Oil Breather Tube Orientation

Further random thoughts;

The mussing over an initial vertical orientation, of the bather pipe, occurred as I was removing oil smear from my aircraft belly.

In the past I have tried a home made oil catch-can on the breather, with little success - I do have a new untested design.

In an automotive engine the function of the crankcase breather is to ;

 # Allow crankcase pressure and volatile fractions/contaminates of the oil to escape, either to atmosphere (older engines) or be ducted into the air inlet system, to be consumed in the combustion process (new engines).

 # Retain oil (droplets/mist) within the engine.

In an automotive engine there is usually a plate, sometimes  + a gauze "filter", at the engine end of the breather pipe, to encourage heavier oil droplets to septate from the hot vapour and remain in the engine.

In Rotax 912, its much the same as in an older automotive engine, without any significant system for retaining airborne oil droplets/mist.

I suspect that just orientating the breather up would have little benefit.

If a metal coiled (copper/aluminium) pipe, were employed, as part of the vertical orientation, to assist the oil droplets to cool/coeles, oil may run back down to the tank. ???????

😈

Sean,

Neither my aircraft nor others I’m familiar with get any oil out the oil tank vent tube.  I’m curious what elevation your oil tank is mounted at as compared to the Rotax installation guidelines.