OS46SF Diesel
 

My homebuild glow to diesel conversion

http://www.rcuniverse.com/forum/atta...mentid=2033828http://www.rcuniverse.com/forum/atta...mentid=2033829

https://www.youtube.com/watch?v=_g2SWA-D1Qw Greetings Jef

Good job with the head and contra piston for the OS 46SF

I have one too. mine has a DDD head and a just engines piston & liner set it runs great .

Nice work, Jef!

What RPM range were you getting? ...on which prop? ...fuel?

I played with a few of these several years back. Brief break-in on glow fuel - to where the initial metal-dirty exhaust ran clean and starting by hand was sure and easy. Then DDD head and Davis ABC fuel. 11" to 13" diameter, 6-ish and deeper pitch props.

Very nice combo.

OS stock P&L are ABN, so medium low oil % worked fine. I don't recall the exhaust being that juicy. (You use a nice extension rig, too!)

Stock OS carb proved to have better economy than another make, even with a case-pressure operated pump.

Engines definitely showed RPM plateau at about 3/4 throttle: wider open, no RPM gain but wetter exhaust and quicker fuel consumption. I didn't fly any of the engines I worked on, but the guy I did them for had good in-air performance.

Where is your contra-piston sitting when adjusted for best RPM?

Up in the head? Or with some of the lower portion protruding into the chamber?

I have not be able to measure RPM , tachometer is broken , on the movieclip I have used a graupner 12 "x 6" , then I tried a 13 "x 6" APC and I think that was OK too , fuel = 25%casteroil / 30% ether / 42% petroleum and 3% ignition improver from Barhdall

The bottom of the contra piston sits a little bit in up the head , about 0,5 mm

@ w8ye and Lou Crane ,

Thanks for the compliments

Kind regards Jef

One extra head gasket should get the contra-piston setting near perfect Jef. Well done.

Jef,

Just checked some of my notes. I worked on the 46XF, not the FS.

Results sound similar. Still a good package!

FX and SF?

Right.

Double checked after your "PM."

It's been a while....

That's a good advice , thanks Fiery

Regards Jef

Nicely set up. Well done.

Ingenuity with the 'shed friendly' goop minimisation as well :cool:.

I have seen and met Dr. Diesel at Toledo, he runs the exhaust down into a bucket of water, works like a charm.

I do the same thing if I'm breaking engines in at home. Makes a huge difference in noise. You just don't want the hose dipping into the water. That is if you're using muffler pressure to the fuel tank.