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Re: another electric airplane first flight
by Neon John
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On Sat, 17 May 2008 08:04:21 -0500, gary <gkrysztopik@...> wrote:
>The inventor also notes density altitude will never affect motor
>performance... nor will high prices at the gas pumps.
Ya gotta love that.
http://www.electraflyer.com/prices.html
$16,885.00 for the turnkey plane. That's about twice the price of a gas
powered one. Add $3000 more for the long run time battery pack. I can buy a
LOT of gas for almost $6500.
Let's do some figuring.
Run time. 16 hp motor is (assuming 100% efficiency) 746*16 = 12kw. The
largest battery pack ($7500) is 5.6kwh. I see a little less than half an hour
run time at 100% efficiency. He says the motor is 90% efficient and the
Alltrax Axe controller I see in the photo is similarly efficient so the
overall efficiency is 81%. Using that value, the run time reduces to 0.37
hours or about 20 minutes. (Yeah, I see his 1 to 1.5 hour flight duration
claims but like most EV range claims, I take that with a large grain of salt.)
Strangely enough, he doesn't list a recharge time or the amperage capacity of
the $895 charger, though for the price we can assume that it's a fairly high
capacity unit. He does say that it can charge from an ordinary 120 volt
outlet so we can do some figuring.
Assume it's large enough to fully load a 15 amp branch. 15 amps at 120 volts
is 1.8kW. Accounting for a bit of loss from efficiency, let's say 1.6kw. The
biggest pack listed is 5.6kw. 5.6/1.6 = 3.5 hours assuming 100% charge
efficiency. At 90% charge efficiency, that stretches out to 3.9 hours. Call
it 4.
To summarize, for the price of a fairly nice car, I can fly around 20 minutes
out of approximately every 5 hours, assuming I have some source of electricity
handy. At a flying field, that's probably a "smelly ole generator spewing
fumes everywhere" (did I get that verbiage correct?) Or I suppose that I
could drop the down payment on a nice house on a second battery pack and get
almost 40 minutes of flying time between charges.
Given that I can fly longer than I have the physical endurance for on 5
gallons of gasoline, why is my enthusiator not perking up? Looks line just
another media stunt/rich man's toy to me.
John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
Give Blood. 8 Billion Mosquitoes can't be wrong.
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
>The inventor also notes density altitude will never affect motor
>performance... nor will high prices at the gas pumps.
Ya gotta love that.
http://www.electraflyer.com/prices.html
$16,885.00 for the turnkey plane. That's about twice the price of a gas
powered one. Add $3000 more for the long run time battery pack. I can buy a
LOT of gas for almost $6500.
Let's do some figuring.
Run time. 16 hp motor is (assuming 100% efficiency) 746*16 = 12kw. The
largest battery pack ($7500) is 5.6kwh. I see a little less than half an hour
run time at 100% efficiency. He says the motor is 90% efficient and the
Alltrax Axe controller I see in the photo is similarly efficient so the
overall efficiency is 81%. Using that value, the run time reduces to 0.37
hours or about 20 minutes. (Yeah, I see his 1 to 1.5 hour flight duration
claims but like most EV range claims, I take that with a large grain of salt.)
Strangely enough, he doesn't list a recharge time or the amperage capacity of
the $895 charger, though for the price we can assume that it's a fairly high
capacity unit. He does say that it can charge from an ordinary 120 volt
outlet so we can do some figuring.
Assume it's large enough to fully load a 15 amp branch. 15 amps at 120 volts
is 1.8kW. Accounting for a bit of loss from efficiency, let's say 1.6kw. The
biggest pack listed is 5.6kw. 5.6/1.6 = 3.5 hours assuming 100% charge
efficiency. At 90% charge efficiency, that stretches out to 3.9 hours. Call
it 4.
To summarize, for the price of a fairly nice car, I can fly around 20 minutes
out of approximately every 5 hours, assuming I have some source of electricity
handy. At a flying field, that's probably a "smelly ole generator spewing
fumes everywhere" (did I get that verbiage correct?) Or I suppose that I
could drop the down payment on a nice house on a second battery pack and get
almost 40 minutes of flying time between charges.
Given that I can fly longer than I have the physical endurance for on 5
gallons of gasoline, why is my enthusiator not perking up? Looks line just
another media stunt/rich man's toy to me.
John
--
John De Armond
See my website for my current email address
http://www.neon-john.com
http://www.johndearmond.com <-- best little blog on the net!
Tellico Plains, Occupied TN
Give Blood. 8 Billion Mosquitoes can't be wrong.
_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
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