Lycoming O-360 Shut-down techniques
Thread Starter
Lycoming O-360 Shut-down techniques
G'day all,
Been reading about O-360 shut down tips especially:
1. Lean, operate at 1200 rpm for 1-minute. (While taxiing?)
2. Operate at 1800 rpm for 20-seconds
3. Reduce to 1200 rpm and kill with mixture.
How true is the above? Has anyone seen the major issues surrounding improper shutdown?
Cheers,
Mach1
Been reading about O-360 shut down tips especially:
1. Lean, operate at 1200 rpm for 1-minute. (While taxiing?)
2. Operate at 1800 rpm for 20-seconds
3. Reduce to 1200 rpm and kill with mixture.
How true is the above? Has anyone seen the major issues surrounding improper shutdown?
Cheers,
Mach1
Folklore.
Aggressively lean for all ground ops (such that any attempt to apply more than a little power will result in stumbling rather than increased power). Shut it down by pulling the mixture at idle, as soon as you no longer need the fan running.
(For entertainment purposes, can you post the explanation, by the brainstrust that came up with that 'technique', as to the technical underpinnings for it?)
Aggressively lean for all ground ops (such that any attempt to apply more than a little power will result in stumbling rather than increased power). Shut it down by pulling the mixture at idle, as soon as you no longer need the fan running.
(For entertainment purposes, can you post the explanation, by the brainstrust that came up with that 'technique', as to the technical underpinnings for it?)
Thread Starter
Folklore.
Aggressively lean for all ground ops (such that any attempt to apply more than a little power will result in stumbling rather than increased power). Shut it down by pulling the mixture at idle, as soon as you no longer need the fan running.
(For entertainment purposes, can you post the explanation, by the brainstrust that came up with that 'technique', as to the technical underpinnings for it?)
Aggressively lean for all ground ops (such that any attempt to apply more than a little power will result in stumbling rather than increased power). Shut it down by pulling the mixture at idle, as soon as you no longer need the fan running.
(For entertainment purposes, can you post the explanation, by the brainstrust that came up with that 'technique', as to the technical underpinnings for it?)
That's just the thing about it, it didn't come with any explanation which is why I wanted to ask!
That's unsurprising.
I'm not aware of even a folklore-strewn POH that has that 'technique' in it.
Millions of hours of operation of a simple machine designed in the 1940s and still the fertile soil of folklore sprouts new stuff.
Best thing you can do M1M: Fly aircraft with an all-cylinder engine monitor and do some research to understand the implications of the information it's presenting to you.
I'm not aware of even a folklore-strewn POH that has that 'technique' in it.
Millions of hours of operation of a simple machine designed in the 1940s and still the fertile soil of folklore sprouts new stuff.
Best thing you can do M1M: Fly aircraft with an all-cylinder engine monitor and do some research to understand the implications of the information it's presenting to you.
Thread Starter
That's unsurprising.
I'm not aware of even a folklore-strewn POH that has that 'technique' in it.
Millions of hours of operation of a simple machine designed in the 1940s and still the fertile soil of folklore sprouts new stuff.
Best thing you can do M1M: Fly aircraft with an all-cylinder engine monitor and do some research to understand the implications of the information it's presenting to you.
I'm not aware of even a folklore-strewn POH that has that 'technique' in it.
Millions of hours of operation of a simple machine designed in the 1940s and still the fertile soil of folklore sprouts new stuff.
Best thing you can do M1M: Fly aircraft with an all-cylinder engine monitor and do some research to understand the implications of the information it's presenting to you.
Idle at 1,135RPM for 12 seconds plus 1.5s for every 1,000’ of density altitude over standard. If the engine is aligned within 20 degrees of magnetic north, you can reduce that by three seconds, but only on Tuesdays and Fridays.
Run at 1,750RPM for four seconds while going rich/lean/rich as fast as you can, followed by another five seconds on the left magneto only at 900RPM. Sing the last two lines of “The Star-Spangled Banner” while slowly moving to cutoff, which completes the procedure. If in the Southern Hemisphere, it goes without saying that you should use the right magneto instead.
Run at 1,750RPM for four seconds while going rich/lean/rich as fast as you can, followed by another five seconds on the left magneto only at 900RPM. Sing the last two lines of “The Star-Spangled Banner” while slowly moving to cutoff, which completes the procedure. If in the Southern Hemisphere, it goes without saying that you should use the right magneto instead.
That's the juice, FullWings.
Of course, that's just for the injected 360. In the case of the carby version, you add 3.72% to all those numbers and the singing is instead of the last three lines of "Does Your Chewing Gum Lose Its Flavour On The Bedpost Overnight?"
(Mach1Muppet: If someone advises you to carry a metric shifter and a left handed screw driver in your flight bag, be dubious.)
Of course, that's just for the injected 360. In the case of the carby version, you add 3.72% to all those numbers and the singing is instead of the last three lines of "Does Your Chewing Gum Lose Its Flavour On The Bedpost Overnight?"
(Mach1Muppet: If someone advises you to carry a metric shifter and a left handed screw driver in your flight bag, be dubious.)
If in the Southern Hemisphere, it goes without saying that you should use the right magneto instead.
Of course, that's just for the injected 360. In the case of the carby version, you add 3.72% to all those numbers and the singing is instead of the last three lines of "Does Your Chewing Gum Lose Its Flavour On The Bedpost Overnight?"
I was similarly skeptical when I heard of this procedure.
Actually, it's good advice. The lead scavenging agents in 100ll do not work at the combustion temperatures at idle. Leaning on the ground will reduce the quantity of lead built up, but will not remove the lead build up. The 20 second run at 1800 RPM gives a high enough temperature to activate the scavenging agents and remove lead build up. Basically you're doing a lead cleaning procedure at the end of your flight.
Actually, it's good advice. The lead scavenging agents in 100ll do not work at the combustion temperatures at idle. Leaning on the ground will reduce the quantity of lead built up, but will not remove the lead build up. The 20 second run at 1800 RPM gives a high enough temperature to activate the scavenging agents and remove lead build up. Basically you're doing a lead cleaning procedure at the end of your flight.
Solid gold, ahramin. Solid gold!
O-360 ÈÍ Series Operator’s Manual Lycoming Part Number: 60297-25 ©2007 by Lycoming. All rights reserved.
10. ENGINE SHUT-DOWN. a. Set propeller at minimum blade angle (where applicable). b. Idle until there is a decided decrease in cylinder head temperatures. c. Move mixture control to the idle cut-off position. d. When engine stops, turn ignition switch to off position.
10. ENGINE SHUT-DOWN. a. Set propeller at minimum blade angle (where applicable). b. Idle until there is a decided decrease in cylinder head temperatures. c. Move mixture control to the idle cut-off position. d. When engine stops, turn ignition switch to off position.
O, HO, IO, AIO, HIO, TIO-360 Series Operator’s Manual Lycoming Part Number: 60297-12 ©2005 by Lycoming
9. SHUT DOWN PROCEDURE. a. Fixed Wing. (1) Set propeller governor control for minimum blade angle when applicable. (2) Idle until there is a decided drop in cylinder head temperature. (3) Move mixture control to Idle Cut-Off. (4) When engine stops, turn off switches. b. Helicopters. (1) Idle as directed in the airframe manufacturers handbook, until there is a decided drop in cylinder head temperature. (2) Move mixture control to Idle Cut-Off. (3) When engine stops, turn off switches.
9. SHUT DOWN PROCEDURE. a. Fixed Wing. (1) Set propeller governor control for minimum blade angle when applicable. (2) Idle until there is a decided drop in cylinder head temperature. (3) Move mixture control to Idle Cut-Off. (4) When engine stops, turn off switches. b. Helicopters. (1) Idle as directed in the airframe manufacturers handbook, until there is a decided drop in cylinder head temperature. (2) Move mixture control to Idle Cut-Off. (3) When engine stops, turn off switches.
I've always found that the circa 700 degrees C EGTs and 200 degrees C CHTs on the next take off and climb are good indications of temperatures that are preventing 'lead build up'. That and proper leaning. Boroscope and spark plug inspections confirm it.
O, HO, IO, AIO, HIO, TIO-360 Series Operator’s Manual Lycoming Part Number: 60297-12 ©2005 by Lycoming
9. SHUT DOWN PROCEDURE. a. Fixed Wing. (1) Set propeller governor control for minimum blade angle when applicable. (2) Idle until there is a decided drop in cylinder head temperature. (3) Move mixture control to Idle Cut-Off. (4) When engine stops, turn off switches. b. Helicopters. (1) Idle as directed in the airframe manufacturer’s handbook, until there is a decided drop in cylinder head temperature. (2) Move mixture control to Idle Cut-Off. (3) When engine stops, turn off switches.
9. SHUT DOWN PROCEDURE. a. Fixed Wing. (1) Set propeller governor control for minimum blade angle when applicable. (2) Idle until there is a decided drop in cylinder head temperature. (3) Move mixture control to Idle Cut-Off. (4) When engine stops, turn off switches. b. Helicopters. (1) Idle as directed in the airframe manufacturer’s handbook, until there is a decided drop in cylinder head temperature. (2) Move mixture control to Idle Cut-Off. (3) When engine stops, turn off switches.
Engine monitors don't lie.
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LB's advice about "Aggresively lean on taxi is good" .When others (usually a cross-hire or flying school) used the aircraft, I had mag drop issues which were usually cleared by high RPM runups, leaned for max RPM and left for 45-60 second until reducing revs for second mag check. I attributed this to poor leaning in taxi.
I had a fouled plug on an O-360 at about 400 ft after takeoff - still climbed ok, but really rough running. Underpants were in danger territority. Quick PAN call and early turn to downwind with a very tight base leg for an uneventful landing. $150 coffee at Rottnest canned and I replaced the plug.
I had a fouled plug on an O-360 at about 400 ft after takeoff - still climbed ok, but really rough running. Underpants were in danger territority. Quick PAN call and early turn to downwind with a very tight base leg for an uneventful landing. $150 coffee at Rottnest canned and I replaced the plug.
Thread Starter
Idle at 1,135RPM for 12 seconds plus 1.5s for every 1,000’ of density altitude over standard. If the engine is aligned within 20 degrees of magnetic north, you can reduce that by three seconds, but only on Tuesdays and Fridays.
Run at 1,750RPM for four seconds while going rich/lean/rich as fast as you can, followed by another five seconds on the left magneto only at 900RPM. Sing the last two lines of “The Star-Spangled Banner” while slowly moving to cutoff, which completes the procedure. If in the Southern Hemisphere, it goes without saying that you should use the right magneto instead.
Run at 1,750RPM for four seconds while going rich/lean/rich as fast as you can, followed by another five seconds on the left magneto only at 900RPM. Sing the last two lines of “The Star-Spangled Banner” while slowly moving to cutoff, which completes the procedure. If in the Southern Hemisphere, it goes without saying that you should use the right magneto instead.
What a ripper of a comment this is! Jokes aside thanks all for clearing this up!
For the sceptics, the following is an extract from the Lycoming Flyer Key Reprints, page 66 under the heading of Spark Plug Fouling;
“Prior to engine shut-down the engine speed should be maintained between 1000 and 1200 RPM until the operating temperatures have stabilized. At this time the engine speed should be increased to approximately 1800 RPM for 15 to 20 seconds, then reduced to 1000 to 1200 RPM and shutdown immediately using the mixture control."
This is an engine manufacturers recommendation, which hasn’t been adopted by aircraft manufacturers.
Interstingly, the above procedure is identical to the published shutdown procedure for a number of radial powered Yak aeroplanes.
“Prior to engine shut-down the engine speed should be maintained between 1000 and 1200 RPM until the operating temperatures have stabilized. At this time the engine speed should be increased to approximately 1800 RPM for 15 to 20 seconds, then reduced to 1000 to 1200 RPM and shutdown immediately using the mixture control."
This is an engine manufacturers recommendation, which hasn’t been adopted by aircraft manufacturers.
Interstingly, the above procedure is identical to the published shutdown procedure for a number of radial powered Yak aeroplanes.
Folklore.
Aggressively lean for all ground ops (such that any attempt to apply more than a little power will result in stumbling rather than increased power). Shut it down by pulling the mixture at idle, as soon as you no longer need the fan running.
(For entertainment purposes, can you post the explanation, by the brainstrust that came up with that 'technique', as to the technical underpinnings for it?)
Aggressively lean for all ground ops (such that any attempt to apply more than a little power will result in stumbling rather than increased power). Shut it down by pulling the mixture at idle, as soon as you no longer need the fan running.
(For entertainment purposes, can you post the explanation, by the brainstrust that came up with that 'technique', as to the technical underpinnings for it?)
the procedure is also mentioned in the following Lycoming Service Letter:
https://www.lycoming.com/sites/defau...%20Fouling.pdf
Last edited by roundsounds; 3rd Dec 2021 at 10:47.