Continued Development of Airborne Wind Energy System Ground Station

Airborne Wind Energy (AWE) is still a relatively new field but is growing quickly. There are approximately 13 other AWE companies worldwide that appear to have the technical competence and realistic understanding of business such that we view them as realistic competitors. As we have detailed above, eWind differentiates itself from them by focusing on following current FAA (or European) flight rules, staying small and competing against the traditional small wind market with a better value proposition and being able to go straight to selling systems to farmers without bureaucratic waivers.There is increasing business focus on the field, there is increasing university funding to study basic problems common to most AWE systems. TU Delft, a university in the Netherlands, is a leader in this field and has even started a fledgling academic department focused on it. This has produced numerous papers and theses dedicated to various problems of AWE (e.g. Ahrens et al. (2014); Fagiano (2009); Haug (2012)). In addition, there have been publications about simplified control systems and prototyping lessons and guidelines (e.g. Fagiano (2012); Fagiano et al. (2013); Fagiano and Marks (2014); Fagiano et al. (2014); Zgraggen et al. (2014)). Unfortunately, much of this work has centered on soft kites with multiple tethers that allow control systems for the airborne device to be placed on the ground.While we agree that this greatly simplifies the control system problem, the cost in drag (and, thus, electricity production) of additional tethers makes the business and financial case for these systems tenuous at best. AWE represents a significant increase in mechanical and control complexity and, thus, must also come with an even greater increase in energy production and value to make financial sense to farmers. Additionally, soft kites (imagine a kite-boarder or para-sail) are very likely to be harder and costlier to maintain in the field for years at a time. In short, rigid frame crafts (such as ours) are more efficient, rugged and easier to launch and land. Conversely, they are less studied, harder to control on a single tether, and less stable, requiring a more robust control system to manage them.The other major category of AWE is called "sky-gen". In this case, the generator is placed on the flying craft itself (as opposed to on the ground) and the electricity is transferred down the tether. There are numerous benefits and disadvantages of both sky-gen and ground-gen. There is a legitimate business case to be made for each one within certain operational regimes. However, while sky-gen is likely better at higher altitudes (i.e. greater than 1000m), ground-gen is better at the altitudes currently allowed by regulations (i.e. below 150m). Companies such as Makani are pursuing sky-gen systems, but because of this height/efficiency tradeoff, they are building utility scale systems that require individual waivers from the FAA to even test. This is not an appropriate model for farmers.As previously detailed in Section 3, we have based our design around the needs of small farmers. We maximize the financial return to farmers while following all current regulations and permitting, allowing the customer to reap the benefit as easily as possible. This focus leads us to the rigid frame flying craft, a ground-gen system and automating the system to minimize farmer involvement. This approach places a greater burden on the research and development side by increasing the design complexity of TED, its controls and the flight software.Previous work on our system has focused on TED, its aerodynamic design and physical control surfaces. This work has already led to a utility patent 9,643,721 titled "Wind Energy Conversion System, Device and Methods" that was issue 05/2017 it covers a flying system with multiple lifting surfaces and side rudders to maximize lift in a given wingspan and improve maneuverability, as well as it's flight path. As noted earlier,