power2speed: For a given power, the speed that a cyclist will develop.

In Bolshom/optimumtt: A colection of functions to help cyclists.

Description

Using a given climate, bike specifications, athlete characteristics and terrain information, this function returns the speed developed by a cyclist generating a certain wattage.

Usage

power2speed(G, W, Crr, CdA, Rho, Ldt, Vw, phi, P)

Arguments

G	Gradient of slope. It's given by the heigth of a climb divided by its distance.
W	Weigth of the system, athlete, bike, clothes and all the gearing necessary.
Crr	Coefficient of rolling resistance. The resistance of the tyres to the ground.
CdA	It's the drag coefficient of the system. Usually the range is .4 (tops) to .17 (Obree 1994)
Rho	The air density in kg/m^3.
Ldt	The percentual loss of the drivetrain. Usually ranges from 1.5~5 percent.
Vw	Wind speed in m/s.
phi	The angle at which the wind affects the cyclist.
P	The power, in watts, performed by the cyclist.

Value

spd	The speed, in km/h, that the cyclist will develop.

Author(s)

Natan Freitas Leite.

References

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

Examples

## The function is currently defined as
function (G, W, Crr, CdA, Rho, Ldt, Vw, phi, P)
{
    v = seq(0, 100, 0.001)
    p = speed2power(G, W, Crr, CdA, Rho, Ldt, Vw, phi, v)
    spd = v[which.min(abs(p - P))]
    return(spd)
  }

w=65+11
cda=.3
dt=3
g=0
crr=.005
rho=1.226
vw=0
phi=0
p=200

speed=power2speed(g,w,crr,cda,rho,dt,vw,phi,p)
speed

Bolshom/optimumtt documentation built on May 24, 2019, 8:56 a.m.