Check 6
Perhaps we are divided by a common language, my apologies.
Mfr/Mdl Code Manufacturer Name Model Name Type Engine Horsepower
03019 ALLISON 250 SER Reciprocating 00420
03002 ALLISON 250 SER 250HP Turbo-Shaft 00250
03003 ALLISON 250 SER 250HP Turbo-Prop 00250
03010 ALLISON 250 SER 317HP Turbo-Prop 00317
03011 ALLISON 250 SER 317HP Turbo-Shaft 00317
03012 ALLISON 250 SER 400HP Turbo-Prop 00400
03013 ALLISON 250 SER 400HP Turbo-Shaft 00400
03014 ALLISON 250 SERIES Turbo-Prop 00300
03017 ALLISON 250-B17 SER Turbo-Prop 00385
03018 ALLISON 250-B17 SER Turbo-Shaft 00450
03035 ALLISON 250-C10D Turbo-Shaft 00500
03020 ALLISON 250-C20 SER Turbo-Shaft 00420
03021 ALLISON 250-C28 SER Turbo-Prop 00500
03022 ALLISON 250-C28 SER Turbo-Shaft 00500
03015 ALLISON 250-C30 SER Turbo-Shaft 00650
03029 ALLISON 250-C47 Turbo-Shaft 00600
Same gas generator/turbine engine, different fandangle on the other side of the gearbox.
Whether an engine core was originally designed intended for fans, helicopters or propellers is moot. The Garrett Turboshaft/prop/jet/fan engine series started life as the ubiquitous truck turbocharger.
We have come a complete circle with the fans on the current engines absorbing almost all of the energy (80+%)with similar nominal residual thrust from the turbine as from turboprops.
Cogen is a whole nother industry derived from the use of said residual energy from industrial turbines.
Our local Govt Aircraft Factory decided in their wisdom to use two ALLISON 250-B17B Turboprop version of the B17 Series, turboshaft, if you wish, instead of a single PT6 as the original design intended for their Nomad. They never did get the gearbox right or the subsequent C of G issue under control either.
The Nomad made a paraplegic of the Chief designer and succeeded in killing many others, predated the C208 Caravan by some 20 years. The Cabin dimensions are almost identical in that it is a C208 cabin on its side and it had the same mission spec. Then as long as you could put up with bicycle chain operated retractable U/C, a dodgy stabilator, didn't ask too much of the gearboxes amongst a dozen other foibles it wasn't a bad aircraft.