> I've been told by some Mazda enthusiasts that the single turbo
> 13B developed
> 230 hp in the US. This is plenty of power for my needs. Can
> anyone refer
> me to specific model years I should look for? I do know the
> twin turbo 13B
> developed 280 hp but I am also concerned this might be too
> complicated for
> aviation use.
>
> Thanks,
>
> Rick
>
> A 1990, 1991 to 1992 are good years but you will to do something
> to make the
> turbo live. I think Dave Leonard has his turbine trimmed down
> and a larger
> compressor installed. If you don't slow down the turbo some how
> the turbine
> has a life expectancy of only a few hours in aircraft service.
>
> --
> Paul Lamar ...No rotor no motor.
>
>
> With this in mind is it possible for me to contact Dave?
> Perhaps more
> importantly, what about a completely different turbo?
>
> My perspective is that the OEM turbocharged engine will be a
> conservative system and therefore a good foundation. However,
> with your fatalistic
> response I'll have to make sure I understand the issues well before
> finalizing any decision.
>
> Can anyone else here educate me regarding why aviation use
> degrades the OEM
> turbo so quickly?
>
> Thanks,
>
> Rick
>
> With this in mind is it possible for me to contact Dave?
> Perhaps more
> importantly, what about a completely different turbo?
>
> My perspective is that the OEM turbocharged engine will be a
> conservative system and therefore a good foundation. However,
> with your fatalistic
> response I'll have to make sure I understand the issues well before
> finalizing any decision.
>
> Can anyone else here educate me regarding why aviation use
> degrades the OEM
> turbo so quickly?
>
> Thanks,
>
> Rick
>
> OK let me explain it to you. Automotive turbo chargers are
> designed to accelerate
> quickly for car acceleration purpose. F = M x a. Therefore a =
> F/M if you want a lot
> of "a" you need a a lot of "F". In an automotive turbo charger
> this happens for only a
> few seconds at a time. Most of the time the turbo charger is
> loafing. Not so in an aircraft
> engine. To run the compressor at a constant speed you don't need
> a lot "F" (read HP).
>
> Now the force on a turbine blade tending to throw it off on a
> tangent from the hub
> is F = m x V^2/r. V is the speed of the blade as it travels
> around in a circle. m is the mass
> of the blade and r is the radius of the circle. Pretty soon the
> force on the blade exceeds
> the strength of the blade and the turbine disintegrates. So
> what you need to do is load
> down the "F" with a larger compressor or cut "F" down by
> trimming the blades. Adding
> to all this of course is the high heat of the exhaust which
> weakens the metal the turbine
> is made from.
>
> This is fundamentally why un-modified automotive turbo chargers
> are not suitable for
> aircraft use.
>
> On the up side it is possible to mix and match turbo charger
> parts. For example: larger
> compressors fit on given turbines slowing down the turbo charger
> while generating
> the same amount of boost. This reduces the V (RPM) and the
> turbo charger last longer.
> Of course the turbo charger no longer accelerates quickly but
> you don't care
> about that in aircraft engines.
>
> Paul Lamar

Very nice explanation Paul.  You are generous with all of us.  Thank you.

Marc J
NexusMustang


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