earlwb

Oh yeah one other point to mention is that with a new engine, it usually damages a glow plug during break in. Minute metal particles come off the insides of the engine and some of them will contaminate the glow plug element. That causes the element to not react with the methanol as good. So it goes bad. I have a box of used glow plugs that I use for engine break in purposes. If I am experiencing something odd with a engine where it isn't running right, I try a new glow plug out to see if that helps or not. If it doesn't then I put the used plug in the box to be reused later. It is sometimes amazing how a new plug fixes it all back up again. Just because a glow plug can glow nicely doesn't mean it is working OK as the platinum glow element may have been contaminated. Sometimes I can have a glow plug work with a engine for a very long time, and sometimes they don't last very long.

blw

My Feedback: (3)

Earl, I do the same thing you do and that got an argument started up over it. Still, I've got my break in plugs and never have had much problem doing it this way. All that break in material slinging around the engine and hitting the platinum element can't be good.

earlwb

Yeah it is hard to imagine an argument developing over that. But then what do I know, sometimes stuff happens I guess.
I like to save the new plugs to use after running in a engine some first. On some engines you run them so rich to start with that it has to tear up the glow plug like that. Then the little minute particles of metal and other stuff in the engine such as the oil used to store the engine in some cases is bad for the glow plug too.

hsukaria

That brings up the question: I store my engines full of after run oil in the off season. Lately I have remembered to remove the glowplug and spin the engine to blow out the extra oil. But there is always plenty of oil left and the engine runs super sloppy for a period of time at the beginning of the season until the ARO is burned off. Based on what you are saying, that can also stress the glowplug. Would that mean also using an old plug when first running the engine after storage?

Cougar429

My Feedback: (3)

I would think running running problems after storage would depend on the type of oil used and if there has been any contamination or corrosion during the interim.

I mentioned this before and it is simply my own opinion, but for the last 30 years my ARO has been a mixture of ATF and air tool oil, (basically turbine engine oil). This thin mixture does not seem to damage seals or other flexible components, allows free movement, good lube flow and burns off very quickly. As a normal bit of caution, I always turn my motors over by hand before hitting them with glow heat and starter. Not only does this ensure no hydraulic lock is present, but gives a good feel for roughness or other mechanical woes.

On a side note, I've seen a lot of people turning engines over on the bench or at a point of purchase to check compression and such. If an engine has not been well oiled beforehand this can cause all sorts of grief. This is especially true with non-ringed versions with sleeve taper.

Over the last few seasons I opted to add a relatively thicker metal conditioner to help maintain film strength. However, I found if left long enough it congealed, to the point that in one case it built up and bound in the ring. Not the best idea and classed as just another failed experiment, (and to be honest added to quite a few others).

For long term storage engines get a good dose of ARO and if not mounted, go into a sealed and relatively thick freezer type bag. Have found them perfectly serviceable and ready to go, some hidden away for 20+ years!

p.s. For engines that are accessible, I always plug the carb inlet and exhaust at the end of a flying session, (after the ARO has been injected). On most of the cowled installations I can at least cap off the exhaust outlets and try and remember to close the carb. This keeps the vehicle clean and prevents moisture from finding a way in during temp and humidity changes where the crankcase can "Breath".

earlwb

Yeah I have those same thoughts too. Some oils may contaminate the glow plug when it is first run after storing for a long time. The mineral oils used aren't the same as the synthetic oils (refrigerant oils) and castor oil. But I think that some types of oils may be a lot more worse on the glow plugs than others are. But as Cougar429 mentioned there might be some corrosion inside the engine and the minute particles that result from the oxidation going on may be the real culprit. But at that point it is hard to say for sure, so maybe a combination of the two. So it may be wise to first run a used glow plug for a while until you think you have flushed out the engine good. Then put in a good plug for flying.

carlgrover

Thanks for all the suggestions. There were a few things tossed out that I had never considered so I'm really glad I asked. There were a couple of questions asked about the engine mounting and prop size. This motor is mounted at a 45 deg. angle in a Sig Kougar. I don't know how far down the centerline of the tank is in relation to the fuel inlet but it's worked fine for other engines I"ve had mounted in it. Not sure of the prop at the moment but it could either be a heavy APC or a lightweight top flight rev-up.

The new engine has a couple dozen flights on it so it's still breaking in. I'll try playing with the low speed needle a bit then change out the plug to see what that does. I'm also of the opinion that a new engine is tough on a plug and will wear it down fast.


carl

blw

My Feedback: (3)

If you have flown and worked on turbines you learn from chip detector plugs that engine oil just about always carries metal bits around at some point in time. The chip detectors pick up the metal which is sometimes just fuzz, but larger chunks do break off and hopefully get caught before real damage occurs.

FSII

BLW, it's not the bit (and I'm not talking about fuzz) floating around in the oil that is a concern, it's that bit that it's come from as there's usually an impending failure of a bearing or a gear not to far away.

Cheers

blw

My Feedback: (3)

Yep.

Rocketman_

When I began chasing needle valve settings to get a satisfactory engine run I knew it was time to replace my very old Fox glow plugs that had many many flights on them. Believe me, I squeezed every bit of life out of a plug until I got tired of fiddling with the needle valves.
My only Fox engines that killed off glow plugs when they were new were the Fox Eagle III's. I got very upset about that because they would ruin a new glow plug in just one flight. Then one day they would suddenly get well and the plug would last nearly forever.

Listening to BLW and FSll talk about turbines I'm remembering all the times when some jet engine tester brought a chip detector full of fuzz and chips for me to look at and decide whether to halt a test or continue at the risk of crunching something. Most of the time I told them to just wipe it off and continue until the chip detector light flashes on the control panel again. Isn't that what we do with our model engines? Does anyone disassemble and inspect? Well, I did retire from that major US jet engine company without having blown up any engines.

1QwkSport2.5r

I pull down every engine I buy new or used and inspect. I've found swarf in a number of engines both of the 'bargain' variety as well as higher end 'performance' engines. I wont buy used tapered bore engines, too risky IMO. If any of the engines I buy have metal-caged bearings, I replace the bearings with phenolic caged bearings before running it. Extreme, maybe.... but if I have a bearing come apart, I'd rather have the retainer being plastic float around rather than metal... At least you have a chance of saving the engine in the event of a bearing failure.

I did not find any swarf or particles in the Fox 1.20 I got NIB, though Fox engines are all factory tested before leaving the factory.

carddfann

There's just something unholy about a nice scale plane that whines instead or roars. Electric just ruins the scale effect unless you put a sound generator in it but that's more battery drain.

blw

My Feedback: (3)

I just reread what I wrote about metal bits getting caught on the chip detector plugs. What I meant about damage to the engine was damage from whatever lost the metal pieces, not the pieces themselves.

av8tor1977

My Feedback: (6)

Wow do I agree with this post! With the notable exception of Park Flyers, electric flight is just wrong! Real airplanes make noise and it's beautiful!

AV8TOR

Charley

My Feedback: (2)

That's just BS. Most of the noise from an airborne warbird is from the prop, not the engine. My electric warbirds roar at high throttle settings.

CR

av8tor1977

My Feedback: (6)

Hmmm..... Guess you never heard a Rolls Royce Merlin engine at idle or in flight, or the F-16's of the Thunderbirds in flight like I did a short time back..... Sure doesn't sound like just prop noise.

To each his own.

AV8TOR

earlwb

When I used to live in Arizona, I worked at a company across the street from the Deer Valley Airport. Someone there had a P51 Mustang that he would run every week or so. He usually would just run the engine and park out on the tarmac idling and rev'ing it up some. But now and then he would warm it up good, taxi out and take off and fly it around some and come back and land. It was pretty awesome to be eating lunch outside when he was playing with it. Yes it was spectacularly loud too.

Charley

My Feedback: (2)

Just remember that loud model airplanes get flying fields shut down.

CR

blw

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P-51s have their own sound.

Charley

My Feedback: (2)

You're ducking.

CR

blw

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More like a loud whirring noise?

av8tor1977

My Feedback: (6)

I used to manage ANACO aircraft maintenance at Love Field in Prescott, Arizona. There was a Mustang based there that the owner would fly often. Man, everyone in the shop dropped their tools and ran outside when he came rumbling by our hangar taxiing out to fly! Unfortunately he had engine problems one day, and he crash landed it up near Williams, Az. (The pilot was fine.) We never saw the airplane again, but heard that it was shipped to Chino, Ca. where apparently they had factory jigs and could fix most any type of Mustang damage.

Another time I was taxiing out to fly at Tucson International when a Mustang pilot called in and requested permission for a high speed low approach. EVERYONE, even all the airliners called the tower and said, "YES, WE'LL HOLD, LET HIM DO IT!!" So they did and he came out of a dive, leveled off about 10 feet above the runway, and did a full throttle pass the full length of the 11000' runway, then pulled up to a 45 and did rolls until we couldn't see him any more. What a cool sound they make.

Electric? Bah Humbug.....

AV8TOR

blw

My Feedback: (3)

I considered moving to Prescott for school. I stayed with a professor/ instructor pilot named Ben Beagle when my wife and I came to look around. This was about 30 years ago. I loved Arizona.

50+AirYears

My former club invested in a sound level meter. Loudest plane we ever measured was a Byron P-51 with their quiet mount and a Quadra (42?). Over 120 dBA slow scale at roughly 100 feet distance and airborne at roughly 50 feet altitude. Second loudest was an electric powered Weight Lifter for the College competition. 118 dBA slow scale at 9 meters on the ground. The Astro 120 (I think I remember it being a 120) was turning a 16-6/8 reinforced fiberglass prop fast enough for the tips to be supersonic. The class actually had several props delaminate under the stress. It hurt to stand close. Quietest high power we measured were a couple turbines. 72 dBA Slow scale at 100 feet and 60 feet altitude, full throttle. Many small electrics have been measured at higher than that.
Interestingly, we had been at the club's current field for over 6 months before any of the neighbors, 1800 and more feet away, even came by to see what was up. That was when the gas engine people started showing up. Before that, with just glow and electric, the noise level was not high enough to attract attention.
There have been a number of articles on engine noise in the model press. A large part of the noise does come from the prop, especially small diameter high rpm props. The noise level drops off significantly when running larger diameter props at lower speeds. Then there is the sound of an internal combustion engine exhaust. Can be reduced with efficient mufflers. Then another component of sound from the internal combustion engine, glow or gas, is actually the noise generated by the airflow into the intake. This actually is measurable, and with a great muffler and slow prop speed, can even be heard. And sometimes,on high wing area planes, resonance can set in on the wing covering and structure, creating an even higher sound than even an unmuffled engine might make. And I would imagine I'm not the only person who has heard flutter from a plane, often just before an aileron, or even a tail, decides to go it's own way.
Engine noise is quite a complex topic of discussion.