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Engine Break-In

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View Poll Results: A poll
Just fly it in the model and run it rich for awhile.
18.18%
Strap down the model to run it and break it in.
38.18%
Use a stand to mount it and break it in.
34.55%
Don't break mine in at all!
1.82%
Other...
7.27%
Voters: 55. You may not vote on this poll

Engine Break-In

Old 07-14-2004, 10:32 PM
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-pkh-
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Default Engine Break-In

How do you guys break in your new airplane engines?
Old 07-14-2004, 11:12 PM
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Trombe
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Default RE: Engine Break-In

run it rich on a stand so i can do tests and stuff SAFELY
Old 07-15-2004, 12:28 AM
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jcflysrc
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Default RE: Engine Break-In

I use a combination of the two. I run it in on a stand for a few tanks to find out if the engine has any air leaks or other problems. Once it will idle somewhat reliably and transition well, then I put it in the plane and fly it. Lots of loops...

Now it DOES matter what kind of engine you are breaking in, as far as how you would run it on the stand. You will not break in an ABC engine the same as one with a ring for example.

Jim
Old 07-15-2004, 11:52 AM
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bryris
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Default RE: Engine Break-In

I just bought an OS .46 AX (Wanted the discontinued FX, but decided its OK to get the AX). I don't know anything about breaking in engines. Will the engine come with break-in instructions? Can I break it in while its strapped to the plane, just anchoring the plane down? Or do I need a seaprate engine mount to run it on the bench?
Old 07-15-2004, 11:54 AM
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Jim Thomerson
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Default RE: Engine Break-In

There are engines and there are engines. Iron piston, ring, ABC, revlite, etc. Each requires its own fairly specific breakin routine. The question as asked is too general.

Jim
Old 07-15-2004, 11:58 AM
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Montague
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Default RE: Engine Break-In

Jim is right about all the different types of engines.

However, you can always mount it to the plane and break it in there. You won't want to fly it, just use the plane as if it were a test stand. Obviously, anchor the plane down well, and make sure you aren't going to suck anything in to the engine or have anything go in to the prop. Doing it in the middle of the pit area of your local flying field is a good way to annoy people as well. If you do it at the flying field, do it off to the side. (or in accordance with any local customs or rules, obviously)
Old 07-15-2004, 12:10 PM
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Default RE: Engine Break-In

ORIGINAL: Jim Thomerson

There are engines and there are engines. Iron piston, ring, ABC, revlite, etc. Each requires its own fairly specific breakin routine. The question as asked is too general.

Jim
More specifically, how would you break in an OS .50 SX Ringed engine with the stock muffler...
http://www2.towerhobbies.com/cgi-bin...&I=LXALM2&P=ML
Old 07-15-2004, 12:57 PM
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bryris
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Default RE: Engine Break-In

I won't be breaking in my engine for another month or so, I bought it a bit early. When the time comes, I'll research it and get it done. As far as the .50SX is likely very similar to the .46AX as far as break in procedure is concerned. That was my 2nd choice for an engine, but I decided I would get that one next time.

Thanks.
Old 07-15-2004, 01:08 PM
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Default RE: Engine Break-In

ORIGINAL: bryris
...As far as the .50SX is likely very similar to the .46AX as far as break in procedure is concerned...
They are not similar, the .50SX is a ringed engine, the .46AX is not...
Old 07-15-2004, 01:46 PM
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Default RE: Engine Break-In

I just got a new OS .46 AX engine and have broken it in or run it in. I followed the directions in the user manual.
I have about 4 full tanks of fuel run thru mine so far. I'm at the point where if I give full throttle, pick it up like its flying verticle,
the engine don't bog out. Doesn't even sound like this affects the motor at all. Heck, I don't even need the torque starter for it.
I just connect glo driver and hand turn the spinner. She fires right on up! Of course I'm gonna have one of the club guys check it
out before it actually flies...

Dave...
Old 07-15-2004, 03:13 PM
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bryris
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Default RE: Engine Break-In

-pkh-

I stand corrected.
Old 07-15-2004, 03:37 PM
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Default RE: Engine Break-In

I own 3 OS AX engines and all I did was run 2 tanks thru them in the airplane on the ground as the instructions indicate... then flew a bit rich for 6 flights and was gold..This engine is great..never dies on me..runs strong..


ORIGINAL: bryris

I just bought an OS .46 AX (Wanted the discontinued FX, but decided its OK to get the AX). I don't know anything about breaking in engines. Will the engine come with break-in instructions? Can I break it in while its strapped to the plane, just anchoring the plane down? Or do I need a seaprate engine mount to run it on the bench?
Old 07-15-2004, 04:49 PM
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Lancair-RCU
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Default RE: Engine Break-In

PKH,
I broke in my OS50SX with two tanks on the ground, alternating between very rich and just breaking in to two stroking as per the instructions supplied, then flew it for about 8 tanks running rich before leaning it out to peak and then rich a few clicks. About 20 tanks later I started having problems with it, it wouldnt rev hard, woudltn hold peak in flight after about 5 min flying and the oil from exhaust was always very dark during those tanks. I then went to a smaller prop and ran it quite rich for another 15 or so tanks and its come good, back the original 11x6 prop and it pulls around 12000rpm on the ground. I would suggest running it about 1/2 to a full turn rich for at least 20 tanks BEFORE trying to get absolute peak RPM from it in flight. It appears to me and others at my club that it likes a richer mix for quite a while to seat the ring in really well then it will hold peak power for the duration of flight.
Everyone has different ideas but thats how Id do it if I had another to break in.
Old 07-15-2004, 05:04 PM
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Default RE: Engine Break-In

ORIGINAL: Lancair-RCU
...back the original 11x6 prop...
Thanks for the OS .50 SX break-in info. You say you're running an 11X6... I thought you were supposed to run an 11X7 or 10X8 with that engine...
Old 07-15-2004, 05:07 PM
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Default RE: Engine Break-In

Yes the break in procedure for different types of engines is different.

For ABC (Aluminum piston in a Chrome lined Brass sleeve) or ABN (Aluminum piston in a Nickel lined Brass sleeve) engines (like the 46 AX), you want to run a couple tanks through it set on the slightly rich side of lean. Run it for a couple of minutes to get to operating temperature, then shut it down and let it cool. Repeat. Generally, a couple of tanks like this is sufficient to get to the flying stage.

For a ringed engine like the 50 SX, run the engine slobbering rich for nearly a tank, then start to lean it out a little. Let it cool off completely between tanks. For each consecutive tank, run it a bit leaner, but richen it periodically to keep the engine cool. To properly break in a ringed engine can take 10 or 12 tanks at least, but you can usually do it in the air after 5 or 6, but comtinue to run it quite rich.

The reasoning? An engine with a ring requires that it be run on the cool side during break in so that the parts can "seat", or wear in together. Running rich will carry away most of the combustion heat with the excess oil and fuel that dumps out the muffler, thus keeping things cool.

An ABC (or ABN) engine is manufactured with very tight tolerances. The sleeve is actually tapered so that there is NO clearance between the piston and sleeve at top dead center (for compression). Which is also why an ABC engine is very hard to turn over by hand, and sometimes even with a starter when brand new.

Running an ABC engine rich will result in the piston (and/or sleeve) wearing too much, which will result in a fairly rapid loss in compression. Running it leaner, and hotter, will allow it to wear in much more slowly, keeping compression high. Just don't run it too lean!

OS instructs people to run the engines slightly rich so that they "break in" quicker, which is essentially what I described. I use to describe a different procedure for ABC engines, but have caught flack for going against OS's instructions, so....

Good luck with those new engines!
Dennis-
Old 07-15-2004, 09:18 PM
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Default RE: Engine Break-In

Just came back and saw that Lancair had posted while I was typing earlier. (I'm pretty slow on the keyboard. ) But at least it sounds as though he's giving the same advice.

The 11 X 6 is a better prop for break in because it is smaller in diameter. Most manufacturers recommend a slightly smaller load on the engine for break in.
Dennis-
Old 07-16-2004, 08:03 AM
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Default RE: Engine Break-In

Yeah I had intended to go up to the 11x7 later on but seeing as Id had troubles and had to go back to a 10x7 for a while Ill stick with the 11x6 at 12000pm static now. Id hoped Id get more than 12000rpm but its plenty enough. I got 13300 with the 10x7 though, but the 11x6 is better in flight I feel.
Just keep it rich for as long as you can stand flying around at slightly reduced power, if I had to do it over again Id keep it really rich (about 1/2 to 1 turn rich will give about 200-500rpm less from my testing) for at least 10 tanks before leaning it out.
Old 07-16-2004, 08:13 AM
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Default RE: Engine Break-In

I own almost all Saito four strokes. I break them in mounted on the model per the engine manufacturer's instructions. I usually spend 2 to 3 hours per engine in the backyard breaking them in and adjusting the needle valves. I usually pays off at the flying field, I hate to go to fly and spend the afternoon tinkering with my engines.
Old 07-16-2004, 10:28 AM
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Default RE: Engine Break-In

It all depends on the piston and cylinder matirial on the suggested break in process. I usually use the manufacturer's suggested meathod of breakin.
Old 07-16-2004, 03:16 PM
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Default RE: Engine Break-In

Doing it in the middle of the pit area of your local flying field is a good way to annoy people as well.
For REAL![>:]

They are not similar, the .50SX is a ringed engine, the .46AX is not...
There you go...

I just got a new OS .46 AX engine and have broken it in or run it in. I followed the directions in the user manual.
You mean they come with manuals?

It all depends on the piston and cylinder matirial on the suggested break in process. I usually use the manufacturer's suggested meathod of breakin.
Now your talkin!

Jim
Old 07-16-2004, 03:38 PM
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Default RE: Engine Break-In

Yeah, they come with manuals... but that wasn't the question...

The purpose of this thread was to find out, in general, what people do when they go through their break-in procedure. You can do pretty much the same stuff with the engine in the model, strapped down, as you can with it in a break-in stand... I was curious to find out how many people chose each of these methods. In addition to this, many people don't follow the manual procedures and do their own thing... like just fly it rich for several tanks, or not worry about break-in at all (yikes)! For example, my OS50 SX-H engine manual says to just fly it rich for break-in... while other's highly recommended getting a prop and breaking it in on the bench because they had much better luck that way.

It was a general question with general answers expected... and much more specific answers welcome as well.

Old 07-16-2004, 04:05 PM
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Default RE: Engine Break-In

I got a OS LA and read the book on break-in,first tank on the ground,rich and no flying,1/2 of the second tank the same except i leaned it just a tad,havn't touched the airbleed yet,still a little rich but it flew that way,for each tank after,lean just a tad more and about 6 tanks it should be ready for maximum engine speed.

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