20kWatt outrunner motor

Goedendag,
A 20kW outrunner motor from Rolf Strecker (
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)
Vriendelijke groeten ;-) Ron van Sommeren
near Nijmegen, the Netherlands
E-fly-in, Aug.26.2007
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Reply to
Ron van Sommeren
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Goedendag,
A 20kW outrunner motor from Rolf Strecker (
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)
Vriendelijke groeten ;-) Ron van Sommeren near Nijmegen, the Netherlands E-fly-in, Aug.26.2007
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Reply to
Ron van Sommeren
Hi Ron,
That is obscene.
I will have nightmares for weeks !
"Ron van Sommeren" wrote in message news:4512c426$0$2030$ snipped-for-privacy@text.nova.planet.nl...
Reply to
fred
W-O-W ! ! ! That one could get my Dodge Ram in the air.....
I bet the LiPos necessary to turn it would cost more than a Dodge Ram, too. :-)
Thanks for sharing that most interesting photo.
Good flying, desmobob
Reply to
Robert Scott
what a difference a K makes I never even opened the original post as I dismissed it as a 20watt motor I missed the K oh my god what size could you make a shockie with that
Reply to
funfly3
I saw it and thought I had seen something like it before. Look at the size of the LiPo's strapped to the back of this thing.
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Cheers
Reply to
Richard
| >> A 20kW outrunner motor from Rolf Strecker (
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) ... | W-O-W ! ! ! That one could get my Dodge Ram in the air.....
Well, 20 kW is only 27 hp, so I doubt it.
It could probably power your VW Bug, though it wouldn't be as powerful as the stock engine, as the stock engine is 40 or 50 hp, and the 27 hp figure is probably power in rather than power out, so the performace will be even lower.
| I bet the LiPos necessary to turn it would cost more than a Dodge Ram, too.
Well, a $50 LiPo pack can put out 200 watts at 10C, so multiply that by 100 ... not quite _new_ Dodge ram prices, but more than a used one!
Reply to
Doug McLaren
| >4 minutes of flying, 4 weeks of charging. | | Maybe, but that would almost power a motorised glider.. full size. | That's a 27 HP engine, no less!
No, it's less.
First, 20 kW = 26.8 hp, which _is_ less than 27 hp.
Also, electric motors are generally rated by their input power, not their power output, while IC engines generally rated by output power.
Assuming this motor is 90% efficient (which is probably pretty close to the mark), that works out to about 24 hp.
But yes, you're right about what it could be used for -- I'll bet it would power an ultralight nicely, for example.
LiPo batteries tend to be expensive when you get that many of them, but NiMH cells might work nicely, as would lead-acid if it were used in something that wasn't meant to fly so that weight wasn't quite such an issue.
Reply to
Doug McLaren
Reading about electric (full-size) cars and equivalent power output, I hear that electric motors do significantly better HP for HP than IC engines.
The reasoning is that car manufacturers show a bit of economy with the truth, quoting peak HP at optimum RPM, torque etc. Electric motors will give the rated output continuously across a wider range of torque and rpm. And of course, they can deliver *considerably* more for shorter periods.
So to get the equivalent performance from a 300HP car, you need quite a lot less than 300HP output (or input) from an electric motor. Particularly with direct drive to wheels.
Full-size high performance gliders are now available with electric motors in a retractable pod (I have the link somewhere). They are powered by NiMh cells. So I'm surprised there isn't more activity in the paragliding community.
Have fun! -- Adrian
Reply to
anonymous
For what it's worth (and I am not sure what relevance this has to the topic under discussion) I was always under the impression that an electric motor produces its maximum torque at zero revs. This is interesting, if useless, information for a flight forum I guess. But the engine of an electric train, for example when pulling out if a station, produces its max torque before the train even begins to move.
OK I'll shut up now :-)
Travec.
Reply to
Travec the Dacian
Hey Travec, forget the 52 four stroke for your pup. Stick one of these on !
I'll have a pickle & garlic mayo please on my kebab please.
Reply to
fred
You know what, Its not true. It depends totally on the type of electric motor. If you take a DC motor with fixed magnets stator, then your right.
But If you take any other sort of AC (3 phase) motors, you can almost do anything, including max torque at high revs.
And for the train pulling out, you have no idea of all the switching they do to keep the motor performing well at all speeds. You could compare it to a electric (electronic) gearbox.
;-)
Peter.
Reply to
Peter J. de Vrijer
Of course I was referring *only* to a DC motor with fixed magnets stator ;-) Actually I never knew any of that, but it's interesting just the same.
T
Reply to
Travec the Dacian
It's useful information Travec, certainly for electric helicopter pilots. It explains to them why there's no need for a clutch and it also explains why it's difficult to hold the main rotor in case of RC equipment problems (contrary to IC helicopters).
Vriendelijke groeten ;-) Ron van Sommeren near Nijmegen, the Netherlands 2007 E-fly-in, Aug.26.
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Ron van Sommeren

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