liftingkites

Lifting Kite AoA Actuator

6/8/11

Today we remotely controlled our newest inflated Rok lifting kite’s angle of attack (AoA) using a linear actuator in the kite’s bridle. The actuator was controlled from the ground via bluetooth using an Android phone and tablet. The kite flew with comparable stability and lift to a standard-issue Rok that we used as a control, even after some bridle adjustments to accommodate the new actuator.

We found that the 10cm range of the actuator was enough to make a noticeable difference in the kite’s elevation and line tension, but not enough of an adjustment to explore the full useful range of AoA. In the next test we will use a pulley system to double the effective range of the actuator. […more]

AoA adjuster test with G9 rokkaku

6/2/11

We flew the G9 rokkaku kite at the runway, and again at the parking lot outside the shop, to test the angle of attack adjuster that Don and Jamie have been working on. The adjuster operates by changing the length of the back lines. While flying, the front lines take most of the load–the back lines take only about 25%. Shortening the back lines changes the angle of attack so that there is less load on the flying lines, which is helpful for reducing the force on a winch when reeling in the kite. Meanwhile, lengthening the back lines would change the angle of attack to project more kite area and increase the kite’s power, in order to lift a […more]

G11 rokkaku kite test

6/2/11

Flew the G11 rokkaku kite on the runway today. The G11 kite has the same strut-spar connection design as the G9 and G10 kites, but the G11 is 25% smaller overall, and its tubes are made of Dacron, not cuben fiber. The kite flew stably but had a tendency to steer in one direction, which is a problem that many of the earlier roks had. We may be able to solve with bridle readjustments, however.

Lifting kite testing: rok G9 & fled – May 6

5/6/11

Today we took the inflatable lifting kites out to Crown Beach to test them with Armand. Dudu and Armand flew the most recent rokkaku, the G9, in about 15 knot winds and used it to lift a payload of sand. The front spar on the G9 kite is fused to the center strut, while the back spar is free to rotate, as on the G8 kite. There is a tube that links the back spar to the center strut at the cross point, and this allows the entire kite to be inflated via one rear valve. We loaded the kite with sand bags until it began to deform, and then observed the flight pattern with that weight suspended from the […more]

Rokkaku & Android camera setup test – Mar 31

3/31/11

We took the “good” kite from the last two rokkaku tests out to the parking lot to compare its performance to that of the original carbon spar kite in very low wind.

Additionally, Jamie debuted his Android phone camera system by attaching one phone, in a padded cardboard box, to the kite line of the carbon-sparred kite and letting it out about 75m. In his hand he held another Android phone, which displayed the image taken by the lofted camera.

Meanwhile, Don and Dudu discussed weight differences in the two kites and experimented with bridle positions on the inflatable one. We also briefly attached a GoPro to the line of the inflatable kite to get an aerial view of the […more]

Rokkaku kite test – Mar 28

3/28/11

Dudu, Jamie and Renata tested two Rokkaku kites today, both with inflatable cuben fiber struts. Kite A was the best one from Friday (#4), which had 50% of the original curvature, 90% of the original diameter, and long battens. Kite B was a new one with the same tube diameter, 75% of the original curvature, and short battens.

From Dudu:
Both kites flew well with the same stability and held all gusts with no issue. The 50% kite still had better flying angle.
This test proved we can have smaller battens at strut tube tips and still spread the loads. This can save weight and storage.