Gary, how much would the allison give at 24,000 feet? I assume it's considerably less than a tsio-550. Colyn
The whole alternate engine thing is very frustrating. Consider that a spark-ignition engine is inherently better in small sizes, while a turbine is inherently better at the larger sizes. Although a turbine-powered leaf blower would rock. Anyway, I've analyzed the data every which way, turning, twisting and smashing the numbers bloody and the result was that our power levels (below 700 maybe) the best compromise is a large-bore spark-ignition air cooled piston engine. A highly-boosted water-cooled piston engine looked interesting, but the weight and potential failure modes killed it in my analysis. Right back where I started. I couldn't find that magic silver bullet no matter where I looked.
Back to your question, I don't know how much the Allison (Rolls Royce) is flat-rated, but I would guess that the TSIO-550 is at least capable of more power at 24,000. A not-overpowered turbine installation - a 450 hp turbine instead of a 350 hp piston engine - is probably no faster at altitude than a piston engine. But will get there a lot faster.
Gary Casey |