PARAGLIDER DESIGN HANDBOOK
CHAPTER 4. LONGITUDINAL EQUILIBRIUM

4.7 ADJUSTING THE SPEED OF THE PROTOTYPE

Establishing a simplified vertical balance between the lift force and the total weight in flight, it follows that: The speed of a prototype is directly proportional to the square root of wing loading.

This result is very interesting because it allows us to extrapolate the speed of the prototype for different weights in flight or other surfaces.

In particular, if we determine theoretically, the horizontal flight speed should be our prototype, measuring the actual speed in flight, we will know if the trim of the wing is ahead or behind on schedule.

 Example: Prototype speed calculus Green Input data (to be modified by the user) Blue Automatic calculation results mp 75,0 kg pilot mass mv 4,0 kg wing mass me 5,0 kg harness and instruments mass m 84,0 kg total mass g 9,81 m/s2 acceleration of gravity Cz 0,65 lift coefficient S 25,00 wing surface k 1,15 empirical adjustement factor v 10,53 m/s prototype speed v 37,90 km/h GR 8,0 glide ratio Vh 37,61 km/h Vz 1,31 m/s