I originally posted this in the Maintenance Section but got no replies. Perhaps this is the correct forum?
Flying a 1963 C182 with the o-470 Engine and 260 HP.
The plane has an EGT/CHT sensor but no user manuals for anything.
Plane is used for Skydiving. I climb at 23" MP and 2450 RPM and watch the EGT on the way up for leaning purposes. Once the jumpers are away I close the Cowl Flaps and switch to CHT to make sure I don't shock cool the engine on the way down. I enrich the mixture in steps on the way down to prevent the added fuel from further cooling the engine.
I have been doing some reading on proper leaning techniques and would like some opinions from here.
Questions:
(1) Should I be leaning during the climb?
(2) If so, at what altitude should I start to lean?
(3) What are acceptable Exhaust Gas Temps in the Climb?
I was taught that the proper way to lean was to pull the mixture until engine roughness is reached and then add a little fuel. From what I have read, this practice can't hurt a carbureted engine during cruise... but what about during a long climb to 10 5000 FT?
To date, I've been leaning above 3000 FT and shooting for about 1450 Degrees EGT.
Is there a better setting and or proceedure?
Regards,
Crispy3M
Exhaust Gas Temp's
Moderators: sky's the limit, sepia, Sulako, lilfssister, North Shore, I WAS Birddog
EGT is probably most useful in cruise, which isn't what you're doing with jumper dumping.
For climb from sea level density altitudes, I would start with full rich mixture for takeoff, and keep an eye on the CHT. Passing through 3,000 to 5,000 the air has thinned out that you're probably going excessively over-rich, and can start to gently lean the mixture, even with the throttle wide open, because you aren't developing max power any more as the air thins out.
Best power is generally reached at 100F rich-of-peak (ROP) - that is, lean slowly to peak EGT, then push it in for an EGT drop of 100F.
However, you may require additional enrichening beyond that to keep the CHT within acceptable limits. I might suggest not letting the CHT rise above 400F for maximum cylinder life.
Also, you may shock cool your cylinders after levelling off, which might surprise many pilots. As soon as you level off, close the cowl flaps and keep the speed down until the CHTs have a chance to fall.
For climb from sea level density altitudes, I would start with full rich mixture for takeoff, and keep an eye on the CHT. Passing through 3,000 to 5,000 the air has thinned out that you're probably going excessively over-rich, and can start to gently lean the mixture, even with the throttle wide open, because you aren't developing max power any more as the air thins out.
Best power is generally reached at 100F rich-of-peak (ROP) - that is, lean slowly to peak EGT, then push it in for an EGT drop of 100F.
However, you may require additional enrichening beyond that to keep the CHT within acceptable limits. I might suggest not letting the CHT rise above 400F for maximum cylinder life.
Also, you may shock cool your cylinders after levelling off, which might surprise many pilots. As soon as you level off, close the cowl flaps and keep the speed down until the CHTs have a chance to fall.
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Intentional Left Bank
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I can't offer you advice specific to your question.
However, I also didn't have a manual for an electronic fuel flow/totalizer gauge in my a/c. The manufacturer wasn't indicated on the face of the gauge, but I eventually found it listed in the detailed w&b report. Found the manufacturer on the web, e-mailed them a description, and they sent me a .pdf manual.
With regards to the O-470, Continental publishes a VERY interesting manual specific to the engine, rather than aircraft. It details best practises, something the AFM doesn't really get into in any depth.
They also detail the testing the engines go through in the certification process, and it's amazing what kind of abuse they can take without failing.
That being said, I think that shock-cooling is as great a stress to an engine as high temperatures.
However, I also didn't have a manual for an electronic fuel flow/totalizer gauge in my a/c. The manufacturer wasn't indicated on the face of the gauge, but I eventually found it listed in the detailed w&b report. Found the manufacturer on the web, e-mailed them a description, and they sent me a .pdf manual.
With regards to the O-470, Continental publishes a VERY interesting manual specific to the engine, rather than aircraft. It details best practises, something the AFM doesn't really get into in any depth.
They also detail the testing the engines go through in the certification process, and it's amazing what kind of abuse they can take without failing.
That being said, I think that shock-cooling is as great a stress to an engine as high temperatures.
EGT's
Thanks for the information guys and thanks to hz2p. 400 Degrees on the CHT is exactly the information I was looking for. WILCO 
The EGT/CHT gauge is digital and therefore has no peak setting which makes knowing the numbers so important.
Anyone know what the Peak EGT setting should be on this engine?
Best Regards,
Crispy3M
The EGT/CHT gauge is digital and therefore has no peak setting which makes knowing the numbers so important.
Anyone know what the Peak EGT setting should be on this engine?
Best Regards,
Crispy3M
CHT probe always plugs into the same place (threaded) in the head, so absolute temperature is useful.
Actually, I lie. If you've got an upscale pre-heater with elements where the CHT probes usually go, there are some truly crummy spark plug washer-type probes. Don't like 'em.
Now for something completely different: EGT. Depending upon where the hole is drilled in the exhaust manifold, you get different absolute temperatures. So what matters is what peak EGT is for your engine and installation.
At less than 75% power, from full rich lean the mixture slowly. You will note that the EGT will rise: you are ROP (rich of peak). At some point, the EGT will peak, then start to decrease: you are now LOP (lean of peak). Everything is done relative to the measured peak EGT. As I mentioned before, best power is usually attained around 100F ROP.
Carbureted engines rarely run very well LOP, however fuel injected ones often do. Fuel injected engines are easy to lean: go for max airspeed which by definition is best power
Actually, I lie. If you've got an upscale pre-heater with elements where the CHT probes usually go, there are some truly crummy spark plug washer-type probes. Don't like 'em.
Now for something completely different: EGT. Depending upon where the hole is drilled in the exhaust manifold, you get different absolute temperatures. So what matters is what peak EGT is for your engine and installation.
At less than 75% power, from full rich lean the mixture slowly. You will note that the EGT will rise: you are ROP (rich of peak). At some point, the EGT will peak, then start to decrease: you are now LOP (lean of peak). Everything is done relative to the measured peak EGT. As I mentioned before, best power is usually attained around 100F ROP.
Carbureted engines rarely run very well LOP, however fuel injected ones often do. Fuel injected engines are easy to lean: go for max airspeed which by definition is best power
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Always Moving
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- Location: Always Moving
decisions decisions
Everything said earlier is Correct! (with injectors the newer ones you can lean on the lean side...never flown a NEW one thu)
But I would take the whole approach as DTM( I just made it up) diferential tempeture managment,I expalin.
The idea is to keep the engine with as little chage in tempeture without clogging the engine(too rich) or blowing it up (too lean).
So like BENWA hinted look at the trend, AND the trend that is not there but you know it will happen(leveling off or start the dive down) and adjust accordingly.
400F NO NO NO..... like HZ2P said..it dependes. Look for the peack yourself THEN you got the magic number-s and they Will change( time, tempeture pressure,etc).
Last thing I read an article about this and they said that the mixture is the one that most afect the plane, specially diving, more so than cowflaps or speed, it left me a little buffle.
But I would take the whole approach as DTM( I just made it up) diferential tempeture managment,I expalin.
The idea is to keep the engine with as little chage in tempeture without clogging the engine(too rich) or blowing it up (too lean).
So like BENWA hinted look at the trend, AND the trend that is not there but you know it will happen(leveling off or start the dive down) and adjust accordingly.
400F NO NO NO..... like HZ2P said..it dependes. Look for the peack yourself THEN you got the magic number-s and they Will change( time, tempeture pressure,etc).
Last thing I read an article about this and they said that the mixture is the one that most afect the plane, specially diving, more so than cowflaps or speed, it left me a little buffle.
