Building an Unmanned Aircraft

Written by Kelvin Hutchinson, an embedded journalist in the Australian Pilot Magazine.

It is estimated that there are around twenty thousand Remotely Piloted Aircraft (RPA) flying in Australia today. The vast majority are under 2 kg and flown in parks and backyards by unlicensed enthusiasts.

Approximately five percent of those RPA are custom built for specific commercial operations. 250 CASA approved UAV Operator Certificate holder’s utalise these devices for day-to-day commercial operations.

These Aerial Robots comprise static balloons, multirotors and fixed wing assets.

Most commercial operations are undertaken using multirotors, primarily hexacopter (6 blades) and or octocopters (8 blades) which are used because they offer a relatively high degree of protection for the payload which generally comprises sensors worth tens of thousands of dollars. If a motor or propeller malfunctions during flight there is a reasonable chance with the remaining motors/propellers you can get the RPA and the camera on the ground safely.

So what’s needed to build a suitable commercial multirotor platform? Firstly you need to determine what type of operational activities will be undertaken. It’s important as it will have an impact on the design… size, motors, props, autopilot system, undercarriage, gimbal (camera mount) will all vary depending on the intended use.

Lets assume for this exercise that the camera onboard will be used for cinematography i.e. ads, movies, news reports and the like. We will also assume the camera is a Red Epic worth over $40,000. With this payload we have size considerations, weight, potential centre of gravity issues to consider (as the camera moves around), the value of the payload is substantial so it needs to be protected and the camera gimbal will need to be large and sophisticated to cope with this type of camera.

To handle this criteria I would recommend an 1.2 meter octocopter, 15 inch blades with a pitch of 5.5, T-motors (Tiger Motors), retractable undercarriage, Kestrel Autopilot and Taro or ZeroUAV gimbal.

In addition to this complex and expensive equipment you will need esc’s, silicon cables, UBEC devices to provide various voltages to operate different devices onboard, distribution boards, GPS, transmitter receiver, ground control station duplex modem, batteries and battery platforms. All of this and miscellaneous nuts, bolts, screws, solder, relevant tools etc. with cost you around $22,000 before you apply any labour costs.

So where do we start? Cheep multirotor frames from China will not prove to be suitable platforms. Frames built in New Zealand or building your own with quality components is the way to go. The build time will be around 100 hours.

The gimbal will also take some time to setup. It is a precision piece of equipment with unique parts and software system to operate it. Each gimbal build need to be customized to a certain degree to suit the camera. The setup needs to ensure the C of G of the RPA is not affected during flight as the camera nearly always operates separately and requires a second operator on the ground to manage the gimbal and camera. This means training on gimbal and camera operations is needed also.

Professional gimbal setups are generally three axis (pitch, roll, yaw) and have associated software, which required hours of adjustment to get the gains and balance configured. Gimbals can be set to auto stabilization or manual control.

You will need to setup a Remote Pilot Ground Station which comprises a Windows OS computer and familiarize yourself with the Kestrel Flight Systems software that will effectively fly the mission for you from the ground. You will also need a ground based flight control transmitter with all of the RPA onboard systems controlled by the knobs and switches on that transmitter. This also take quite some time to setup.

In addition to the RPA build, ground control station and gimbal setup you will need to secure from the Civil Aviation Safety Authority (CASA) an approval for this RPA category (<7kg, <20kg etc.) before it can fly. They will require you to submit for approval a pilots manual, maintenance and line maintenance manuals and detailed specifications. CASA treats any RPA as if it’s a manned aircraft. They expect the RPA to be built to a high standard, have professionally prepared documents, a number of failsafe systems and be flown by a qualified and well trained Remote Pilot.

Retail, a ‘system’ like that outlined above will cost around $40,000.

Flying the Octocopter with the gimbal and camera onboard will initially be a challenge and should be undertaken by a well trained and qualified RPA pilot or you will have issues. Expensive ones!

So becoming a commercial operator is a challenge but it’s proving to be a lucrative career and business for many Australian’s. You need to be passionate, dedicated, patient and professional at all time in your approach or CASA or clients will ground you.

Next edition we will look at how Remotely Piloted Aircraft can save money for business and governments and create income for commercial operators.

RPA Training AcademyKelvin Hutchinson is a Chief Flying Instructor in the aviation sector and has a wide range of RPAS operations including an RPAS Training Academy based out of Warwick Aerodrome in Queensland. Contact Kelvin at www.rpas.net.au or on 0407733836 or visit the RPA Training Academy for more details at www.rpas.net.au.

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