FWIW I had opportunity to speak with a guy in the business today about increasing efficiency on small turbine aircraft engines. He immediately started talking about flight weight recuperators, which would recover waste heat from the exhaust to improve cycle efficiency. It hasn’t gone anywhere because the whole engine needs to be redesigned and there’s a perception that you can’t do it within a reasonable weight budget. He thinks you could, and in doing so would much improve SFC.
There is info on the web if interested, for instance Link and Link
I’m just a bit skeptical about their -20% fuel burn claims
Motor Sich is kind of in the middle of the separatist war area… something to keep in mind.
So no more turbine start up sequence videos on youtube with this thing….
I somehow didn’t expect that this DA50 will go into production when I saw the pictures for the first time. But then again Diamond has ma few projects which are still not around, like the conventional DA50, Diamond Jet, DA52…..
Anyway, it still remains the operator’s choice. People don’t seem to mind turbines in helicopters and most of those fly at 500ft
But then again people also don’t seem to mind to pay 1000$ or so for a basic turbine helicopter per hour…
It’s just that the SHP needed for a say 1 ton helicopter would require a big and heavy piston engine, so the turbine can play its weight advantage. Also, endurance doesn’t seem to play such a big role, as helicopter legs are often only a quarter of an hour or so.
A turbine has a very high air throughput, so it needs more fuel in dense air to get the stoichiometric ratio in denser lower levels
That’s exactly the same for a piston engine. TB20:
At sea level, 12 USG/hr for 140TAS.
At FL160, 8.5 USG/hr for 140TAS.
Both peak EGT.
Are turbines really worse than the above, or is it that they merely show up the contrast more – because the enroute sector is normally flown so high up?
Anyway, it still remains the operator’s choice. People don’t seem to mind turbines in helicopters and most of those fly at 500ft 
Other than that it really doesn’t make much sense to fly a turbine in FL100
Why not?
- A turbine has a very high air throughput, so it needs more fuel in dense air to get the stoichiometric ratio in denser lower levels.This makes the turbine a real gas guzzler. The overall efficiency is much lower than a piston engine, this is caused by thermodynamics and will not change much.
- The drag/power ratio goes down the higher you climb. You have more power for forward speed available in higher levels as drag is reduced.
Besides Materials and precision, the turbo engine (no matter if turbojet or turboprop) needs a considerable higher amount of engineering than a piston engine. Especially if the company is looking to improve the core process, it takes a lot of engineering to put the thermodynamics, aerodynamics, materials and mechanics together
Now is this really true. Lots of people are building jet engines in their garage as well. The cost, the engineering, the complexity is more a result of the business in which the product can enter in a meaningful and profitable way. Jet engines are technology driven because the customers wants it, not because it is needed to make an operational engine. A working and operational jet engine is not rocket science anymore. The customers are willing to pay lots and lots to get the level of sophistication they want or need. No one is interested in a low tech jet, because a low tech jet offers no benefits that can be utilized profitably. The exception is RC jets, fully operational engines that anyone can afford, and also build from scratch with garage equipment. These engines can easily be scaled up, but will be so inefficient/heavy/unreliable that all the benefits are gone. You see a similar effect in F1 car engines also, engines that are light years ahead of any modern ordinary engine. Only no one outside the F1 industry has any use for this level of sophistication, so they remain a circus attraction. Nevertheless, the sophistication of F1 engines are way up there with newest jets.
There is a reason, why companies – even the big players – tend not to touch their core processes whenever possible and new developments are mostly tackled by a joint venture of several high profile companies in the field.
Or sometimes they don’t tackle them internally at all.
