Z

zman

Member
Anyone have any thoughts on the following procedure for engine shutdowns...

While at the Reno Air Races this last weekend (in the pits)...I noticedthat
many of the race aircraft after the race and taxi back ran-up there engines to a intermediate RPM for about 30 sec then cut the mixture to shut down the engine while at the higher RPM...I am guessing it was to keep the spark plugs hot an clean...I have and XP IO-360 on my RV-8 and think that this may be a better way to shut down and engine after a days flight...a run-up to 1500-1800 RPM then after 20-30 seconds... Mixture-Idle Cutoff...Any thoughts??


Zman
 
Lycoming Shutdown Procedures

The procedures for large radials/liquid cooled Merlins are different than for Lycomings. Recommend you go to the Lycoming website and obtain a copy of their operational procedures manual. It provides procedures for operation including shutdown. You generally can't go wrong following the OEM procedures. Fly Safe.
Randy
 
On the Lyc its not a bad idea to lean aggressively on the ground once you are taxing back to the hanger. Then, before shut down, run her up to about 1200 rpm for 20 or 30 seconds, then go to idle cut off. They lycomings run pretty rich on the ground.
 
If you lean agressively on the ground you do not need to bring the temp up (increase rpm) just before shut down (my opinion). I lean to the point of engine dying (and then push in a tad) while taxing in and out from a flight. Never have had spark plugs fouled or rough run-ups.
Leaning or running up is done to get the temps up to allow a better burn and activate the lead scavaging agents in the fuel. I have heard that you want to get the EGT to over 1100F. Lycoming recommends the run-up to 1800 rpm for 15-20 sec. See page 66 of the Lycoming Flyer (page 32 of the pdf file)
 
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Right Again, Mike!

The reason for the run-up on radials and the Merlins is to scavenge the oil from the lower end of the engine prior to shut down. These engines have "dry sumps" meaning that they have a remote oil tank.
It looks and sounds cool, but we certainly do not need to be doing that with our Lycoming's for the reasons stated in previous posts.

Mike S said:
Oil scavenging for dry sump, at least for the radials.
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Not only for oil in the sump, but many Ham Standard c/w props also recommend shutting down in high pitch which also forces the oil out of the cylinder and back to the tank along with all the other oil being scavenged back to the tank.

Me in the RV....most of the time I just pull the mixture as I'm rolling up to my hangar. By the time I reach the hangar the engine is stopped and if I do it right I'll have exactly enough momentum to just swing the tail around ready to push in the hagar!

Cheers,
Stein
 
SteinAir said:
Me in the RV....most of the time I just pull the mixture as I'm rolling up to my hangar. By the time I reach the hangar the engine is stopped and if I do it right I'll have exactly enough momentum to just swing the tail around ready to push in the hangar!

Cheers,
Stein
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Trained by Bob Hoover????;)
 
tip

Just a tip for those who fly with mags---

Right before you shut the engine off, at idle, shut the ignition off for a short while, just a quick off, and then back on. Then use the mixture to shut it off as normal.

If the engine FAILS to shut off while the ignition is off, you have a bad mag ground ---"P"---lead, and a HOT mag.

Fix it soonest, a hot mag can really spoil your day.
 
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Mag off-on issue

Turning mags off on a running engine, then back on can cause a **** of a backfire. I'd strongly suggest only doing one mag at a time.... don't turn both mags off at the same time. "Been there done that"
 
rv9av8tr said:
Turning mags off on a running engine, then back on can cause a **** of a backfire. I'd strongly suggest only doing one mag at a time.... don't turn both mags off at the same time. "Been there done that"
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I did this for 20 years on my old Stinson, every flight.

Never a problem.

As was mentioned above, do at idle.

By the way, I did find a hot mag one time :eek:
 
rv9av8tr said:
Turning mags off on a running engine, then back on can cause a **** of a backfire. I'd strongly suggest only doing one mag at a time.... don't turn both mags off at the same time. "Been there done that"
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If you have a "key" type ignition switch turning off one mag at a time will not check the "off" position of the switch. This position should be checked periodically, but I recommend letting the engine die.
Mag switches have been known to fail in just the off position leaving you unknowingly with a hot mag.
 
I don't know about RVs but we always do a mag check (both - OFF - both) before shutting down on the C172 I flew. It was part of the checklist and / or POH...
 
Lycoming shut down recommendation

Per the Lycoming Flyer "Operations", to minimize the chance of spark plug fouling the engine should be shut down as follows.

"9. Prior to engine shutdown, 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 shut down immediately using the mixture control.?

The Lycoming Flyer's are a great source of information on your engine. They have ones for Operations, General, FAQ, etc.
 
Just a reminder.....if you prefer a shutdown proceedure with some significant RPM showing on the clock, that's fine. However, please be aware of aircraft behind you. It's downright rude to blow them around, and it happens all the time.
 
Thanks for that Dan.

DanH said:
Just a reminder.....if you prefer a shutdown proceedure with some significant RPM showing on the clock, that's fine. However, please be aware of aircraft behind you. It's downright rude to blow them around, and it happens all the time.
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It just happens to be one of my pet peeves.
There was a guy at Copperstate Fly-in one year with a C-195 that blew several displays down and his only comment was, "That's the way I always shut down."
 
Courteous Pilots

DanH said:
Just a reminder.....if you prefer a shutdown proceedure with some significant RPM showing on the clock, that's fine. However, please be aware of aircraft behind you. It's downright rude to blow them around, and it happens all the time.
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Dan makes a very good point that I try to abide by. I find that I can only follow Lycs recommendation for shut down maybe 70% of the time because of this. The other 30% of the time I pull mixture without run up and I don't loose any sleep over it.

Like wise, we tail dragger pilots need to be considerate and not rev the engine up when pivoting the tail around into a parking spot if it is going to blow dirt on others or their airplane. It's no big deal to push the tail around by hand in such cases.

I believe the vast majority of pilots are considerate and reasonable people that if politely informing of a problem that affect others they would respond positively.
 
Thankx All...excellent inputs !!

I reviewed the Lyc Op spec(after all the XP is the same engine) ...and they "DO" recommend a engine run-up to around 1500-1800 rpm for about 20-30 sec, then reduce to 1200-1000 rpm followed by an immediate mixture cut-off for shut down.

zman
 
rv9av8tr said:
Turning mags off on a running engine, then back on can cause a **** of a backfire. I'd strongly suggest only doing one mag at a time.... don't turn both mags off at the same time. "Been there done that"
Click to expand...
I do it all the time at idle, ie turn both off to check mags. Never had a backfire
 
Frank Smidler said:
Per the Lycoming Flyer "Operations", to minimize the chance of spark plug fouling the engine should be shut down as follows.

"9. Prior to engine shutdown, 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 shut down immediately using the mixture control.?

The Lycoming Flyer's are a great source of information on your engine. They have ones for Operations, General, FAQ, etc.
Click to expand...

I would rather save my prop than run at 20 seconds at that high power setting in front of my hanger. Besides there are other dangers doing this at the hanger like failing brakes or foot traffic.
 
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