BeechTalk - BT

Username Protected · **Posted:** 23 Oct 2014, 13:00

It is harder than you think. Very high RPMs and a lot of heat. Material quality is very very critical. Not many of them produced makes them more expensive per unit. Piston engines are easy to make. Sand cast case and cylinders and machined pistons and rods. If turbines were that easy to make a new company would come in and build them for the small GA fleet. Obviously nobody sees a profit in it.

Username Protected · **Posted:** 23 Oct 2014, 13:29

I agree that if it was that easy to design a turbine engine, someone else would do it.

Its all in the material, these turbines are red line at 800-850 deg .

Username Protected · **Posted:** 23 Oct 2014, 14:35

Someone did do it... check out the PBS TJ-100 engine

Username Protected · **Posted:** 23 Oct 2014, 15:10

Like Todd said, not as easy as it seems...

http://www.rolls-royce.com/interactive_ ... index.html

Username Protected · **Posted:** 23 Oct 2014, 18:19

Username Protected wrote:

I'd be interested in doing some work on such a project. The hot side is a bit more material critical on a turbine vice turbocharger. Higher temps.

I did build a functional jet out of a turbocharger in high school and worked at Pratt & Whitney in college. I have some engine experience. FYI, most turbine blades are cast, not milled. It's not the finish machining that's stupid expensive, it's the materials.

I don't think piston engine costs can be matched, but I think the piston to turbine delta can be dramatically reduced.

Yeah cost of some blades are off the charts. $80k a side

Username Protected · **Posted:** 23 Oct 2014, 20:24

Username Protected wrote:

Fred/Adam,

I hate to say this because I really want this to be true but I am EXTREMELY skeptical.

My last Masters Degree was in plasma physics. Although I did my degree at University of Toronto, my research project was on one of the experiments at Princeton's TFTR (Tokamak Fusion Test Reactor) in the mid-1990's.

This would be such a huge leap in technology that in aviation terms it would be like somebody developing a Diesel engine, certifying it with the FAA, getting an STC for Aerostars within the next year...and then selling them to us installed for 10AMU.

I hope I am wrong.

Glenn

Glenn, I agree it is a huge leap. Much larger than your analogy I think. Something I would expect from a company in the nuclear power business, or a lab. Not Lockheed Martin. It will be interesting to see if it proves itself.

Username Protected · **Posted:** 23 Oct 2014, 20:28

Username Protected wrote:

I agree that if it was that easy to design a turbine engine, someone else would do it.

Its all in the material, these turbines are red line at 800-850 deg .

Typical turbine blades operate in a much hotter environment than 800-850 deg......and it doesn't matter if you mean deg C, deg F. The blades have internal passages to keep them cool enough that they do not melt. And yes, the material are not the typical materials you purchase locally.

Username Protected · **Posted:** 23 Oct 2014, 20:39

Username Protected wrote:

the engine companies work hard to reduce costs, but we also want the engines to perform better use less fuel, last longer, etc. Lots of expensive materials, expensive manufacturing.

I just don't buy it. With todays 5-axis CNC machinery, I can't see a turbine have to cost any more than a piston. It's got a lot fewer parts and the tolerances this can be made to with CNC is staggering. Remember - when they were certified they had to be hand milled manually as there was no CNC then. Now a machine can churn them out 100 times faster and do them better.

Another example - I can buy aircraft grade certified turbo for about $3000. We can all agree that they are basically half of a turbine in construction. They both have a centrifugal compressor of about the same size, they both have bearings that need oiling and cooling. Sure the turbine has burner cans and an axial turbine stage, but that can't account for the $250K extra they charge for the thing. No way. Someone is making a lot of money along the way, that's all I'm saying. And as long a the military (which is yours and my money) is willing to pay any price for this stuff, there's no incentive from the old boys network to lower prices.

Username Protected · **Posted:** 23 Oct 2014, 21:23

Good news, if one of you guys wants to build a turbine, you don't have to make your own blades. Many of them, if not most, are cast then machined by outside shops. There's one in Georgia but I can't remember the name of it. They make everything from little bitty blades small enough to be worn as jewelry to huge turbofan blades several feet long. I'm sure they would love to build to your specs.

Leland Snow who has been building the worlds best ag planes for decades decided to build a turbine engine and they actually built and ran the compressor, but never finished it prior to his passing. It's very closely based on the Pratt I think. I also seem to remember that he had hired a man who previously designed turbine engines for the military to head up his engine department. Might be a starting point. I wouldn't be surprised if they didn't take anyone seriously who didn't have access to tens of millions of dollars for the project.

Username Protected · **Posted:** 23 Oct 2014, 21:33

There's my problem with both my turbine abd diesel designs. Both work on paper. I had a one cylinder version of the diesel working fifteen years ago when I was working on my masters (proof of concept for injection and head, non representative bottom end)

R&D to the standards the FAA wants is EXPENSIVE.

Username Protected · **Posted:** 24 Oct 2014, 08:02

Username Protected wrote:

...
This would be such a huge leap in technology that in aviation terms it would be like somebody developing a Diesel engine, certifying it with the FAA, getting an STC for Aerostars within the next year...and then selling them to us installed for 10AMU.
...
Glenn

Glenn, I agree it is a huge leap. Much larger than your analogy I think.
...

Username Protected · **Posted:** 24 Oct 2014, 17:47

Granted the fusion concept presented by Lockheed is optimistic to say the least. I do appreciate folks that are willing to research such out of the box ideas.

Username Protected · **Posted:** 25 Oct 2014, 09:15

Username Protected wrote:

Granted the fusion concept presented by Lockheed is optimistic to say the least. I do appreciate folks that are willing to research such out of the box ideas.

Who knows? A fresh approach might even work - after all, people tried for years to fly and then someone did - by challenging what everyone thought they knew (specifically Smeaton's coefficient, Lillianthals lift tables and the use of 3 axis coordinated controls, if you are interested).

But I doubt it.

How far CAN we drift this thread?

Username Protected · **Posted:** 25 Oct 2014, 11:31

Username Protected wrote:

Granted the fusion concept presented by Lockheed is optimistic to say the least. I do appreciate folks that are willing to research such out of the box ideas.

Who knows? A fresh approach might even work - after all, people tried for years to fly and then someone did - by challenging what everyone thought they knew (specifically Smeaton's coefficient, Lillianthals lift tables and the use of 3 axis coordinated controls, if you are interested).

But I doubt it.

How far CAN we drift this thread?

Username Protected · **Posted:** 25 Oct 2014, 13:01

Username Protected wrote:

...
How far CAN we drift this thread?

With the discovery of the Higgs boson, can I get my antigravity skateboard now?

Twin Prices Crashing