G
Guest
Guest
40/1
azbill
Active Member
it was recommended to me to run 20-25:1
it will help keep it a little cooler when it gets really hot here (desert)
it will help keep it a little cooler when it gets really hot here (desert)
J
jeffspeeder
Guest
really cuz someone told me that i should run like 50:1 and 40:1 to break in and thay said running to much oil mix will be bad for your motor leaveing a black build up on it. is it true?
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Hugemoth
Guest
It's not true that running more oil in the fuel will make the engine run cooler, in fact it's just the opposite. Oil makes the fuel slightly more viscous so less of it gets through the jets, making the engine run leaner and hotter.
Moth
Moth
G
Guest
Guest
You are correct sir! More oil=leaner fuel mixture.
Ultralight background?
Man, you sure don't want one of those to go quiet on you 100'AGL right over the trees at the end of the runway approach! Made it by about a foot.
Ultralight background?
Man, you sure don't want one of those to go quiet on you 100'AGL right over the trees at the end of the runway approach! Made it by about a foot.
H
Hugemoth
Guest
I've been flying PPCs for 10 years now, Rotax 582. For those who don't know what a PPC is, here's a link to a pic I took of a friend during a flight around the local mountains.
http://img.photobucket.com/albums/v499/QDM/gethigh.jpg
Most ultralights use 2 stroke engines because of the power to weight ratio. The engines are very expensive, over $6000.00 for the one I use so we want to take care of it.
Moth
http://img.photobucket.com/albums/v499/QDM/gethigh.jpg
Most ultralights use 2 stroke engines because of the power to weight ratio. The engines are very expensive, over $6000.00 for the one I use so we want to take care of it.
Moth
Bikeguy Joe said:You are correct sir! More oil=leaner fuel mixture.
Ultralight background?
Man, you sure don't want one of those to go quiet on you 100'AGL right over the trees at the end of the runway approach! Made it by about a foot.
G
Guest
Guest
That's the same engine as the one we use in the two place trainer (fixed wing) my Dad is a BFI.
T
Thejman
Guest
I think i would s**t myself if one of those engines quit on me mid flight. Then again, it would be like a 2 seater airplane just glide, if you could find a spot to land.
G
Guest
Guest
Well, like bicycles, planes can only "coast" so far. The difference is when a bike is done you get off and push, when a plane is done, you hope you find a good place to "quit coasting" and that you can walk away.
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rcjunkie
Guest
Lots of fallacies posted, some already corrected.
Yes, more oil equals leaner mixture. Anything that dispalces fuel (such as oil) results in less fuel per same unit of air...e.g. leaner mixture
For a set air/fuel mixture, increases in altitude result in a richer mixture. If fuel jetting is kept same as you increase altitude, you have less partial pressure of oxygen, meaning that the decrease in 0xygen with same amount of fuel results in a correspondingly richer mixture (relatively more fuel for given volume of air).
The increase in altitude is why airplanes have mixture lever(s) that allow you to lean mixture as you increase in altitude.
If mixture is appropriate for a given altitude, you still will lose 3% horspower for each 1000 feet gain in altitude. At my altitude of 6800 feet, my loss in horsepower is about 20% compared to same engine at sea level. This is why I need a 48-50 tooth sprocket to maintain speed going up steep Colorado Hills.
Yes, more oil equals leaner mixture. Anything that dispalces fuel (such as oil) results in less fuel per same unit of air...e.g. leaner mixture
For a set air/fuel mixture, increases in altitude result in a richer mixture. If fuel jetting is kept same as you increase altitude, you have less partial pressure of oxygen, meaning that the decrease in 0xygen with same amount of fuel results in a correspondingly richer mixture (relatively more fuel for given volume of air).
The increase in altitude is why airplanes have mixture lever(s) that allow you to lean mixture as you increase in altitude.
If mixture is appropriate for a given altitude, you still will lose 3% horspower for each 1000 feet gain in altitude. At my altitude of 6800 feet, my loss in horsepower is about 20% compared to same engine at sea level. This is why I need a 48-50 tooth sprocket to maintain speed going up steep Colorado Hills.
