If you just want comments, I have a few?
The race cars have huge radiators. Much bigger than you can hide in
an airplane. Continuous power is a test of the heat transfer rate. As you have
noticed there has always been a problem getting a balance between cooling drag
and cooling at all. I have had cooling problems on very hot days using the
biggest radiator that Griffin makes. Also its a double pass layout, and I am at
125 HP per rotor. This is with three 13 row Setrab oil coolers. When the temps
are above 95 degrees, my coolant is at 190 degrees and oil at
200.
The three rotor has a very long path for coolant flow and an extra
housing pouring in the heat.
This is not to say it is not possible. But save that 8,000 RPM idea
for something AAA can handle in a street car. That may be the rev limit in a
Cosmo or even 8,500 RPM but that is for short bursts (Pun) when shifting gears
and the Cosmos are all automatics?. At high revs the engine starts to lean on
the oil temps real heavy. Fuel consumption will be way up along with wear rates.
Base engine RPM on propeller tip speed (well subsonic) more like
7,000 RPM for take off and 6,000 or even 5,500 for cruise. The engine will be
very happy between 6,000 and 6,500 RPM.
The turbos that come on the engine are not suitable for aircraft
use. They will over-speed and come apart as you climb. Too little resistance. If
the exhaust side fails, the pieces will be in the muffler. If the compressor
wheel fails, the engine will be in the muffler.
If these are road racers just smile and say thank you. If they are
drag racers, explain that you need the engine to last for more than 9
seconds.
Road Racer, Lynn E. Hanover
In a message dated 2/11/2008 1:51:03 A.M. Eastern Standard Time,
gregw@onestopdesign.biz writes:
O.K., time to throw a little F matter into the
fan. I am sitting in my new shop, with a Lancair Legacy RG, and a
relatively new 20B "D" series on a palette. I got the engine complete
with everything it had in the Cosmo that it came out of. There isn't
even a coat of grease on this thing. Radiator, oil cooler, air
conditioner, condenser, ECU, injectors, coils, motor mounts, and about 100
pounds of extra stuff came with it. My buddy (he has been selling
engines for 15 years) in LA that sold me this engine ($4500.00) is in constant
contact with people who race this motor, and I am getting a lot of input on
how to set this thing up. I have ordered Tracy's gear drive, and plan on
generating 400 HP on take -off, and about 75-80% at cruise. My max rpm
will be 8000. You have no idea how much input I am getting from the
racing set. They are saying that with a variable boost (electronic)
controller, I can vary the boost at any given altitude, as much or as little
as I want, and tweak this thing for max performance. They can't believe
that I am asking so little from this engine.
This will get us started;
Greg