chris
Well-Known Member
Hey guys,
Got some Qs regarding mixture control and fuel injection. These come after reading the "mixture magic" article on avweb (pelican's perch).
1. Let's say I'm flying at 9,000 ft and I've leaned to peak EGT. If I change my power, will I have to relean it or enrichen it again? I always thought it would be necessary to enrichen your mixture with power increases (more power= more air= more fuel needed). Or, if its a fuel injection engine, will the fuel air control unit take care of this? Does it differ for carb engines?
2. Why is it that fuel injection engines pose more problems with hot starts? What makes them more prone to fuel vaporization? ie. why is it that it is recommended to wait 45 minutes to restart a fuel injected engine after shutdown?
3. The author of the article suggested that if you have problems trying to start a hot fuel injected engine, you should turn the fuel pump on and bring the mixture to ICO for 60-90 seconds- how does this do anything? I understand that if the mixture was rich you would certainly flood the engine, but if the mixture is at ICO, can you still get fresh cool fuel flowing thru the lines (i.e if the mixture control is at ICO, I thought all fuel flow is stopped?) I've never heard of this technique before and I found it odd.
4. Why is it that when starting the plane, if its a cold start, the mixture control is full rich, and if it's a hot start, the control is at ICO? There's probably a simple answer to this one which I am completely overlooking.
Also, if anyone read the article, what do you think of it? Do you agree with his recomendations and opionion? I really liked his article on Manifold Pressure and Props, but this one was a little tougher to follow.
Thanks in advance.
Got some Qs regarding mixture control and fuel injection. These come after reading the "mixture magic" article on avweb (pelican's perch).
1. Let's say I'm flying at 9,000 ft and I've leaned to peak EGT. If I change my power, will I have to relean it or enrichen it again? I always thought it would be necessary to enrichen your mixture with power increases (more power= more air= more fuel needed). Or, if its a fuel injection engine, will the fuel air control unit take care of this? Does it differ for carb engines?
2. Why is it that fuel injection engines pose more problems with hot starts? What makes them more prone to fuel vaporization? ie. why is it that it is recommended to wait 45 minutes to restart a fuel injected engine after shutdown?
3. The author of the article suggested that if you have problems trying to start a hot fuel injected engine, you should turn the fuel pump on and bring the mixture to ICO for 60-90 seconds- how does this do anything? I understand that if the mixture was rich you would certainly flood the engine, but if the mixture is at ICO, can you still get fresh cool fuel flowing thru the lines (i.e if the mixture control is at ICO, I thought all fuel flow is stopped?) I've never heard of this technique before and I found it odd.
4. Why is it that when starting the plane, if its a cold start, the mixture control is full rich, and if it's a hot start, the control is at ICO? There's probably a simple answer to this one which I am completely overlooking.
Also, if anyone read the article, what do you think of it? Do you agree with his recomendations and opionion? I really liked his article on Manifold Pressure and Props, but this one was a little tougher to follow.
Thanks in advance.