Architect, DPROX,

I did some fact-checking last night after my post. Here's some information which I got.

1) www.goldenmotor.com makes electric bike hub motors, $95 each in small quantities. These are rated at 22 N-m maximum torque, 216 rpm, 700W power dissipation, 70% mechanical efficiency and weigh only 6 kg. So at maximum power, each hub motor puts out 0.66 hp at the wheels.

2) If you get four of these and put them on the 4 wheels, you can get an aggregate maximum torque of 88 N-m and power output of 2.63 hp. This sounds horrifically low but 88 N-m is nothing to sneeze at; niky's Lynx RS puts out 180 N-m (a bit over twice) but at 4000 rpm! with this scheme you get 88 N-m all the time. The stall torque I am sure is much, much higher although goldenmotor gives no figures.

3) From my old notes, I found that to propel a 2500-lb car at 45 mph (72 km/h) requires 7.2 kW of motive power. We only have 2.8 kW available from our four hub motors, so we either reduce the total weight (including cargo and passengers) to 970 lb (440 kg) or settle for a lower top speed.

More tellingly, the hub motor only runs at 216 rpm. If we put 22" motorcycle tires on it, we can only get a top speed of 22 km/h which is pretty pathetic. So hub motors won't cut it for a PhUV, but for a small 4-passenger town car, it might work.

22 km/h is still pathetic.

Here's another approach I thought of. You can get this motor:

www.enigmaindustries.com PMG 080 motor - $465, weight 7.5 lb

specs at 24V
Peak Power 3.95hp
Stall Current 505 A
Stall torque 2320 ozf-in (12.08 ft-lb)

This thing turns at 3600 rpm. If we put it on a conventional rear rigid-axle differential with a 4.8:1 final drive ratio, our stall torque becomes 58 ft-lb or 79 N-m. Again, nothing amazing but since you get that torque at zero RPM, it is drive-able.

Turning at 3600 rpm with a 4.8:1 final drive ratio means the road wheels turn at 750 rpm. Driving 13" tires gives a top speed of 47 km/h which is much more reasonable. Gross vehicle weight would be about 500 kg.

You would need a gasoline engine and generator of about 5kW rating to drive the above motor. You would also need a golf cart battery to handle the peak current surges. The Motolite GC8-165 weighs 65 lb. One would probably suffice. Unfortunately a Honda 2.5 kW generator already costs 35K pesos (retail). This can get a lot cheaper by going Chinese. Use a Honda GX180 engine (10K pesos) but a Chinese generator, so at least your engine is ultra-reliable.

But you see my point: if you're worried about the engine and drivetrain already costing >100K because you need a new engine, there are other ways to approach the problem. And a hybrid would be far more environmentally friendly.