How To Lean Your Engine: Boldmethod Live
2019 ж. 30 Қыр.
24 267 Рет қаралды
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How should you lean your engine? Is it OK to run lean of peak? Or should you always lean rich of peak?
Tune in to find out!
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This is a fantastic presentation! I have a background in engines from tinkering with cars and motorcycles. Most of the things you hear people get wrong, these guys got absolutely right. Normally you have to seek out the technical writings of a race-engine tuner to find some of the nuggets that were hit upon in this. The explanation of octane was literally perfect given the time and scope of the talk. No one goes the extra mile to point out that octane is a hydrocarbon molecule. For those interested, technically the octane rating is an equivalence thing and avgas has a relatively low amount of actual octane molecules (at least compared to other high-test fuels). This is because octane is heavier than most of the other hydrocarbons in gasoline, and in aviation we have a thing about weight. Compared to a similar octane-rating race gas, avgas produces a bit less power because those lighter molecules contain less energy. If you use avgas in a carbureted motorcycle, for example, the lighter molecular weight actually requires you to change your jetting, much like when switching between ethanol and non-ethanol gas. In order to get the high rating, avgas uses more stabilizing and flame-retardant compounds (including but not limited to lead) to prevent detonation and pre-ignition. That doesn't help power either, but it gives us the safety margin we seek, and a weight-efficient fuel. By looking at airplane engines, you can tell that ultimate power is way down the priority list - these things are slugs for their size. In racing they'd rather have the extra power over the slight weight savings, and they pay even more per gallon than we do in aviation. Plain car pump gas is amateur hour compared to either of them, but is much better for the environment, and obviously much cheaper.
One of the best videos I’ve seen yet about leaning and engine operations. Good job !
Excellent presentation!
Absolutely useful! Thank You!! Great Channel, keep it up.
You are the best guys! Please keep up the good content
Great info thank you.
Barometric pressure has an effect on this as well. That is the air pressure around you. The higher the better for HP.
You guys are amazing! Thank you
Спасибо!
Very good tutorial. Great presentation. Good visual aids. Thank you
Thanks
This is so helpful and your explanation is brilliant. You took a lot of time to do this and I thank you.
Always great stuffs.
Exelent explanation. Just one question. You've showed how to lean by RPM (ex.old 172), but what about when you have constant speed propeller, and you've got tacometer and manifold pressure gauges (like my old 182). ??
I think with a constant-speed but no EGT, you're supposed to lean by sound and feel. When the engine makes peak power, you may hear the prop taking a bigger bite, and the plane will want to trim out faster. The engine will also sound more "healthy", for lack of a better technical term. LOP would be easy to find - just pull the red knob until you get rough running, then put it in to the leanest setting where the engine is smooth. In my experience with fixed-prop 172s, the tach doesn't ever seem to move at all between peak and grossly rich, so I'm doing basically the same thing I just recommend to you in your 182.
Boise Idaho
Great explanations and graphics. I have a question though. Does altitude density have anything to do with leaning?
Absolutely.
As density altitude increases your ability to produce horsepower (and burn fuel decreases)
Maybe I should restate. When leaning, do you use density altitude or pressure altitude? eg. when leaning above 3000 ft, should that be density altitude?
@@dvsmotions Ask a CFI but I would say 3000 Density Altitude because that what the engine feels. The engine has never heard of an altimeter. Thats my simple logic. Not a professional.
Hi there hope this question can still get answered but just wondering about high density altitude takeoff and the mixture required for best power? Kind regards
High DA in a Lycoming powered engine will be managed by the Carby or the Fuel Control Unit reasonably well. If you have EGT data you can make a small adjustment to about 1300dF on the takeoff roll. On a Continental engine without the ACFP which is most engines you will need to manually lean, and again to about 1300dF. BEWARE.....turbo charged engines must be full rich for all takeoffs regardless of DA because they are boosted to the desired MAP and not subject to MAP loss from DA. If you want to read more search out Jogn Deakins Pelican Perch articles on AvWeb. or www.advancedpilot.com
@@jaba430 thank you so much for this reply been amazingly helpful Best regards
What are x and y axis on graph?
why don't use water injection to cool the engine. operating at peak EGT and if is too hot then inject water. mass of water no problem because you need less water vs fuel for cooling effect
That’s beautiful intro! Where is that airport though?
What about leaning for taxiing?
Thanks great info
How do you capture your PFD?
First you should dig a hole. Fill hole with wood. Burn to ash. When pfd walks up to hole and looks in, kick it in the ash hole.
Isn't leaning to peak EGT and then enriching 50 degrees older "conventional wisdom"? I've read that Lycoming and Continental have updated and modified their recommendations to not find peak EGT. Peak EGT is also peak cylinder pressure, which is hard on the engine. The new wisdom is to lean quickly to engine roughness and then richen just enough that the engine doesn't complain. This minimizes the amount of time that the rpm is in the danger zone of peak EGT and peak pressure. ???
My understanding is that peak EGT is fine as long as the engine is not producing maximum power. I think Lycoming says 75% horsepower and below and Continental 65% and below. So at altitude or with less than full throttle operations, assuming good fuel, you should be safe to experiment around. POH should have a chart to determine when you're in the safe range. Safe to say, full throttle at sea level it's a no-go zone for finding peak EGT. I heard that the safest way to find your LOP target is to go "too lean" like you said, and then find the peak from there, because you get to it much quicker from the lean side. Peak CHT and peak power are usually on the rich side of peak EGT, so it's safer to poke around on the lean side than the rich side.
Could someone share the bgm at the clip in the beginning please thanks
You may want to adjust that 50 ROP number, based on todays' engines.