A (train of) parasail(s) as AWES ?

[PierreB]

The sink rate of parachute rescues is low, being generally between 3 and 6 m/s, depending on whether they are soaring or not.

@PierreB

If we take a look on the specifications page 6, we can see a low sink rate of 3.93 m/s, loaded with 115 kg, with a horizontal speed of 2.62 m/s for a glide ratio of 1/1.5 (0.666), elevation angle of 33°40’), calculated Ct, Cd, and Cl similar to the values above; then a still lower sink rate of 3 m/s, loaded with 90 kg, horizontal speed of 2 m/s, calculated Ct of 4.56, Cd of 3.8, and Cl of 2.53.

But at higher airflow speed, the drag (and also thrust) coefficient Cd (or Ct) is lower, for parasails (drag + lift = thrust) or parachutes (only drag):

@PierreB

According to my calculations (which can be made with the elements below), if the area of 139 m² (the indicated value reported below is 139.3 m²), the thrust coefficient CT is approximately 1 (about 0.96 with air density of 1.2), for an airspeed of over 11 m/s. But if we take the diameter of 39 feet (11.8872 m) into account, the diametral area (which should be taken into account) is about 111 m², and the thrust coefficient becomes approximately 1.2.

If we take a look of previous publications, it looks that this value is likely constant when the Reynolds (scale and/or airspeed) number increases, after a significant initial decreasing then a short climb. The short climb of drag (here thrust) coefficient can be an explain for the following. Indeed the traction force of 1102.23 kgf at 11.62 m/s is proportionally higher than the traction force at lower air speeds (16.5 mph = 7.37 m/s, for 830 lbs = 376 kgf), probably because the traction force, including the CD and the CL, increases slightly before stabilizing while the

The parasail is advantageous because it provides a lift component allowing it to fly at an elevation angle of about 30 or 35 degrees, which is a typical value for several AWES. As a result, the helium-inflated balloon is not required.

[PierreB]

@PierreB

Perhaps a depower tether retaining the AWES would be a possibility, a bit like the circus tent in the video which is still retained.

AWES parachute and wing-type systems feature a circular design that facilitates the installation of a depower line, possibly a crown line, near the power cable. This allows the kite to be retained by inverting it at its upper end in the event of a power cable break. It should be noted that depowering is performed via the control pod during reel-in phase, but this system may prove insufficient and present a risk of unexpected failure in the event of a break in the main tether during power reel-out phase.

The depower line from other kite systems could also be suitable, but can also be detrimental to the crosswind flight, by adding drag, weight, and complexity.