Achim, I think there has been plenty of turbofan development. Weight, efficiency, noise etc have all improved dramatically.
There will be a time when converting 20% of fossil fuels into propulsion and wasting 80% will no longer be acceptable, even in a King Air or Meridian.
Acceptable to whom?
Turboprops are a tiny market and only really a King Air could justify development of a new engine. But they work and I don’t think they will be replaced with a reciprocating engine.
The old Walter is correctly called M601, and the new generation under GE ownership is H75, H80 and H85 (750, 800 and 850 shp, respectively). They claim a somewhat lower SFC compared to M601E/F. The least powerful model in the M601 series is M601Z (512 shp takeoff, 328 shp max. continuous).
What about the walter 610? or is its power range different.
And hasn’t it now been refreshed as the GE H60.
The PT6A-52 was a new engine for the Kingair B200GT, and was introduced in 2008.
Yes it is based on previous versions, but so is the Rolls Royce Trent.
Jason, my basic assumption is a very simple one: there will be a time when converting 20% of fossil fuels into propulsion and wasting 80% will no longer be acceptable, even in a King Air or Meridian. My conclusion based on the thermodynamic characteristics of a small turbine is that the most likely solution is going to be reciprocrating engines burning jet fuel in a 2-stroke cycle.
And when you say “There will be plenty of development of turbofans” you should ask yourself why there hasn’t been any. Also I’m referring to turboprops, not turbofans.
Achim, I still just don’t believe this. There will be plenty of development of turbofans – the blisks and other more radical changes like open rotors are being looked at. I do not think reciprocating engines will make a comeback for CAT – no matter how many times you say it! ;)
As to the PT-6, it is a fairly low volume, reliable engine. Yes, FADEC etc would be nice. But I still wouldn’t swap it back for a piston…
Except that it is prob99 beyond man’s ability to make reciprocating engines as reliable as people expect of jets today.
Maybe for homo lycomicus but homo sapiens sapiens should be well capable. The Jumos in the 1930s were extremely reliable. 2 stroke ship diesels operate virtually without failures. Even the engine oil gets filled in when the engine is installed and remains in there for decades until the engine is retired.
such a stable non-compete situation typically only lasts for some time until a new player enters the market and takes it
In theory, but not in practice.
The optimal strategy for a disruptive newcomer is not to bomb the market price. The optimal strategy is to enter the market at a slightly lower price point, say 20% lower, and with a load more features. “Features” often cost next to nothing and were missing in the original products purely to maintain an artificial graduation in the product range. So you eat somebody’s lunch, replacing five of their products with one of yours, and make almost as much money as they were. That is what I have always done in business 
If you go in at a low price, you attract a lot of price sensitive customers but those are the worst kind of customer to have. They have zero loyalty, and the moment the next vendor comes in at a lower price point, they will all run off to him.
We have this in avionics. There is a lot of cash cows around which cost say $300 to make and sell, trade, for $2000-5000.
The future in the 400-1500hp class or so is combustion engines
Except that it is prob99 beyond man’s ability to make reciprocating engines as reliable as people expect of jets today.
The existing engines are pretty good functionally
James Watt’s steam machine is “pretty good functionality” by today’s standards, too In comparison to what would be possible, today’s small turbines are just plain awful products. It is going to change eventually because fuel consumption will become the all determining factor. Rolls-Royce sell an upgrade to the Trent 900 (A380) reducing fuel consumption by 0.8% and they charge big bucks for it.
No, the answer is much simpler. All the turbine manufacturers are part of giant conglomerates that have as main customers lucrative military contracts. They don’t want to rock the boat or kill the golden goose. They’re making billions on selling old rope. They’re not stupid.
There is probably truth in that. However, such a stable non-compete situation typically only lasts for some time until a new player enters the market and takes it. There are “wannabe” players in the small turbine market but it’s hopeless. The market is so small and so conservative. In addition, small turbines are simply the wrong solution, they are thermodynamically inefficient. The future in the 400-1500hp class or so is combustion engines. Fuel prices will take care of it eventually.
I just refuse to believe the talk about the R&D costs and development costs. It’s bullshit.
Strike one: These engines used to be produced by hand on metal lathes and mills. There wasn’t even CNC when they were all developed. Are they trying to tell me that in the 50 years since then, with new materials, production tolerances and proaction methods don’t come cheaper? Give me a break. I can buy a 5-axis CNC mill for less than $100K today.
Strike two: The “new” Honeywell H80 is just an old Walther 601. The “new” RR300 is just an old Allison C250. The Garrets and the PT6’s were also developed in the 50’s. So what huge R&D costs are they talking about? Nothing has been developed.
Strike three: a turbine today with solid CNC machined blisks (not individual blades that have to be put into slots) is in parts numbers a lot less complex than a piston engine. The hot side only has one moving part. A modern 5-axis CNc mill could probably mill that out in half a day.
No, the answer is much simpler. All the turbine manufacturers are part of giant conglomerates that have as main customers lucrative military contracts. They don’t want to rock the boat or kill the golden goose. They’re making billions on selling old rope. They’re not stupid.
