codycarlisle25

Just keep it rich and take your time. When running in on the bench, you can see better manners developing through the process. I do let it heat cycle between runs. On the bench takes a little more discipline here. At the field you can BS between flights. I do use a smaller prop and stay away from hard G's and extended verticals, and vary the throttle during the flight.

Cody

Sport_Pilot

Ringed engines tend to have a lot of friction heat when first run in. That is because of the ridges left by honing. So if you run rich enough to 4 stroke the rings will be near operating temp. IMO not required if flying because the air flow helps cool the engine, but on the ground I have seen many get very hot on the first run. Especially four strokes.

As far as prop load I use a small diameter with plenty of pitch. That way it revs and has plenty of air over the engine.

Broken Wings

My Feedback: (20)

I like to read the manufacturers instructions. They know what materials the engine was made out of...

turbo.gst

My Feedback: (8)

Broken Wings brings up a good point as materials should dictate specific method used for break-in.

pmerritt

My Feedback: (118)

AGREED. Run a tank or two through it and break the rest of it in flying conservatively. A gallon on the stand. NOway Jose!

downunder

The instructions for my ringed Enya 61CXL say to run it rich for 30 minutes before flying but that it could take another 1-2 hours before fully run in. As far as materials go, the Enya is somewhat different because it uses a brass liner that's Nickasil plated. Being cautious (and mine being a CL engine so no throttle in case of a lean run) I ran mine for an hour on the bench starting from absolutely slobbering rich to just getting slightly into a 2 stroke which is where I wanted it to run in flight anyway.

One thing that hasn't been mentioned so far is that it's not just the ring to liner seal that has to mate but also the ring to the bottom of the ring groove which needs a perfect seal against combustion pressure.

I might add that the hour of running on the stand consumed about a quart (for the Yanks ) of fuel.

freakingfast

My Feedback: (3)

LOL, You named the one engine that may out live us all and takes about two gallons till it reaches full strength. If you run fuel containing zero nitro the bearings last forever also in a Moki/Mark engine. 5% nitro max, but you wont notice much difference in power or idle-ability, so don't waste your time. They run great on 0%.

MJD

My Feedback: (1)

Yes, everything I have read about the Moki talks about long break in, and long service life. Always wanted one.

gene737

It appears all the experts have their own idea on how to break-in a ringed engine. The expert I would listen to would be the owners manual. They know a thing or two about that engine. Personally, if I can get it to hold an idle and transition OK, I go flying. Good luck, it is a nice engine. Treat her nice.

1QwkSport2.5r

It would be nice if the owners manuals were written by engineers or designers that designed the engine. Most often they are not.

The topic of engine break-in is a can of worms as stated earlier. Everyone has their own way of doing it.

Tony Iannucelli

My Feedback: (193)

O.S. engines don't need running on the ground except for the first half tank. In due respect, some of the advice on here is from 30 years ago. A ringed engine will do just fine in the air as long as you set the low end properly so you can land safely. Most will idle out of the box with 15% nitro which helps the idle. Call me crazy, I use 20/20 for everything. Pull some big loops and split esses. Get the engine working a bit for 4-5 flights. My OS ringed engines, including every helicopter engine, run fine from the go. Castor, low nitro, etc, and extensive ground running have never been necessary. Someone said follow the book (agreed!), and most OS now say "use the prop you plan to fly with" and the fuel nitro range isn't changed for any break-in. And yes, I have an OS95, both 2 and 4 stroke, and 1.20s, and 1.60s, and 91s, and 61s. Helis include .32, .50, .70, never any issues. You get what you pay for with OS, which is a dependable, beautifully machined, work of metal art.

MJD

My Feedback: (1)

I don't really put much faith in owner's manuals except in the most general sense. I've read enough crappy engine instructions that I tend to think of them as written with a careful combination of "cover our ass to avoid complaints" and "make it as easy as possible for the user" without really conveying anything deeper. It's nice to think the manual contains the gospel and no other information could possibly trump the instructions contained there-in. But if you read enough engine instruction sheets what I think you tend to see are very conservative fuel recommendations and boiled-down procedures intended to make life easy for the general RC public by avoiding undue burden on the owner for break-in. Think how many people report "it ran right out of the box" as a positive statement of quality. An engine that needs minimal attention before mounting and flying will appeal greatly to the masses, and many of the comments to date on this thread support that notion IMHO. How many end users really track the life span of their engines? How many end users can say "I'm getting all the performance and life out of my engine that is possible" and back it up with data? How many of us, unbeknownst to ourselves, are only getting 95% of what an engine could offer with more careful handling? I sure don't know.

Some manufacturers are very specific and talk the language of a company that wants to convey detailed, accurate technical information for the owner without diluting the operating procedures for the mass market - Jett for example.

OS engines are pretty darn good quality, I agree, but what they chiefly are to me is user-friendly, i.e. you can fly with minimal break-in and they are generally easy to adjust. Quality can be defined in a number of ways, depending what is most important to the owner. I think there is a strong tendency to think that the quicker you can get the engine into the air and get on with flying, the better it is in all other ways. To me it speaks of good quality control and manufacturing techniques, but also of an engine whose fits are kept conservative to avoid headaches for the owner.

Sport_Pilot

OS engines are well made with very good machining and casting quality.  They are engineered to be user friendly and that includes a quick break in.  Close tolerances are part of it, but most good brands have just as close tolerance.  Softer metal is another reason for quick break in.  This is why the lower end OS breaks in quickly and has a short life.  The higher end OS engines takes longer to break in and lasts longer.

jeffie8696

Hey, who doesnt like to argue about a controversial and complex subject like break in, or castor oil, or religion,,,,,,,,,,,,, politics,,,,,,,,,, gas prices,,,,,,,,,,,

MJD

My Feedback: (1)

Interesting, I don't own a wide enough variety of OS to have seen differences in metallurgy/construction for myself, hence my comments are from an OS sport engine user. I never argue their quality, as to "best" - that depends what criteria you use. Definitely top of the heap sport engines for the price, reliable and always a wise investment, and although I don't own any "high end" OS products I am sure the performance is there as well. I still love my old .15 FP - reliable, dependable, idles forever, and decent though not earth shattering performance - IOW a great sport engine like so many others. And I have a NIB .25 VFDF with absolutely no detectable pinch up top when stored in my 57 degree basement - I find that odd.

jeffie - Theodore von Kármán - a legend in aero circles if there ever there was one - was a strong advocate of debate and controversy in the learning process. Mind you, I don't think he was talking about mindless arguing.. not that we have any of that here, just a variety of observations and opinions.

Wingspam

I have had two of the ringed motors from OS, a 91 and a 95. I ran the 91 for over 6 years and broke it in according to the manual. I still have the 91 to this day, now its on a 40 size stick with a pipe.
The 95 was a pain to get fully broke in, did the breakin per manual and it took over a gallon more to get it running good.

Sport_Pilot

Keep in mind when I say softer metal I am not talking a huge differance. Not that the metal is really soft or extra cheap. The engines have plenty of life for most, just not the near indestructible longivity of some others. Some of the old Fox engines for example did not get to full power for several gallons and run for hundreds of hours maybe even over a thousand hours before being worn out. Most sport engines are lucky to last two hundred hours. But that might be a couple of decades or more for some.

I think Duke ran one engine till a 55 gallon barrel of fuel ran through it and it still had good compression. I think it ran over a thousand hours.

Rob2160

This is a good read...

Tells you how to break in a REAL aircraft engine... (from the manufacturer)

Don't baby your engines....

http://republicseabee.com/Files/Tips...ine%20Care.pdf

dbacque

My Feedback: (3)

OS provides clear instructions on break in. I've broken in ringed OS 91's and 1.20's and I usually go a couple more tanks on the ground than they recommend but that's about all. However I've had a couple of .91's and both of them required many more flights than they quoted before I could reliably lean the engine out. That's not a problem, just a note that you should be aware that you may need to run 25 - 30 flights or more before you can lean the engine out and expect peak performance. The thing to watch for is if several minutes into a flight, epsecially when you pull up into a vertical climb, suddenly the engine drops in RPMs and just won't spin back up even after you level out. If this happens, land immediately, richen it back up and fly another handful of flights before you lean it out again. But mostly, follow the instructions for a few ground runs, then run it rich for a good while and pay attention to the sound as you fly listening for a sudden loss of RPM. Remember, no two engines are the same.


Dave

sparkw7809

I have owner many OS engine over the past forty years. They have all been temperamental. The new style carbs have been extremely hard to work with. I would like to pass along what I learned over these many years.

I have an OS 91 and 95 currently. I believe your problems will be resolved for the most part by replacing the glow plug with a Fox long plug with "idle bar". You can order these from Fox direct if your local shop doesn’t carry them. Tower stopped showing them in there catalog but stillhave them.

Of further importance is that you read and re read OS low end needle valve adjustment. Make adjustments 1/8 turned at a time. Run engine if response is not correct, shut down, make 1/8 turn adjustment and start up and try again until sounds and tacks well when holding up.

Pass this on and let me know.

TimBle

+2 to both comments.

Ringed engines don;t need a long break in period. Having the ring run cold for long periods will actually wear it out faster since the the engine is not up to its working dimensions.
Set the needles to just slightly rich and heat cycle it on the ground using the throttle.

idle - gradually increase throttle to mid - leave there for 10 secs, throttle back to idle,
repeat but stop at a slightly higher throttle setting on each cycle till youhave cycled it to WOT.
Make sure the engine does not die at idle i.e. ensure the transition is good, then go fly it keeping WOT to a minimum (but it should be run at WOT for short periods) and avoid verticals that are longer than 5 seconds give or take a few either way.

Its should be broken in after the 4th or 5th tank and thereafter you can start to extend the verticals.

avoid changing the throttle responce hydraulically i.e. openig and closing the needle between excessively rich and just above. This places a lot of unnecessary stress on the ring.

jaka

Hi!
Temperamentel???? OS engines are like kittens!!! Very easy to run,set and handle!
All you have to do is to use 5% nitro fuel and 18-20% oil,and rest methanol.
Suitable glow plugs are the old stand byes: OS 8 or Enya 3.