Acceptance flights of new UAV - Swampfox Anonymous Sunday, December 01, 2013

Prof. John B went to Palmerston North last week to conduct acceptance flights of AUT's new Swampfox UAV.

The Fox is totally New Zealand designed and built - the airframe was designed by Skycam UAV Ltd. in conjunction with the University of Queensland, the autopilot was designed by the New Zealand Defence Technology Agency, and the whole aircraft and systems were constructed Skycam UAV.  The Fox is a flying wing configuration, rather than a conventional wings plus tailplane combination.

Dr. Tim Brooks with the Swampfox

As usual for this time of year, the Manawatu weather was unreliable and rain was forecast for the whole week.  However, carpe diem!  Monday dawned cloudy and a bit windy, but Prof. John B and Dr. Tim Brooks of Skycam packed the control vehicle and headed out to Mangahao in the Wairarapa to fly in Danger Area 522, which allows Beyond Visible Line of Sight (BVLS) flights up to 2500ft AMSL (approximately 2000ft AGL).

After assembly, which is very straightforward, Tim demonstrated the launch procedure.  The Fox can be operated from the same GCS as our Hawk, but the launch handling is a little different.  After pre take-off checks are complete, the Fox is attached to the bungee catapult and the Operator enters the Take-off command into the GCS computer.  In contrast to the Hawk, the motor does not immediately start, which is initially a bit disconcerting.  This is actually a good thing, because the Handler holds the Fox by the trailing edges, which places a very large propeller right between the wrists!  When the aircraft is released, the accelerometers in the autopilot sense the launch and the motor is turned on.  Rate of climb is around 700fpm.  Prof. John B did the second launch; the aircraft is 'bounced' on the catapult and released at the top of the bounce, so that the Fox is pointing about 15 degrees above horizontal. 

We had fitted two Sony NEX5-N cameras into the sensor cassette and during the two flights totalling about 50 minutes, we took around 3200 high resolution photographs, half in RGB, the other half in nIR.  These will be processed with Pix4UAV software and will be a little bonus for the farmer - we will provide the orthomosaics to the farmer.  It appears that the areas of grass grub infestation show up very well in these images.

Recovery of the UAV was straightforward - after the Return command was entered, the Fox returned to the launch point; Landing Mode 4 entered commanded the aircraft to descend to 150ft AGL and fly upwind before releasing the parachute.  The parachute allows the UAV to land upside down, thus protecting the sensor window and the winglets.

The remainder of the week was far too windy and wet for further flights, though we did go out again on Tuesday and did some ground testing of the video downlink on the Hawk.

The next time the Fox flies, it will probably be in Antarctica - the UAS is on its way to Christchurch now for transport to the ice.

Airtime! Anonymous Friday, September 14, 2012

At last, we have had a day without rain or high winds.

We took the Hawk to the North Shore Model Aircraft field and did two flights under the direction of Dr. Tim Brooks.  The field itself was very wet, but the sky was clear and the wind only about 10 kph.

After setting up the GCS, assembling the aircraft and doing the pre-takeoff checks, Tim launched the Hawk and we flew for about 40 minutes, programming orbits, waypoints and loiter points.  The parachute recovery went well, the aircraft landed gently and avoided the surface water.

The short video clip shows the actual catapult launch.  The controller calls to the aircraft handler "Clear prop", handler responds "Prop clear"; controller: "Takeoff mode entered" and the GCS commands "Takeoff mode".  The motor winds up and the controller checks that full power is maintained and calls "Launch", whereupon the  handler releases the aircraft.  The catapult yoke falls away and after a slight dip, the aircraft climbs.  The controller waits for the system to report "Takeoff", confirming that the autopilot has established control.  At this point, the controller can manually steer the aircraft if necessary to avoid obstructions, though an ideal launch site should have none.

Then it was our turn.  Again the pre-takeoff checks were performed (this is necessary before every flight, even if the aircraft has flown only minutes before).  This time, John R. was the controller, John B. the handler.    Again, the aircraft took off and flew flawlessly for about 25 minutes, the video camera was turned on and the on-board system recorded the flight.  The aircraft was automatically recovered by parachute.  Though the wind had dropped, a sudden gust, probably a thermal taking off, caused the touchdown point to be about 100m away from the target area - a bit closer to the fence than we would have liked.

After the successful trial, the aircraft and GCS were packed into the Pelican Storm cases and returned to AUT.  Post flight procedures included examination of the aircraft for damage, recharging of flight and GCS batteries and, of course, the paperwork to log the flights.

The video card was removed from the aircraft and the video downloaded for examination.  One thing is clear - the amount of data generated in a single flight is going to require a lot of analysis.