Hi,
I took my trainer out to the field yesterday for the first time. It has an os la .46 on it. Anyway, I found an instructor and he checked it over. We started the engine and ran it for about 30 seconds before taking it up. It had 2 regular length flights at mostly full power. The engine had never been run before and my question is is this OK? Some bits of stuff about engine break-in before flying crossed my mind when we were doing preflight, but I didn't mention it because I assumed he knew what was best for the equipment. After fling I talked with some other members and they said the plane should never have flown without break in. Is it OK and is there anything I can do to help it at this point? Thanks.

Well, it is always best to break them in on the ground so you have more control over the mixture, and if it should quit while flying a new engine.. well, you get the picture. It should be run more rich than normal. But, if you were able to fly it without breaking it in, well, I suppose that's ok. I would still run it a tad rich for another couple of full tanks before leaning it out any.

CGr.

The O.S. .46 LA can be flown right away so long as it's flown slightly rich of peak rpm power. The idle will benefit from running a tank of fuel through the engine, but you probably didn't reduce the plane to idle until it was time to land anyway.

Your instructor didn't harm your engine at all, it's just as easy to break in your .46 LA in the air as on the ground.

If it happens that your instructor did not give any advice regarding a break in procedure, then your instructor failed teaching you the right way.

Even if your engine will be fine (I hope so), a correct break in procedure is a must for many reasons, but I will suggest only one which is the one where your instructor failed.

A break in procedure leads to the owner of a particular engine to know how it should perform. Adjustments of the needle valves, temperature range of operation and deduct when your engine is completely reliable are just a few reasons.

I have seen many engines destroyed just because the user did not get aware of a break in procedure, the break in procedure is a relationship between the engine and the owner, this procedure tells the owner many things like the best prop and the best mixture, (What your engine likes and dislikes) many people override this procedure maybe for time consuming or lack of interest or knowledge.

With the exception of the evolution engines I have not seen until now any engine's owners manual which skip the break in procedure.

Even that the technology of these days where the tolerances in machinery are very tight, they do always recommend a break in period, minimal if you want but at last there is the recommendation "Break in".

When some new modelers have issues with their engines, they just can't figure out what is the problem, just because they do not have that relationship with their engines.

I also have read about the evolution engines and a short period of brake in and the gain of a bit amount of revs.
Sorry for this long post.

thanks guys.

The following is direct from the O.S. Max .46 LA owner's manual:

"All internal-combustion engines benefit, to some degree, from extra care when they are run for the first few times - known as running-in or breaking-in. This is because the working parts of a new engine take a little time to settle down after being subjected to high temperatures and stresses. However, because O.S. engines are made with the aid of the finest modern precision machinery and from the best and most suitable materials, only a very short and simple running-in procedure is required and can be carried out with the
engine installed in the model.

The process is as follows:

1) Start the engine and, with the throttle fully open, open the needle-valve an extra half turn (180°) from the optimum setting. This will produce a rich mixture that will result in cooler running. Allow the engine to run out a full tank on the ground. (Avoid dusty surroundings.)

2) Now fly the model with the needle-valve re-set 20-30 degrees open from the optimum setting ( i.e. 40-60° from the highest rpm setting ).

3) Close the needle-valve very slightly on successive flights so that the engine is running on its optimum needle setting at the fifth or sixth flight."

Basically, your flight instructor set your trainer engine rich of peak power as described in step 1. Per the manual, one tank of fuel run on the ground would be best. Running that same tank through in the air won't hurt anything so long as the needle is set a 1/2 turn rich of peak rpm

alfredbmor and your flight instructor were both right. You need to follow the manufacturer's recommended break-in proceedure for whichever engine you're breaking in. Your instructor did that simply by tuning the engine to run a bit rich for the first few flights. alfredbmor is correct in pointing out that most engines can't just be fired up and flown quite like the O.S. Max LA-series engines.

Again, your .46 LA is fine. Be sure to read the instruction manual for the break-in proceedures for future engine purchases, however, as not all glow engines are quite so flexible.

Well, actually nowhere in your post do you say that the instructor set the engine rich. And nobody yet has mentioned how YOU or any beginner should learn to insure that their engine is running rich in the air. And it's something you need to learn.

It is probable that your instructor did check a couple of things. And you should too, before every first flight of the day.

Start the engine and let it run for about 30 seconds to warm up. Then go up to full throttle. This clears out the engine and insures it's warm. It also lets you look at the exhaust. You should see some "smoke". That's actually "the rich" showing up in the exhaust. If you don't see the smoke, adjust your needle. Lot's of descriptions how all over these forums. Basically you needle it to show smoke, then lean it until the rpms sag, then back the needle back out some. When an engine is new, you want to back the needle until you see some smoke. Now throttle to idle and let it run about 20 seconds, and then go to full throttle quickly. If the engine stumbles or dies, you got problems. And if this isn't done on a new engine every time it's taken to the field, you're missing the chance to solve deadstick landing problems on the ground instead of the next flight.

You ain't done yet..... That first flight, you've tested the needle settings and are pretty sure the engine is good to go. So go. And first order of business is to judge how the engine is actually operating while pulling the plane. If it seems too rich, not enough power and lots of smoke, then land the sucker and give the needle a couple of clicks lean. If it didn't seem too rich, but you don't see any smoke with full throttle, land the sucker and give the needle a couple of clicks rich.

You actually need to learn how to insure the engine is running rich, or the engine is running optimum. Close to the same symptom. In the air, a touch of smoke is when it's optimum. More smoke is rich. Too much is too rich.

It'll come to you. And your engine will run with power for you for a couple of years or more.

I sort of relied on a 'good smoke trail' when flying to determine if it was running rich enough. The club pro's, however, told me that this is not necessarily the way to check if it's rich or lean. The best way is on the ground before putting it up in the air, and this should be taught by a competent instructor.. someone that knows what is going on. Nothing in the original post said that it was checked or that it was running rich, nor was there any mention about a smoke trail.

Probably a lesson well learned here.. to learn how to tune the engine prior to flight and make sure it IS running with the proper mixture. I tend to run mine a tad bit rich. They all have plenty of power and get the proper lubrication.. and the wing gets nice and wet.. [:@]

CGr

OK then, let's focus a bit closer on having a rich setting in the air. We've had two very similar descriptions, but let's get just a touch more detailed.

Every first flight of the day should start the same. You need to feel out the needle setting to set the high speed needle for the conditions on that day. The following assumes the engine lowspeed needle has been adjusted properly.

Engines start really well with the throttle closed completely and then opened just a touch. Throttle sticks are ratcheted, and about three clicks seems to work with most. When the engine starts, let it run at that throttle while you move stuff out of the way and move around behind the airplane. Remove the glow starter and smoothly advance the throttle to max. Now, the important stuff.......

Slowly back the needle a click at a time. The rpms may increase. Or not. What you're wanting to see is the engine obviously going rich. As soon as you see it, you can start the needle back in. What you've just done is to establish positively that the needle setting is starting from a safely rich needle position. Didn't take but a couple of seconds to do.

As you click the needle in, obviously the rpms are going to increase. At some point they won't continue to increase. Keep clicking and the rpms will start to fall. Instantly go back some. "SOME" ????? JEEZ, this is pretty sloppy advice, isn't it? Well.............

What you want to do is get familiar with your needle response. And you're doing it right then. As you moved the needle from full rich to that max rpm setting, you had the opportunity to observe how much you had to move the needle. You did pay attention, right? And from that FLAT OUT needle position, you kept clicking until you heard the engine sag a bit. And you were carefully noting how far you turned the needle then, right? So "some" shouldn't be much mystery for you. Crank the needle back to where the max rpm was. But now keep backing a few more clicks. You want to adjust the needle so the engine is running safely rich on the ground. And if you stopped the needle setting where the engine was at max rpm on the ground, the setting would be too lean in the air. The advice is still too sloopy, isn't it. Good reason for that.

You need to take note of what you've just felt the needle do, and then observe how the engine/plane responds in the air. You're learning how your engine needle setting handles. And ain't nobody can tell you how many clicks are right for your engine. Not even the manufacturer will know. Or any field expert (although they'll have no problem giving a number, most times) for that matter.

Now, there is still one more part to this song and dance. You need to look for exhaust. With 2cycles, you will almost always be able to see some. If you do, kewl. If you don't (and there will be few days when you won't when the engine is rich enough) then pull a hard loop or somesuch and listen to the engine. It should pull ok and not sag. Truth is, after you've gotten comfortable with this song and dance, the needle will be close and you'll be able to feel how the plane handles on takeoff and climb out and know if you want to land right away.

Whenever the takeoff and climbout and whatever doesn't feel right, or you think you should be seeing exhaust and you're not, land the sucker and give the needl a couple of clicks. Here again, "some" clicks are how many you'll want ..... grin......

Once you have done this song and dance a few times, you're going to have a really good feel for how many clicks you'll need throughout the dance. But that doesn't mean you can blow it off after some number of outings. Because our engines are fairly sensitive to the atmosphere they suck down their little throats. Way more sensitive then we are. We have almost no feel for humidity, temperature and atmospheric pressu