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Is electric propulsion worth it?

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DangerZone

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https://www.youtube.com/watch?v=Mhm5IVB6gb4

=2:30=controll boxes for 12 small flappers for 2kg flying soucer...
=5:55=big flapper thrusters for man flying trike \10:15\ with SOLO 210 engine...
If the goal is to keep a 2kg flying saucer in air then this would mean around 20N of static thrust, not 2000N (2kN). That is a complete different story, don't you think 1kW for 20N of static thrust would be bellow an efficient propeller thrust for a comparable size project?
 

henryk

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If the goal is to keep a 2kg flying saucer in air then this would mean around 20N of static thrust,

not 2000N (2kN).

That is a complete different story, don't you think 1kW for 20N of static thrust would be bellow an efficient propeller thrust for a comparable size project?
=2kN/1kW=2N/1W =20N/10W \thrust force/drive power\-I dont know proper term...
 

DangerZone

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=2kN/1kW=2N/1W =20N/10W \thrust force/drive power\-I dont know proper term...
It seems somebody made a slight calculation error and multiplied by 10 (9.81 of gravity force) rather than devide, hence the result of 2000N per kilowatt instead of 20N. If the styrofoam aircraft model weighs 2kg, then the force of 20N is just about right to keep this 'flying saucer' thing in air to oppose the slightly less than 20N of gravity pull. And 20N of thrust per kilowatt is feasible yet not very efficient for electric propulsion systems since well designed props on electric motors reach 60N per kilowatt of static thrust. The Geiger HPD-10 motors were producing up to 80N per kilowatt some 5 years ago so anything less than that is a step back instead of progress.

There is a way to simplify things, gravity is the difference between the pulling and repelling electromagnetic force and veries slightly on the surface of Earth between 9.79N and 9.82N, an average is 9.80665 or 9.81N short per kilogram of mass. So, to lift a flying object of 1kg you need more than 9.81N of force in the opposite direction, round it up to 10N. Thus, 20N is enough to lift this object and make it float in air, simplified it means you are using 1000W (1kW) to oppose the pulling force of 2000g (2kg), which means 2g/1W. Efficient internal combustion engines reach 2.5g/W, electric motors with well designed props from 2.5g/W to 10g/W, ionic thrust is from 10g/W to 30g/W and above that are only ionic turbines and similar propulsion units, as a rough estimation. So when analyzing claims as 2N/W you could convert that to 200g/W and you will immediately see there is a problem because transferring electromagnetic enrgy to mechanical work creates losses way beyond this claim.

I can't understand what they were talking about in Russian but physics apply everywhere so it is more probable the author or the news reporter made a conversion error than this system being able to create 2000N out of 1W or 1kW of power. The thin plastic foil could not stand the force of 2000N too, so common sense leads us to conculde there is no real breakthrough in this idea. Specially since it has been investigated in the 50s and 60s with clear conclusions that props are much more efficient.
 

henryk

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It seems somebody made a slight calculation error and multiplied by 10 (9.81 of gravity force) rather than devide, hence the result of 2000N per kilowatt instead of 20N.

I can't understand what they were talking about in Russian .
=for NOT misunderstanding=200 kG thrust force from 1 kW driver power
or\the same\ =200 G/1 W...

\for comparation 60 kG propeller thrust from 10 kW dr Werners HPD-10 motor\...


for moore you can read dr Sorokodums site=

vortexosc.com

https://www.youtube.com/watch?v=gjQi2j4PyRA

=dr Sorokodum was involved into Korolov rocket fuel smoothnees\tornado\ and submarine "flapping tail" thrusters...
 

Speedboat100

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Nice summation. I'd add the "it will never be worth it for any decent (100 mile) range.

But most importantly, they work. Reliability in service for the few electric planes is a few orders of magnitude better as their reciprocating brothers and sisters. Especially for some missions (powered sailplanes) that's a huge win.
How do you possibly back up this claim ?

I figure we ought to make'em like they used to when combustion engines were heavy and inefficient.....Anthony Fokker made even a triplane.

Biplane would be awesome when made today....in order to get more range by lowering the wingloading drastically.
 

rv7charlie

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This is a 6 year old thread, but it's always amusing to read all the 'never' statements related to tech.

I've seen reports that some of the European car makers intend to be totally electric within a very short time frame, and just within the last couple of days I read an publisher's piece in an automotive industry (not consumer) magazine titled 'Canary in the Coal Mine', that said that there are no new internal combustion engines being developed at the major car makers. *That* is something to chew on.

Charlie
 

YMO

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This is a 6 year old thread, but it's always amusing to read all the 'never' statements related to tech.

I've seen reports that some of the European car makers intend to be totally electric within a very short time frame, and just within the last couple of days I read an publisher's piece in an automotive industry (not consumer) magazine titled 'Canary in the Coal Mine', that said that there are no new internal combustion engines being developed at the major car makers. *That* is something to chew on.

Charlie
Thank you for sharing.
I think we should see small aircraft powered by electric motors or hybrid electric by 2025.
This assumption is backed by:
EASA has certified a Pipistrel two seater with electric propulsion very recently
MagniX, Ampaire, VoltAero havé tested existing aircraft equipped by electric propulsion
300+ eVTOL projects are in development worldwide. Not all will survive but around 10 are well financed and are at the stage of flight test
climate change push for reducing CO2 footprint. This is a strong incentive for electric/hybrid propulsion even if in the present stage of our economies
I am happy to discuss further.
i wish you a good Sunday
 

Lendo

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If I could understand how they can turn Radioactive Material into electricity, without generating steam driving a Generator, it might be a winner. I know they can generate electricity from heat fluctuations, but to what level of power I don't know.
I live in hope.
George
 

Dan Thomas

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Biplane would be awesome when made today....in order to get more range by lowering the wingloading drastically.
I sure hope you're being sarcastic. Biplanes had horrific induced and parasitic drag. Struts and wires, four wing vortices instead of two, and interplane interference. I wonder why we don't see biplane airliners?
 

Speedboat100

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I sure hope you're being sarcastic. Biplanes had horrific induced and parasitic drag. Struts and wires, four wing vortices instead of two, and interplane interference. I wonder why we don't see biplane airliners?

Biplanes don't have to have struts at all.
 

TFF

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That style of RC biplane is actually happy to have the extra drag of the extra wing. Pattern flying judges judge on constant speed of the aircraft. They don’t want to perceive the plane speeding up or slowing down. Those planes have double the power to weight so up lines there is plenty of power to accelerate upward. Downwards the drag keeps the plane from accelerating due to gravity. Fuselage is fat because of that too. Very fun to fly. Very stable; not fast. Very agile.
 
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