By Matt Vance
Are you thinking about buying an unmanned aircraft system for research in your academic program?
I’ve been there. This two-part series builds on lessons learned from purchasing three different classes of UAS.
The first question you need to ask is, what do I want or need to do with it? Identifying the objective of ownership is the most important consideration because all other considerations will be subtended to the question. If the objective of the purchase is clear, then the purchase can be focused around meeting the objective and the supplier/UAS decision space will likely significantly narrow. If, however, the objective is not clear, then the supplier/UAS decision space opens widely where the volume of choices rapidly becomes overwhelming.
The variety and types of UAS on the market is constantly increasing, providing even more choice. A three-fold increase in registered UAS and a 2.5-fold increase in UAS manufacturers have occurred between 2005 and 2011. The UAS industry base is expanding across all continuums: vehicles, avionics, sensors, payloads, services and command and control systems. Given the volume of choice, it is essential to define the objective of the UAS to be purchased before considering buying one.
You also need to think about the performance requirements: What sort of payload weight, endurance, speed and altitude do you need? Typically the most restrictive of these characteristics in the smaller aircraft, known as group 1 or 2 vehicles, is endurance.
The operational performance characteristics drive an important air vehicle choice — the propulsion system, which is also the third purchase consideration. For smaller UAS, the most prolific propulsion choice is electric. Electric propulsion is simpler, cleaner, easier to operate, store and use than liquid-based propulsion.
An aerospace vendor for the Center for Aviation Science at St. Louis University conducted a proprietary market survey of 86 Group 1 and 2 UAS in 2012 which revealed that electric propulsion is currently the preferred choice in greater than 80 percent of this class of UAS.
The next most popular choice was gasoline, followed by solar/electric hybrids and one turbine propulsion system. The limiter with electric propulsion, and especially for vertical takeoff and landing UAS, is endurance. The electric propulsion itself is not the limiter, but the relationship between battery weight and stored energy. Longer flights will require some method to charge the batteries with either solar or liquid-fueled supplementary power.
Another question to ask is, do you need runway independence? If so, some form of a launch and recovery system or a VTOL capability is necessary. If runway independence is not a requirement, then a conventional takeoff and landing capability significantly opens the payload weight and endurance opportunity for a given fuel load and vehicle empty weight — larger aircraft, larger payloads. Runway independence or dependence will also influence the support infrastructure required to operate the UAS.
To complete the system, the following components will either need to be verified as included with the air vehicle purchase or they will need to be purchased a la carte: sensors; command and control systems; a launch mechanism; a recovery system; operating and maintenance manuals; spares sufficient to support uninterrupted operations; hardened storage containers; transport capability to and from the home base of operations to the operating locations; manufacturers’ operator training; and long-term product support.
Be prepared for the fact that the sensor costs will typically dwarf the air vehicle costs, and the command and control system that is to be used in the field must be field-compatible. Field-compatible means that unless an enclosed mobile C2 center is also purchased, which replicates a hard site power and cooling environment, the C2 system has to be operable in the open elements and can withstand the normal wear and tear of being exposed to the fluctuations in atmospheric temperature, humidity and bright, ambient daylight.
The common difficulty in viewing a computer screen in indirect sunlight is an often overlooked consideration. Dependable vertical support for antenna arrays is another often overlooked consideration. Retractable and extendable antennas are attractive and utilitarian but can add significant cost to a C2 system.
It’s also wise to consider that the purchase and operating budget will generally equate to payload weight, payload sophistication, vehicle size, and endurance. At the lower cost range, professional Group 1 UAS quadcopters can be in the thousands of dollars neighborhood to purchase and operate. Or, for example at the higher cost range, a Group 2 fixed-wing Insitu ScanEagle can approach $1 million in purchase costs.
An additional consideration is that there will likely be a direct and significant correlation between the sophistication of the UAS and the time requirements for the crew to become proficient it its use. Simpler, plug-and-play systems with intuitive software may be mastered in weeks, while UAS with autonomous capability, multiple payloads and reprogrammable software will require a significantly longer investment of time for the crew to gain proficiency.
At this point in the decision flow, because the UAS system has been defined in terms of initial requirements and budget compatibility, a market survey is appropriate. Identifying multiple potential UAS and UAS suppliers that can meet your requirements is recommended.
The second article in this series will explore considerations in selecting a UAS supplier and will discuss taking ownership.
Matt Vance is currently assigned as a flight instructor/senior researcher at Saint Louis University’s Parks College Aviation Science program. In addition to duties providing primary flight instruction in SLU’s professional pilot curricula, he leads new lines of analysis and research oriented around improvements in the cockpit learning environment.
A former U.S. Navy officer and career aerospace executive, Matt began his academic career in the fall of 2011 with Parks Center for Aviation Safety Research (CASR), where he was instrumental in airspace acquisition, procurement and operation of Zagi, Prioria Robotics’ Maverick and Tetra, and Williams Aerospace Taurus unmanned aircraft. Matt completed his dissertation in May 2014 on the factors that may be essential in the decision to fly as a passenger on fully autonomous airliners.