Oil-System

As we all know, the oil system of most engines is designed with the engine used in upright position. In flight we will have different attitudes, in aerobatic flights also upside down. This will be not a big problem if this position is held only for a few seconds. If flown with positive G-loads the centrifugal force will help to have the oil where it should be (Please read the article of Greg Koontz: Very basic flipping). A significant amount of oil is located in the sump during normal attitude, runing back from bearings and parts which need to be cooled and lubricated. This amount is critical during inverted or negative G flights.

1. A bigger amount of oil in the sump drops/flows down onto the moving parts in a moment. This may stress the bearings and cause vibrations but also lubricate these parts.

2. A smaller amount gathers in the engine case top where normaly no provision is made and also where the oil breather is located. Oil may run out.

3. The oil-pump doesn't supply enough oil due to lack of oil at the suction port

There are special provisions we can use to have these oil 'outside' of our engine. The Christen inverted oil system cost around 1200$ if you install the system yourself. This could be one way to solve the problem.

Another oil inverted system similar to the Christen is available from Raven.

The oil separator available from Aerovee is a solution for limited inverted or negative G manoeuvers.

I consider also using a deep sump and let the (heavy duty) oil pump doing what it is made for, but sucking from the deeper sump. The suction hose has to be modified (extended) for this process. Additionally the port to the deep sump has to be downscaled with a special kind of shim to provide a lower backflow of oil during inverted or negative G manouvers. That is the basic idea to give us a few more seconds for the inverted portion of flight - what do you think about that?

..and whats about designing a new simple inverted oil system?