My thoughts...

https://m.youtube.com/watch?v=dxNidpRNA0g

20% better fuel specific? I doubt it.
I ask that question to Klampmeir at Osh this year and he told me it was about the same as a PT6-67.
I will take the PT6 any day.




Maybe not totally, but on life support.

The Kestrel had a lot of good ideas and would have been a real performer had it hit market. In particular, switching to using a TPE331-14 engine which gave it significantly better fuel specifics and lower engine cost than the PT6A-67 series engine found in the PC12 and Epic. Fuel flows would have been down 20% which means 20% more range or that much more useful load, either way. HSI and OH costs are also way down versus the PT6, probably half as much.

At one time they were interested in having me fly my MU2 up to their operation and evaluate spoiler roll control, but alas, that didn't come to pass. I think they idea was to increase the flap span to get the stall speed lower (which is why Mitsubishi did it in the first place). Stall speed on a single can be a limiting thing to gross weight given the FAA 61 knot (or slightly more if you get an ELOS) limits.

It is really, really hard to start an aircraft company. The FAA is all about regulations and the established makers like it that way as a barrier to entry for others. Unfortunately, that is likely to be a short term strategy that fails long term for everybody, even the established guys.

Mike C.

TPE331-14GR ESFC is 0.497 lbs/hp/hr.

20% more than that is 0.59 lbs/hp/hr which is PT6 range (varies up or down a bit depending on exact model). The free turbine engine simply can't be as efficient as a fixed shaft engine.


Your choice, but HSI and OH costs are double per hour.

Indeed, the fuel savings alone pay for the HSI and OH costs of the TPE331 so they are effectively "free" compared to the PT6.

Mike C.

Whatever,
Not sure were you got your number but im getting 0.50 ibs/hp/hr on the TBM 900.
64 gph on 850 hp at FL280 ISA, 326-330 KTAS.

I only have one engine so I will take the best turbine engine built.

I'm ignorant - can the PT6 installed in the TBM a make 850hp at FL280? Impressively de-rated if so.

Absolute pressure at FL280 is about 1/3 of that at sea level. Hard time imagining that the 850 is a 2500hp thermodynamic engine.

Apparently, it can.

The point at which the curve breaks is when you reach temp limit and power decreases.

That's impressive! Zoom!

PS: dotted line is 6300 lbs, solid line is 7100 lbs.

Mike C.

At 320 knots, you get some ram air benefit that gets you the extra air.

The PT6A-66D engine is 1825 HP thermodynamic. The TBM900 is hugely derated at 850 HP.

Mike C.

It does, even my 700 is getting 100% torque or 700 hp to FL260.



I'm ignorant - can the PT6 installed in the TBM a make 850hp at FL280? Impressively de-rated if so.

Wow. Very good!