesn't have to be switched on all the time. But when I switch it off after T/O the engine quits.:cry: Link to comment Share on other sites More sharing options...
fastfreddie Posted December 7, 2014 Share Posted December 7, 2014 In the original manual it says that you have to turn on the electric fuel pump when the fuel pressure at high altitudes drops below a certain pressure, so this means the electric fuel doesn't have to be switched on all the time. But when I switch it off after T/O the engine quits.:cry: Just leave it on ... haven't seen the fuel pump die yet. Link to comment Share on other sites More sharing options...
Altflieger Posted December 8, 2014 Share Posted December 8, 2014 Turned mine off after start up, taxiied out to runway and crashed on take off. Did the same, crashed again. Third time got up in the air but the wings are fluttering up and down?, turn on pump and effect disappears? And it's not the joystick doing this, just weird. Explanation Yoyo? Link to comment Share on other sites More sharing options...
SkyCaptain109 Posted December 9, 2014 Author Share Posted December 9, 2014 According to the original manual the electric fuel pump is only used during T/O and landing as a back up for the engine driven pump and at high altitudes to prevent vapor lock. So the engine shouldn't quit when you turn it off in low level flight. In the DCS Manual it says that the P1+P2 are fuel pumps which I think is not correct. They are just fuel cocks allowing the engine driven fuel pump to take the fuel from the rear and front part of the fuel tank. Those are different fuel lines including their own fuel filters. This system must be checked prior to take off. Link to comment Share on other sites More sharing options...
Random Posted December 9, 2014 Share Posted December 9, 2014 Anyone tried turning off the fuel pump breaker rather than the big lever on the throttle box? Link to comment Share on other sites More sharing options...
SkyCaptain109 Posted December 9, 2014 Author Share Posted December 9, 2014 I tried it. P1+P2 selected, electric fuel pump circuit breaker out--> Fuel pressure drops and engine quits. That should not happen because there is still the engine driven fuel pump. Link to comment Share on other sites More sharing options...
SkyCaptain109 Posted December 12, 2014 Author Share Posted December 12, 2014 After reading the Bf109 Workshop Manual by Malcolm Lowe and Paul Blackah I can confirm, that the electric fuel pump is only used for take off and landing, so the engine should not quit after turning it off. P1+P2 are no fuel pumps, only fuel lines including filters. Still don't know what the winter start handle does. Link to comment Share on other sites More sharing options...
Belphe Posted December 12, 2014 Share Posted December 12, 2014 Still don't know what the winter start handle does. Page 99 of the Manual says: "Cold Weather Start Handle (not implemented)". Never say never, Baby! [sIGPIC][/sIGPIC] Link to comment Share on other sites More sharing options...
SkyCaptain109 Posted December 12, 2014 Author Share Posted December 12, 2014 I read through the manual for the Bf109 F, which mentions a cold start system, actuated by the mechanics through a lever outside: When starting in cold weather fuel is allowed into the oil system to make the oil thinner, which leads to lower oil pressures. Obviously in the Bf109 K4 the lever is in the cockpit actuated by the pilot. So it's like the oil dilution switch in the Mustang. Link to comment Share on other sites More sharing options...
sobek Posted December 12, 2014 Share Posted December 12, 2014 AFAIK winter start handle supposedly changes the ignition timing. It has nothing to do with oil dilution. Good, fast, cheap. Choose any two. Come let's eat grandpa! Use punctuation, save lives! Link to comment Share on other sites More sharing options...
fastfreddie Posted December 13, 2014 Share Posted December 13, 2014 I started losing fuel pressure today while running the engine at max for short periods of time. If I reduced speed down to 2500 Rpm the fuel pressure would gradually come back to normal. I just leave the fuel pump on because turning it off seems bugged or doesn't work as the manual states. This happened with MW50 on or off but it didn't begin until a refuel/rearm stop. Link to comment Share on other sites More sharing options...
GumidekCZ Posted December 18, 2014 Share Posted December 18, 2014 Please move this toppic about electric fuel pump into "Bugs and Problems". P1+P2 are able to feed the engine when the engine is actualy running. Link to comment Share on other sites More sharing options...
Zooker Posted December 19, 2014 Share Posted December 19, 2014 I started losing fuel pressure today while running the engine at max for short periods of time. If I reduced speed down to 2500 Rpm the fuel pressure would gradually come back to normal. Had this problem myself, with fuel pump circuit breaker IN. Any idea of the cause? VF-111 Sundowners [sIGPIC][/sIGPIC] Carrier Group 1 - Battlegroup Delta Beware the lessons of a fighter pilot who would rather fly a slide rule than kick your ass! -Commander Ron "Mugs" McKeown, USN Commander, U.S. Navy Fighter Weapons School 2 Victories, Vietnam Link to comment Share on other sites More sharing options...
Zooker Posted December 19, 2014 Share Posted December 19, 2014 Just realized my generator circuit breaker was in the OFF position. I'm assuming my fuel pumps weren't operating with the generator off. VF-111 Sundowners [sIGPIC][/sIGPIC] Carrier Group 1 - Battlegroup Delta Beware the lessons of a fighter pilot who would rather fly a slide rule than kick your ass! -Commander Ron "Mugs" McKeown, USN Commander, U.S. Navy Fighter Weapons School 2 Victories, Vietnam Link to comment Share on other sites More sharing options...
SkyCaptain109 Posted December 19, 2014 Author Share Posted December 19, 2014 Yes please move this thread to "Bugs and Problems". Link to comment Share on other sites More sharing options...
SkyCaptain109 Posted December 28, 2014 Author Share Posted December 28, 2014 Did some more testing: During taxi and run up I switched the electric fuel pump off, the engine didn't quit which is correct. But in flight the engine still quits, however at low power settings it takes a while. Link to comment Share on other sites More sharing options...
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