Engine Leaning Altitude for Cruise

ARFlyer

ARFlyer

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ARFlyer
Our Club MX is complaining that we are burning through mufflers like crazy. They want us to stop leaning until around 5-6k. Currently our manual states for the pilot to lean when above 3000' in cruise.

Any of yall have any good input or the best place to find guidance ?
 
A) How did they determine leaning was burning up the mufflers?

B) If it costs you nothing (wet rate) and causes no operational safety issue where you as PIC need to do it, why care? Do what they want? It's their gas bill.

Unless... In your setup it isn't?

Depends on what altitudes everyone flies at regularly as to whether it'll increase rates, but muffler replacement(s) are already baked into the current price (maybe by not enough, but some of it) so it probably ends up a wash?

I assume then after the above assumptions that what you're looking for is something that says running too rich in climb is going to create a safety issue? I doubt it. Just wastes gas. Maybe could foul a plug in some persnickety engines.
 
ARFlyer said:
Our Club MX is complaining that we are burning through mufflers like crazy. They want us to stop leaning until around 5-6k. Currently our manual states for the pilot to lean when above 3000' in cruise.
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What would hey have you do at a high altitude airport on a hot day? You would surely have to lean to compensate for density altitude. 3,000 fi isn't going to work if the airport is at 8,000.
 
I lean constantly throughout the climb.

I'll take a snapshot of the EGT @ 1,000AGL and then lean to keep the needle in the same position all the way up. Works in every NA airplane I use.
 
ARFlyer said:
Our Club MX is complaining that we are burning through mufflers like crazy. They want us to stop leaning until around 5-6k. Currently our manual states for the pilot to lean when above 3000' in cruise.

Any of yall have any good input or the best place to find guidance ?
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Go here. Read the section titled "when to lean". Or if you want lots of details and have lots of time, go here and read all of it.

Cliffs notes: ALWAYS lean for cruise, AT ANY ALTITUDE.
In the climb, take note of your EGT at 1000 AGL (or sooner if you can do it safely) and then maintain that EGT during your climb. Then, see the previous line.

BTW, maybe club Mx wants to spend less money on mufflers, but I bet the treasurer doesn't want to more than make up for it by buying extra fuel, plus I bet you'll be buying more cylinders if you don't lean properly. I would also say that if you're burning through mufflers, something else is wrong. Cheap mufflers, bad mag timing, contaminated fuel, tons of different possible causes.
 
Here in the Rockies we lean significantly just for taxiing. We take off lean, and lean more at cruise altitudes. I'm no A&P, but it sure seems better than flying with fouled plugs!

I got a touch too lean on my last flight, which I discovered by way of my engine running a bit warmer than I'd like (still green)... Bumping up the mixture a touch brought the temp back down to a more comfortable level.

Bottom line from my amateur perspective? Low elevation aviators often give the mixture too little thought (it was that way when I learned to fly back east). We live with aggressive leaning out here, and I've heard of no wear issues associated with it.

Admittedly, even in winter my home field often gets days with DA above 7,000 ft, and 10,000 can happen in summer.
 
That's a new one for me, burning up mufflers with the red knob. Anyone hear of it before?
 
flyingcheesehead said:
Go here. Read the section titled "when to lean". Or if you want lots of details and have lots of time, go here and read all of it.

Cliffs notes: ALWAYS lean for cruise, AT ANY ALTITUDE.
In the climb, take note of your EGT at 1000 AGL (or sooner if you can do it safely) and then maintain that EGT during your climb. Then, see the previous line.

BTW, maybe club Mx wants to spend less money on mufflers, but I bet the treasurer doesn't want to more than make up for it by buying extra fuel, plus I bet you'll be buying more cylinders if you don't lean properly. I would also say that if you're burning through mufflers, something else is wrong. Cheap mufflers, bad mag timing, contaminated fuel, tons of different possible causes.
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I'll Look at it. Thanks.

Yeah I was a bit confused on the burning the mufflers up, but I didn't want to start another MX vs pilot war .
 
I'll throw another one out here...

How's MX going to know where you set the red knob? These aircraft have engine monitoring with data downloads? If not... :p
 
I always thought, If you run too rich there is combustible mixture in the exhaust and it backfires in the muffler, making holes.
 
coloradobluesky said:
I always thought, If you run too rich there is combustible mixture in the exhaust and it backfires in the muffler, making holes.
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The pedant in me says that is an afterfire, not a backfire. Backfires push the burning exhaust through the carburetor. :eek:
 
coloradobluesky said:
I always thought, If you run too rich there is combustible mixture in the exhaust and it backfires in the muffler, making holes.
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If the mixture seriously fuel rich, well above stoichometric it would seem all but impossible to get a combustible mixture in the exhaust. All the oxygen would be consumed in the cylinders since the mixture is oxygen deficient. If a combustible mixture ends up in the exhaust it would suggest at least one cylinder is not igniting at all.
 
denverpilot said:
I'll throw another one out here...

How's MX going to know where you set the red knob? These aircraft have engine monitoring with data downloads? If not... :p
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Well, if you run out of gas and crash like the guy in Rick's story did because he was at 2500 feet and was taught not to lean below 3000, they're gonna know!
 
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