Author Topic: OS 25 LA-S MAX break-in (Read 3331 times)

JamieHolford · « **on:** January 31, 2011, 09:46:52 AM »

I have a Brand new OS 25 MAX that needs break in. I have a couple of questions and I know I should use the search function but alot of the explanations are greek to me.

I need to break in this engine but my dad insists that " back in hte day" breaking in a engine was putting it on the plane and start flying. This cant be all right.

Can someone explain to me in good detail on how to 4-2-4 break? IS it right for this engine.

In what way or process should i break in this engine?

What is running in 4 stroke on the ground?

Give me a cox .049 and I do can my magic... Give me a bigun and Im lost!!!

FLOYD CARTER · « **Reply #1 on:** January 31, 2011, 02:18:59 PM »

The usual procedure for these ABC engines:

Use a prop one size smaller than you intend for flying. For a .25, probably a 9" by 4" pitch

Use a fuel with some castor oil content. SIG 10-10-10 works well.

Adjust for a fast 4-cycle. Then pinch the fuel line so the engine runs FAST for about 10 sec. Then release the tubing for a 4-cycle run for another 30 sec. Repeat this procedure a few times.

Then, let the engine cool completely, and repeat the above fuel-pinching procedure.

About 15 minutes run time and it should be ready to fly.

Floyd

Kim Mortimore · « **Reply #2 on:** January 31, 2011, 07:52:46 PM »

To answer a couple of your other questions, this engine, like most modern engines is designed to run at a steady speed in the air. The 4-2-4 break is a holdover from the old days and is used on only a few modern engines. It requires a good bit of experience to set up properly and is the last thing you need. A steady speed run is far superior for your purposes

When breaking in on the ground, as you turn the needle in and the engine speeds up, there is a point where you hear a distinct change to a higher pitch sound. This is the transition from 4-cycle to 2-cycle. When you hear this, back the needle out just a bit until you hear the lower 4-cycle note again. This is the fast 4-cycle Floyd referred to. If the needle is set between 4 and 2 you will hear the engine oscillate back and forth between 4 and 2 without changing the needle. In my experience, when you go to fly it, this is a good starting needle setting, as the engine will probably settle smoothly into a single speed once airborn.

Hope this helps. The LAs are very good engines, especially for the price.

JamieHolford · « **Reply #3 on:** February 01, 2011, 04:29:47 AM »

Very good engine especially when its free

Understood on hte 4-2.

Another quik and easy question. WHat fuel and nitro percentage would I want to use. I know nothing on how to mix and its nearly hard for me to tell hte difference between plane fuel and heli fuel since Im mainly a 1/2a guy.

Bootlegger · « **Reply #4 on:** February 01, 2011, 06:04:29 AM »

Jamie, the fast 4 stroke is in the 8500-9500 RPM range, that is where you should run the engine for break-in.
They have a "pinch" at the top of the stroke, and running in the fast four stroke let's the engine build some heat so that the liner will expand and let the piston move as it should.
If you run it slow it can "egg shape" each end of tne con rod and that ain't good!
Like others have advised, let it cool between runs so it goes thru a heat cycle, another way that I use to break-in my engines is a 6" long of fuel tubing between engine and tajk so that I can lower the tank to increase the RPM then raise the tank to lower the RPM. This also let's the engine go thru some heat cycling, and you aren't putting your hand near the prop to change the needle!!!
Give me a call if I can help you some more.
Keep us informed as to how it goes...

JamieHolford · « **Reply #5 on:** February 01, 2011, 06:11:23 AM »

hehe Mr. Gil remote needle

Brett Buck · « **Reply #6 on:** February 01, 2011, 10:35:45 AM »

Quote from: JamieHolford on January 31, 2011, 09:46:52 AM

I have a Brand new OS 25 MAX that needs break in. I have a couple of questions and I know I should use the search function but alot of the explanations are greek to me.

I need to break in this engine but my dad insists that " back in hte day" breaking in a engine was putting it on the plane and start flying. This cant be all right.

Can someone explain to me in good detail on how to 4-2-4 break? IS it right for this engine.

In what way or process should i break in this engine?

What is running in 4 stroke on the ground?

It matters a lot if it's an ABC or an iron-liner engine, show us a picture and we can tell what to do.

Brett

FLOYD CARTER · « **Reply #7 on:** February 01, 2011, 11:05:02 AM »

Pretty sure all of the OS "LA" engines are the same: ABC .

Floyd

JamieHolford · « **Reply #8 on:** February 01, 2011, 12:29:29 PM »

Here goes

JamieHolford · « **Reply #9 on:** February 01, 2011, 12:30:08 PM »

other side

RandySmith · « **Reply #10 on:** February 01, 2011, 01:28:09 PM »

All of the OS 25s are ABN

They are not fitted tight so they do not need extensive breakin, Just a short few runs will be OK
Regards
Randy

JamieHolford · « **Reply #11 on:** February 01, 2011, 01:32:11 PM »

Thanks for the info Randy!

Brett Buck · « **Reply #12 on:** February 01, 2011, 02:26:03 PM »

Quote from: RandySmith on February 01, 2011, 01:28:09 PM

All of the OS 25s are ABN

They are not fitted tight so they do not need extensive breakin, Just a short few runs will be OK
Regards
Randy

Nyet. There were Iron-liner versions, in fact the first one I saw (25FP-S) was an iron-liner. I never ran it very much so I have no idea how it ran, but I am certain it existed.

Brett

RandySmith · « **Reply #13 on:** February 01, 2011, 02:31:00 PM »

Quote from: Brett Buck on February 01, 2011, 02:26:03 PM

Nyet. There were Iron-liner versions, in fact the first one I saw (25FP-S) was an iron-liner. I never ran it very much so I have no idea how it ran, but I am certain it existed.

Brett

Hi Brett

As noted on the title of his post , and the pictures of the motor ,he was asking about the OS 25 LA, All 25 LAs are ABN.
YOu are of course correct about the FPs being iron on some early models

Regards
Randy

Brett Buck · « **Reply #14 on:** February 01, 2011, 02:32:58 PM »

Quote from: JamieHolford on February 01, 2011, 12:29:29 PM

Here goes

  LAs are all ABN (but I didn't know it was an LA until now...) so little or no break-in. The only thing to watch for is the fuel consumption. It will start high, and then drop dramatically over the first 10-15 flights. By about a factor of two in some cases.

   I would only recommend this with OS ABN engines. You could probably get away with it on quality AAC/ABC engines but never ever on iron-liner engines no matter who says otherwise. The chances are too high of having something go wrong (i.e. lean) when you don't have any control and wrecking the fits.

   I have flown official flights with brand-new never-run engines (20FPs) and it's really no big deal, except for the fact that it tends to richen itself up as the flight goes along, and on subsequent flights you tend to chase the needle in and end up too slow most of the time.

   Brett

Kim Mortimore · « **Reply #15 on:** February 01, 2011, 06:42:02 PM »

Jamie also asked about fuel.

5-10% nitro. Opinions differ on oil, especially whether to use castor and if so how much. 20-22% total oil is a good range. This is % by volume, not by weight. Some RC fuels list oil % by weight, which results in less oil for a given %.

Brett, what are your thoughts on running all-synthetic in LAs?

Jamie, do you have a local hobby shop or other fuel source, and if so do you know what brands of fuel they carry?

JamieHolford · « **Reply #16 on:** February 01, 2011, 07:10:08 PM »

I do but they are all a hour or so away.

I wanna say Sig and Omega?

Bill Little · « **Reply #17 on:** February 02, 2011, 02:16:22 AM »

Quote from: JamieHolford on February 01, 2011, 07:10:08 PM

I do but they are all a hour or so away.

I wanna say Sig and Omega?

I would suggest 5% or 10% nitro Sig Champion either 20% or 22% oil (I think it comes either way) for break-in and flying. others might disagree..... but that has always worked well for the newer OS engines I have had. Anyway it has been Sig "Champion". And I am not so sure you would need 10% nitro right now.

Big Bear

Dennis Moritz · « **Reply #18 on:** February 02, 2011, 01:01:19 PM »

Randy's statement about break-in is consistent with my experience of LA25s. First one I owned was fitted to a Flite Streak ARF. Ran half a tank on the ground, filled the tank, flew it. Aside from installing a through the venturi FP needlevalve, no further changes needed. Flew it regularly for a season and half. 9x4 prop most of the time. Powermaster 5%, 22% (50/50). Very consistent run. No fuss, no muss. Other folks in our club have been equally cavalier. No problem.

Brett Buck · « **Reply #19 on:** February 02, 2011, 02:19:33 PM »

Quote from: Bill Little on February 02, 2011, 02:16:22 AM

I would suggest 5% or 10% nitro Sig Champion either 20% or 22% oil (I think it comes either way) for break-in and flying. others might disagree..... but that has always worked well for the newer OS engines I have had. Anyway it has been Sig "Champion". And I am not so sure you would need 10% nitro right now.

I haven't run the LA very much at all, but I though the 20/25FP liked 10% a lot better than 5. It wasn't a matter of how much power it put out, it just ran a lot steadier. Going from 5% to 10 greatly improved the run quality, and 15% was a little better. Any more than that seemed to have diminishing effect, up to about 30% or so. That's as much as I ever ran, and it clearly wasn't worth the cost. LA might be different but I would be very hesitant to recommend anything less than 10.

And if it's cold out, I would be tempted to at least prime it with 15 or 20% nitro just to make the starting a little easier. Or, as Warren was doing this last weekend, lighter fluid.

Brett

Steve Fitton · « **Reply #20 on:** February 02, 2011, 02:44:33 PM »

My FP-25 really liked Powermaster 10/18 fuel. It ran ok on 5%, but tended to want to run in a 4-2-4. On 10% it ran the "pipe" style 2 run which suited the Veco Tomahawk it was flying much better.

Dennis Moritz · « **Reply #21 on:** February 02, 2011, 05:05:40 PM »

We run %5, 22%,50/50 Powermaster in the LAs and most everything else. Including FP40s. Dan Banjok even ran it in his Saito 72 as well as his current PA75. (I believe.) Dan might try 10% Powermaster in this and that or a mix of %5 and %10. Issue is power, not run quality. Never found a need for 10% in the LA25s. Jack Weston got himself into Expert flying an FP40 powered Gieseke Nobler. Same fuel. Unless there is a setup issue, defective tank, fuel line pin hole, bad profile vibes, etc., the fuel has worked for us. Oh. Yeah. We also run it in LHA Fox 35s. Year after year. LA 25s, in our experience, are exceptionally user friendly. Not at all fuel sensitive. Can be run on %10. We just never found the need to do it.

Bill Little · « **Reply #22 on:** February 02, 2011, 05:31:00 PM »

HI Dennis,

My "recommendation" on the Sig fuel is that Jamie said he can get it at his "local" hobby shop. he didn't mention if they had Powermaster, Fox, Red Max, or Taffinder's available.

If the shop don't carry it, it doesn't matter what kind of fuel it is.

Big Bear

Dennis Moritz · « **Reply #23 on:** February 02, 2011, 05:38:37 PM »

That makes sense.