Never close-throttle idle?

[wilkersk]

Why not go below 1000RPM?

Because, like a previous post said, below 1000 RPM, the spark plugs load up quicker.

Lycoming just says, "avoid prolonged idling."

I've been told that a rule of thumb to follow is, when stopped, keep RPM at 1,000. When taxiing, reduce throttle as necessary to keep from having to drag the brakes to keep taxi speed down. By sticking to this rule-of-thumb you're "avoid" -ing "prolonged idling".

What I've always assumed is that at some point below 1000 RPM, the plugs just don't fire as hot, so they load up quicker.

 

[oilburner]

Prior to shutdown, we always cool the turbo by running at fully closed throttle & way lean for several minutes.
Pulled the plugs this week and ran a borescope; looked nice & clean as to any obvious fouling.

 

[unsafervguy]

Easiest solution, throw out the mags, put in dual light speeds and never see a fouled plug again.

Bob

 

[GlennAB1]

Just get a turboprop.

 

[Jay Honeck]

Lean aggressively on the ground. If you're stopped, don't go below 1000 rpm. If you're taxiing, it should be ok to go to idle to keep from having to drag the brakes. This is what I've been taught in every airplane I've ever checked out in.

That was the exact advice I received and followed as a renter.

Then...I bought an airplane. After I bitched to my A&P about all the stone chips in my prop, wheel pants, and paint (that I never noticed, as a renter), and he advised "Never idle faster than 1000 RPM and you will never pick up stone chips."

I tried it, and, sure as hell, I have never had another stone chip! But now I read that I'm doing it precisely wrong for the loving care of my engine -- all thanks to this effing 100LL that has four times the lead my engine needs.

Ya just can't win!

 

[jesse]

That was the exact advice I received and followed as a renter.

Then...I bought an airplane. After I bitched to my A&P about all the stone chips in my prop, wheel pants, and paint (that I never noticed, as a renter), and he advised "Never idle faster than 1000 RPM and you will never pick up stone chips."

I tried it, and, sure as hell, I have never had another stone chip! But now I read that I'm doing it precisely wrong for the loving care of my engine -- all thanks to this effing 100LL that has four times the lead my engine needs.

Ya just can't win!

We've got three O-320(s). Pilots are taught to idle them at 1,000 RPM and lean until the damn thing barely runs. Two of them are well past TBO, running great, perfect compressions, and the engines aren't full of lead. They look great inside. I've yet to see a single instance of a spark plug getting fouled up in our rental fleet.

Don't run wheel pants, so can't speak to chips on them, but certainly don't have issues with our props.

Our primary maintenance issues are brake pads and tires. Several flap issues have popped up in the last month or two that have cost us more money then I would have liked.

 

[SCCutler]

Jay, if you're getting lots of lead (sludge or plug fouling), you simply aren't leaning adequately. As suggested, lean extremely aggressively during ground ops.

Yes, it would be better if you could get uncontaminated car gas; but, you cannot.

 

[N801BH]

Jay, if you're getting lots of lead (sludge or plug fouling), you simply aren't leaning adequately. As suggested, lean extremely aggressively during ground ops.

Yes, it would be better if you could get uncontaminated car gas; but, you cannot.

This is the angle I want to expand on since I personally prefer Ethanol laced fuel for my plane. For all you guys /gals with certified planes, well you are stuck with FAA regs so there is nothing you can do... For experimental stuff, there is more leeway..

During my build, I purposely designed and used Alcohol proof materials in my entire fuel system since I knew this
blend" was coming from the Feds mandate.. Also, as a racer that has burned ALOT of Methanol over the years in my race vehicles I am a big fan of Alcohol and it's benefits. ie, Cooler running, able to run higher compression ratios, increased detonation margins, cheaper to buy, etc etc.

I like to fly as high as possible on my Cross Country flights and I am convinced the OWT of vapor lock is highly overstated.. I have been as high as 23,000 during initial testing and NEVER had a sign of fuel delivery problems. Yeah, the fuel burn is slightly greater but that is offset with the fact Ethanol / Methanol laced gas has Oxygen molecules in it and that actually does "chemically supercharge" the motor up where the air is thin.. Kinda like running NOS, without all the pesky issues a NOS system can bring..

YMMV...

 

[Let'sgoflying!]

"Don't close throttle idle on any engine."

I am trying to figure out how he lands without chewing up a lot of runway doing this.

 

[Fearless Tower]

Prior to shutdown, we always cool the turbo by running at fully closed throttle & way lean for several minutes.

Pulled the plugs this week and ran a borescope; looked nice & clean as to any obvious fouling.

Not sure what you are flying, but Flying or Aviation Safety did some research a while back and observed that running the engine on the ground to 'cool' the turbo after landing was an OWT: the temperatures in the turbo actually increased by doing that than if you just taxied to parking and shut down.

 

[James331]

That was the exact advice I received and followed as a renter.

Then...I bought an airplane. After I bitched to my A&P about all the stone chips in my prop, wheel pants, and paint (that I never noticed, as a renter), and he advised "Never idle faster than 1000 RPM and you will never pick up stone chips."

I tried it, and, sure as hell, I have never had another stone chip! But now I read that I'm doing it precisely wrong for the loving care of my engine -- all thanks to this effing 100LL that has four times the lead my engine needs.

Ya just can't win!

Another way to avoid rock chips (esp in calm winds) is to keep the stick/yoke back for ground ops, keeps stuff from hitting the tail, or coming back forward to the prop, always trying to be moving when your running helps too.

 

[Chip Sylverne]

Keep up the air pressure in the cowling with the prop. The 260 Commanche has a special prop available that carries an extra 'flap' of chord length at the blade section that goes over the cowl inlets.

Yeah, I've got one of those. Marketed as the "Synchro Pulse" prop. Hartzell HC3YK It was developed for he Lopresti cowl, because the inlets are so much smaller. Does it make a difference?
Meh...best thing about it is no ad's.

 

[Capt. Geoffrey Thorpe]

Shell:


Lycoming:


Continental:

So, they say idle at the normal idle speed except for warmup and when idling for "prolonged" periods.

 

[Jay Honeck]

Jay, if you're getting lots of lead (sludge or plug fouling), you simply aren't leaning adequately. As suggested, lean extremely aggressively during ground ops.

Yes, it would be better if you could get uncontaminated car gas; but, you cannot.

Actually, I just bought 100 gallons of that sweet, pure, unpolluted 87 octane car gas from a coop in Odem, Texas. Tankered it home in my fuel truck, after delivering our cylinder to J & J Airports in Pleasanton.

So, I'm good for a few fill-ups.

We did the break-in ground runs yesterday, and today we fly. The only casualty of the cylinder change was a broken EGT probe that was hanging by a thread. Got it ordered.

Cleaner running unleaded gas is one of the reasons our car engines now routinely run 150K miles, but used to be junk at 60K when we were kids. I, for one, can't wait until 100LL is a bad memory.

 

[Jay Honeck]

Another way to avoid rock chips (esp in calm winds) is to keep the stick/yoke back for ground ops, keeps stuff from hitting the tail, or coming back forward to the prop, always trying to be moving when your running helps too.

Yep, that is on our checklist: "Stick back for taxi". It's usually the copilot's duty to perform.

With the cost of a paint job, no precaution is too extreme. I went ballistic on our airport manager when he used dry patch on the taxiway in front of my hangar for this very reason.

 

[Dan Thomas]

Easiest solution, throw out the mags, put in dual light speeds and never see a fouled plug again.

Bob

A hot spark is one thing. A hot sparkplug is something else. A cold plug, which we find at idle, will still foul up because the fuel has so much lead in it and these engines often tend to suck oil past the rings and intake valve guides at idle. A hot spark won't stop that.

Best available solution is to use REM37BY plugs. They are extremely foul-resistant and don't cost any more than 38E's or 40E's.

The old 1000+ idle RPM thing is a carryover from the old generator days, I think. Alternators (in good condition) are capable of plenty of output at idle. An alternator can be made to produce 110 volt at 60 amps--6600 watts--if one knows what to do with the field circuitry and run the RPM up some.

 

[bdlarkin]

Not directly related to your question, but during my Instrument training I pulled the throttle back on a C172 to idle to do a power off stall under the hood.

And.... things got might quiet.

Turns out the idle was set to low, throttle cable stretch, whatever, and the damn thing quit.

Because we were stalled the prop stopped dead in the vertical. Lesson ended early that day.

So one of the things I do now is always test the idle setting of an engine before takeoff. Will it run at idle?

 

[GeorgeC]

The old 1000+ idle RPM thing is a carryover from the old generator days, I think.

I fly an aircraft manufactured in 2011 whose POH says to do ground ops at 800-1000 rpm. It complains about low voltage at idle.

So one of the things I do now is always test the idle setting of an engine before takeoff. Will it run at idle?

I learned to test idle w/ carb heat applied.

 

[dell30rb]

Even a week of idling at 600-700 rpm won't foul the plugs if aggressively leaned.

I think the low temps would lead to fouling. Our basic injection systems and carbs don't deliver perfect air/fuel mixture to each cylinder. Need some heat to keep the carbon buildup down.

 

[dell30rb]

Another way to avoid rock chips (esp in calm winds) is to keep the stick/yoke back for ground ops, keeps stuff from hitting the tail, or coming back forward to the prop, always trying to be moving when your running helps too.

Or buy a taildragger. I haven't seen a rock chip in a long time.

 

[Jim_R]

Cleaner running unleaded gas is one of the reasons our car engines now routinely run 150K miles, but used to be junk at 60K when we were kids. I, for one, can't wait until 100LL is a bad memory.

That, and the combined effects of 50 years of inproved engineering and technological advancement, like computer-controlled fuel-injection, platinum spark plugs, coil-on-plug ignition, synthetic oils, and a jillion other advancements.

 

[unsafervguy]

A hot spark is one thing. A hot sparkplug is something else. A cold plug, which we find at idle, will still foul up because the fuel has so much lead in it and these engines often tend to suck oil past the rings and intake valve guides at idle. A hot spark won't stop that.

Best available solution is to use REM37BY plugs. They are extremely foul-resistant and don't cost any more than 38E's or 40E's.

The old 1000+ idle RPM thing is a carryover from the old generator days, I think. Alternators (in good condition) are capable of plenty of output at idle. An alternator can be made to produce 110 volt at 60 amps--6600 watts--if one knows what to do with the field circuitry and run the RPM up some.

Yes, but... With the electronics and auto plugs I have never found a spot of lead on a plug. Plus at 2 bucks apiece I change them at lease every annual.

Bob

 

[Dan Thomas]

Not directly related to your question, but during my Instrument training I pulled the throttle back on a C172 to idle to do a power off stall under the hood.

And.... things got might quiet.

Turns out the idle was set to low, throttle cable stretch, whatever, and the damn thing quit.

Because we were stalled the prop stopped dead in the vertical. Lesson ended early that day.

So one of the things I do now is always test the idle setting of an engine before takeoff. Will it run at idle?

Carb ice commonly does exactly that.

 

[Tom-D]

Easiest solution, throw out the mags, put in dual light speeds and never see a fouled plug again.

Bob

I can clean a hell of a lot of plugs for the price of that conversion.

 

[James331]

I can clean a hell of a lot of plugs for the price of that conversion.

Plus replacing BOTH mags, I'll pass.

Chit happens and I prefer to at least have one form of ignition which doesn't rely on electrical power, I want to be able to fly or hand flip it on a completely flat battery, just a certain level of insurance I require.

 

[Henning]

Plus replacing BOTH mags, I'll pass.

Chit happens and I prefer to at least have one form of ignition which doesn't rely on electrical power, I want to be able to fly or hand flip it on a completely flat battery, just a certain level of insurance I require.

Your magnetos rely on electrical power, they just generate their own, as do some of the electronic ignition distributors with internal alternators to feed the power. Same difference in redundancy and autonomy, more reliable, and in flight/demand variable performance parameters. If I had to replace a set of Slicks or Bendix, I would likely pursue one of these EI options.

 

[Tom-D]

Your magnetos rely on electrical power, they just generate their own, as do some of the electronic ignition distributors with internal alternators to feed the power. Same difference in redundancy and autonomy, more reliable, and in flight/demand variable performance parameters. If I had to replace a set of Slicks or Bendix, I would likely pursue one of these EI options.

Show me a STCed electronic ignition system that replaces both mags.

 

[unsafervguy]

Tom, I'm sure you have priced a set of mags and harnesses lately, even the 500 hr service on slicks is getting pricey. Also jay flys a rv-8 so no stc required.

Even when I was running a single electronic I never saw any fouled plugs.

bob

 

[Tom-D]

Tom, I'm sure you have priced a set of mags and harnesses lately, even the 500 hr service on slicks is getting pricey. Also jay flys a rv-8 so no stc required.

Even when I was running a single electronic I never saw any fouled plugs.

bob

You tell me what in today economy that isn't costing more than it ever has?

I'm still waiting for some one to show me a STCed electronic ignition system the replaces both mags.
Because I'll go for it in a minute.

 

[wilkersk]

Not directly related to your question, but during my Instrument training I pulled the throttle back on a C172 to idle to do a power off stall under the hood.

And.... things got might quiet.

Turns out the idle was set to low, throttle cable stretch, whatever, and the damn thing quit.

Because we were stalled the prop stopped dead in the vertical. Lesson ended early that day.

So one of the things I do now is always test the idle setting of an engine before takeoff. Will it run at idle?

I went to an independant CFI to get current in a taildrager after not having flown one for awhile.

He insisted his Super-D's throttle was rigged properly, even though it wouldn't idle. It seem to be much more difficult to keep it going straight on rollout than the 7ECA I'd gotten my tailwheel endorsement in, even with a direct headwind. It was quite a handful trying to milk that thing on the deck with a crosswind, not float and keep the engine running.

 

[unsafervguy]

You tell me what in today economy that isn't costing more than it ever has?

I'm still waiting for some one to show me a STCed electronic ignition system the replaces both mags.
Because I'll go for it in a minute.

I'm with you there I would love to eliminate both on my pa28 but I don't see the federal antiquated administration approving any in the near future. I would settle for a cost effective single unit. The cost of the stc units are way out of line.

Bob

 

[Clark1961]

You tell me what in today economy that isn't costing more than it ever has?

gasoline...

 

[Jaybird180]

So one of the things I do now is always test the idle setting of an engine before takeoff. Will it run at idle?

I can't think of an airplane I've flown that didn't have that on the BEFORE TAKEOFF checklist.

 

[Jim_R]

You tell me what in today economy that isn't costing more than it ever has?

Every piece of consumer electronics in existence. TVs, radios, computers (especially component parts like hard drives and RAM), etc. Any apples-to-apples comparison would show that capability X a year ago cost more than that same capability today.

 

[Dan Thomas]

Every piece of consumer electronics in existence. TVs, radios, computers (especially component parts like hard drives and RAM), etc. Any apples-to-apples comparison would show that capability X a year ago cost more than that same capability today.

Clothes. Furniture. Toys. Just about anything made in Asia. When I was a kid my dad would have to work a couple of hours to earn a new shirt. Now I can do it in less than 20 minutes.

 

[Tom-D]

Every piece of consumer electronics in existence. TVs, radios, computers (especially component parts like hard drives and RAM), etc. Any apples-to-apples comparison would show that capability X a year ago cost more than that same capability today.

Not really, The first TV I watched cost 86 bucks.

 

[yetti]

The very old former WWII bomber flight engineer, test pilot, DE, A&P had a flight school policy of 1100-1200 while sitting for the purpose you suggested

 

[txflyer]

A practice I don't do that almost all instructors try to drill into you is to firewall it when you're taking off from almost a standstill. This will guarantee you some rock chips on a dirt strip.

You get rolling first then ease into full throttle.

And lean that ***** until she chokes and pukes and pops back at you on taxi.

 

[Silvaire]

Not really, The first TV I watched cost 86 bucks.

86 bucks in 1960 was equal to 700 bucks in 2015
Source: CPI Inflation Calculator

 

[2Airtime2]

Every piece of consumer electronics in existence. TVs, radios, computers (especially component parts like hard drives and RAM), etc. Any apples-to-apples comparison would show that capability X a year ago cost more than that same capability today.

Exactly. I was once in the consumer electronics business. When VCR's first came out we sold them for $1600, but not very many. I remember when they dropped to about 1/2 that and we couldn't keep them in stock. We unloaded trucks every single day, restocking. When I got out of the business Walmart was selling VCR's for $39.95