It would probably be more spectacular a test flight of 4 hours but i was very interested in performing this test because it is very near to real use of Hybrix.20. 4 or 4.5 hours are possible for demonstration test but operational flight time is around 3 hours with light payload to 2 hours for heavy payload.
Lately many customers are telling us about electric multi-rotors flying for 2 hours or hydrogen fuel cells with 4 hours of endurance. It would be interesting to see these multirotors with heavy payloads.
I hope you like it guys
Jose Luis Cortes
Quaternium
Comments
Hello guys!
does anybody have some feedback from Quaternium? I try to send several email but no answer at all so far!
Jose? still there?? do not give up right know :-)
You have email...thank you
I believe it was Ferdinand Porsche who stated "A piston engine is a convenient hot gas generator for a turbine engine"
It's this sort of thinking that leads to the insane performance produced from modern racing engines. They are not simply a piston engine with a turbo bolted on to give a little boost. It's a different way of thinking. The turbocharger and piston engine work together as one thermodynamic unit, the piston engine part really just being used to produce shaft power.
Actually to toss one more into the mix the 4 stroke turbocharged diesel could easily be the most efficient especially at these smaller sizes.
The engines mentioned above suffer genuine scale problems as they become smaller, resulting in worsening efficiency, inadequate cooling and in turbines incredibly complicated internal aerodynamics producing unwanted internal turbulence and cavitation as well as sufficient heat dissapation.
To the best of my knowledge, very little development on 4 stroke compressed diesel is going on for airborne vehicles, probably due to the simple perception that diesels weigh too much.
But given the state of incredibly high performance steel and aluminum alloys, it actually should be quite straight forward for a decent engine design engineer to come up with a tiny light weight 3 or 4 horsepower turbo or supercharged diesel.
It could even incorporate regenerative heat recovery.
When you start doing things like that you can begin to approach and possibly even exceed the 37% max efficiency of an internal combustion engine. (by some aspects incorporating regenerative heat recovery and supercharging begins to push the engine more over towards the external combustion realm where there are no absolute thermal/performance limits.
Electronic camless variable valve timing and per stroke adjustable fuel injection would help too.
I do not think that the engine I describe would be cheap, not initially anyway, but possibly at least twice as efficient as anything available now.
Most conventional centrifugal/axial microturbines are fuel guzzlers to be sure, and the typical efficiency boosting solution of recuperators does no favors due to weight.
Rotary ramjet style supersonic turbines in theory can reach diesel levels of efficiency (due to shock compression), at least according to RamGen, and offer opportunities for motor/generator integration
http://www.ramgen.com/apps_ASCE_breakthrough.html
Here's a flipping type single rotor
http://turbomachinery.asmedigitalcollection.asme.org/article.aspx?a...
Effectively a carbureted type single rotor rotary ramjet
https://deepblue.lib.umich.edu/bitstream/handle/2027.42/76924/AIAA-...
Another single rotor ramjet, with a shared combustor zone rather than individual ramjets wrapped around a rotor
http://mecano.gme.usherbrooke.ca/~jsplante/turbomoteur_anglais.htm
http://www.camusdesign.ca/FR/Recherche/Ramjet.html
Getting these small enough, and pairing two to remove torque (because these are operating in 60K+ RPM regime) would be the main implementation problem for UAV use. Secondary implementation issues include whether to use carbureted single rotor systems, and bearings (hydrodynamic, foil, magnetic).
It's certainly possible to use a 4 stroke engine at this scale. Honda make a nice little engine, 35cc GX35. Proper crankcase oil system, doesn't need to burn oil. The problem is, it only makes 1 hp, compared to 2-2.5hp for a similar size two-stroke.
Now, it doesn't have to be this way. Modern larger engines typically demonstrate 4 stroke having better power/displacement than 2-strokes. But they are sophisticated and expensive. And 2 strokes do still tend to be lighter weight.
I believe the GX35 could be tuned up to produce quite a bit more power. I believe it's actually the focus of a lot of university teams for hypermile competitions, so you can get all sorts of things for it, fuel injection kits.
A turbine engine, while light weight and powerful, are terribly inefficient. You would end up carrying WAY more fuel to achieve the same flight time. Like 2-3 times as much. There is no question that a piston engine is more efficient here. A turbine would only be useful if you wanted massive power for a short time for really powerful performance.
At this scale though, are generators confined to two-stoke oil premix fueled piston engines? Will there ever be a viable microturbine turbogenerator with foil bearings to avoid the lube issue and use straight gasoline or diesel? Will Liquid Piston's inverse wankel rotary be a potential alternative?
Hugues, please point to a single scientific study about the danger of *any* drone system. Just one. Even a theoretical energy study. Thanks.
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