This is exactly correct. And the same goes for turbines as well, except add a decimal point. I can get all the parts, service, and support I need for an engine model that was last produced in 1985.

I'm not trying to be stubborn Larry, but when was the last time Lycoming or CMI had any
significant engineering/R&D costs on the piston GA fleet?

Lycoming has their iE2 engine that's going in the Tecnam Traveller. It has single lever power, electronic control (and timing I guess), pushbutton start. But it took a customer (Cape Air) and an OEM (Tecnam) to commit to a certain number of units for them to do it, I would imagine. If Cirrus told CMI they are going to switch to Lycoming unless they certify an engine with electronic control, I bet they would do it. It all derives from demand. If CMI and Lycoming don't believe they will sell any more engines even after a significant amount of development work, then why do it? They both tried the Jet-A thing and it got them nowhere.

Although the operating principle is simple, just spinning wheels, the realization of a working engine is pretty complex. Specialized materials, precise tolerances and the creation of things we don't think about like air passages in turbine blades to create air films over the blade surfaces so it doesn't burn in operation.

If you look at a single turbine blade from a very modern jet engine, you'll see just how complex they are to make, with lots of tiny passages drilled through extremely tough alloys. Then there are hundreds of them, perfectly made in every engine.

The other thing you fight in building turbine engines is the physics of squeezing air through small passages. Large turbine engines over 500hp, are more reasonable than building small turbines of say, 100hp. Smaller sizes make it more difficult or impossible to implement things like air film cooling, which means you can't operate them as hot, which means they're not as efficient. Fuel specifics are much better on a large turboshaft engine of a few thousand HP, than they are of a 250hp small turboshaft engine.

Reciprocating engines make a lot of sense under 300hp. Turbines start to make sense above 300hp.

I think the expense of current piston engines for aircraft are telling of the industry. You're buying more than an engine, you're buying years and years of support and liability. CMI and Lycoming exist because we pay them enough to operate, supplying parts and service and responsibility for these dinosaurs. There's not much of a market and there's a high burden for every engine in service.

We can't compare them to car engines, where the engineering and other costs are amortized across a couple of orders of magnitude more units.

Only if can match or exceed the material properties of machined blades.

Last I knew, 3D printing had not done that as of yet.

Mike C.

Only if can match or exceed the material properties of machined blades.

Last I knew, 3D printing had not done that as of yet.

Mike C.

Only if can match or exceed the material properties of machined blades.

Last I knew, 3D printing had not done that as of yet.

Mike C.

From the GE article:
"The 3D printing factory, which looks like a blue and gray jewel box of steel and glass from the outside, holds 20 black, wardrobe-sized 3D printers, made by Arcam. A single machine can simultaneously print six turbine blades directly from a computer file by using a powerful 3-kilowatt electron beam. The beam “grows” the blades, which are 40 centimeters long, by welding together thin layers of titanium aluminide powder, one after another.

Jet engine designers love this strong, heat-resistant wonder material, also known as TiAl. It weighs 50 percent less than the metal alloys typically used in aviation. But TiAl is also very brittle. Until 3D printing came along, the only way to shape it involved molding, a somewhat dirty process that requires expensive tools. “This factory has helped us understand what the art of the possible is with additive manufacturing,” said David Joyce, president and CEO of GE Aviation."

Please tell me why these engines have not decreased in price....

I believe the technology is being developed for the GE Catalyst, to be used in the Cessna Denali. I guess we’ll have to wait to learn what the effects on price will be.

I'm not trying to be stubborn Larry, but when was the last time Lycoming or CMI had any
significant engineering/R&D costs on the piston GA fleet?

[
Only if can match or exceed the material properties of machined blades.

Last I knew, 3D printing had not done that as of yet.

Mike C.

If you dig through the GE material and press. GE is there now. As engines, parts and other items get redesigned, they are going to move more and more to addative manufacturing.

Tim

As far as I know there are no complex cooling channels in any of the turbine blades on the common turboprop GA engines. Don't think the PT6 has any, not does the TPE331 or the RR250. They're just slabs of shaped metal. Also, all the common TP engines precede automated CNC machining, so at some point someone milled these entirely manually on a lathe/mill. Which makes it a little surprising they cost so much.

Adam, I don’t have a pic handy but unlike the -1, -5, -6 etc., a -10 1st stage blade has internal air cooling and are $1,000/each, approximately.

Addictive manufacturing is a great technology for making complex parts such as cooled turbine blades, heat exchangers, etc. However, the process is not as simple as many believe. The material properties are not the same as conventional manufacturing processes. Printing is a slow process, not necessarily less expensive than conventional processes. In addition, most of the materials used in turbine engines tend to be expensive. Most modern engines the turbine is subjected to temperatures above the melting point of the metal. These high temperatures mean improved performance which most everyone desires.