While we managed to avoid damaging any aircraft today聽and brought a 6th plane聽back to flight status, that's about all for this 3rd day at Oliktok. The first flight showed that the changes made last night solved the pitot/static isssue, but did not keep the autopilot from hanging.聽By rigging an aircraft with a dedicated RC receiver to control the servos and monitoring the status of the autopilot with the groundstation, we were able to maintain control of the aircraft during all of our聽flights while testing the autopilot in flight. Multiple test flights showed that the autopilot would run reliably at low altitude and at high altitude, but that around 50m above the ground the autopilot would often聽hang. It never took place at a flight time consistant across different flights, nor could the problem be replicated on the ground, even in flying mode.
Since the drop out occurs at such a regular聽altitude, radio interference, especially from the long-range radar on site, seems to be a likely聽explaination. To hopefully counter this, the entire payload bay, and most of the electronics,聽had a foil shield applied. A聽few test flights聽after dinner showed that the shielding did not work, and that the autopilot still froze up. Unfortunately, this put us almost back at square one.
Luckily, we have a few ideas about antenna placement and telemetry聽frequency which we look forward to testing tomorrow.聽
In conclusion, today was generally slow day, but we did manage to get some excellent flight tests聽and collect plenty of data about the issue.
聽Visitors on the flight line!
聽Gijs launching the DataHawk
聽Nathan and Gijs prepare to launch the DataHawk in the shadow of the suspicious聽radar dome