gtalbot

My Feedback: (5)

I have a new OS .46 FX.
I broke it in according to the manuel with help from experienced club members (2 brains are better than one).

I've been unable to get better than 11,500 with an 11x6 APC prop and standard muffler. I went to a tower muffler and got on 12,100 or so. I swiched to a different brand prop (12x7) and still get about 12,200.

Shouldn't I be turning faster than this?
I'm flying a Kaos..I'd like speed, but also a reasonable amount of torque for loops etc...

I'm running with Morgan Omega 10% and a K&B long w/idle bar

w8ye

My Feedback: (16)

The Tower engine is a couple hundred rpm stronger than the OS 46 FX when both are stock. The OS has a little more power if you take the baffle out of the muffler. You could also put the Tower muffler on your OS. It'll bolt on like it was made for it. Then it will be a toss up as to which one has more power.

Enjoy

War Eagle

Elwood

My Feedback: (2)

Give it more time to run in. Also, Hot and Humid + loss of power.

ed42d-RCU

My Feedback: (13)

I was just taching my 3 year old OS 46 on Saturday. With a 12.25x3.75 , mac's onepiece muffler and 15% Wildcat fuel, I was getting 12,200. I switched to a 11x5 and my Sig SE seemed to like that better.

rcfaq.com has some rpm data. They show 12,200 with a 11x6 stock muffler.

Carlos Murphy

My Feedback: (72)

I have two of these engines and use 15% Powermaster with a APC 10/6 prop. I've tried a 9/6, a 9/7 and a 11/5 and the 10/6 gave me the best speed.
The 9/6 gave me more RPM with less speed and the 11/5 gave me less RPM with less speed.
We race these engines on World T-34 Mentor's, remove the baffle and drill out the exhaust "pipe" two or three sizes.

ramcharger

I have a 5 or 6 year old OS 46FX that was originally in a Global Cutlass 45 and now in a Dazzler. It has well over 300 or 400 flights with 10% Cool Power and a 11x6 MAS prop and a baffleless OS muffler it gets 13,000 rpm and perhaps a 100 less with a 11x6 APC. MY OS 46 SF which I just flew yesterday gets 12,000 to 12,100 with a 11x5 wood prop and came fuel and either a OS #8 or Tower glow plug. The OS 46SF was new about a month or so back and has got 200 to 300 rpm stronger after 15 or 20 flights and still the same prop. The Tower 46 (GMS 46) is not any stronger than the OS 46FX. We have a couple flyers who had Tower 46 engines on trainers and have long got rid of in favor of OS 46FX and they will tell you the 46FX is superior in reliability, rpm, and consistency.

w8ye

My Feedback: (16)

One has to justify all the money he spent on buying a particlar engine to keep his mental state up to par! He feels better that way?

Jim

jjmiller1

Try an APC 11x5, that 11x6 isn't letting your engine get "on the pipe" (over 13,000 for the tower muffler). My 46FX w/15% and APC 11x5 and tower muffler turns 14,000 on the ground and unloads a great deal in the air.

JJ

w8ye

My Feedback: (16)

JJ,

What you say seems to be also my experience with the Tower muffler no matter which 46 type engine it is mounted on. (That the engine has to get up to a certain speed to "get-on" the tuning aspect of the muffler.)

Jim

rcflier_gi

My Feedback: (2)

What method of break-in did you use? I believe some of the OS manuals had an error and told you to break-in ABC engines running "4-stroke" rich. Rich "4- stroke" break-in on an ABC type is not a good thing. The piston and sleave don't get hot enough to expand properly causing premature wear and poor compression.

w8ye

My Feedback: (16)

They should be 2 stroke rich.

Jim

ramcharger

The OS 46FX running-in (break-in) instructions are:

Start engine and run 2 or 3 minutes with the throttle wide open and rich (4 cycle operation). Then close the needle valve and run about 10 sec at 2 cycle operation. Repeat this procedure with 10 sec intervals until the tank is empty then establish an idle and you are off.
Start fling the engine at 4 cycle operation and gradually break-in to 2 cycle operation avoiding prolonged nose up flights for the first 3 or 4 flights.
After 10 or 15 flights the engine should run at optimum needle setting.

w8ye

My Feedback: (16)

A guy at the field last thursday brought his new one out and started flying. Of course he dead sticked a couple times but soon he had it in good order and enjoyed himself the rest of the day.

He attempted to set the needles when he first started it and took -off. His dead stick problem was more with the glow plug he had in it than with the needle settings.

At the end of the day, he was telling everyone what a fine engine the 46FX was and how he enjoyed it. He was right. It did run good after he changed glow plugs a couple times.

This is done more often than not. I'm not recommending it, I've just seen it time after time over the years at different flying fields with all kinds of engines including the ringed type.

Enjoy

Jim

rcflier_gi

My Feedback: (2)

Here is a direct quote from A.M. Cross of Great Planes taken from another thread on the .46FX

"The 46FX manual has a translation error. The 46FX should NOT be allowed to 4-cycle or the liner will not seat properly during breakin."

bgi

My Feedback: (7)

So if I'm reading this right, my 46FX liner did not seat properly because I followed the published break-in procedures? I'm wondering if I should see about getting a new liner/piston assembly.

ramcharger

I never had a problem after 300 to 400 flights on 10% Cool Power. I guess the liner is still perfect because I still can fly at 13,000 rpm.

jjmiller1

Unfortunately, all 3 of mine were broken-in per the incorrect 4-cycling procedure, but without doing a side-by-side test with one broken in the correct way, mine seem to run with the best of em'.


JJ

jaka

Hallo!
You guys must understand that the running in process of a model engine, be it fourcycle or twocycle is not that critical...Modern engines tolerate a lot !!
What you do must remember is to not let the engine run too lean!! Thats the only thing you got to be real finicky about!
Modern sport engines like the OS ,40FX and ,46 FX does not have to be run-in rich at low rpm as ringed engined have to ...but they will not be destroyed in any way if you do!!!
All ABC,ABN,AAC engines should be run-in at a fairly high rpm, (10.000-12.000 for a .40 engine) this is because the piston and cylinder must reach the right operation temperature to really fit each-other.
ceartainly you have not destroyed your OS.46 engine because you run it at rich when you run it in!!! Do not worry! Just fly and have fun

Regards!

Jan K
sweden

downunder-RCU

I have to agree with jaka...modern engines will tolerate just about anything except lean runs or not enough oil even when being run in. If you read the Jett web site for running in their engines they say the initial run should be with the needle turned out an extra 2 turns and to leave the glow driver on so it'll keep running. Now that's gotta be WAY richer than just a normal 4 stroke rich!

rcflier_gi

My Feedback: (2)

An engine that is properly broken-in will tend to put out more power and last longer compared to an engine that was not properly broken-in. The engine that wasn't broken-in may run great but it probably won't run great as long as the other engine. As engines age they lose power and sometimes become harder to tune. This occurs because the fit between the internal parts wears out. So if improper break-in causes more wear then a proper break-in it is easy to see which engine will start to lose power first with all else being equal.

Sure lean runs are more destructive to an engine and usually the damage makes itself known more quickly. That doesn't take away the fact that improper break-in is bad as well. An engine that was properly broken-in will be the better engine in the long run.

breeza

The OS FX.46 I have is by far the most powerful .46 I have. All though I have a tach. I usually use my normark digital fish scale to measure the thrust of the engine. I do this by connecting the scale to rear of the airplane an go full throttle on the engine and measure pull ( thrust) on the scale in lb and oz. With the FX.46 with a master airscrew 11x7 prop I am measuring 6lb 5oz which is over 10oz more then any of my other engines and that was on a very hot day. The other engines I have our tt.46, fox .46abc and a mag .53 they all measure around 5and1/2 pounds of thrust with 11x6 props they won't ever pull a 11x7 with out starting to over heat. The other engine our fine, run great but just don't have the power of the OS.


biker