electric plane

November 27th, 2017 at 12:00:13 AM permalink
Pacomartin
Member since: Oct 24, 2012
Threads: 765
Posts: 9037
A Nissan Leaf comes with a 30 kWh battery and a 24 kWh battery
The weight of the Nissan Leaf pack checks in at 648-lb, for the 24 kWh battery.

A small Cessna 150-152 burns about 6 gallons per hour or 18.3 kg per hour.

The total energy received from the burned fuel within one hour, per hour is 11.9 kWh/kg.
11.9 *18.3 = 218 kWh

I saw an estimate of the total energy that is used for useful work during the flight as 20%. That would imply that I need a 43 kWh battery to fly my Cessna.

I think there is two things wrong with this calculation
1) The weight of the battery pack is considerably higher than the weight of fuel which means I need a bigger batty
2) I am unsure of how to do a better job of calculating "useful work"
November 27th, 2017 at 1:37:25 AM permalink
Fleastiff
Member since: Oct 27, 2012
Threads: 50
Posts: 5278
Most work is done during takeoff and climb out.
Power must be available for any TOGA upon intended landing.

An electric generator would be better than relying solely on a battery.
November 27th, 2017 at 6:09:55 AM permalink
Nareed
Member since: Oct 24, 2012
Threads: 332
Posts: 11982
Quote: Pacomartin
2) I am unsure of how to do a better job of calculating "useful work"


Flying is too energy intensive to allow for electric power given today's energy density per kilo of battery. Additionally, batteries don't get lighter as they're used up. The max takeoff weight would also be the cruising weight and landing weight.
If Trump where half as smart as he thinks he is, he'd be twice as smart as he really is.