Correct break in?

[4DPILOT]

Hi

I found this on **************

http://www.*******************/how-t...-nitro-engine/

"The key to a break in process is understanding that you CAN get away with just a few fairly rich tanks and then letting it rip. THIS said, engines treated this way never develop their absolute power capability because the fit of the ring and sleeve is never optimized through a more methodical, patient break in.
I’ll take a new engine a burn the better part of (at least half) a gallon in a rich hover. I’ll land every one in a while and let the engine idle for a bit. If I get bored, I’ll do some gentle circuits, but I don’t turn on the idle up. Head speed is at most 1450-1500 rpm. You needn’t shake the model to death running it too rich, but you know well enough what nice and rich means.

When I get to the next gallon, I’ll fly the engine upstairs. Gentle aerobatics are OK, but DO NOT load the engine hard. It’s wise to depitch the collective so you can get to WOT without lugging the head. You can’t set the high speed needle if the engine is loaded up with 14 degrees of postive pitch. Think more along the lines of 8 or 9D at WOT in FFF. You can add the pitch back later on. The needle will be set so that it’s just barely lean enough to be mostly “clean”, but it’ll still break rich on occassion. Now, here’s the trick: when an engine is just barely leaned in enough to run as I describe and as it progesses through break in, you’ll notice it get more rich than where you had it originally set. All you do then is lean the high speed a click or two to get the mixture right back where it was, IE just a bit rich. The engine will repeat this process over the better part of 2-3 gallons of fuel. It’ll “ask” to be leaned in just a fuzz every few tanks of fuel. During this methodical process, you’re optimizing the fit between the ring and sleeve, which has a big reward in power in the end. When the needle setting stops getting a bit rich every few tanks of fuel, you’re more or less broken in. Since you’ve been maintaining a slightly rich needle, you can tune more for maximum power at this point. Given the tremendous power that the HZ has, you’ll need to think twice about whether you really need to lean the thing in to the point it’s running as hard as it can. A bit a margin is good for engine longevity. At this point, you need to go back and fine tune the midrange needle to be just a few clicks richer than as lean as you can get it without any midrange cackle. Doing this maximizes midrange torque and response. If the midrange is too rich, you’ll be tempted to overlean the high speed to compensate. This SCREWS EVERYTHING UP.
If you do the quick and dirty break in method, you’ll never see these subtle changes in needle settings as the ring beds in. In some ways, engines treated this way aren’t being broken in; they’re being “worn” in. Fuel isn’t cheap, but these engines darn sure aren’t either. To me it’s worth spending the time and effort through 2-3 gallons of fuel to really get that broken in correctly, after which you’ll have a stump puller for dozens of more gallons before an overhaul is needed.
Ben Minor"


What do you think?

It does make sense but 2-3 gallons are about 30 flights with a 50.

I am about to build my first nitro heli (600 LE with OS 55HZ)
so i am trying to get some knowledge before i ruin it.


thanx

Stefan

[Bob O]

I'm going to use the Finless method.

[TheBum]

Just make sure the engine doesn't stay too cool by running too rich. If it doesn't heat up a little, things won't seat properly. That's not to say that you should run at normal operating temperature though.

[Bobbyk]

The OS 55 has three needles, so the break in procedure will be slightly different to the OS 50 which has a two needle, if the manual is anything like the OS50 I will say follow it for the needle start up process and take it easy.

Thanks

Robert

[Tradhunt]

Stefan,
I've used that break-in method on a few engines and it works great. Just set the engine needle's to the factory setting and go from their.

[4DPILOT]

Ok If I understood that correct for the OS 55 I have to
tune the high end first then idle and after that finally the midrange?

but can I leave the idle rich and have optimum power on high end?

so for break in I will have idle stock/rich and midrange rich/stock

Then I will do break in and keep leaning the high end to optimum power(slightly rich is where I will end up at the end of break in)

then set idle correct and midrange so It'll transit good?

[Tradhunt]

Yes thats correct.