Starting yesterday, August 6th, we began data collection flights. Because the autopilot is still on the blink, they are manually flown up to around 500m (1640ft). Unfortunately, this means that the shape of the profiles is very dependent on the wind and that the ascent and descent rates are not as consistant as is possible with an autopilot. Futher, this limits our maximum altitude to significantly less than the 2km (6561ft) originally sought. Our record is 850m (2788ft), but that is less than half of what is desired, and it is very unlikely that we will profile that high again as the aircraft is little more than a dot tracing an arc against the sky. At that range, the possibility of losing control is huge. Finally, since the manual pilot needs to maintain visual contact at all times, this method precludes any flight into, or above clouds. Since the development of clouds at the shoreline is a focus of this research, there is a significant handicap in operating manually.
Fortunately, our friends back in Boulder have not yet forgotten us, and were kind enough to send a series of packages with the hardware necessary to reliably regain manual control from the autopilot. Since the autopilot drop outs occur between 35m and 175m, the current plan is to manually fly the sections of the profile below 200m, and hand off to the autopilot above that level. This will allow the profiles to continue through clouds, and hopefully up to 2km. From repeated testing, we know that zoom climbing up to 200m in a wings level attitude and a normal descent from 200m in a wings level attitude provides repeatable success at transiting the "danger-zone". Of today's seven profiles flown using this method, all seven made it though the altitude band in question with zero lockups. We're hoping for the same level of success with the autopilot connected, but new hardware will let the pilot take over even if a lock up occurs.
We're very much looking forward to getting the autopilots up and running, but for now, capturing any data is great step forward, and we'll continue the hourly 500m profiles as weather (and the bears) allows.
Our resident polar bear confirms that the Arctic Ocean is, indeed, cold.
Preparing for a profile from our mobile groundstation.
DataHawk off the bungee!