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Originally Posted by Bicycle Bob
With my body weight added, I'd have about 40 lbs/hp, so I wouldn't out-accelerate many cars, unless your motor is just rated at constant duty and the controller can heat it up.
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It's not just power to weight ratio that matters, but torque. The Leafbike hub motor that I plan to use can make car-like torque without destroying itself, in a vehicle whose laden weight is 1/10th that of a car. In order to get this thing to take on cars at lower speeds, the traction of my rear tire will be the limiting factor, and I do not yet know precisely how much traction it has. It's a Schwalbe Marathon Plus, and if I pedal with full strength at a stop in 1st gear in either the 28T or 38T rings, I can make the back tire break traction without a motor. So its traction isn't all that great if it can't even handle human power, let alone human power coupled with an electric motor.
I ran a simulation of this hypothetical vehicle fitted with a 1500W continuous Leafmotor with the 5T wind at 72Vmax, 6 kW, 83A, 120A phase current, 30/40/60T front chainring, 42-11T in the rear, and the rider pedaling with 500W going through the rear gears up to top speed. At a 0.25 Cd, 6 sq ft frontal area, 300 lbs laden weight, 0.008 Crr, 26” wheel, controller voltage/current limiting factors(assume for this calculation a battery powerful enough to run this with minimal sag and that traction won't be an issue), and the rider starting out in a 60T front and 28T rear gear, no traction limit accounted for, I get the following performance:
0-10 mph: 0.8 seconds
0-20 mph: 2.3 seconds
0-30 mph: 4.1 seconds
0-40 mph: 6.6 seconds
0-50 mph: 12.3 seconds
Top Speed: 53 mph
1/8 mile: 11.8 seconds @ 49.6 mph
That's very car-like. I don't know how close reality will bring me to the above figures, but my acceleration will certainly be adequate for merging into traffic and accelerating like a low end car.
With modifications, the Leafbike motor could be allowed to peak at 10 kW. This will require drilling holes in the casing and installing fans. I plan to start with 4 kW, because among those on endless sphere who have used this motor, unmodified, the general consensus is that you won't hurt it at 4 kW. At 10 kW, acceleration would start matching some $30,000+ modern sports cars, *if* I can get enough traction(highly doubtful).
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Have you compared estimates between fairing the wheels separately vs installing a 40" door? Some houses are much improved by double doors, too.
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Installing a door is not an option. I don't own the place I live in, and the landlord is not keen on the idea.