Author: betsy

New line camera mount

6/23/11

Joe made an improved line camera mount that allows for easier adjustment from the boat and a more reliable angle.

Kitefoiler test – Jun 22

6/22/11

Don, Joe, and Dudu tested the Kitefoiler again today, using the old 30 sqm kite from 2003 to compare performance to our newer kites.

Kitefoiler Test – Jun 21

6/21/11

We took the Kitefoiler out again with the original J-foils, as they’ve proved the most reliable in allowing us to sail upwind. We took out an old kite from 2003 that has a high aspect ratio and a very simple bridle, in order to compare its performance to our newer kites. The wind proved light, so we did not sail quickly enough to get the boat on the foils. We did, however, verify that the simple bridle on the kite was much easier to handle on the launching mast than the more complicated ones. Also, we realized that the launching mast needs to be expandable, in order to be made taller for larger or higher-aspect-ratio kites.
Additionally, Don and […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.

Wireless GoPro

5/19/11

From Jamie: We have made a circuit board that gives us wireless, networked control over GoPro Hero cameras and requires no camera modification. To minimize overall complexity, we took the approach of connecting to the cameras entirely via the exposed bus connector. We will be able to start and stop all cameras at the same time, and keep a record of those times in our logfiles. This makes it possible to record video and images that are synchronized to the other test data and will conserve camera battery life. The wireless range using smaller, lower-power Atmel ZigBit transceivers is not sufficient to reach the kite, but those receivers should work well for the cameras attached to the kiteboats.

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]