Engine endurance

What is the longest running engine anyone has or knows about? I mean just run till the the thing pops out. I sent an e-mail to Fox asking them if they had ever run an engine to destruction. They said they knew of no such test.

I have an article from an Oct. 1954 MAN that is about a 24 hr continuous flight (control line). A Veco .35 was used and was still going strong after the pilots (2) were exhausted. Apparently, it could go probably for days & days.

Comments?

>
>I have an article from an Oct. 1954 MAN that is about a 24
>hr continuous flight (control line).
>Comments?

24 hours continuous??? Must have had a huge fuel tank,,,,, maybe in flight fueling????

I watched a few hours of that flight on a saturday afternoon in Barberton, Ohio. The Participants were Duane Sanders (owner of the Barberton Hobby Shop)and his brother in-law, Bob Bell.The news was out among the local modelers about the attmpt so I rode my bike the five miles or so from Akron to Barberton to the U.L.Light junior high school athletic field where the flight was to be made. The plane was a Debolt Livewire cruiser r/c cabin model built as a u/c plane. This was chosen for its wide cabin space, needed for the quart fuel can they used for a tank.They kept the tank fueled by means of a garden sprayer adapted to 50+ feet of neoprene fuel tubing (remember that stuff?) wired to the up line. the engine was an early Veco.35 three bolt that was their favorite stunt motor(Duane flew the first real stunt patterns I'd seen.) They flew for 24 hours and some minutes and pilot fatigue was the limiting factor.At the time, it was a world record but for only a few months. A group of four flyers in another state (Illinois I think) surpassed them.

In the December 1990 RCM magazine Enya describes an engine they ran at 10,000 RPM for 104 hours, only stopping to refuel and change plugs. The Trans Atlantic flight last year took 39 hours.

>In the December 1990 RCM magazine Enya describes an engine
>they ran at 10,000 RPM for 104 hours, only stopping to
>refuel and change plugs. The Trans Atlantic flight last
>year took 39 hours.

Arguably, the hardest engine to break in and wear out were the old Enyas. I say that not having any experience with the new ones. I used to have a very early production Merco 35 that outlasted new OS Max-S 35s. Regrettably, it did not outlast leadout failure...

Key to long engine life is the quality of the fuel both in terms of contamination and lubricant quality. One can achieve "run until failure" much faster with a Fox 35 or an OS Max-S 35 when running low lube content fuel designed for ABC/AAC engines than with old Fox Superfuel.

Our model engines don't run forever. They will show wear, and the stopping starting (heating, cooling) can be the hardest on them. Matt's first pipe engine was overhauled after about 1100 flights, which would be the equivilent of about 115 hours. Now if this were in an endurance run, it could have gone considerably farther, and if it hadn't had those 1100 start/stop situations it would have shown less wear at this point as well, also. So the wear was noticeable enough to say "time to overhaul" but not such that it couldn't have continued to run. But this was hard running as well. Some that are set up so they don't need to work as hard will last longer than others. Our first 35 FP (iron piston version) lasted 7 years of hard running and contest work. We never logged the flights or hours on the engine, but it never went to destruction, either. Although it was "worn out" by most people's standards (low hand compression, leadked out the crankshaft bearing) it was still running strong and its last flight was an official at the Nats.

Running to destruction? I don't know how long these things would go. But the better built engines would obviouisly last longer than others--if they are doing the same work. In an Indy race car they want the engine to go 500 miles and last for about 3 hours of hard running. In a fuel dragster they want it to go a quarter mile and will then overhaul it. Maybe our engines don't do so bad after all.

Ron B.
F4Fguy

I seem to remember an Ohlsson ad from 'way back touting several hundred hours of continuos running on a .23.
On the other hand,Leonard is absolutely right,most of the wear in any engine is at the start.The question is not"how many hours?",but"how many cold starts?".This applies throughout the size spectrum,from .010 to 500 cubic inches,or you name it.
The most critical tests we ran in our lab were the cold starts.Not only do cold starts present minimal lubrication conditions,but during warmup,highly corrosive combustion products are condensed which cause additional wear throughout the engine.

I know of two life tests of engines, one by Duke Fox, the other done at Cox many years ago. Duke hooked a .35 stunt up to a 55 gallon drum of fuel, and everyday when he arrived at work, he'd start it up. Shut it down when he went home. After he finished that drum and the engine was still just fine, he terminated the test. Duke personally told me this tale, it is not rumor.

Just who at Cox or when the test was done, I don't know, but my boss Bruce Paton told me that they ran a Tee Dee .049 for over 400 hours. At the end, it could only be started with an electric starter, but it would still run.

The jist of all this is that bad lube, dirt, and overheating are the death of our engines, not normal wear. If your oil is sufficient and working, no metal ever actually touches other metal on the running surfaces, and oil wears things out even slower than water, I'll bet.

Ever wiped off the bottom of your plane and found grit in the oil? Guess where some of that grit went?

Yep! Clean and oil it and it and keep it so and will last nearly forever.

Jake

A top fuel dragster,s crankshaft turns how many revolutions from the green lite to the finish line?

Answer-------------------- 600
yeah thats right -600
Seldom if ever do one of these babies hold together for more than two passes if you are foolish enough to run them in consecutive runs without inspection and parts replacment.

Continental engines did some duration testing on thier old flat head engines .
All engines were the same, except for the water temp at which they were run.
The warmest was 195 F. The coolest was 160F.
The 160 wore out first.
I could go on & on like the engines started at 30 below zero and run at rated load for hours with 10 w oil thinned with jet fuel. no damage.
Long story short; there are many factors in the equation.
A few are;RPM
load
run temp
length of run time(cycle)
Lubrication
Ive seen big engines log 12000 hours and a sister engine go down in 30 days.
Unless your a piston farmer, the best thing to is play follow the leader using a known engine builders advice and do exactly as he instructs .Not just some of what he says but ALL-- And enjoy

LAST EDITED ON Mar-15-04 AT 10:36 PM (CDT)
 
600? Assuming a 4.5 second run, I'll bet the crank turns at least 30K revs, not counting warm up and burnout!

@ 10000 RPM, an engine is turning 167 revolutions per second.

A 4.5 second run would last 750 revolutions. I doubt even

a top-fueler is turning a full 10000 rpm. So 600 revs is about

right.

>A top fuel dragster,s crankshaft turns how many revolutions
>from the green lite to the finish line?
>
> Answer-------------------- 600
> yeah thats right -600
> Seldom if ever do one of these babies hold together for
>more than two passes if you are foolish enough to run them
>in consecutive runs without inspection and parts replacment.

Racing automotive engines are typically assembled with very loose tolerences - so they are, in effect, worn out to begin with.

A production auto is another story. These engines run for several thousand hours before rebuilds are needed.

Everyone always talks about the "good old days" when things were built better. Getting 100,000 miles out of the family sedan was a big achievement. Today's engines run 100,000 miles between tuneups!

MIT associate, Mark Stevens formerly of the Labs here in New Mexico said that in the seventies they were evaluating "all known" model engines for drone use under all conditions, as decoys to test the Stinger missles. He said, that the HB made then in West Germany ...'hands down, beat the crap "by weeks" of endurance running, out of any model engine tested'. That is what he said?

Well, in my personal experience, I don't recall ever actually wearing out an engine without very traceable mistreatment. Other than a couple of major physical distasters like the top of the piston coming loose from the bottom, or punching the conrod through the case. Now as a kid, I would splatter an engine into the dirt, give it a minor flush of fuel and go on flying. The engines died at a horrible rate, for some unknown reason. (Well, I had "cleaned" it) Now, if I see grit on the outside of an engine, it is through for the day! I don't get free parts anymore.....

But a carefully run stunt engine with no dirt injestion, no damage, I have never actually seen one "wear out". I put 3 gallons of diesel fuel through an OS 25fp, often running it overcompressed (how can you tell until you land?). Last I heard, that engine still runs fine after yet another gallon. That's about 70, 6 minute flights per gallon on a .25 diesel, so we are talking about 28 hours of very abusive running for a glow engine. And it had an hour of running as a glow before I ever dieselized it.

We run ludicrous amounts of oil through our engines, mostly to control the heat, not provide lubrication. They just should not "wear out".

LAST EDITED ON Mar-16-04 AT 02:42 AM (CDT)
 
I'd have to look up the details -- I wrote a historical article about this in MAN around 1979 -- but in 1957, the Eugene Prop Spinners of Oregon flew a single flight that lasted 64 hours, 30-some minutes. It was written up in a couple model mags of the time and featured in a K&B advertisement later.
The plane was a Veco Chief with a specially modified dual-plug K&B .35, with the fuel supplied to a hard tank by tubing running down the lines from the pilot, who wore a gallon can on his belt. The engine setting was adjustable remotely via a servo, also I believe powered via insulated lines.
All of this was the project of the local club at the time with the aid of CL pioneer Oba St. Clair, who rigged the servo, etc.
The flight was approximately the third attempt; one of the others had gone about half the distance.
I believe the flight started on a Friday and ended on a Monday. Some of the local fliers here still remember it.
The engine was reportedly still in good condition but both plugs had lost their elements. The plane still exists in a hobby shop here in Eugene, but the trick hardware has been removed.

--jt

>I'd have to look up the details -- I wrote a historical
>article about this in MAN around 1979 -- but in 1957, the
>Eugene Prop Spinners of Oregon flew a single flight that
>lasted 64 hours, 30-some minutes. It was written up in a
>couple model mags of the time and featured in a K&B
>advertisement later.(snip)
> The engine was reportedly still in good condition but
>both plugs had lost their elements. The plane still exists
>in a hobby shop here in Eugene, but the trick hardware has
>been removed.
>
> --jt
>

We run about 6 minutes and 20 seconds per flight. Even if that were 6 minutes, that would be ten flights per hour, or with 1100 flights on an engine before going to overhaul that would have been 110 plus hours. The engine, as I mentioned, would still have fun fine, just no longer up to full expectations. And this was also with 1100 stop start situations (plus 2 additional hours of stop/start break in). So the engine, in the above situation, should certainly have been found to be in good condition after the flight. And all they have to do is run it. They don't have to go at maximum power, maximum speed. They just need to sustain a speed to keep it in the air for the endurance run. But...

The problem as you reported is the plug. That is why they used two of them. It is not the engine manufacturer who should get the publicity in this case. Big deal. It is the plug manufacturer. Anyone out there getting 600 flights out of a plug?

The plug...so that's another reason Maynard used diesel for the trans-atlantic flight. It was a dieselised OS 60 I think. There was some reason he couldn't do the lengthy mixture setting routine so the poor thing ran lean for two days, but as it turned out it would not have made it at the proper setting! Don

Re plug life...it is one thing to make a single, many houred flight on a single plug, where it is heat cycled just once from a cold start. It is something else to slice this same number of hours up into a series of 6 or 7 minute flights, each cycling the plug. This latter condition would be harder on the plug, I would think.