The way i understood the video is that you gonna have two batteries 5.2 kWh each.
EDIT: It does seem possible. One battery pack should weigh around 25kg each, on a cell level they should cost around 600$, so well within the $10k drivetrain budget. The smaller single seater have a useful load of around 200kg if you subtract the Rotax engine. probably even a bit more by removing all the supporting system for the engine. EV propulsion system should be well under 100kg, maybe 70-80kg. leaves enough weight for the pilot. All together not in the realms of the impossible.
I did not interpret the video that way. However, let's assume you're right, but I'm also going to drop the absurdly optimistic scenario I used above. So we'll use the correct cruise 65% of max power that Fisher recommends for it's gasoline engines, and let's use 800 ft/min climb rate, the maximum of any of their lower powered aircraft. And let's increase it to a slightly more sane, but still very risky, reserve for two 1000' climb, 2 minute cruise patterns.
25kW for 3 minutes climb (to 2400' AGL) would use 1.25kW, leaving 9.15kWh for cruise. Climb to 1000' will take 1.25 minutes at full power, using 0.52 kWh, 2 minutes at 65% power uses .54kWh, for a power usage of 1.06kWh per go around. A 2 go around reserve will leave 7.03kWh. 65% of max power is 16.25kW , leaving enough for 26 minutes of cruise, total flight time of 35.5 minutes, including using all of the reserve. This scenario is still optimistic, I'm not flying a plane until it has only enough fuel for exactly 2 go arounds, and I don't know many pilots that would volunteer to do so. A 45 minute total flight, using the climb and all of the reserve, would require a cruise power setting of 46%. Keeping the reserve capacity in , well, reserve, then the power setting would need to be 38% for cruise.
Which Fisher plane did you do these calculations on? What did you use for engine weight? I didn't do a extensive search, but the lower powered ones didn't have a useful load of 100kg, and their complete engine weight (w/ exhast, gearbox, etc) was in the 35kg range. The highest gross weight of all the FP-x0x planes was 540 lbs (245kg), a 200 kg available for drivetrain and pilot would only leave 45kg for the entire rest of the aircraft. The Avenger and Dakota would leave just 72 kg for the airframe. Their planes that can have 200kg available require between 50-65 hp, requiring much more battery and motor.
I like electric planes, and want them to succeed, but the ones that use bad math and questionable physics need to stop and promote reality. Plausible sounding BS isn't acceptable. I don't fault Fisher airplanes, I'm glad they're offering this package, but they need to be realistic about what they're selling. I do blame the guy who sold them this based on fantasy numbers.
EDIT: recalculated to use correct 25kW max power instead of 26kW used originally.
