[keenerd]

Mass estimate: A 40hp motor is around 200kg.

40 hp is 30kW. Assume 100% efficient gearing and motor. Stall speed is around 80 km/hr. For 20km of powered flight, that means 0.25 hours runtime. For high performance li-ion (250 Wh/kg) that is 30kg of batteries.

Add some weight for <100% efficiency, remove some weight for the part of the 20km where you glide.

Speculation: Given the difference in motor vs batteries, either they have an extremely light weight motor technology or they are using lower density li-ion for safety. A LiFePO4 pack (130 Wh/kg) would be 60kg. They could afford to double the battery size, since that is only a 25% increase in weight. Either they have a very lightweight motor technology, or there is some magic price or weight number they are trying to squeak under.

[mrfusion]

200KG for the motor sounds very high?

[bri3d]

That's definitely extremely high - brushless motors with much higher power (~80hp) are in the 50kg range (see for example EV218).

[keenerd]

Interesting! UQM has the "PowerPhase® Select 50" which is a 30kW motor. I would say this counts as the "very lightweight motor technology" I speculated they were using because you can't get any datasheets or information or even a price for the UQM products.

40hp 200kg brushless motors are extremely common by comparison. Dozens of places will sell you one for a few grand.

[keenerd]

Find us a lighter one for sale.

[dpark]

http://hpevs.com/catalog-ac-3X%20oil%20cooled.html

If I'm reading correctly, the AC-35 has a peak rating of 47.78 horsepower, and weighs 43.9kg.

Presumably the 200kg motors you're looking at are not intended to be part of a moving vehicle. Those are likely intended for use in factories or shops where the weight is of little concern but durability is at a premium.