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Cessna working on electric-powered plane

Posted By:
Emily Willemse
65
Posts
17
Rod Witham
Homebuilder or Craftsman
62
Posts
17
#2 Posted: 8/6/2010 01:19:28

And for a 172, nonetheless!

I would've thought that their new LSA would've been the airframe of choice...

 



Peter Bednar
24
Posts
1
#3 Posted: 8/13/2010 15:40:22

Woof,   that is a big / heavy airframe application for electric flight.  I wonder if they're going to clutch a few smaller electric motors together or try a single big 120-150hp affair.  That conversely is going to require quite a few amps to stay up, which would put a stout drain on the batteries, which they do not like.

From what I've seen and studied, the battery power density right now is okay for applications such as intermittant power for sailplanes or low constant use for motor-gliders such as the Yuneec e430, and possibly anything from the Golden Age that flew with a motorcycle engine, like a Heath Parasol, provided you work at taming the drag. 

 

I wish them luck though, it is always good to experiment.

 

 



Emily Willemse
65
Posts
17
#4 Posted: 8/13/2010 17:02:29

I don't think power is a problem.  There are a few supercars and sports cars that are electric.



Peter Bednar
24
Posts
1
#5 Posted: 8/16/2010 18:22:26

Yes, but those super-cars are fine with comparatively high curb weights and short ranges.  There's no problem with output. With electric motors you can have full torque, even excess torque instantly, and just sink the resistive heating into your motor mass for as long as you feel comfortable.  Actually given how rare earth magnets in brushless motors don't like heat, this is not advisable.  This is why you see electric cars like Tesla Roadsters being able to flounce their Petrol powered Brethren on the drag strip.   You won't however see a Tesla Roadster's batteries being able to hold up at that level of acceleration for more than a few minutes.

The generally best available batteries, Lithium Ion or Lithium Polymer  have a energy density of only 1.30 MJ/L at best, not including packaging or cooling where in comparison regular mogas delivers 34.2 MJ/L.    Of course we can't burn gasoline that efficiently in a piston engine to get all of this energy, but we can say that the balance as far as capability is still strongly in favor of petrol when you're trying to put miles underneath your wings in a complete package. 

 

I build and fly electric RC airplanes as a daily hobby, and get to fuss with some really neat equipment with efficiencies now good enough for man-rated flight.  I'd really like to build an electric Heath Parasol or something similar.  But I'm pretty familiar with the limitations of the technology, sustained output - being one of them.  




Emily Willemse
65
Posts
17
#6 Posted: 8/16/2010 18:59:45 Modified: 8/16/2010 19:28:34

I just said that power is not a problem, not that the electric motor was superior to the gasoline engine.

I'm aware of the drawbacks to the electric vehicle concept.

sheesh.

 

 



Kevin Slezewski
Homebuilder or Craftsman
40
Posts
6
#7 Posted: 8/18/2010 12:31:21

 

"And for a 172, nonetheless!

I would've thought that their new LSA would've been the airframe of choice..."

 

 

My theory is...If you are doing something that someone else is already doing, you're behind the competition.  I say go for bigger aircraft and push the envelope!

 



Kevin Slezewski aka "SLEZ" www.crispycedars.com
David Deweese
Young Eagles Pilot or VolunteerHomebuilder or Craftsman
61
Posts
21
#8 Posted: 8/18/2010 21:32:12

The implications of the powerplant are as interesting as that of the intended airframe. Up to now we've seen the first sport pilot sized planes such as those of Sonex and Yuneec. After Cessna's electric 172 flies it won't be long until the first electric RV takes to the skies.



John Eiswirth
112
Posts
19
#9 Posted: 8/18/2010 22:18:20

They don't build the LSA.  The 172 is an aircraft they already build, the process is already certified.  They are only changing the power plant on a certificated airplane.  I think it's brilliant.