New player on the mini - turbine market

That’s a very good SFC (I see they are using exhaust heat recovery) but does this engine exist other than a CAD model?

I have been involved with a project like this in the past and the running engine never got anywhere near the simulations.

This is just too cool. If they can make that 120 hp turbine, and it can use Rotax mounts, then they really have done it. People will form long lines to get that thing. I mean, the sound, the smell. Anyway, how exactly does this recuperator work?

I wish this team every bit of luck, and oh, do they need it. Innodyn, may they rest in peace, went as far as testing their turbine in flight on two different aircraft, yet they never delivered a single engine to its customers. PBS Velká Bíteš, a Czech company, and Diemech, their partner in the US, have also flown their engines and have yet to deliver.

There are various issues with small jets, some less than obvious. One of them is that since the turbine blades are obviously thinner, due to erosion they don’t last long, so you don’t get the 3600hr TBO of the PT6 or anywhere near that.

Heat recovery is an old technique and was done e.g. by one UK power generator company… can’t remember its name but I vaguely recall its AIM shares lost 99% of what I paid for them (about right for an AIM listed company, one might say)

Ultranomad wrote:

PBS Velká Bíteš, a Czech company, and Diemech, their partner in the US, have also flown their engines and have yet to deliver.

PBS has flown for years already, and 3 or 4 private owners have already built and are flying their Subsonex. I would assume somewhere around 30-50 kits would have been sold by now, with engines. I saw it in action at Osh last year, and studied it in detail later. The BPS engine is very real, they have sold over 500 engines, mostly to the UAV market I’m sure. Knowing I can afford one and have no problems building it, hmmmmm John Monnett said it flies sort of similar to a glider, rather than a SEP. I have no idea how to get a rating though. How do you get a single engine jet rating in Europe? Is there such a rating at all?

The Innodyn is another story. The former leader of EAA here in Norway tested it on a RV-4 in the US. I’ts a long time since I talked to him about it, but as I remember it he wasn’t overly impressed with the solution.

IMO we will see more turbines. Turbines and electric, also for GA. But that GA segment will exclusively be microlights and experimental. No one in their right mind would certify these things.

Turbines do need to achieve a good SFC for GA.

On bigger planes, say King Air, it doesn’t matter much because the scaling-up of everything means you have room for the fuel even though you are burning 1.5x to 2x more of it than a piston would.

But small GA is always severely range limited, unless you are talking about “toys” used for the aviation equivalent of cafe cruising and that is never going to be a big market. To make it big, somebody would need to produce a say 300HP engine with IO540 mounting points, or similar. And then you have certification…

Peter wrote:

Turbines do need to achieve a good SFC for GA

They will never do that. A gas turbine of any size is by design and physics, the worst thing possible regarding efficiency (disregarding things like pulse jet and other exotic stuff, which are way worse). On the other end you have the two stroke engine, which is the best. For power production (electricity) a gas turbine is OK because you can build it into a system using cycles to improve the total efficiency. Weight penalty is no issue there. That’s why I don’t understand what that recuperator is, and how it will increase the efficiency for propulsion? How do you convert heat into power when there is no surplus pressure? A steam generator? What exactly is that recuperator?

Peter wrote:

But GA is always severely range limited, unless you are talking about “toys” used for the aviation equivalent of cafe cruising

Ahh, you mean not the real GA, but the other kind of GA ? Well, after I got my eUp (electric car) 2 1/2 years ago, I have to say range is over rated. Statistics show that 95% of all driving (on average), you only need a range of max 100 km. For more than 95% of my car use is with the eUp, and I drive approximately 22-23 k km each year. For the rest I use my BMW, which will last for 100 years because it’s hardly used. In fact I have to use it deliberately from time to time exclusively to make sure the brakes won’t be damaged due to rust. Translate this into airplane, and the range would be 1 1/2 to 2 hours. Cruising at 150 knots, I will get 200-300 NM. Not very much, but – if the idea is to use it exclusively as transportation, this is no big deal. It takes a bit longer for the long reaches, but I will get there faster than car/train and probably also faster than airlines, due to all the security and checking in and transport to/from airports. If the idea is to use it as recreation, then it suddenly becomes a real nuisance sooner or later. It is exactly like my eUp. Perfect for the utility driving you do every day to get to work, to do shopping, to get to the airport. Pretty much useless as a long range holiday vehicle because of the nuisance of charging is every 1 1/2 hour.

Anyway, for a turbine, range is not a problem of weight, but the size of the tanks. Just put in bigger tanks, and you will have all the range in the world. Electric is different of course, but a small turbine combined with electric would be perfect. Long range, lots and lots of power, and very good economy cruise.