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.

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 |