alex a v

Hi guys.

Just want to share my experience with this engine.

engine: OS120AX
configuration: inverted
tank: tettra 500 at the CG @ 1/2 inch above the carb, 2 lines only
fuel: cosmo 20% nitro - 18% oil synthetic
pump: none
prop: APC 16 x 8

comments:

Back pressure was more than enough. Had to lean out low end by 3/4 turn. Can be used to practice P-11 schedule.
It starts like any other OS engine does, easily.

More stick time than wrench time.

More power and Big Thanks to JeffRCU for the help.

Jeff-RCU

My Feedback: (4)

I appreciate the thanks, but it was Arch (rcpattern) who gave me the advice originally.

alex a v

Then I'd have to tank Arch (rcpattern) too.

Thanks guys!

guille2006

29% castor?!?!? "ONLY" 20 min to clean?!?!

I'm pretty sure that a 18% - 20% castor + 5% nitro + Perry pump will solve you all problems... in plus you'll be able to place the fuel tank near the CG.

Good luck!!!

G.

PS: may be someone posted you about the same solution... I did not read all the thread.

Jetdesign

My Feedback: (8)

I just propped down to a 16x6 on my 1.20 and love it. I started with 15x10 but didn't like the spool up time it took for good verticals, went to a 16x8 and it got a little better. For grins, I wondered what would happen with even less prop - much improved throttle response, still good speed with the higher RPM.

I run pretty much stock, tank a few inches behind firewall, 10-15% nitro with 18% oil.

Any issues I ever had with the engine were from some kind of film on the carb when it was new. I really struggled with the motor quitting during simple maneuvers when it was on a Perry Pump. Pulled the pump and still had problems - seemed to tune fine and run great on the ground, but would just cut out as I'd throttle up for a Cuban. Finally soaked and scrubbed the carb in alcohol and everthing is fine.

F-4

This thread has been inactive for 2 years, so maybe all have gone electric. Still, I have a question. Has anyone set up the OS 120 AX with header and tuned pipe? If so, please provide specifics of set up and performance differences. Thanks.

John

aerobear

My Feedback: (4)

In pattern, mostly electric now.

The AX works very well with tuned exhaust. The Jett tuned muffler gave about an extra 800 rpm over the stock muffler with an APC 16x8. The Jett has no adjustment so you have to stay within it's tuning range, around 9500+. Pretty loud exhaust. The carbon pipe boosted anywhere from 750 to 1000 depending on prop and nitro content. I did not try it but I would bet APC 15x10 or 16x10 would work well for pattern use with a pipe.
Header length? If you have to ask..... It's best to learn how to tune it. This is another attraction of electric, it's just simpler.

The pics show a Mueller header which is no longer available. Just Engines will custom make headers.

Whatever exhaust works on the AX will also work on the DLE 20 with a flange change. The DLE probably outsells the AX by 10:1 these days. About the same power and weight. Pump carb is a plus over glow.

flywilly

My Feedback: (121)

Macs products also makes a wrap around header. It is a two piece design: adapter for the engine exhaust and a separate wrap-around pipe. It is a 'floating' type design meaning there is a rubber 'o' ring at the exhaust flange which the tubing fits over. Eliminates the header breakage issue when used with a soft mount. here's the link:
http://www.macspro.com/cpftuhp.asp

F-4

Aerobear

Thank you for the response. I will look at the Jett muffler. No argument on the advantages of electric. Whose CF pipe is that? I have used the Aeroslave pipe on my 160s, so have some tuning experience.

John

F-4

Flywilly,

Thanks for the link. Think I will look at pipes and mufflers and pick one.

John

aerobear

My Feedback: (4)

It's the [link=http://www.escomposites.com/2%20cycle.htm]ES2C120AX[/link] pipe from ES Composites. About 150g with header and coupler.

The Jett muffler requires an adapter to mate up to the AX. About 210g total. I made my own but Jett could probably supply what you need if you go that route.

Your Aeroslave pipe may work OK on the AX if you still have it.

MTK

The 20 cc gas engine and the 20cc glow engine can indeed take the same pipe. The only difference will come in with header length. Where the glow will require a tuning length of 22-24" from plug to baffle, the gas will require around 25-27"