The Razorback project started on 3 Sep 2004, with a decision to build my own kit aircraft. At that stage, I had no idea what I wanted to build - just that build it I must.

I had just completed my PPL in a low-wing all metal aircraft (Robin R2120) and so I first cast around trying to find something similar to build. In rapid succession I spied out the Lancairs and Glassairs and ran for cover. The cost was enough to frighten passing horses. Then I considered the RV series of aircraft. Nie, but not cheap either. Someone suggested a Sonex. It was about the ugliest plane I had ever seen, but it was cheap-ish, relatively good performance, and the more I looked at it, the less ugly it became. I ordered my first set of plans.

The next few months were spent cutting aluminum, grinding, drilling, measuring and cataloguing. As the little pile of Sonex parts started growing, so did my feeling that this wasn't quite what I was after. Not sure exactly where this thought came from, but it was there, and unavoidable. Some time in June 2006, I had stopped cutting and drilling aluminum, and was starting to draw designs of my own on paper. I had somehow decided to design my own airplane.

These first designs were based on the traditional low-wing tractor configuration, but none of them pleased me sufficiently for them to last much beyond the initial sketch phase. However, I blush to admit, three of them made it into the proof-of-concept phase, and lived short lives as wooden mock-ups in my workshop before being chopped into firewood.

I was at my local airfield one afternoon, and got talking to the designer of the UFO gyro. I had never before heard of gyros, and was fascinated. The next weekend I travelled down to the factory (about 30min from my home on Auckland's North Shore) and saw a line of UFO gyros looking like alien eggs about to hatch. I was hooked.

I researched gyros on the web, discovered the Rotary Wing Forum, read everything I could about PPO, CLT and their ilk. And I began sketching again. Very poorly.

When I first decided to design and build my own gyro, I really didn't have any idea of what I wanted. All I knew was that i wanted to start from scratch.

My first design was drawn on the back of a paper napkin while sitting at a bar one rainy afternoon. I drew what can only be described as a horrible and naive concept - but it was mine, and I was extraordinarily proud of it. In fact, I toasted the design with many beers after that initial burst of creativity.

What followed was a bewildering series of designs, as this original concept evolved and morphed into things which approximated flying objects. I started building six of these designs. I spent over $2000 on wood and fibreglass and resin. I chopped and sanded and measured every day, till all six proof of concept full-size models began to take shape - only to fall prey one by one to various maladies. Poor design, poor execution, poor materials.

Then I stumbled on a truly innovative little Russian built gyro which was little more than a composite "blade". I was fascinated by the potential. It was a far easier way to build a plane. Here's the original...

One of my problems is that I can't leave well enough alone. Instead of designing my own version of the simple little Russian gyro, I had to expand on the theme. I added an overhead boom (of course) and a sleek fuselage. And tandem seating.

The design also made it into prototype proof of concept production. It stood magnificent in the workshop, full-size and able to be sat in. But there was one problem. The jigs I used for the mock-up were too flimsy, and over time I noticed that they had begun to warp. Try as I might, I could not get them to true up. I had no choice - since I had the original 3mm MDF patterns, I had to dismantle the mock-up and start again.

By the time I came to rebuild the wooden mock-up, I had had time to consider a niggling problem I'd been avoiding. The single strongback down the middle made it extremely difficult to mount the wing. There was just nothing to attach it to.

So I began working with TWO strongbacks, one under each side-by-side seat. Suddenly there was something solid and secure to fix the wings to, and the landing gear to. But now the overhead boom had to go. It just seemed too weird to have two of them. It took nearly two months of agonising over this decision before I gave in, and moved to twin tails, low-wing, side-by-side seating. Still able to be converted into a gyro. I'm reasonably happy with the design, but the twin tails (while looking way cool) worry me. Complexity and weight without adding much value.

Designing something is like writing a poem - it is never finished. I can't live with the twin strongbacks - even though they give me a solid base for the wings, main gear, engine etc. I've returned to the single strongback - but have staggered the seating, placing the passenger in front of the pilot, directly over the CG.

This acomplishes two things:
(1) It gives me zero CG movement
(2) It allows for a far narrower fuselage

Keeping the CG movement down to a minimum ensures that there will be no surprises. Gas is stored in the wings directly on the CG. Payload is directly on the CG also. The Static Margin is 12.5% and the TVC is .64 Both of these will probably change as I work on them more - but for the moment, these are pretty good figures.

With staggered seating, each seat base is hard up against the central strongback, which means that the inside shoulders of the occupants can actually overlap quite a bit leading to a noticeably narrower fuselage with no loss of space for the occupants.

But the old problem of how to mount the wings had not gone away.

Solution? Construct the fuselage out of 1/2" thick foam sandwich (rigid in its own right) and add strategically placed bulkheads to accept the wing carry through spars. They both fit neatly inder the seats, so that problem is now solved.