[Orv Neisingh]

Until very recently all Rotorway helicopters came stock with an oil tank cap/dip stick/vent that allowed the oily engine vapors into the engine/drive train area coating everything with an oily film that attracted dirt and caused belts to slip. Years ago VPS designed and produced custom oil tank caps that incorporate a removable dip stick and a side vent that a hose is attached to that vents all engine vapors out of the engine bay and overboard.

This is the stock cap with vent holes around the bottom.


Here are several examples of vent caps with removable oil level dip sticks that are installed on the helicopters in my hangar.

[Homer Bell]

Easy fix for this is to slip a piece of soft foam around the tube and slide it up around the bottom of the cap. This absorbs all the vapors and keeps them until you remove and wash it out. Cheap , lightweight and it works.