Could someone out there explain to me exactly what Schnuerle Porting is ?? Thank Ya-All Mr. Bill M.[sm=confused.gif]

Schnuerle ported engines have a flat top piston (piston without baffle on top) and typically a dome combustion chamber with a squilsh band around the edges.

On each side of the exhaust port are the main intake ports directed towards the back of the combustion chamber.

Opposite the exhaust port there is usually (but not always) a boost intake port.

Schnuerle engines have superior throttling characteristics to the loop scavanged engines. They often produce more power and have better economy as well.

Jim

Thanks for the quick reply. I heard talk or read somewhere that idle bar plugs were NOT necessary with Schnuerle Ported engines. True or False. Thanks again. Bill

That's correct. I've never had a idle bar plug do anything for me on a Schnurele type engine.

In fact, idle bar plugs are getting harder to come by. I don't use them period anymore.

Jim

Idle bar plugs were designed for the early r/c engines with a baffle piston. It prevented the incoming charge from dampening the glow plug as the charge was directed directly at it. Schnuerle engines kind of have a swirling intake charge and it's not directed at the glow plug. As a result, one doesn't need the protection of an idle bar.

Max

Yo, Max....

....even the K&B loop-scavenged engines did not benefit
with the idle-bar plugs.....this was proven to me about
20 years ago....blocking the fuel from the fire does not
work.

Dave.

Some Schneurle ported engines, namely MDS and others, do not run well without an idle bar glow plug. The Schneurle ports in such engines are (wrongfully) angled in a way that dowses the glow plug with raw fuel.

A classic Schneurle porting only has the side ports, angled away from the exhaust port.
The boost port is an addition that further boosts power. Hence "Shneurle plus boost port..." term.

If you want to see all the diufferent porting designs that have been used in model engines since they began, get Dave Gierke's book on two stroke model airplane engines. Its a wealth of info and a history lesson too!

AJC

I agree with Dar again on this... allthough I do not use idle bar plugs myself some engines do run better with them. As for being hard to get, Fox still makes TONS of them.

Thanks to all for the replies and info. I do have several Fox Idle Bar plugs and also the plugs with no idle bar. I'll try both to see which works better - - -However, ya-all explained the porting bit to me very well... Thanks RCU and a bunch of friendly and helpful members.... Mr. Bill M.