In a message dated 3/26/2003 8:21:46 AM US Eastern Standard Time,
ianb@ozzienet.net writes:

> Subject: [FlyRotary] Re: Aircraft oil in Rotary
>  
>  
>  > Posted for ronald GOWAN <rongowan@yahoo.com>:
>  >
>  > The race guys have been doing this for years and they
>  > run their engines a lot harder than we will ever dream
>  > of.
>  >
>  Sorry Ron but I run my RV6A Mazda WOT for up to 4 hours from 2 to 10
>  thousand feet. On the race track I am on the brakes for much of the time.
>  Ian
>  > >>  Homepage:  http://www.flyrotary.com/
>  >
 
Both accurate. The racing application represents a different kind of service.
Very hard on the oiling system and bearings. Even the 13Bs now are shifting
above 9,000 RPM. Much higher heat loads. In GT-3 the 12As have about 245HP at
9,400 RPM. In GT-2 the 13Bs have 300+ HP at 9,300 RPM. These are both bridge
ported engines. In E production the 13Bs have about 215 HP at 9,000 RPM with
a big street port. The average race is about 40 minutes. So to compare just
the stress level, even though the race engine is at fully closed throttle
about 5% of the time, the engine is being operated at the highest possible
bearing loads. The highest heat loads require water and oil coolers to be of
larger capacity. Both for the higher loads related to the higher power
output, but also because the cars are operating below 100 MPH most of the
time. Generally, two large GM air conditioning cores are adequate for the
airplane. Another GM core or even a stock oil cooler is fine for oil cooling
with thoughtful ducting. The typical aircraft installation will be between
160 and 180 HP without porting or turbocharging. In those cases additional
cooling will be required. The rotor bearing loading actually is lower between
6,000 and 6,500 where most airplane engines will be running.
Lynn E. Hanover