I don't remember the model number but the Allison
     turboprops on the Lockheed Electras and C-130's turned
     a constant 13,000+ (I think it was 700) RPM. Power was
     controled by prop pitch  change. Karibian



That's the T56 Allison..  Used on Electras and still on P3 Orion, and
C130's up to the C130 (which has been re-engined with the Rolls Royce
AE2100D).


Matt-

I was a mechanic on the P3 Orion at Moffett Field, CA in the 70's.  The
Allison T-56 Turbine produced approx 15,000 Shaft horsepower; approx 10,000
for the compressor and approx 5000 Shaft Horspower to go to the 13.5 ft dia
four blade Hamilton Standard 54H60-77 TurboHydrodynamic Propeller.  The
Turbine ran at 13820 rpm and the propeller rpm is reduced through a very
large two step reduction gearbox to 1020 rpm.  This engine also has a low
engine speed ground operation - don't remember the respective rpm's.

I had a good repour with the Hamilton Standard tech rep George Heskee who
told me how Allison took the propeller contract for granted when they won
the engine contract.  Hamilton Standard somehow won the Navy contract much
to the shock and chagrin of  Allison.

Norm DeBoer



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