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 Post subject: Re: Kestrel vs SF50
PostPosted: 17 Dec 2014, 10:58 
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Joined: 11/08/12
Posts: 12805
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Location: Jackson, MS (KHKS)
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My thoughts...

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


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 Post subject: Re: Kestrel vs SF50
PostPosted: 17 Dec 2014, 12:07 
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Joined: 05/23/08
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Location: CMB7, Ottawa, Canada
Aircraft: TBM - C185 - T206
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.



Username Protected wrote:
Kestrel is dead.

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.

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Former Baron 58 owner.
Pistons engines are for tractors.

Marc Bourdon


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 Post subject: Re: Kestrel vs SF50
PostPosted: 17 Dec 2014, 12:35 
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Joined: 12/03/14
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Company: Ciholas, Inc
Location: KEHR
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Username Protected wrote:
20% better fuel specific? I doubt it.

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.

Quote:
I will take the PT6 any day.

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.

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 Post subject: Re: Kestrel vs SF50
PostPosted: 18 Dec 2014, 22:19 
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Joined: 05/23/08
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Location: CMB7, Ottawa, Canada
Aircraft: TBM - C185 - T206
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.

_________________
Former Baron 58 owner.
Pistons engines are for tractors.

Marc Bourdon


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 Post subject: Re: Kestrel vs SF50
PostPosted: 19 Dec 2014, 00:44 
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Joined: 11/08/12
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Location: Live in San Carlos, CA - based Hayward, CA KHWD
Aircraft: Piaggio Avanti
Username Protected wrote:
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'm ignorant - can the PT6 installed in the TBM a make 850hp at FL280? Impressively de-rated if so.

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-Jon C.


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 Post subject: Re: Kestrel vs SF50
PostPosted: 19 Dec 2014, 00:52 
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Joined: 11/08/12
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Location: Jackson, MS (KHKS)
Aircraft: 1961 Cessna 172
Username Protected wrote:
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.


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 Post subject: Re: Kestrel vs SF50
PostPosted: 19 Dec 2014, 01:05 
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Joined: 12/03/14
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Company: Ciholas, Inc
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Username Protected wrote:
I'm ignorant - can the PT6 installed in the TBM a make 850hp at FL280? Impressively de-rated if so.

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.


Please login or Register for a free account via the link in the red bar above to download files.

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Last edited on 19 Dec 2014, 01:09, edited 1 time in total.

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 Post subject: Re: Kestrel vs SF50
PostPosted: 19 Dec 2014, 01:08 
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Joined: 12/03/14
Posts: 20311
Post Likes: +25451
Company: Ciholas, Inc
Location: KEHR
Aircraft: C560V
Username Protected wrote:
Absolute pressure at FL280 is about 1/3 of that at sea level. Hard time imagining that the 850 is a 2500hp thermodynamic engine.

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.

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 Post subject: Re: Kestrel vs SF50
PostPosted: 19 Dec 2014, 22:46 
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Joined: 05/23/08
Posts: 6060
Post Likes: +710
Location: CMB7, Ottawa, Canada
Aircraft: TBM - C185 - T206
It does, even my 700 is getting 100% torque or 700 hp to FL260.


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


Please login or Register for a free account via the link in the red bar above to download files.

_________________
Former Baron 58 owner.
Pistons engines are for tractors.

Marc Bourdon


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 Post subject: Re: Kestrel vs SF50
PostPosted: 20 Dec 2014, 02:30 
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Joined: 11/08/12
Posts: 7372
Post Likes: +4834
Location: Live in San Carlos, CA - based Hayward, CA KHWD
Aircraft: Piaggio Avanti
Username Protected wrote:
It does, even my 700 is getting 100% torque or 700 hp to FL260.

Wow. Very good!

_________________
-Jon C.


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