EGB

This may sound like a rediculous question but not owning a four stroke engine requires me to ask this anyway. Is there enough oil generated from the engine (other than the muffler) that is a concern regarding oil soaking on an airplanes frame? I am aware of the significant oil generated from the 2 strokes, but have not had any experience with the 4 strokes. My question is based on a recent airplane plan from MAN. It is a Fokker DVII designed for a .30 size 4 stroke. It is designed without a vertical firewall behind the engine. This arrangement allows air flow past the engine and through the airframe and then out an open area at the bottom end of the fusealage. My concern is whether or not oil from the engine will blow back and contaminate the airframes interior. This is a recent airplane design and I believe the designer would know about potential problems but I have to ask.

Thanks,

EGB

mscic-RCU

My Feedback: (6)

there is still a significant amount of oil generate by four strokes. not only from the exhaust, but also from the crankcase drain. the drain oil can be routed via a piece of fuel tubing, and the exhaust oil can be directed with the muffler.

MinnFlyer

My Feedback: (4)

4-strokes produce FAR less mess than 2-strokes do, but I still wouldn't want it going inside my fuse

tailskid

My Feedback: (34)

My Saito 180 put more gunk on the airframe from the breather than from the exhaust! And yes, if not redirected, could easily fuel soak the front end of a plane - especially via the tank opening.

Jerry

wind junkie

My Feedback: (1)

Tailskid,

That little hole in the backplate center is a breather ! ? I'm new to the 180, but I love my 72, and the 72 has one underneath the camshaft. I know that one spews like old faithful.

I thought the backplate nipple was just a pressure tap if you drilled through it. You mean there's a hole in there already?

Campy

My Feedback: (1)

MOST 4 strokes have a "pressure relief" vent. Some (like Saito) have a vent nipple under the front part of the crank, some have it in the backplate. I vent mine to the outside of the plane with a piece of tubing.

Another thing to remember is that if a 4 stroke is not "putting out smoke" it is most likely to lean.

tailskid

My Feedback: (34)

Yep Wind Junkie that nipple is so the engine can 'breath' and coat your firewall with excesssssss luberication

The pressure nipple is on the muffler, not on the crank!

Jerry

The Ghost

EGB,
.

In reply to the question, You would have to fuel proof the inside of the airframe opened to the engine/air flow.

Cheers,

Remember, Always look after the ORGANIC part of the model.

wind junkie

My Feedback: (1)

Oooh.. Thanks for the explanation. So that's where all the fuel came from! I thought it was coming out of the carb! Wonder why the 72 and 100 have different locations for the nipple? Seems like the cams and front bearing won't get as much lubrication this way.