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IO-360 Operation

VF84Sluggo

Well Known Member
A couple of weeks ago I posted a thread asking what folks are using for MP/RPM settings for an IO-360. Some AVweb articles were mentioned, YouTube vid, and talk of the "red box."

So...I finished reading the suggested AVweb articles, watched the YouTube vid....man, looks like all this time I didn't know how to operate an IO-360. I'm not sure I know how to now.

WOT ALL the time? REALLY? Wow. Even if just local "sightseeing" at 1000 ft, not going anywhere in particular or in any particular amount of time? 23/2300 is wrong? I should be WOT?

Setting, say, 24" and 2400 RPM (or even 23/2300) on a cross-country is bad juju?

Leaving prop RPM back and mixture leaned when landing?

Man...
 
I ain't no expert but I do have a RV-4 with IO-360, Licon IO-360-EXP with Hartzell prop.

For me:

Mixture rich and prop high rpm for landing ready for go around.

I'm lazy and a little cheap. I usually use 21x21 and lean to peak. I get around 200 mph above 8,000' at under 8 gph. When I can't get 21" I increase RPM to get a sum of 42 (18x24, etc). This probably ain't the optimum for economy or performance but it yields good oil temperature and good cylinder head temps.

I take off at 25x25 and get off in less the 400'.
 
A couple of weeks ago I posted a thread asking what folks are using for MP/RPM settings for an IO-360. Some AVweb articles were mentioned, YouTube vid, and talk of the "red box."

So...I finished reading the suggested AVweb articles, watched the YouTube vid....man, looks like all this time I didn't know how to operate an IO-360. I'm not sure I know how to now.

WOT ALL the time? REALLY? Wow. Even if just local "sightseeing" at 1000 ft, not going anywhere in particular or in any particular amount of time? 23/2300 is wrong? I should be WOT?

Setting, say, 24" and 2400 RPM (or even 23/2300) on a cross-country is bad juju?

Leaving prop RPM back and mixture leaned when landing?

Man...

I read all the things you did, and watched the videos.
My head exploded also. I’m still trying to wrap my brain around this. Espescially the short, down low local flights. Also, what to do for aerobatics?!
 
Down low or just putting around, then pull it back all you want. 20 inches and whatever low rpm feels comfortable. The WOT thing is when you are going somewhere, and you are going up high 8k or more. Since you can't get more than 75% at 8k and above, just leave it WOT and lean from there. If it's carbureted, then you pull the throttle back just until the MP starts to move. This closes the "enrichment valve", introduces a bit to turbulence to aid in mixture, yet doesn't sacrifice power. Some props are more efficient at certain RPMs. I think i saw a recent review on the Hartzell blended airfoil that said it was fastest at 2500, yet a MT 3 blade I flew had no loss in speed from 2500 down to 2200, so at 11,500 feet, I was WOT, way down on MP from the altitude, I was able to pull the RPM down to 2200, and lean more than I could at 2400, yet no speed difference.
 
Down low or just putting around, then pull it back all you want. 20 inches and whatever low rpm feels comfortable. The WOT thing is when you are going somewhere, and you are going up high 8k or more. Since you can't get more than 75% at 8k and above, just leave it WOT and lean from there.
Now this makes sense to me. Thanks!

Gotta admit, though: this "red box" (ie triangle) has me worried. Looks like a LOT of the power/mixture settings are right in there where I was told by the instructor to set the power. Man.
 
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The way I do it normally...

Take off: everything forward
Quick Climb: 2500/25"
Easy Climb: 2500/23"
Normal cruise: 2400/22"
Slow cruise: 2400/18-20"
 
Now this makes sense to me. Thanks!

Gotta admit, though: this "red box" (ie triangle) has me worried. Looks like a LOT of the power/mixture settings are right in there where I was told by the instructor to set the power. Man.


There is another option...down low you can leave it WOT, you just need to go really deep LOP. Lean enough and you’ll bring the engine back to about 85% power with nice temperatures.
 
The way I do it normally...

Take off: everything forward
Quick Climb: 2500/25"
Easy Climb: 2500/23"
Normal cruise: 2400/22"
Slow cruise: 2400/18-20"

I'm not sure what easy climb is, I've never heard of that. :D

I run mine everything forward for takeoff, at around 500' or so I pull the RPM back to 2500 and it stays there, throttle stays wide open. Lean a bit, keeping cylinders ROP and below 390 for climb, then level off and go LOP, and stay that way until descent. I cruise WOT and 2500 normally, with AFR in the 15.8-16.0 range, which is about 100-LOP

On descent I just pull power to keep speed under control, and dropping below 4000' I'll go back ROP. RPM comes up on short final for a go-around but the throttle is usually at idle by then so I don't annoy everyone with the sound change.
 
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I'm not sure what easy climb is, I've never heard of that. :D

I run mine everything forward for takeoff, at around 500' or so I pull the RPM back to 2500 and it stays there, throttle stays wide open. Lean a bit, keeping cylinders ROP and below 390 for climb, then level off and go LOP, and stay that way until descent. I cruise WOT and 2500 normally, with AFR in the 15.8-16.0 range, which is about 100-LOP

On descent I just pull power to keep speed under control, and dropping below 4000' I'll go back ROP. RPM comes up on short final for a go-around but the throttle is usually at idle by then so I don't annoy everyone with the sound change.
I'm just not a fan of working the engine that hard unless I need to, typical power setting is <=75% , cruise 65% hence my power settings.
 
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Lots or articles out there talking about the dangers of power changes and the possibility of an engine failure while making a power reduction on takeoff like that. At 500 feet, are you ready for an engine failure? Making a power reduction is increasing your chances for having an engine failure. Yeah it seems like babying the engine, or don't a partial power takeoff is going to make the engine last longer, but you arent. Full powrr takeoff gets you to altitude faster, where you can handle a failure. Also the engine runs richer (read COOLER) at WOT, especially with a carb and it's enrichment valve. Take a look at your EGTs when you make a power reduction, they'll climb. Just pulling back the prop without reducing MP actually puts more strain on the engine.

Anybody here experience an engine failure during a power change care to come in here? I've never had an engine failure, so most of this is theoretical for me. .then again, I never make a power change below 1000 feet.
 
I'm not sure what easy climb is, I've never heard of that. :D

On descent I just pull power to keep speed under control, and dropping below 4000' I'll go back ROP. RPM comes up on short final for a go-around but the throttle is usually at idle by then so I don't annoy everyone with the sound change.

I really like this technique too! I see so many people pushing the prop in on downwind, making all kinds of noise and drag. I leave it pulled back until I throttle back enough to come "off the governor", then the prop doesn't make any aditional noise, yet it's ready for adding power if you need it. On a plane with manual cowl flaps, I leave them closed though touchdown, as 99% of the time you don't do a go around, and opening them just dumps whatever warm air you still have. After clearing the runway, I open them. If I do need to go around, I'll open them after I get full power and I'm moving away from the ground. The engine isn't going to overheat in the few seconds before you get them open. The only reason I see to open them for landing is of you are practicing touch & goes, or if you can't reach them safely while climbing out. .
 
I really like this technique too! I see so many people pushing the prop in on downwind, making all kinds of noise and drag. I leave it pulled back until I throttle back enough to come "off the governor", then the prop doesn't make any aditional noise, yet it's ready for adding power if you need it. ...
Same here. No reason to make a lot of noise with no benefit.

I also do the takeoff with the prop full forward, which gets me right at 2700, and then bring it back to something less than 2500 as part of my climb check. A full power / 2700 RPM climb gives me nothing but sky, and more noise than needed.
 
Lots or articles out there talking about the dangers of power changes and the possibility of an engine failure while making a power reduction on takeoff like that.

Are you kidding? Most 4 stroke, gas engines, like the 10's of millions of cars, see constant power and loading changes. A lycoming is really not that different. Pretty much the same as a VW engine from the 60's, just with a lower RPM rating due to the valve springs.
 
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I think most people are way over complicating the operation of these engines. There's very little we can do to actually hurt the engines. I had a boss who taught me to lean slightly for takeoff in a Bellona Scout with an 0-360. We were at about 1000'msl in the summer and he said lean to peak RPM. Climb was full throttle, fixed pitch returned about 2500rpm and still leaned to peak rpm. Cruise was quite rich low altitude and throttled to around 2300rpm. He absolutely loved the longevity of the engines. We would call this abuse, yet the engine tolerated it.

It wasn't long ago that all LOP would burn through the pistons, the engine would fail and we'd die. My flight school even had an old piston with detonation damage to scare "proper" leaning techniques into us students. These were mostly 172s with a 150hp O-320.
 
My 2 cents worth.....
Many of the Continental and Lycomings are rated maximum continuous power. Thew were tested to maximum oil temperature and maximum CHT at full rated power for 50 hours. then torn down and examined for any abnormal wear. They passed! Pulling the throttle back right after take off on a normally asperated engine caused the fuel injection to come off an enrichment setting, much like the MS carbs with the economizer valve. When slow, the engine needs fuel for cooling since there is not as much air available. I don't baby it! Right after take off, I leave full throttle all the way to altitude, but reduce the RPM to 2500 for noise. I then check whatever EGT I use as a reference, that is the only time I care about a specific value, and lean to that EGT every 1000' in the climb. At level off, I leave climb power in until the aircraft accelerates to cruise speed, then set cruise power. My usual flight is at about 9500 feet, I leave full throttle and bring the power back to 2300 RPM, lean to peak for cruise. We have 7 aircraft in the fleet, all flown this way, never had a cylinder issue, and always have made it to TBO and beyond. I have torn down a lot of customers engines, and the biggest issue I see is cocked up valves, cocked up oil control and piston rings, caused by running too rich! These engines are temperature and pressure limited. Keep them in limits, run them lean, and they run like they were designed to! Just my opinion, there are about 100 other opinions out there.

DAR Gary
 
A couple of weeks ago I posted a thread asking what folks are using for MP/RPM settings for an IO-360. Some AVweb articles were mentioned, YouTube vid, and talk of the "red box."

So...I finished reading the suggested AVweb articles, watched the YouTube vid....man, looks like all this time I didn't know how to operate an IO-360. I'm not sure I know how to now.

WOT ALL the time? REALLY? Wow. Even if just local "sightseeing" at 1000 ft, not going anywhere in particular or in any particular amount of time? 23/2300 is wrong? I should be WOT?

Setting, say, 24" and 2400 RPM (or even 23/2300) on a cross-country is bad juju?

Leaving prop RPM back and mixture leaned when landing?

Man...

You can’t believe everything that you read on the Internet or in a YouTube video.
 
Help me out: what's "AFR"?

Air-Fuel Ratio. Literally how many pounds of air are being mixed to how many pounds of fuel for the engine. I have an oxygen sensor in the exhaust (just like your car) that reads out AFR to me on the panel. 14.7 is stoichiometric, lower is rich (around 11-11.5 is what we call "full rich") and higher is leaner. At about 16.5 to 16.8 most airplane engines will start to stumble from being too lean, if they don't have very well balanced injection. A few can get up to 17 without getting rough, just a decline in power.

In cruise I use mixture to control power, not throttle. The throttle is always wide open and the RPM is usually set at 2500, and I'm operating lean of peak. If I pull back the mixture a little more (or turn the knob, in my case - it's a potentiometer to the engine computer) then I burn less fuel, make less power and speed, but efficiency goes up. Tweak it to the right, more fuel, more power, more speed - less miles per gallon. The throttle stays on the forward stop from takeoff roll until top of descent.

Most of the "old wives tales" about how to, or how NOT to, operate your engine relate to low altitude and high power. Realistically once you are above 8000' there is nothing you can do with the engine controls that will harm the engine - you're not developing enough power to do damage below 75% power.
 
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