
Originally Posted by
mvivion
I always laugh when the subject of oil comes up with regard to radial engines. The old argument that if a radial isn't using oil, there's something wrong with it....etc.
The R-985 in the Beaver has an oil tank that sits between the pilot and copilot's feet/knees. That tank holds, if memory serves, about 6 gallons of oil. Let's compare that to an O-320: The 985 has three times the displacement, and about three times the rated power. The max oil quantity of the O-320 is eight quarts, or two gallons....the 985 carries three times that. So far, so good.
Now, if a 320 uses say, a quart every ten to fifteen hours, why wouldn't a 985 use about a gallon over the same period?
And, as we all know, a LITTLE bit of oil thrown makes a HUGE mess. It's all proportional, basically.
In the Beaver I flew in Kodiak, I always carried a 1.5 gallon jug of engine oil. Sort of like carrying a quart or two in a Super Cub. One winter, our maintenance folks needed to do some work on my airplane, so I flew it up to Anchorage for the work. They handed me the keys to a newly refurbished Beaver that'd just been completely re-worked in the Seattle area, including an overhauled engine.
When I arrived in Kodiak with that plane, I noticed it had a single quart can of oil in the baggage compartment. I had to laugh. But, over the next few weeks, I found myself adding just a quart of oil every once in a while. That engine was really tight.
The locals familiar with radials told me they wouldn't trust that engine....sorta jokingly. But, it ran fine, and very clean.
A couple months later, I flew that plane back to ANC and picked up my regular ride. Back to a 1.5 gallon jug.
And, a well lubed belly.
MTV
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