LOP operations with a Lycoming IO360 turbo-normalized

[Moonbat]

Is there anyone among us (and within about 200 miles or less from Newport VT, KEFK) who is adept at setting up to fly LOP? The details are that the engine is an IO360 A1A, (fuel injected), has GAMI injectors, and is turbo-normalized. 1967 M20E (Casper) 670008. There is a nice EDM930 engine monitor in the plane to help us out as well. I would like to fly with someone who really understands LOP operations in such an engine in order to learn how to set things up for LOP flights. I think that about an hour up at 7 or 8 thousand feet on a nice day would would suffice to get the details worked out.

[Shadrach]

2 hours ago, Moonbat said:

Is there anyone among us (and within about 200 miles or less from Newport VT, KEFK) who is adept at setting up to fly LOP? The details are that the engine is an IO360 A1A, (fuel injected), has GAMI injectors, and is turbo-normalized. 1967 M20E (Casper) 670008. There is a nice EDM930 engine monitor in the plane to help us out as well. I would like to fly with someone who really understands LOP operations in such an engine in order to learn how to set things up for LOP flights. I think that about an hour up at 7 or 8 thousand feet on a nice day would would suffice to get the details worked out.

I wish I was close as I would love to see how well the engine does with a TN system.

[N201MKTurbo]

After you get to cruise, reduce MP to 25 inches. Set the RPMs where you like it. Pull the mixture till you notice a serious reduction in power. Push the MP back to 30 inches. Enriched to a TIT of 1500.

[PT20J]

John Deakin ran a TN Bonanza and wrote a lot of articles about LOP operations. They’re on Avweb. 

 

[KLRDMD]

7 hours ago, Moonbat said:

Is there anyone among us (and within about 200 miles or less from Newport VT, KEFK) who is adept at setting up to fly LOP? The details are that the engine is an IO360 A1A, (fuel injected), has GAMI injectors, and is turbo-normalized. 1967 M20E (Casper) 670008. There is a nice EDM930 engine monitor in the plane to help us out as well. I would like to fly with someone who really understands LOP operations in such an engine in order to learn how to set things up for LOP flights. I think that about an hour up at 7 or 8 thousand feet on a nice day would would suffice to get the details worked out.

LOP, % power is determined exclusively by fuel flow. Nothing else. Manifold pressure doesn't matter, RPM doesn't matter. Your Lycoming IO-360 has a compression ratio of 8.7:1. Set up for normal cruise, close cowl flaps, etc. I like 27" MP and 2500 RPM for your configuration (I had a RayJay Lycoming IO-360 in a previous F model Mooney). Pull the mixture back to 8.5 GPH. That's 65% power, LOP and the setting I prefer for that engine. You're done. It isn't difficult. CHTs should be in the 320-350º range. Keep them below 380º and you're fine.

If you want 75% power, LOP, do exactly the same above but pull the mixture to 10.0 GPH. 50% power, for sake of discussion is 6.5 GPH.

[carusoam]

All great answers above...

The cool thing is there is a lot of experience with the engine flying LOP... just at lower altitudes.

We have a guy... who knows a few things about TNs on IO360 powered Mooneys... i’ll Invite him along to the conversation to see if he can add anything...

 

@tomgo2 got an interesting thread you might have some insight for..? Or can gain insight from?

Best regards,

-a-

[Austintatious]

12 minutes ago, KLRDMD said:

LOP, % power is determined exclusively by fuel flow. Nothing else. Manifold pressure doesn't matter, RPM doesn't matter. Your Lycoming IO-360 has a compression ratio of 8.7:1. Set up for normal cruise, close cowl flaps, etc. I like 27" MP and 2500 RPM for your configuration (I had a RayJay Lycoming IO-360 in a previous F model Mooney). Pull the mixture back to 8.5 GPH. That's 65% power, LOP and the setting I prefer for that engine. You're done. It isn't difficult. CHTs should be in the 320-350º range. Keep them below 380º and you're fine.

If you want 75% power, LOP, do exactly the same above but pull the mixture to 10.0 GPH. 50% power, for sake of discussion is 6.5 GPH.

This post has me really confused.

[KLRDMD]

15 minutes ago, Austintatious said:

This post has me really confused.

% power LOP is determined exclusively by fuel flow.

For the engine in question, set cruise parameters as you wish and pull the mixture to the value stated to achieve the % power you wish.

Keep CHTs below 380º.

[KSMooniac]

While the Advanced Pilot Seminars live version in Ada OK are currently not offered, I believe their online version is still available. It should be required consumption for any owner...it is that good in helping one understand what happens under the cowl, and especially while moving the mysteries red knob of death.

Sent from my LG-US996 using Tapatalk

[Austintatious]

On 8/12/2019 at 11:48 PM, KLRDMD said:

% power LOP is determined exclusively by fuel flow.

For the engine in question, set cruise parameters as you wish and pull the mixture to the value stated to achieve the % power you wish.

Keep CHTs below 380º.

"exclusively by fuel flow"

But what about air fuel ratio?  If you have a set MP and RPM, can you really maintain a combustible mixture between 60% power and 100% power with all else being equal ?

I am not doubting you, I really just dont understand how you can have 27" MAP / 2500 RPM and change your power setting by the mixture.  I understand that the power output will change by going from ROP to LOP, but as I understand, there will be a limit to the amount of power reduction achievable due to the eventual flame out of one or more cylinders if you lean too much for the MP/RPM at the time.

 

 

[jetdriven]

On 8/12/2019 at 11:16 PM, KLRDMD said:

LOP, % power is determined exclusively by fuel flow. Nothing else. Manifold pressure doesn't matter, RPM doesn't matter. Your Lycoming IO-360 has a compression ratio of 8.7:1. Set up for normal cruise, close cowl flaps, etc. I like 27" MP and 2500 RPM for your configuration (I had a RayJay Lycoming IO-360 in a previous F model Mooney). Pull the mixture back to 8.5 GPH. That's 65% power, LOP and the setting I prefer for that engine. You're done. It isn't difficult. CHTs should be in the 320-350º range. Keep them below 380º and you're fine.

If you want 75% power, LOP, do exactly the same above but pull the mixture to 10.0 GPH. 50% power, for sake of discussion is 6.5 GPH.

I take issue with the statement that MP doesn’t matter. It still does. 
for example, 1500 feet, 28” MP 2500 RPM 10.0 GPH. The engine is running at about 80 degrees LOP and theoretically, 75% power.  
However, pull the throttle back to about 26.5” MP.  The fuel flow falls a little, now richen to 10.0 GPH. Same fuel flow, but the plane speeds up 5-7 knots. It’s now 30 LOP.  And faster. Same ff. 

there is a certain economic threshold on LOP, leaner is slower and costs more. For the IO360 it’s around 25-30 degrees LOP.  

[Bob_Belville]

John Breda @M20F-1968 is in Boston, about 200 miles from you... he has a nice F with TN... I guess I don't know if he runs LOP.

[KLRDMD]

13 hours ago, Austintatious said:

"exclusively by fuel flow"

But what about air fuel ratio?  If you have a set MP and RPM, can you really maintain a combustible mixture between 60% power and 100% power with all else being equal ?

I am not doubting you, I really just dont understand how you can have 27" MAP / 2500 RPM and change your power setting by the mixture.  I understand that the power output will change by going from ROP to LOP, but as I understand, there will be a limit to the amount of power reduction achievable due to the eventual flame out of one or more cylinders if you lean too much for the MP/RPM at the time.

Start with these three articles and see if it makes more sense:

https://www.avweb.com/flight-safety/technique/pelicans-perch-15manifold-pressure-sucks/

https://www.avweb.com/features/pelicans-perch-16those-marvelous-props/

https://www.avweb.com/features/pelicans-perch-18mixture-magic/