There are two vital questions you need to ask about any new engine, but especially about turbines. What is the expected cost? And what is the expected TBO? TBO is critical for these small turbines. I know of one helicopter whose engine has a TBO of 25 hours!
@@philv3941 where is that data from? JMB published nothing about performance of the VL3 with turbine on their website, and 19 L/hr with this engine would be less than 60 hp... can the VL3 cruise at 290 km/h on that power? What does a Rotax burn for the same cruise speed in the same airframe?
@@brianb-p6586 I've got a model of a similar sort of GT which can break through 35% thermal efficiency. That would net just under 50KW on the power turbine. You need a recuperator that can provide outlet temps of around 650c which is probably doable. But the thing is, turbine inlet temps on this model are right at 1050c, so there's not much higher you can go without active blade cooling and fancy ceramics. If you stick a steam cycle on the back, you get another 20ish KW but you no longer have an airplane engine.
@@pouyan225 It did get manufactured as a prototype but I don't think it was marketed properly as Rolls were obsessed with small helicopter/ turboshaft engines and even passed on a chance to produce a rival to the T700 type fan engine.
did you use a low pressure ratio to realize a low sfc, at the cost of power density. We tried to modify a T62 with a heat exchanger mounted behind the combustion chamber, build up with parallel small diameter tubes, first the compressor flow after the diffuser fed the outside tubes, surrounded by the leaving radial outflow exhaust flow, after crossing a second set of tubes feeding the rear of the reverse flow combustion chamber. A bit difficult to describe. The fuel savings were substantial, despite the added pressure losses in the tubes . Recalling the pressure ratio by the centrifugal compressor was just below 3. TIT 900°C Noise reduced compared to the bare T-62 titan
You can also have a higher compression in a small scale turbine engine by use of a radial compressor instead of an axial one. In fact the first turbine engines had radial compressors and also radial expanders. Also the turbine engine of the Lotus F1 race car was a radial turbine engine. Its issue was not the fuel consumption but the small power band. Today this would be no more an issue because of the possibility of serial electric hybridization.
You mean centrifugal compression, these are not more efficient than a multi stage axial compressor and stator arrangement. Lets not rewrite history here, the first attempts at a gas turbine engine date back to the 1700s and maybe even earlier. The 1800s saw more serious efforts with a bunch of patents filed, in the early 1900s Frank Whittle took the credit for inventing the gas turbine engine, but he really just stood on the shoulders of many before him.I have no idea what serial electric hybridization is, nor does google, maybe it'll come up if I play buzzword bingo long enough, but gas turbine engines are fuel hogs. Under the current F1 regulations, 110 kilograms of fuel would barely get them through the warm up lap.
@@nohandleleft In a series hybrid, the electric motor is the only means of providing mechanical power to the wheels. In parallel hybrids ice as well as electric motors are mechanically connected to the drive train. I ment that a gas turbine engine makes no economic sense for operation of the drive train by use of a torque converter. But this was also done with the Plymouth Sportcoupé in 1954 und Chrysler Turbine in 1963. Later there were several small series of gas turbine cars around like Dodge Charger, Dodge Coronet (1966) and Chrysler LeBaron (1977). The Lotus 56 was a Pratt & Whitney ST6 helicopter gas turbine driven Indi car and F1 car piloted by Graham Hill, Joe Leonard und Art Pollard in the Indi races and Emerson Fittipaldi in the F1 races between 1968 und 1971.
@@glsracer yeah it wouldn't be in the European one either, but if they manage to get some sales, hopefully with economics of scale they can drive the cost down to something more reasonable that would make the return on investment more certain and faster
Runs on hydrogen? Why would they ever want to do that? May was well store the hydrogen in a large bag above the fuselage. Liquid hydrogen doesn't have much of a "shelf life".
Cryogenic liquid is the form of hydrogen which major aircraft industry projects (such as those by Airbus) intend to use, because it is the only one which offers the hope of low enough weight per unit of fuel energy value carried. Yes, the time that fuel is held on the aircraft is a concern, which is why it would only be for scheduled commercial operations. Liquified Natural Gas has similar concerns (although of course with a less extreme temperature), and in select applications it works. Where "shelf life" is more of a concern compressed gas is the solution (whether that's CNG or high-pressure hydrogen gas), but for aviation pressure vessel weight is a real problem.
I see that Robin quoted 28l/h for a 155hp version. No doubt it will weigh less than the Continental diesel engine of the same power but it uses 40% more Jet A.
@@nigelcharles511 19l for 130hp is not physically possible. 20l have about 200kWh of energy, of which 30% can be turned into mechanical energy, that is 60kWh. If you fly one hour at 130hp = 100kW you need 100kWh. So either they don't know what they are talking about or they think of flying at 60% power. 28l/h for 155hp on the other hand is in the realm of possible and could be a realistic number for an efficient engine.
The 19 l/h is likely for cruise power, much lower than the ~100 kW (130 HP) maximum rated power. On their website, Turbotech labels this fuel flow as for "Eco-cruise"... which generally in the industry might mean 55% power.
My CD155 engine is at 60% power at 20l/h. I am not sure what power setting they are at to achieve 28l/h. The Robin DR400 airframe best operates in the range of 105-115kt (60-75% for a CD155). Matching powerplant to airframe is an important consideration which is sometimes overlooked.
@Nigel Charles yes, matching the engine to the aircraft's requirements is important, but even ideally matched, I think we agree that the efficiency of this turbine will be nowhere near that of a diesel. You are operating the Continental CD155 at about its ideal point. Turbotech isn't even telling us what that point might be for their engine.
nope: 400hp is not allowed for 90% from the PPL licensed pilots...need a high performance PPL HP Rating over 200HP, and in addition turbine engines need a specific Rating
Not at the same time! It is very similar in power, weight and fuel consumption as the Rotax 915iS. About 98 HP at 31 litres per hour but, in Europe, Jet A can be half the price of MoGas.
An image from one of their videos shows 72.26 kW (97 HP) at 31.2 l/h (8.24 USgal/hr) in a test... the numbers mentioned by Philip Galway-Cooper in his comment.
We don't need effing turboprops, they are the worst of both worlds. Super expensive and still front noise maker like a piston prop. We need a small turbofan jet engine, which is quiet, much lighter, natural twin engine configuration for ocean redundancy. Turbofan engine has world distance record of 40000km at 500km/h without refueling so when jet can be fuel efficient then why would you ever go after the much more complex turboprop.... come on, people.
@@Adolf_Meowtler world distance record of 40000km at 500km/h belongs to the off the shelf simple turbofan jet engine Williams FJ44-4. Explain that then.
@@DanFrederiksen in a airliner? Nope. It's all about efficiency. Props are slower thats why most airliners don't use it. And Piston is much more fuel efficient.
@@Adolf_Meowtler you didn't address the world distance record. I had also heard that turboprops are more efficient but then where is the world distance record then... Some of the best airliners can fly to the other side of the world. There are no turboprops with such ranges.
does not need 120° w, 90° is the best angle for a V6 (compact and easy intake design), with a offset crankshaft...the speed record (official 405km/h but was in real a bit more) in 24h Le Mans race was take from a V6 PRV (910hp) WM P88 in 1988...One aircraft was made with a PRV (Robin R3000), was never built in serie despite it work very well, for the same cause the flat 6 Porsche aircraft engine was discontinued: too expansive to buy= not enough sales to make a profit...
@Alexander Biersack a camless system like Koenigsegg's Freevalve (which still isn't in production) might save weight, but reliability will be low compared to traditional camshafts. The big advantage of these systems is in accommodating widely varying operating conditions, but aircraft have very little of that variation compared to cars, so it's not a good application.
@@brianb-p6586 I know the range in which aircraft engines operate is smaller but I would think that Freevalve would be more reliable because if one valve fails all the others could still operate fine. Why do you think Freevalve would be less reliable? There is a lot of redundancy and independence.