Originally Posted by
ion_berkley
Serious back of the envelope calculation here with a little real world data thrown in:
Islander with 2x 300HP engines = approx 400kW peak power output
Lets assume that the whole 2 min sector is flown at full power to be nice and pessimistic...so 13.3kWh per sector.
Now the complete battery assembly for the Tesla Model3 is pretty representative of the bleeding edge of EV battery technology and it comes in at 168Wh/Kg.
The total mass of the ~75kWh battery pack in a Model3 is approx 470 Kg. Empirically I can tell you that my Model3 charges from say 20% to 80% in about 40 minutes from a DC fast charger.
That passes the smell test for me, it seems very practical for this particularly odd air route.
The math is a little bit out on this one, it's actually better than you calc
300hp = 223 kw, not 400. Also the Loganair BN2s are carb so only 265hp, meaning 197kw.
Assume one of the longer legs, say 15 minutes. You would fly 1 min @ full power, 13 mins @ 75% and 1 min @ 50%. This equates to 14.8kwhr. You could satisfy this + 30 mins reserve with a 50kwhr battery pack, using tesla math is ~300kg.
Very achievable!
Hot swap battery packs on turnaround and charge them while they're not on the aircraft. Keep those sub 5 minute turnarounds going