"Ron Natalie" wrote in
m:

The aircraft certification requirements state the that oil capacity
must be such as to provide the maximum consumption at required
temperatures for the endurance of the AIRCRAFT that the engine is
installed in. Any oversizing of the tank is hence to accomodate the
range of uses Lycoming envisioned.

I believe Ron is correct. If I recall correctly, it's a function of
several factors. The engine mfr. sets a maximum allowable oil consumption
rate below which the engine is considered airworthy. [And it's pretty
amazingly high... over a quart per hour for some big bore engines.] The
aircraft mfr. determines the endurance of the aircraft at "rated power"
(which may be 75%, but I believe it's up to the airframe mfr.) by sizing
the fuel tanks for the engine fuel consumption.

The required oil capacity is however much will allow for this flight, at
worst case consumption, with the aircraft ending the flight with "adequate
oil remaining." This "adequate" oil limit may be determined by necessary
cooling under certification requirements (climb at max gross, etc.) or by
the design of the oil pump system (will it still reliably pick up oil at
all normal/utility category flight attitudes).


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James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
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