Interesting generator

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Vigilant1

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Thanks, it will be interesting to see if they have/can overcome the lubrication challenges and emissions issues these designs often encounter.
 

John.Roo

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Thanks - interesting link 👍

16 kW / 110 kg....
Meny people will say:
"That is far too much, is possible to make it lighter."
Yes, in theory on paper is all possible.

However I prefer realistic numbers...
16 kW of continuous power in 110 kg box (version for aviation) seems to me acceptable (if really works).
aquarius.jpg
15-17 kg motor
3-5 kg controller
50 kg battery (10 kWh)
110 kg Aquarius generator
-----------------------------
= +-190-200 kg installation weight of propulsion system (incl. wiring etc.)

Plus...
200 kg for airframe.
180-200 kg for pilots... and we are on the border of LSA MTOM 600 kg.
That means no large reserve for fuel but for prototype could be acceptable :)

I still would have few questions....
1) of course - price
2) dimensions
3) other characteristics when is engine/generator running (vibrations, noise, temperature etc.)

Lets see if they will show photos/videos from real installation.
So far is the web obviously designed more for investors :)
 

rv7charlie

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16kw (21 HP, before conversion losses through wire/electric motor) from well north of 200 lbs, using unproven tech?

The same 15-17kg motor mentioned earlier could easily be used for the generator segment, and the driving engine could be (the 1st thing that comes into my head) the little Yamaha Phazer snowmobile engine at ~55kg running, but capable of around 60 kw (80 HP) output, so it'd be not much above idle to run the generator at 16kw. And you'd at least know that the engine will 'just work'.

And we haven't yet talked about the piston/shaft moving end-to-end with no balance mechanism....
 

berridos

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It runs on hydrogen. The hydrogen paste from the frauenhofer institute would avoid pressure tanks i think they opted for the paste
 

dog

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Its interesting all right,like how the "piston rod"
is also one of the valves and manifold all in one.
So it might be hard to scale up and down and
have the flows work out.
Kind of like a compression ignition driver for putting pipe piers in the ground.
 

GeeZee

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Just a modern take on the “Screamin Demon”. The Demon used the free piston as a ”gas generator“ the “Work“ was thrust from the exhaust. It was reported to be horrifically loud so I’m betting this will be too, so add a fair amount of weight for a muffler…
 

Bill-Higdon

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Just a modern take on the “Screamin Demon”. The Demon used the free piston as a ”gas generator“ the “Work“ was thrust from the exhaust. It was reported to be horrifically loud so I’m betting this will be too, so add a fair amount of weight for a muffler…
Also the "Free Piston" engine
 

vhhjr

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I am curious why such a large battery. Fuel for the engine is always lighter than an equivalent energy battery. Maybe a smaller battery to assist with take-offs and climb outs.

I built a free piston engine a while back. It really was a screamer and I can see why the muffler would have to be significant to make the drone acoustically stealthy.

Vince Homer
 

dog

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I am curious why such a large battery. Fuel for the engine is always lighter than an equivalent energy battery. Maybe a smaller battery to assist with take-offs and climb outs.

I built a free piston engine a while back. It really was a screamer and I can see why the muffler would have to be significant to make the drone acoustically stealthy.

Vince Homer
The gap between the energy density of fuel and batteries is closing,and the rate of closure is accelerating.Fuel is useualy lighter,exceptions are the high altitude electric solar planes with endurance that is truely amazing,the mars flyer,rovers,there are going to be more.
And whadaumean you built a free piston motor?What other motors do you build?
You gota know better than to just toss out something like that to a bunch of gearheads.
 

vhhjr

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I was leading a small team trying to develop a compact power supply for the Army on a DARPA contract and we thought a FPE powered linear generator was a good candidate. Starting from scratch a small test engine was designed using model airplane pistons and cylinder sleeves. As I remember a .60 cylinder was used as a power piston and a .90 size used as a bounce piston. Poppit valves were used for compressed air intake and for propane fuel. A 2 cycle style side exhaust port was used. A model airplane glow plug was used as the ignition source. It was started by pulsing the compressed air to the intake valve. We had a difficult time getting it to run. Several times we blew out the center of the glow plug. Our computer simulation showed the combustion pressure to be as high as 5000 psi. Occasionally it did run for a short time stopped by a glow plug failure or inadequate cooling. It was extremely loud. I can't imagine what a larger one would have sounded like. The project ended before we could refine the engine and add the linear generator to it.

FPEs are very tricky to get right as they depend on self cycling. The bounce cylinder has to be the right size and starting pressure to get adequate compression in the power cylinder and cycling to adequately open the exhaust port. Other problems include getting the combustion mixture correct and cooling is necessary as lots of heat is generated.

That's about it for my engine building , but I have built some interesting water turbines using turbocharger rotors.

Vince Homer
 
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