This is pretty exciting. You have to think that the newer design will result in much better efficiency and lower price point than the PT-6's. They clearly are going after that market which will give GA options as well as aircraft designers. Cant wait to see what's coming!

http://www.avweb.com/avwebflash/news/GE ... 201-1.html

About time. PT6's are already about twice as expensive to overhaul per hour as old Garretts. That's what happens when you have 99% of the market and everyone over a barrell.

maybe i will be able to get an evolution in the next 10 years after all

I think it'll have a good effect on the price point of PT-6s.

I'm not convinced it'll be dramatically more efficient. Fundamentally they aren't especially different, in particular both are free turbines. I suspect incremental change to the PT-6 over the years has enhanced the efficiency of the newer versions of those, and that the new GE entry will likely be basically similar.

But competition is good!

You're probably right there, Jon. Between the lines one can kind of read that it's a hotted version of the M601 engine, which was a PT6 knockoff, so the efficiency is probably on par with those. But if they can get the thermodynamic core heat up without weakening metals, then it could improve efficiency.

Exactly, it's a warmed over version of the commie copy of the PT6. Walter copied the PT6A as much as they could, then GE bought Walter and, to their credit, spent a ton of money upgrading the internal aerodynamics and making some materials changes. Their first version, the H-80 did have much better SFC numbers than the Walter but I doubt that they are much if any better than Pratts new PT6A-140AG.

It will be very hard for GE to one up Pratt on an engine that Pratt has been continuously upgrading since the late 50's. If, by some chance GE comes up with some exponential improvement, you can bet that Pratt will include the same upgrade within a matter of months. Having two powerhouse companies upgrading what amounts to the same engine will certainly be good for consumers though.

I liked the walters. Cheap and reliable. Wellstone had a couple DC3's converted to walters, they were workhorses.

But if they can do it... so can Pratt.

This is not how GE typically enters the market after investing $millions$ on R&D to achieve a performance advantage. I bet the price point will be significantly higher but justified by fuel savings.....until the competition catches up.

Mottier said the ATP will have a 16 to 1 pressure ratio

That's different. Will dramatically improve efficiency. Only possible with high temperature materials.

20% lower SFC might be possible. That would put it at or slightly better than TPE331.

Now put fixed shaft plus 16:1 compression together and you'd have a really awesome SFC.

Mike C.

That is significant. Didn't notice the pressure ratio thing before. Interesting. They also said it has something to do with cooling technology from their military engines. Quoted as 10% more HP on 15% less fuel, so your 20% lower SFC guess is probably pretty close.

Would love to see a fixed shaft variant.

This new engine is nothing like an H80.


Me, too, but fixed shaft turboprops are considered marketing pariahs for some reason.

Oh well.

This engine has the potential to deliver fixed shaft SFC with free shaft behavior.

Mike C.

Props are more complicated on direct drive motors, and once you get into the larger sizes they have some prop failure modes that can kill you way faster than a PT6 or a Garrett with a similar prop design.

Pitch lock, Pitch Rate Decay mode, loss of pump flow, etc.

Garrett is a fixed shaft engine, is that what you mean by "direct drive"? There is still gearing involved.


I'm not aware of my engine having failure modes of those names.

What are they?

Mike C.

Your engine no.

Larger non free turbine engines such as the T56 have them.