Menu Sign In Contact FAQ
Banner
Welcome to our forums

Is the PT6 still being developed?

Talking to the people at AERO, it sounds like this design has been frozen since the 1960s and they just make some bigger and some smaller versions. No interest in FADEC.

One would think there would be a decent market, with the King Airs (where I am hangared, a sizeable KA/TBM shop, they are constantly installing new engines) and TBMs and PC12s and so much other stuff, for a more fuel efficient engine.

Administrator
Shoreham EGKA, United Kingdom

Why do it? There’s no competetion and everybody is mostly happy with it. A cash cow par excellence!

Mainz (EDFZ) & Egelsbach (EDFE), Germany

I suspect the PT6 family has evolved more over the years of its existence than, say, (I)O-320/360/540. A somewhat abridged quote from here:

The original PT6 was introduced in 1963 and immediately began to be implemented in aircraft around the globe.

The design team added a two stage power turbine in 1973. This helped boost fuel efficiency and improve overall power in a big way.

1984 saw the introduction of the integral bladed rotor, or IBR. This reduced the overall number of parts inside the PT6A and helped improve efficiency of the engine significantly.

In 2010 the manufacturing process for the PT6 was given a major upgrade by the addition of the CVIS, or Computerized Visual Inspection System. This is an automated inspection tool used to check the quality of every engine created by the company, and dramatically increased the integrity of the engines.

Today the entire manufacturing process for the PT6 is computerized, from the initial part design and beyond. While a team of professionals still oversees production, the precision provided by computers has helped to enhance the manufacturing process significantly.

Today, the engine is a hallmark of power. It delivers 4 times more power than the original 1963 model and has a 20 percent improved fuel consumption rate.

LKBU (near Prague), Czech Republic

The ex CEO of one of the big turbine makers is my hangar mate. He told me the market for small turbines (that includes the Citation line) is so small that new developments are not feasible. There have been and there are radical improvements to turbines (lately the geared turbofan) but every little improvements costs hundreds of millions or billions. Even though the few companies involved are all worth billions, none of them do a new turbine on their own but instead work together in consortiums to split the investment and risk. For the Trent 900 (Airbus 380), Rolls-Royce teamed up with 7 risk and revenue share partners.

Big turbofans are usually sold at a loss with maintenance bringing in the money. GA turbines do not see enough utilization to generate that kind of money. An airliner turbine operates pretty much every day for many hours whereas a PT6 runs like 2 hours per week in average maybe?

I predict that big 2-stroke diesels will eventually replace the small turbines. They are significantly more fuel efficient and cheaper to develop. We can expect in King Airs and bigger in the future. When that will happen, I don’t know.

I can see the issues, but the developments that take place today on the big jet engines are chasing very small efficiency improvements – of the order of a few %.

I would bet that one could squeeze another 20% out of the PT6, just by applying some commonly known expertise. The engine doesn’t appear to have had any R&D on it since 1984.

Administrator
Shoreham EGKA, United Kingdom

… only 30 years? Not too bad, for a North-American propellerdriver.

And (for as little as it is worth) I quite feel with AchimHa: for that class of power, piston diesels are likely to take over, for better fuel efficiency and for lower maintenance cost. The one place where turboprops had a future was in subsonic large transports, like the Bristol Brittania/CL-44 or Tu114. Seem to have lost it, though, somehow.

EBZH Kiewit, Belgium

R&D expenditure in small turbines/controls is today more prevalent for helicopter engines, and the focus is on cost reduction. The existing engines are pretty good functionally so the emphasis is on ROI with the recovery coming from lower manufacturing cost. After a certain point you end up making a cheaper-built engine and then having to price it the same to recover the R&D investment. That doesn’t win friends. Manufacturing automation of the original product can be a better strategy to achieve cost reduction.

In relation to turbine engines generally the big OEMs have outsourced a lot of their design capability and the same people working for design consultancies are designing products for many of them.

Last Edited by Silvaire at 20 Apr 22:40

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.

Last Edited by AdamFrisch at 21 Apr 00:42

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.

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.

Administrator
Shoreham EGKA, United Kingdom
17 Posts
Sign in to add your message

Back to Top