GRAEME BIRD TELLS THE STORY OF HANG GLIDER DESIGN IN NEW ZEALAND IN THE 1970s AND 1980s
I
n 1974 I was keelboat loft manager at Lidgard Rudling Sails located at Ellerslie Auckland. Some friends of friends were flying hang gliders at the time, so I went out to watch them.
I was hooked, and I purchased a home built 17ft Flexi Flyer from Donald Curry, one of the New Zealand’s early pilots. The Flexi Flyer design from the US was a true Rogallo with a totally flat sail set on an aluminium frame that allowed the sail to billow in half conical shapes each side of the keel. Over the next few months I went out at every opportunity to learn how to fly, often with the Auckland Hang Gliding Club. Soon came soaring and there was no turning back.
Sail shaping pros and cons The more experienced pilots were flying the Seagull design from the US, either home built or purchased from Pacific Kites, New Zealand’s first hang glider dealer, run by Rick Poynter and Alister Russell. The Seagull was a lot bigger and more efficient than the Flexi Flyer and I was often the low boy on the ridge. The sail on the Flexi being
flat was pretty unexciting and as a sailmaker I thought to add shape to the leading edge and keel sections of the sail to see if I could improve its performance. First test flights in light air showed a much improved sink and roll rate, it felt like a sports car in comparison. My next flight was in 20 knots at Baileys Beach, a west coast ridge soaring site. I pulled in the bar to penetrate away from take-off and found myself diving towards the beach with negative bar pressure. Luckily the pressure eased as I got closer to the sand and I landed safely. That was a wake up and after going over what had happened with my friend Rob Beresford we concluded that the sail shaping had inadvertently caused the centre of lift to move behind the centre off gravity (hang point) when flying at speed, causing the negative bar pressure. Therefore by extrapolation going forward keeping the centre of
Above; The first generation Skua lift forward off the centre of gravity through the whole speed range was key for good pitch stability.
Skua... the beginning of sail improvements 1975 I abandoned the Flexi and as the Seagull was too big for me, Rob
Beresford and I built a smaller version we called the Skua. I built a sail with leading edge shape, and three flexible plastic ribs each side with a scalloped trailing edge. The Skua performed very well, it was a lot better glider than the Flexi. When
Above; 2nd generation Skua with added shaped keel Left; Flying Fexi at Pah site with Rob Beresford
16 A i r b o r n
Graeme launches a Lancer 4 195 in Spain
Of Lancers and Sharks
