drop in RPMs when inverted.
07-14-2013, 08:37 AM
#26
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RE: drop in RPMs when inverted.
Dirtybird
Last Imac event I went to had a fellow there flying a small plane with a 55 AX glow engine in it. He was competing just like the big boys.
As far as a pump adding pressure to existing pressure depends on which end the pump is fitted onand of course the type of pump used, our pumps on the carb on our engine's are used to suck the fuel not put pressure in the tank like a glow engine does. Nor is the pump in the tank so it has to push the fuel, in all cases in a gas engine with a walbro or similar type carb the gas is pulled.
The small amount of pressure that's created when the vent line is inverted is nothing as compared to what that small pump can pull. Some one said 18 Inches A good pump will pull 3 feet straight up.
I myself use a 3 line set up with the filler line plugged after use and have never had an issue of any kind.
Last Imac event I went to had a fellow there flying a small plane with a 55 AX glow engine in it. He was competing just like the big boys.
As far as a pump adding pressure to existing pressure depends on which end the pump is fitted onand of course the type of pump used, our pumps on the carb on our engine's are used to suck the fuel not put pressure in the tank like a glow engine does. Nor is the pump in the tank so it has to push the fuel, in all cases in a gas engine with a walbro or similar type carb the gas is pulled.
The small amount of pressure that's created when the vent line is inverted is nothing as compared to what that small pump can pull. Some one said 18 Inches A good pump will pull 3 feet straight up.
I myself use a 3 line set up with the filler line plugged after use and have never had an issue of any kind.
07-14-2013, 10:21 AM
#27
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RE: drop in RPMs when inverted.
Did you ask the AX glow fellow if he was using a three or a two line or if he had any opinion about this thread? If not what does that have to do with this thread?
It does not matter which end the pump is on. If you doubt that put a 5 ft line on the carb and try to pump it. It will not pump because the pump will not lift it.
The pump creates a vacuum and air ambient air pressure pushes the fuel up the line. The pump does not suck it up. Any change in the ambient air pressure will be reflected in the pump output.
It does not matter which end the pump is on. If you doubt that put a 5 ft line on the carb and try to pump it. It will not pump because the pump will not lift it.
The pump creates a vacuum and air ambient air pressure pushes the fuel up the line. The pump does not suck it up. Any change in the ambient air pressure will be reflected in the pump output.
07-14-2013, 05:05 PM
#28
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RE: drop in RPMs when inverted.
Gentlemen I got to the field today, with the cowl off, I fueled up the SBACH started it up seemed to run good on the stand, I decided to do a little tuning so I richened the LS and HS 1/8th turn, let it run for a couple of minutes then checked throttle from idle to full, with good throttle response through out. I leaned the HS screw just a hair. I decided to take her up without cowl, I noticed just a slight dropped in RPMS when inverted. I brought her in, richened the HS screw reinstalled the cowl took it back up with just a very slight drop in RPMs. I am going to continue tuning the LS and HS again and see what happens. And for those wondering the MINTOR engines have Walbro carbs, I have tried a three line tank set up (16oz 4titude), my fuel is filtered from my field can to the tank and again between the tank and the carb. I checked the carb screen when I had the engine apart to remove the broken carb bolt, found nothing. Thanks for the advice.
07-15-2013, 05:18 AM
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RE: drop in RPMs when inverted.
Did you ask the AX glow fellow if he was using a three or a two line or if he had any opinion about this thread? If not what does that have to do with this thread?
Hey your the one that said IMAC guys fly the big engines I just pionted out not all do.
As far as having anything to do with the thread ,about as much as your asinine statement about the 2 line versus three.
LOL go ahead and ignore the facts on how a fuel pump works, each application is different.
Oh just for kicks stick your finger over a line sometimes DUH!!!!!!!!!!!! it sucks like some others I know.
Hey your the one that said IMAC guys fly the big engines I just pionted out not all do.
As far as having anything to do with the thread ,about as much as your asinine statement about the 2 line versus three.
LOL go ahead and ignore the facts on how a fuel pump works, each application is different.
Oh just for kicks stick your finger over a line sometimes DUH!!!!!!!!!!!! it sucks like some others I know.
