Edge 540

What are the possible effects of breaking in a new engine in the cold midwest winter? Will it wear in any differently due to the 35 degree air temp? Keep in mind most of the flying season is in the 70-90 degree range outside, so if it is broken in in cold weather will there be any change when it is operated in the summer? Just curious.
The engine in question is my new saito 82A.
Thanks

w8ye

My Feedback: (16)

I've broken in several engines in the winter time when the temp was in the 20's F. I cannot see that they are any different than engines broken in during the summer months?

Enjoy,

Jim

Edge 540

Maybe the cooler temperatures would benefit someone breaking in on a stand. There is not as much air cooling as in flight, but the lower air temp would prevent hot running. Sound reasonable?
Getting engines to start consistently in cold weather is another problem altogether.

DarZeelon

Edge,


My point on the matter is that break-in, at least the initial 2-3 tanks, must be done on a test-stand anyway, the cooling disadvantage, when compared to a flight type break-in, can easily be overcome by using a faster spinning, smaller diameter prop (you don't need much thrust on the test-stand, do you?).

The prop, however, must have the same pitch as a normal flight prop (not a typical 3-D prop), so as not to impair the cooling effect, because a flatter pitch prop would create a slower airflow around the engine.

When in flight, you cannot tweak the needle open, if it appears too lean, or do anything else that would change the running conditions.

On the stand you have got full control and you don't have to contend with the occasional dead-stick, which is somewhat more commonplace during break-in...

cyclops2

90F -70 degrees is no concern.
90F--+70 is iffy for a snug engine during break in.
Heat kills. Cold does not.

Rcpilot

My Feedback: (78)

I like to break my engines in with a small prop but lots of pitch. The small prop lets them spin up and get up into the higher RPM range while still maintaining a slightly rich setting. The higher pitch keeps plenty of air moving across the cylinder.

The only problem I have with breaking in engines in the cold--is that I usually have my finger on the needle valve about 90% of the time. Just in case anything happens, I want to be able to richen it up or yank the fuel line off the carb and shut it down.

My fingers get awful cold.

downunder

I've never worried about prop pitch when running in because all of my engines are short enough to sit right down in the full prop blast and none of my models can fly faster than that anyway.


The engine in question is a ringed AAC so it doesn't matter too much if it runs a bit cooler.

da Rock

Actually, the cooler temps are probably lots better for the engine. They give you a margin of error you don't have in the summer. You won't fry the engine as quickly thanks to better cooling. It ain't no big thing, but it's there. So grin and bear it....

BTW, if your fingers are freezing, I got a suggestion. All my OSMax engines' needle valves are made to take an extension. They got a hole that has a grubscrew in it. I made up a flex, braided cable with a button on the end. I put a holder on my test rigs that holds that cable out and back. Every motor that is run has that braded cable stuck into the needle. It takes about 15 seconds to do.

It took me about 10 minutes to setup the breakin stand to have the holder on it. It's saved me from having to reach in behind the prop every minute since then. And there's less air blast back away from the prop, and it's no problem wearing a leather glove when the needle adjustment is so easy to get to.

Just a suggestion. But I guarantee it: If you're not entirely satisfied, there will be no additional charge.

DarZeelon

Darock,


In an engine that must be broken-in cold, like a ringed engine, or an iron piston lapped engine, the cold air, as you wrote, is an advantage. But for an ABC engine, that must be broken in at working temperature, it is a slight disadvantage, since it takes longer to reach working temperature.

Besides, any engine will be harder, even much harder, to start in the cold.


And, since an engine does not rely, like a live animal, on low temperature chemical reactions to thrive, 200 degrees Fahrenheit is not too hot for it, on the contrary. You should not judge what is good for an engine, using human bodily comfort parameters.

Hobbsy

My Feedback: (102)

The needle setting is the factor that controls the engine temp more than anything else. I've broken engines in when it has been 20 degrees F and when it was 100 plus. On a 100 plus degree day you can make a Saito run barely above body temperature running it very rich. I remember this past summer breaking in my newest Fox .74 ringed engine. I could hold on to the cylinder, it was not comfortable but I could do it. By the same token, when at its flying setting you could barely touch it for a split second.

buzzingb

My Feedback: (2)

I would recomend this method in any weather especially in cold. Use a hair dryer to gently warm up the cylinder and engine. It will do several things that are beneficial. 1 Expand the cylinder slightly to allow the piston to not be galled or scored. It allows the piston to wear to the cylinder better and not be under so much pressure at top of stroke. 2. It alows instant starting due to warmer combustion chamber and fuel combustion. Wear in any engine is greatest at start up as the engines parts expand to their opearating temp. I know someone will find fault with this method but for me it seems to work. I tried this method on a 2stroke engine that was very tight at the top of stroke, so tight you could hardly turn over the engine. I knew that was not good to have precision metal parts fit that tight in a engine. After warming with hair dryer it seemed much better and it started lots easier too. After running the engine I then checked the piston cylinder fit again and it seemed much better. So have at it. If you have tried this method and you find fault please state why. If you haven't tried it wait till you do before critiquing.

NM2K

My Feedback: (14)

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I have to agree with Dar totally on this issue. Folks breaking-in engines in the air are taking a chance.

I realize that some folks live in apartments and do not have ready access to a place to run their engines at home. When I was in that situation, I would pick a time to go to the flying field when the least amount of flyers would likely be there. Then I would drag out the break-in bench and proceed with the break-in. The break-in bench/stand does not have to be a large thing, but it should place the engine crankshaft at least 30" above the ground to minimize the ingestion of dust/etc.

As Dar mentioned, I too tend to run smaller diameter props during break-in in an effort to keep the load down and to provide better cooling for the engine.

cyclops2

Flying a Virgin Engine is risking the fuel mixture to go LEAN.
DO NOT take that risk!
Forget and pull a vertical and a tight ABC Virgin is loose when you go to run it next time.
Do not take the risk.
Tie it down to a ground stake and run it safely.[sm=thumbup.gif]