Oil in radial engines?

GrauGeist · Oct 3, 2012

I know the Wright R-3350 engines on the Mars (JRM-3) sling quite a bit of oil. If I remember right, one of the skippers said she uses about 2 gallons an hour...

Here's the Hawaii on Shasta Lake in 2008...you can see the streaks behind each engine, along the underside of the wing

PWR4360-59B · Oct 7, 2012

GregP said:
The rings on most radials are tapered. That is, they have an angle to the side surface that runs along the cylinder wall.

The angle is supposed to taper from touching at the bottom edge of the ring (in the top cylinder) to not quite touching at the top edge of the ring (in the top cylinder). That way, when combustion happens, the oil is wiped back into the crankcase. If the rings are tapered backwards (installed upside down, I've seen that a LOT of times!), the eninge fairly eats oil and the whole airframe is wet. If YOUR radial uses a LOT of oil, check the tapered rings! Some are backwwards, most likely. That happens when mechaincs don't even realize the rings are tapered. All the compression rings sould be tapered so the smaller diameter is toward the top of the cylinder.

Your talking about Napier rings. I'm not talking about a running engine I'm talking about one sitting for some time. Oil is fluid at some temps and fluid seems to find a way to leak past anything with a clearance. That means an oil pump, piston and rings, valve stems and guides, even some gaskets.

Oil in radial engines?

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GrauGeist

Generalfeldmarschall zur Luftschiff Abteilung

PWR4360-59B

Senior Airman

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