Good test today, kiting between Treasure Island and San Francisco in gusty conditions. We took the 25 sqm v10 kite, which we haven’t used in about a year. This kite creates about the same amount of force at given wind speed as the 18 sqm red kite, but it is a measurably lower-performance design, enough so that the boat moves forward faster with the smaller kite. We’re currently working with the kite factory to create a quiver of larger versions of the 18 sqm design, and Dudu will travel to China next week for that purpose. For now, Dudu is in Alameda, and we used his helicopter during the test to capture aerial photos and video.
We are now recording the foil actuator positions during tests. Looking at tow and kiting test data from last Thursday, we’ve plotted the relationship between the T-foil setting and the boat speed. The T-foil is controlled by the helmsman and is used in conjunction with the J-foils to control the pitch and ride height of the kiteboat. A relatively simple relationship between the two (as we see here) suggests that we may be able to automate the boat’s pitch stabilization, which would free the crew to concentrate on other tasks.
Another great test today. T-foil position adjustment was successful, and boat performance was excellent with 18 sqm kite. We initially tried to kite off Alameda Point, but the wind there was too low to foil reliably, so we packed up the kite and towed to Treasure Island, where the wind was better, and we hit a top speed of 28 knots near the San Francisco waterfront.
After the successful tow tests this morning, we took the boat out again for a test with the 18 sqm red kite. Boat performance was good, and we hit a top speed of 30 knots off Alameda Point. The T-foil position was set so it was slightly biased toward more positive angles of attack, so tomorrow we will move its attachment point to shift the angle of attack range to a better position. Jerry Shalhoob, Earle Alldredge, and Nico Rousselon joined us again for this test.
The new electronics for the foil actuators are now boxed and ready for installation. This design is a major advancement, in that we can now measure and record the foil offsets. The controller can also receive commands from the boat network, which opens the door to multiple control inputs, and eventually assisted or fully-autonomous foil control.
Our first test since the move! We took K2 out today using our new boat launch equipment–Joe’s truck and the boom truck. We launched the kite off Alameda Point and kited within sight of the beach before heading through the gap to practice maneuvering in the protected area by the USS Hornet. We practiced foiling jibes and crew transfers (with Jason driving the Protector for the first time). We also rotated crew on the kiteboat several times so that Don, Joe, Greg, and Don’s friend Phil each spent time on both the kiteboat and the Protector. Greg’s brother Ben also joined us on this test.
