Well, Pilot error!!!!!!! I turned off the auto mixture control, and now I can lean it out with the fuel flow gauge and everything works perfectly.

 

Good to hear, I had just read your previous post and was about to exclaim man there is something wrong with your Maule!!

Interesting read indeed! However, even though I LOVED taking care of the mixture in FSX (usually simply by listening to the engine), I am using auto-mixture in Flight right now... There simply isn't a proper way to set the mixture as it is now, at least not a way that works in all planes.

Well, I've seen the question of "how to use the mixture" come up a few times here, so I thought exploring it would be a good thing. Once it's gathered a few days of feedback for corrections and improvements, I'll submit it to the Tutorials section.

 

And please do offer comments or suggestions. I'm always trying to learn more myself.

I try to watch the fuel flow. But mostly just listen to the engine. The problem with that is it doesn't seem like altitude matters much in Flight, or at least very little difference. I find myself constantly going into settings to make sure it's still on manual control. It says to lean the engine at above 5000 ft. But I find that even at a few hundred feet or maybe just 1000 the mixture can be leaned to about 25% before there is significant sputter. I mean, it just feels like the entire % range is wasted in a sense... like there is 2 settings. Full rich for take off and landing, and leaned at about 25%ish.... while flying at pretty well any altitude.

 

Any pilots out there, is this really how quickly you can lean? Or do you go in stages like acutally leaning a little bit at a time as your altitude climbs above 5000 ft?

Once it's gathered a few days of feedback for corrections and improvements, I'll submit it to the Tutorials section.

If you want to go seriously in depth past mixture and get into engine power percents (since they are all tied together in a loose knot sort of way, mostly when it comes to fuel consumption) here are the manuals for the Maule and RV-6 engines respectively:

 

Lycoming IO-540-V

Lycoming AEIO-320 (unsure if it's the 150 or 160HP model, they're near enough as makes no difference)

 

The others aren't all that interesting. The ICON's ROTAX 912 ULS has automixture, The Cub is always cruised at max 44.4% power. <_< And I haven't a clue what engine the Stearman uses. So that one could be interesting. Edit: Continental R-670-5. That was easy. Time to hunt down the manual.

Oh, good resources... I was thinking about digging those up. I have the Maule's POH, but it's a little sparse on engine-management information. The RV-6, as an experimental-class, has little to even look for POH-wise. I did find a couple of examples that builder/owners have posted online, though.

 

Thanks!

Well, I've seen the question of "how to use the mixture" come up a few times here, so I thought exploring it would be a good thing. Once it's gathered a few days of feedback for corrections and improvements, I'll submit it to the Tutorials section.

 

Excellent job on this with some great information, your efforts on this are very much appreciated!

Oh, good resources...

I updated the IO-320 link with a much cleaner manual. Same quality as the IO-540.

The problem with that is it doesn't seem like altitude matters much in Flight, or at least very little difference. I find myself constantly going into settings to make sure it's still on manual control. It says to lean the engine at above 5000 ft. But I find that even at a few hundred feet or maybe just 1000 the mixture can be leaned to about 25% before there is significant sputter. I mean, it just feels like the entire % range is wasted in a sense...

 

It's most surely table-based, without interpolation in between, like it was on MSFS5,6,...X I can't recall the exact record for it, but I sure one could find at somewhere at Hervé's site...

Or do you go in stages like acutally leaning a little bit at a time as your altitude climbs above 5000 ft?

 

I start leaning at a density altitude of 3000 feet in a c172. That might be on the ground if I want to make sure that I have full performance when taking off on a hot day.

 

I will lean a little more every thousand feet. if the engine starts to runs rough I enrichen a little. Once I get established at cruise altitude I will lean out and monitor EGT to get about 50 degrees LOP.

 

 

The mixture knob on the aircraft I use only pulls out about 2 inches and it is out about three quarters of an inch at 3k feet. At around 6k feet it will be out about one and a quarter inches. I'm guessing at these positions because I put it wherever it needs to be and don't really get concerned with the position unless it is very out of place.

 

I am not able to lean anywhere near as much as flight allows at low altitudes without the engine stumbling.

I start leaning at a density altitude of 3000 feet in a c172. That might be on the ground if I want to make sure that I have full performance when taking off on a hot day.

 

I will lean a little more every thousand feet. if the engine starts to runs rough I enrichen a little. Once I get established at cruise altitude I will lean out and monitor EGT to get about 50 degrees LOP.

 

 

The mixture knob on the aircraft I use only pulls out about 2 inches and it is out about three quarters of an inch at 3k feet. At around 6k feet it will be out about one and a quarter inches. I'm guessing at these positions because I put it wherever it needs to be and don't really get concerned with the position unless it is very out of place.

 

I am not able to lean anywhere near as much as flight allows at low altitudes without the engine stumbling.

 

 

The mixture knob on the aircraft I use only pulls out about 2 inches and it is out about three quarters of an inch at 3k feet. At around 6k feet it will be out about one and a quarter inches. I'm guessing at these positions because I put it wherever it needs to be and don't really get concerned with the position unless it is very out of place.

 

I am not able to lean anywhere near as much as flight allows at low altitudes without the engine stumbling.

 

I would never lean on Takeoff. This is stipulated in the Pilots Operating Manual for the C-172.

I would never lean on Takeoff. This is stipulated in the Pilots Operating Manual for the C-172.

 

You will, if you're flying out of the airport next to my house. 4600' msl, and leaning is standard practice. Start the engine full rich, then immediately lean. Before takeoff, check the mixture again. When you dig into operating manuals, or engine manuals, you'll usually find the 5000' density altitude situation somewhere, and especially in check lists for high altitude airport operations. Mountain flying books will always suggest thinking about leaning at 3000' density altitude. If you do take off at our airport without leaning, you can count on a loss of power. In fact, the engine will run noticeably crappy, if you don't lean to just taxi. And then you'll have to burn excess oil off the spark plugs during the mag check.

 

edit: additional facts. Around here, we never go to full rich, except startup. Landing is never full rich either.

To see high altitude leaning in action at takeoff, load up the RV-6 at Bradshaw.

 

Set the parking brake, then go 100% throttle/prop/mix. The RPM will tap out at 2593. Pull back the mix 5% at a time. The numbers will increase each 5% until it redlines at 70% mix. Now shove the mix back to 100% and listen to the effect it has on the engine. If you proceed to take off at 100% mix and 2593 RPM the RPM will climb as you proceed down the strip due to the ram air effect, but your total take off distance will be longer than if you had mixed to max RPM before releasing the brakes.

 

Even if you do a normal takeoff (brakes off, start at 0% throttle, move to 100% throttle) you will gain RPM more quickly with the mix leaned to 70%. Obviously this specific percentage only applies to Bradshaw and airports of similar elevation. Higher lean more, lower enrich more. Until below 3000' where it's full mix.

 

As far as POH's, pretty much every one I've looked at has high altitude instructions that explicitly say to lean to max RPM when above 3000'. Flight even mentions this in the checklists.

You will, if you're flying out of the airport next to my house. 4600' msl, and leaning is standard practice. Start the engine full rich, then immediately lean. Before takeoff, check the mixture again. When you dig into operating manuals, or engine manuals, you'll usually find the 5000' density altitude situation somewhere, and especially in check lists for high altitude airport operations. Mountain flying books will always suggest thinking about leaning at 3000' density altitude. If you do take off at our airport without leaning, you can count on a loss of power. In fact, the engine will run noticeably crappy, if you don't lean to just taxi. And then you'll have to burn excess oil off the spark plugs during the mag check.

 

edit: additional facts. Around here, we never go to full rich, except startup. Landing is never full rich either.

 

Having got my license in the Miami, Florida area, I guess my knowledge of high elevation procedures is probably not up to snuff. Point taken....

Thanks for all the good info! I haven't been starting to lean until around 2500' to 3000' feet, so that's good. Having never flown a real A/C it's hard for me to know how accurate flight is.

 

*** Flew in a state-of-the-art training simulator once (in the Canadian military), for a CP 140 (P3)... but since it's a turbo prop and all there was no mixture involved.

 

Also if you're mixture is pulled out 1 1/4 " out of about 2" at roughly 6k', that's roughly 38% left to pull. Which is not too far off where I have my lever sitting... 25%-30%. (although Flight will allow me to lean to 15% and still be pretty ok) On my Saitek quadrant, it probably just feels weird since all levers have a long path from 0-100.