Horus Harpy Development Chapter 001 - Impetus

Lets talk about indoor/outdoor quad racing. As a sport, it is a completely different venue all together. The airframes are light, fast and not always strong, but always pursuing an edge. As those of you who have met me, I've been at nearly every IDRA event, trying to get the word out that I was starting something new, a different perspective on 'drones.' This season, traditional H and X frame quads dominated the scene. The latter, the X frame, was almost hailed as the revolutionary and de facto king of racing quads. 

Personally, I had had enough of this, but I have a different stake in the game. What I want to see is the quadcopter concept, evolve, become more sophisticated, more advanced and in fact, the very act of racing them embraces this concept. Racing promotes evolution and technological advancement. The 'X' frame is a step backwards, a regression or cheat of sorts, from my point of view. The fact that an 'X' geometry has always been generally superior to the 'H' geometry is not news but is not also it's rightful claim.

The X centralizes the weight and provides a maximized pivot point for all axis and most mixers are designed for this. Let's not take this factor too lightly. The mixer is the central core of your flight control system, it dictates where power goes and when. Imagine you had a 4WD truck, but it had it's 4WD system swapped for that of a car? It wouldn't work properly, couldn't deliver the power in an optimal fashion even though in principle it's the same. 

This also doesn't mean that the 'H' geometry wasn't optimized, on the contrary it was. It provided room for batteries, action cameras and so forth, while limiting pitch and impacting yaw a bit, if you used the wrong mixer. Most flight control algorithms weren't designed for this. In fact, just looking at the latest version of Cleanflight shows this, there is no 'H' quad option, so most have never experienced this difference. I had when OpenPilot included the H-Mixer, it changed the way my QAV500 flew. So going back to the X frame, it's properties, weight centralization, mass minimization and mixers which already account for its' design gave it the natural ability to be completely optimized from hardware to software.

However to assume that this makes it the ultimate design is reductive in its' reasoning. It means it's better for certain parameters, to which we have no metrics or definition for yet. We are largely stabbing in the dark with no methodology for assigning advantage to one airframe design vs. the other. In truth, that is part of my reasoning for exploring the V-Tail. For me, it is fun to fly first, visually arresting second and most importantly, third, I hope to open the minds of some pilots to the potential of exploring a variety of airframe geometries before settling on an absolute best. One of the only other manufacturers who pursue a completely different frame geometry is Sky-Hero with their spider frames. 

Our industry is in it's infancy and we have a long time before we determine the absolutes. The automotive and aerospace industries have only established these standards and universalities within the last few decades after nearly 100 years of development. The 'Racing' scene has only really been a global phenomenon this year. 

It is with this impetus, that I began designing  the Horus Harpy. The first 250mm VTail designed for racing. 

Sherif