Aeromatic Oil Quantity

[dtreid]

I am in the process of servicing my aeromatic prop. When I got it, there was no oil that drained out when the plug was pulled. There was evidence of oil on the plug though.

The aeromatic service manual that I have says to fill the hub to the brim with oil. If this is done, I would wonder that as the oil warms up it may expand and leak out the seals.

I spoke to Kent Tarver, and he said that a few oz if fine. He even said that it would be acceptable to put some oil in the hub, turn it over a few times and drain out what I could. The remaining oil coating things would be adequate.

If only a few oz was added, could this cause any sort of imbalance as oil goes to one side of the hub?

What does everyone else do as far as oil quantity is concerned?

 

[blimpy]

There is an Illustration in the Aeromatic Manual, showing a curved tube.

I don't read that as full.

Kent espouses a few ounces of 85/90 gear lube.

I would NOT use less. Despite any theorizing otherwise.

Get a glass jar about 2.5 inches in diameter. Put a couple of oz of gear oil in it.
Put a bolt through the lid, with a nut on each side.

Chuck this in a drill, spin it and watch what the oil does.
Tilt it for 'climb' and dive attitudes.

Report back on any imbalance.

 

[twheel47]

Dry is not good but based on experience with my (John Buck of Britt, IA) Aeromatic back in the 80s, it doesn't seem to hurt them to sling most of it out pretty regularly. Every time I checked mine back then (25 hour inspection) it was pretty near empty so the "just keep it coated" advice wasn't wrong as far as impending major siezing/failure went for me but I don't advocate it. I keep my (Tarver) Aeromatic pretty close to full; it doesn't leak much at all, if any, so that's a moot point.

Scott