Geesh, quit with the "attacking" thing....
Both of these guys spend a LOT of time trying to help people on this forum- they use different methods thats all.

"Take what is useful and discard the rest"
Bruce Lee

The reason why your engine isn't coming up on the power curve the way you'd like is because your breaking it in with the "flying" propeller.

MAX rated RPM on this engine is 16,500. Best or practical RPM is 2000-15,600RPM

You want a screamer?

Then put a prop on it that will allow it to spin 15,000RPM on a test bench. Whatever prop that might be. If it takes a 10-8 to get it up to those RPM---then do it. If it takes a 9-6--------then do it. When the engine gets over 15,500----then you put on a bigger prop. Lean it out 1 click. Try an 11-6 or an 11-7. Run it some more. Lean it out 1 click. When it gets broke in a bit and the RPMs come back up to 15,500RPM--------then you put a BIGGER prop on it. Lean it out 1 click. Try a 12-6 or a 12-8------and you run it at 15,000RPM untill it gets close to 15,500 or maybe 15,700.

You get the idea? Make it break in at MAXIMUN RPM and keep putting bigger props on it to slow it back down and keep it from blowing up when it gets near 16,000RPM. You lean it out 1 click at a time--maybe 2--- and keep it rich--but still a good solid 2-stroke.

Keep in mind---you need to be breaking it in at a slightly rich setting. 15,500 RPM and LEAN will cook it in a couple seconds. So, if you need a 8-8 prop to get it up to 15,000RPM and still be on the rich side--then DO IT. But keep it rich enough that you don't cook it.

I'm NOT talking rich---like 3 or 4 clicks rich. Thats the settngs you want to be at when it's all broke in. When your first running it--you should be at least 1/4 turn rich. Maybe 1/2 turn. It needs to be in a good 2-stroke range. NOT SLOBBERING RICH. But nice and rich to allow for plenty of cooling. The OIL is whats gonna keep it cool. You should be able to HEAR it when it breaks from 4-cycling to 2-cycling. DON'T break it in 4-cycling--not even for a second. Start it up with a 9-6 and hammer the throttle. Tach it!!!!!!!! If it's already at 15,000RPM then shut it down and get a 10-6. Make sure it's running at high speed and rich enough to be putting out lots of smoke. LOTS of smoke. But if it starts gurgling and 4-strokin---then lean it 2 clicks at a time untill you hear it come alive and start screaming. Now leave it alone!!!!! Let it scream at 15,000RPM for 5 minutes or untill it gets near 15,500. Shut it down.

I don't know how to describe it. You can either tell the difference between 2-strokin and 4-strokin or ya can't. You CAN hear it.

You want it 2-strokin--but plenty rich. If your 4-strokin---then your just ruining the piston and ruining the engine. Start it and get it up to speed right away. Tach it. Keep it on the rich side. Don't let it 4-stroke.

I run my engines for about 5 minutes and then shut them down for 20-30 minutes. Go have a sandwich or a cigarrette. BS with the guys at the field. Don't rush it.

I ALWAYS mix up a special break in batch of fuel. It's usually 5% nitro and anywhere from 22% up to 24% oil. Run a gallon of fuel through it like this.

Don't know how to mix your own fuel? Buy a gallon of Omega 5% fuel at the LHS. NOT Cool Power!!!!!!!!!!!! Omega has CASTOR in it. Castor is GOOD for engines. Now buy a quart of KLOTZ and add some to your gallon of fuel. You can't get a couple extra ounces of oil in a fresh gallon of fuel----------so, you split the new jug of fuel in half. Put 1/2 of it in an empty fuel jug---you DO save them don't you?----and then you got 2 jugs of 1/2 gallon each. Add 2 or 3 ounces of KLOTZ to EACH 1/2 gallon. Run the whole goshdarned gallon of fuel through the engine on a test bench.

This method of adding KLOTZ to your new fuel might not be the most scientific---but you can bet your paycheck that you won't cook your new engine.

My point is:
Break in a 2-stroke ABC engine at almost MAX RPM with whatever prop it takes to get it into that RPM range. Keep taching it and watch the RPMs increase as the engine breaks in. When it's at almost MAX rated RPM--then you prop it up and slow it down. Keep doing this untill your done with a gallon of fuel.

Now find a prop that will let it run in the range you want and use whatever fuel you want.

I've been doing this with my glow engines for a couple years now. Haven't cooked one yet and they DO run really good.

You can't break in a new engine with the prop that your gonna use to fly. Didn't anyone ever tell ya NOT to load a fresh motor with lots of prop??? If not--then I'm telling you now. Thats a BAD idea. ALWAYS break it in with at least a prop thats 1" smaller than you expect to fly with.

Good luck.

Rcpilet,


I guess you read [link=http://www.rcuniverse.com/forum/Tapered%2DBore_Engine_Break%2Din_%2D_Upgraded/m_1850473/tm.htm]this RCU thread[/link], dealing with tapered-bore engine break-in...
...And all the errors people often make, thinking they are good for their new engine.

No need to rewrite everything.
I just refer people to that thread, for proper break-in guidelines.

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The manufacturer probably gets those rpm figures by running the engine on a dynomometer with no muffler in place. It is a legitimate means of obtaining a useful measurement
of power. However, the figures can be misleading for every day, practical, real world, engine operation.

Most likely, Tower is repeating the specs that their supplier gave them. Who else would be better qualified to provide such figures?

I run 12x6 props on .50 size four-strokes. It stands to reason that a .75 glow two-stroke should be able to spin substantially larger props for better efficiency. Don't get upset if your engine can't swing a practical size prop at the advertised peak horsepower claimed by the manufacturer. Your car can't produce all of its horsepower while mounted in a car that is being driven on the road either.

A 13x6 is a good all around size for this engine, regardless of tuning. Milder tuning does permit one to run larger props without a problem, assuming one keeps preignition under control by varying nitro percentage in the fuel, the type of glow plug being used and the amount of compression the engine has. The latter can be adjusted by increasing or decreasing the number of head shims (old term - gasket) that are used between the head and the cylinder.

Don't worry much about the horsepower claims. Marketing does its best to promote the product. Chances are they are technically correct, but you will probably never see such horsepower being generated while using a practically sized propeller. Go fly and enjoy.

Ed Cregger

Nope Dar--I don't need you to tell me how to break in an engine. This may surprise the heck out of you--but I've never even read your theory on break in--over in that thread.

I get along just fine without your advice.

I'd rather spend the time to explain to someone--in my own words--than refer them to your thread.

Your back on ignore.

It is a democracy... Thank you for ignoring me.


The great majority of engines, are probably incapable of ever producing the power outputs quoted by their manufacturers, under any condition, in the state and configuration, in which they are supplied to the customer.

The manufacturers look to their nearest competitor and what he quotes and either 'quote' themselves equal, superior, or very near in the numbers to it...


Just to set the matters straight; I get no royalties from people who visit that thread...
I just think it compiles the issue pretty well.