voici les propos de PMU (Pump Me Up) sur kiteforum.com
Inflatables are vastly superior to ram airs. I've summarised the reasons for the superiority of inflatables:
LIFT TO DRAG RATIO (L/D)
Rams have HUGE drag ("D") compared to inflatables for 3 reasons:
a) Increased friction at the "boundary layer"; ie interface between air & kite, because of minute ripples in ram air kites.
b) Bridle drag.
c) Thickness. Ram lovers describe the diameter of inflatable leading edges as a liability. However, the thickness of ram airs is typically two to three times as great. Worse, much of the thickness is near the trailing edge, causing gross aerodynamic inefficiency. An inflatable trailing edge, in contrast, is thin and aerodynamically efficient.
Increased drag compromises the L/D ratio, making ram airs less efficient and aerodynamically inferior, compared to inflatables.
MASS & INERTIA
Ram airs contain a huge mass of entrapped air; consequently inertia is HUGE. Large ram airs (eg Flysurfer 19m & 21m) contain >11kg of air in their cells vs 2-3 kg in the tube structure of inflatables. The huge inertia of ram air kites causes a multitude of problems including poor lift, slow turning, difficulty kitelooping, and diminishes the "sweet spot" for unhooking (one of the reasons ram airs are a poor choice for wakestyle riding). Poor turning and acceleration results in inferior dynamic power (the power generated with sinusoidal kite movement).
La preuve, ici on voit que le rider avec la S3 21m n'a pas assez de vent pour faire un waterstart, tandis que la rider sur la RRD 13.5m s'amuse comme un petit fou dans la rivière aux roches juste en face de l'ile des corneilles
pour ma part, ce matin j'ai ride en FAT LADY de 9h AM a 11h20 avec beaucoup de plaisir en compagnie du rider avec la RRD 13.5m, et une autre en Zephyr 17m.
Le fun s'est arrêté quand l'intrus avec la guenille de 21m a launché son kite
patate 
a voir. Wave
