Re-Numbers

Re = v * l * 70.000
Geschwindigkeit v[m/s]
Profiltiefe l[m]
Example: v=10 m/s, l=20cm = 0.2m
==> Re = 140000

Ncrit Parameters

   situation             Ncrit
  -----------------        -----
  sailplane                12-14
  motorglider              11-13
  clean wind tunnel        10-12
  average wind tunnel        9     <=  standard "e^9 method"
  dirty wind tunnel         4-8

Calculate Power for steady flight

Very, simple calculation for an estimate result.

minimal_Sink_rate [m/s] * g [m/s^2] * mass [kg] = ideal_power [W]

required_electric_power [W] = ideal_power [W] / drive_efficency (~0.9) / prop_eff (~0.6) 

Example:

sink rate: 0.5m/s
mass: 0.5kg
g: 9.81 m/s

ideal_power = 2.4525 W
required_power = 4.54 W