A 425km Flight on a Single Battery Pack

After over a year of careful research and development, a New Zealand resident has achieved a long sought after goal. On Saturday, September 10th, Tim Vincent flew an RPFlightSystems, Inc. Vigilant C1 aircraft for a total of 425 kilometers on a single battery pack. Tim thought, and still thinks the goal of 500km could be made after a successful 300km last year using a foam version of the Vigilant. He came tantalizingly close with a 7 hour 48-minute flight racking up an impressive 425km (264 miles) on Saturday’s flight.

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The flight was carefully planned around the weather, breaking developments in technology, and last minute tweaks to the airframe itself to shave weight and squeeze every electron of energy possible out of the 6S Lithium-Ion packs. Tim assembled those packs himself from the standard 18650 cylindrical Li-Ion batteries and managed to stuff just over 30,000 mAh into the Vigilant’s pod shaped fuselage. The wings of the Vigilant come equipped with a flap system that is very effective in takeoff and landing, but Tim opted to save the weight of the servos and fixed the flaps for this effort. The Vigilant has a very long glide with this set up and it was not without some bumps and bruises as the airplane just didn’t want to settle to earth on some landings and overshot the runway several times during testing.

The course for the effort was wide open area near the shore and followed a circular flight path in loiter mode that gave each lap close to 2km distance.

The launch used a bungee assist, and because the flaps were fixed in place, the Vigilant needed a small ramp to get the nose up and the wing producing lift (see video). Regular progress reports were sent to all the anxiously awaiting parties as the calm day progressed into a breeze that could shorten the flight. After almost eight hours of looking up it was time to land the flapless aircraft. With batteries nearing depletion a “go around” was attempted because the long glide path. The power exhausted, the aircraft came up short this time and landed hard on the nose with a little damage sustained, but nothing that can’t be easily repaired or replaced.

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The Setup & Details:

  • Plane Vigilant C1 V tail – fiberglass and carbon fiber construction with 3m wingspan.
  • Stock Vigilant C1 motor – 300kVa
  • Pixhawk autopilot
  • Panasonic 18650B Li Ion batteries. 6S 9P, 30600mAh.
  • Aeronaut 13×11 prop
  • HobbyKing telemetry
  • HobbyKing power module
  • Distance covered: 425km (264miles)
  • Flight duration: 7hr48 min.
  • Average groundspeed 15.3m/s (55km/hr)
  • AUW = 5.7kg (12.5lbs)
  • Goteck DA2311T Servo
  • ZTW 65A Gecko ESC

 

All in all, a very impressive day of flying for Tim and his Vigilant C1. Will there be another attempt? Stand by…… plans are in the works!

 

 

About the Author

Gene Robinson, under the banner of RPFlightSystems has presented at seminars for the Department of Homeland Security, the National Institute of Urban Search and Rescue (NIUSR) in San Diego, California, and other agencies on the use of unmanned aircraft disaster mitigation. Robinson authored, presented and received one of the first Certificates of Waiver/Authority (COA) for the use of unmanned aircraft from the FAA for a county government in the United States. Utilizing 10 years of unmanned aircraft/SAR experience, Robinson wrote and published the book “First to Deploy – Unmanned Aircraft for SAR & Law Enforcement”.

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