I am seriously considering using an OS 140 RX in an artistic aerobatics plane. I just want to know what pipes, headers, fuel, props, and general set up everyone is using. I have read a lot about changing the bearings from day one, is there anything else that should be changed right away? I was also thinking of adding a second glow plug as I have seen at some local competitions, which is said to improve throttling.

Any info anyone has on the engine would be greatly appreciated!

why?????? that sounds like painting a white wall white because it was white before you painted it white again - catch my drift!!! I don't think OS would put inferior bearings in a performance motor to start with - kinda hurts the marketing and future sales don't you think.

two plugs per head - 4-strokes maybe....high performance 2-stroke not worth the effort and the cost. Love to hear OS opinion on that one!!!!

We use OS "F" plugs in all our competition motors - mostly OS140's and 10 - 15% nitro depending on altitude of flying field. No real problems with that.

rgds

The original bearing does not last more than 50 flights. Replace it with the EFI bearing.

The two plug head is a great idea that improves the mid-range performance.

Hi,
The RX is a great throuble-free engine for sure , and used world-wide with great success ... Several combination of set-ups (prop-fuel-pipes etc) works on this engine ... It`s very tolerant ..

The original bearings have worked just fine for me, 200-250 flights interval ... ( 2 engines for about 800 flights )
One thing ,in my opinion, that makes a different how long they last ; is the "everyday - storage" of the engine ...
I set the prop at "top-dead-center" and the throttle fully open so there will be ventilation from the crankcase ...
The nitro seems hydroscopic and absorb water that attack the bearing (rust) if not ventilated ... I have been suprised how quick this process goes ....Just small nicks caused by rust, can soon wear down the bearing ...

some proposal;
* 2 headgaskets
* OS-F plugs
* 15/15 fuel
* Hattori , mac headers
* Hattori , ES pipes

Just mine experience ...
Kjell Olav

I ran these things for years, practically trouble free. I ran 7 of them into the dirt. I only switched because I needed more power for the upper classes and a much larger/draggier plane.

Here is the set up I used, fairly bullet proof:

OS F plug
Cool Power 15% nitro
OS header, standard length
ES 2C140M80 carbon pipe
EFI rear main bearing
16.5x12W prop for pattern, 17x10 for power, 18x6 W for 3d

Have fun!

-Mike

I have 3 I use for pattern in my focus(es). I pretty much agree with Mike H.

My differences are:
APC 17X10N for pattern
Karl Muller custom Header - best header in the world in MHO.
Aeroslave pipe. - lightest pipe in the world in MHO.

Mike. what was your after run procedure?

Personaly, I have always ran my engines dry until they wouldn't fire and then put in a generous amount of Marval Mystery Oil. Say 1/8oz I never measured it, and then spun it over with the starter for a couple seconds.
I found the "Set the prop at top dead center and carb open" interesting. I presume he means the piston is at TDC.

Mike R

In my OS140 i changed the bearing to the EFI bearing. I never use afterrun oil. I don't ru it dry at the end of the day I just clean the plane drain the tank and that's that. When putting the plane to sleep for the winter I run the engine dry it's the only time. I run the ES s8 pipe and a 18.1x10.1 APC or a 17x12 APC. And also the 3M mintor dual plug head 65 bucks from Aeroslave
Excellent motor.

... Your right, the piston at TDC ...
Then the crankcase will ventilate through the crankshaft and carb. I have done this at all my 2-stroke`s, for many years and the bearing have last for a long time ...

Kjell Olav

My after run proceedure? Hmmmm...

Drain fuel, wipe bottom of plane, put plane in van. Done. LOL

Seriously I found the bearing issue is actually sort of odd. The more you fly the more (noticably) runs you seem to get between bearing changes. Rust develops when they sit. If you don't let them sit long, they don't rust.

This is why as a general rule I ask people how often they fly before recommending a fuel. if you fly a lot, run ALL synthetic. You'll hate life if you don't.

If you fly occasionally, with sometimes extended periods between runs, use a fuel containing some small amount of castor. Castor is a double edged sword: It coats the bearings and helps prevent rust. But if you fly all the time with it, it varnishes the inside of the engine causing heating issues and breaking rings. If you fly occasionally and run all synthetic, you take more of a risk of letting rust develop. My solution? Fly a lot, run all synthetic, and always have a spare bearing on hand. It worked for the most part.

This is only for a 2 stroke of course. In a 4 stroke, ALWAYS run all synthetic. I've found Cool Power 30% heli makes ALL 4 strokes run better, no matter the engine brand. And yes, I'm partial!!!! But for good reason. It works.

But after run oil can help, just not in every single situation.

-Mike

Hi There

Fuel for our models is most definitley hygroscopic - absorbs moisture from the air - mathanol is an alcohol and readily mixes with water - don't recommend for drinks though!!!!!

Personally I disagree about TDC and throttle open simply because dust can get into the engine. Being a marine/refrigeration engineer by profession and an avid model flyer I learned that if you leave it open it will get dusty and rust/corrode. And yup - aluminium does rust - 'cepting we call it oxidation/corrosion.

Same as a previous comment - I simply clean everything nice (so my car don't get oily/dirty), empty the fuel tank (so my car don't get oily/dirty) and pack everything nice n snug in it's storage bags/boxes!!!

Never had to change bearings from simply running an engine before.

rgds, Greg

I agree with almost everything above. Mike's right about castor but I just hate running it anymore. I found that running some 80/20 (80% methanol and 20% castor) at the end of the flying session can provide terrific corrosion protection. I would keep a separate tank full that the engine would draw from externally - run for just 20-30 seconds, then run the engine dry. I don't bother anymore because my ariplanes spend their non-flying time in my dehumidified basement workshop.
As an aside, the other MAJOR cause of bearing failure (for me) was nickel peeling off the cylinder wall of the OS liner (especially the first OS .61RF ABC-P engines back in the mid '80s). Solved that problem with Performance Specialties (Dave Shadel) piston and liner sets.
The 2 biggest causes of bearing failure (under normal conditions) are water/moisture (causing rust) and dirt...so avoid flying in mud at all costs .
Good Luck, you'll love the OS 1.40!!
Will B.

Thanks guys I'll give it all a try. I think I'll go with a hatori header and pipe. Hopefully I'll be able to get it running nicely. Has anyone used extra head shims with the 15% nitro? Did it improve performance?