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Small turbines 100hp 130hp

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32 litres per hour of diesel fuel consumption just for the 100HP model means this design has no economic advantage over any IC engine, whatsoever.

An improvement in reliability and smoothness, perhaps - but I can't see light aircraft owners beating a path to their door, waving handfuls of notes.

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Turboprops operate best at higher flight levels 20 to 30 thousand feet and are most efficient between 220 to 350 knots so I guess the best replacement use for these engines would be something that currently runs a turbo, these small turbines are rated 100 HP and 130 HP up to 33 thousand feet and they are very light 28 /30 kg .

Avgas is getting hard to find in manny countries so the diesel fuel would be a advantage.

 

A Black shape prime running one of these small turbines would be a nice toy

 

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Blackshape develops and produces high performance two seater carbon fiber aircraft, for leisure aviation and military training, focusing on innovation and quality.

 

 

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 You would need to have specific fuel consumption figures for different output and flight levels provided to really know range and cost.. A Small turbine would have to operate at around 130,000 rpm's so the reduction gearing set up has to be pretty good. I also reckon it would need a c/s prop which can be  feathered. with overspeed protection. There's no turbo prop I know of working in a fixed pitch that isn't limiting itself severely in it's speed range. It's ideally suited to faster planes and will perform more economically at high altitudes. Loading the prop will make the turbine blades run hotter so it must be controllable. the fuel flow management  for starting might be quite critical also. If you can use them these motors are potentially many times  more reliable than reciprocating engines. Cost?  certainly a fair bit above a piston and fuel flow lots more. Weight? Much less. always. Size ? small frontal area with no cooling radiators.  Nev

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I am griped by the fantasy of flying a very small turbo prop, mated to an air frame that could make best use of its characteristics BUT I am enough of a realist to understand that with existing technology, it is, unfortunately, just not cost effective.

 

I have always liked the idea of an engine that rotates in the same plane as the prop (Wankle & jet turbines) - they just make more sense than the modified steam engine that motivates most of us.

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 I don't quite understand the essence of your description. The steam engine is an external combustion thing and can be reciprocating  or turbine or a swashplate type motor. It has thermodynamic differences and is condemned (however much one may love them) to an inferior efficiency level for many basic reasons you can't eliminate however much you refine it.

    Not having  reciprocating parts is the advantage of turbines. Load reversals promote fatigue and combined with large dynamic loads add to the life reducing factors of a lightweight Aero  engine.

     Turbines where the fuel is burned internally have their efficiency limited by temperatures  being restricted by metallurgy and design  (coling) and pressures not being anywhere near what you can get in reciprocating engines.. Internal combustion engines operate on the Carnot cycle where high temps and pressures equal high efficiency. Fluid flow and pumping losses  can be calculated also You don't have to build these things to evaluate their potential any more.  Nev

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I have been lead to believe that the design of the piston internal combustion engine has been inherited from the steam engine. The source of the energy  & how it is "liberated" to drive the pistons is different but he principal of a reciprocating piston, driving a crankshaft, to produce rotational movement remains the same.

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" modified steam engine" is a bit of a stretch of the imagination though.  Hardly a fair description of an article where there's a  $#1tload of specialized development that's gone into making a rotten principle work very well. in the Infernal combustion engine, over a long period of time, and it's become something most people can use and not think much about.

      IF you want range, In aircraft terms, the piston engine is way ahead on efficiency. especially at low level.. Rover built a turbine car in the 50's which was a test bed to subsequent aero application. You don't and won't see turbine powered cars, except in freakish events... Turbines don't have much character. They either start successfully or melt the turbine and the smell is bad  and they have to be revving  near full revs, or they hardly make any power at all . Some are flow critical and can stall if you don't dump mass  air The centrifugal compressor is almost mandatory for smallish ones for flow stability.. Only precise design and metallurgy makes them any use or able to run at all reliably. The very high temps mean when things go wrong they fail. fairly dramatically. Nev

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On 12/2/2018 at 11:04 AM, onetrack said:

32 litres per hour of diesel fuel consumption just for the 100HP model means this design has no economic advantage over any IC engine, whatsoever.

An improvement in reliability and smoothness, perhaps - but I can't see light aircraft owners beating a path to their door, waving handfuls of notes.

This is a sensible answer..... But I just want one OK, On a Hornet STOL. With Fat tires! So I can pretend I'm Pilatus Porter and do cool stuff.. and never look at a the spreadsheet to see where the money is going, then aviation is fun 😉

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It burns 145 grams of turbine oil per hour?

I think there is a post somewhere about the cost of turbine oil (it's not cheap). 

So there's an added cost in that.

Do all turboprops ( turbines) use oil or is this just a "total-loss" system in this application?

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 It wouldn't be an unusual occurrence for a small turbine type engine. Due to the high temps internally most seals are labyrinth type and the bearings are sprayed with an oil jet some oil loss would be considered normal.. Nev

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9 hours ago, facthunter said:

" modified steam engine" is a bit of a stretch of the imagination though.  Hardly a fair description of an article where there's a  $#1tload of specialized development that's gone into making a rotten principle work very well. in the Infernal combustion engine, over a long period of time, and it's become something most people can use and not think much about.

      IF you want range, In aircraft terms, the piston engine is way ahead on efficiency. especially at low level.. Rover built a turbine car in the 50's which was a test bed to subsequent aero application. You don't and won't see turbine powered cars, except in freakish events... Turbines don't have much character. They either start successfully or melt the turbine and the smell is bad  and they have to be revving  near full revs, or they hardly make any power at all . Some are flow critical and can stall if you don't dump mass  air The centrifugal compressor is almost mandatory for smallish ones for flow stability.. Only precise design and metallurgy makes them any use or able to run at all reliably. The very high temps mean when things go wrong they fail. fairly dramatically. Nev

Thanks Facthunter - Mostly well above my pay grade however the intermediate design must be the Wankle. Such a sham that it did not attract more investment/research. If it had had a nats nuts  of the piston engines R&D it would be a ripper small aircraft engine by now.

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  The wankel would be a good sports engine but is close to a 2 stroke for fuel efficiency. It has been used for outboard racing and if you want more power just supercharge if.  Seals wear and cases distort but if it starts it will get you home. Very noisy and hard to muffle.  Nev

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2 hours ago, facthunter said:

  The wankel would be a good sports engine but is close to a 2 stroke for fuel efficiency. It has been used for outboard racing and if you want more power just supercharge if.  Seals wear and cases distort but if it starts it will get you home. Very noisy and hard to muffle.  Nev

Me thinks that similar criticism might be made about erly automotive/aircraft engines and look where all that R&D effort has got us against all the odds,  piston engines that are actually fairly reliable, quiet (in some applications) and fuel efficient.

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The Szorenyi rotary engine is the latest development in rotary design.  However, it appears to be likely to suffer from the same problem as all rotaries - trying to ensure a durable and reliable seal between rotor and stator.

This niggling problem is likely to be worsened if the Szorenyi rotary engine reaches much higher revolutions than the Wankel.

 

New 4 chamber rotary engine

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 They have a compromised combustion chamber shape with too much surface area to volume ratio so will never be efficient. They don't fly to pieces though.  Like two strokes , they are unlikely to get past emmissions rules, long term.. Very few have mastered the seal problem with the Wankel.  Norton made an aircooled version derived from a motorcycle engine that is used in light aircraft. Nev

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On 12/2/2018 at 2:04 PM, onetrack said:

32 litres per hour of diesel fuel consumption just for the 100HP model means this design has no economic advantage over any IC engine, whatsoever.

 

in Europe avgas is E3.00 and more, diesel fuel and avtur E1.0-1.5. So this is a question of 1. turbine price 2. turbine rating for pilot (not very cheap and easy too).

 

 

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