# Cycling Power and Speed Calculator

(Redirected from Bike Calculator)

Solar vehicle version, 8'x16' body - so 1000W of solar panels.

This would go at 25 mph with a 300 lb vehicle weight, 165 lb rider weight, with 5 square foot frontal area with 500W of power according to this calculator -

https://www.gribble.org/cycling/power_v_speed.html

- 1 kW generator would get you 160 mpg with 300 lb vehicle, 8 sf frontal area, wind drag of 0.2, 165 lb driver, 0.01 rolling friction. Use 1000 for power in the
*Solve for specific power or speed*section to get 40 mph. Since a Honda 1 kW EU1000 drinks 1 quart per hour, that is 160 mpg equivalent. - If we have 1kW of solar on top of that, we get about 240 MPG equivalent.
- Ideal is 850W solar, 150W human, for about 1000 mpg equivalent by considering only 150W of human energy and converting to gasoline equivalent (since 850W is from the sun, we get 160 mpg at 1/6 the energy input - so 6*160 = 1000 MPG). This is for marketing purposes.
- On solar only - we get effective unlimited MPG if this is feasible. This looks very good on paper.
- Worst case scenario from calculator is 0.02 rolling resistance, 16 sf frontal area, and drag coefficient of 0.6 - which still gets you to 22 MPH with no engineering required. Just by using mountain bike tires, open cab and no aerodynamics - 1kW of solar + pedal power gets us 22mph. With a 1 kWhr battery pack, we still get 30 mph. Thus, solar NEVs (solar neighborhood electric vehicles) are completely feasible. With an on-board 1 kw generator - we get 35 mph at a total of 3kW of power. When designed for aerodynamics and drag, we get 65 mph in this case.

# Example

## High Speed

- Drag coefficient of 0.1 from an airfoil type body
- Vehicle 300 lb, rider 165 lb
- 150W of leg power
- Frontal area of 8 square feet
- Crr = 0.1 for mountain bike tires
- 1000W (10 panels, 8'x16' = same length as a typical car) gives 50 mph -realistic but best case scenario of solar car at high noon
- Adding more length at back gets more power, no more drag
- Thus, a practical car can be made, esp if it has batteries or small generator (1kW) for extra power.

## Low Speed

- Same parameters as above, 500W of power - gets you 35 mph

# Notes

- Biggest gain is obtained from reducing coefficient of drag due to wind. Air foil (wing) has the lowest drag - less than 0.1
- Best cars are at cd=0.22 - [1], and VW XL1 cd=0.19 [2]. Impractical cars can do better.
- Aptera - lowest cd=0.15 in history for a production car[3], which is 850 mpg equivalent.
- Stingray/Stealth bomber/airfoil mix type bodies can be around 0.1

# Execution

- Why did Aptera fail? Study this. They could not fund a 3-wheeler - customer and investor acceptance appears to be too low - only in the 10's of thousands range per year. compared to Tesla 300k [4] or GM's millions [5] .
- Are 3-wheeled cars safe? Not as safe, but what are the real figures? [6]. According to Wired [7] - it's just not popular. It appears that any advantage associated with cost or mileage is outweighed by safety. But their practicality is greater than motorcycles - more safety - so if we accept the feasibility of the motorcycle market, then we must accept the feasibility of 3-wheelers. But not on as large a scale. A the same time, the global motorcycle market is 90 billion [8], and 300 billion for cars [9] - so motorcycles are ~1/4 the market.
- More strict 3-wheeler regulations were proposed in 2015 - [10]