Of Lancers and Sharks
GRAEME BIRD CONTINUES WITH PART 2 OF THE STORY OF HANG GLIDER DESIGN IN NEW ZEALAND IN THE 1970s AND 1980s Double Surface
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arly in 1980 the French hang gliding company La Mouette introduced the Atlas, a 30% double surface design with innovative pre-formed aluminium tube ribs that clearly defined the airfoil shape of the sail. The result was a huge improvement in sink rate and glide ratio over the then single surface gliders with flexible ribs such as the Lancer IV. The Atlas dominated the circuit that summer until Ultralight Products (UP) a California based company, released the Comet. UP moved what the Atlas had started forward a quantum level. Now the wing was 65% double surface with the completely enclosed cross bars eliminating a major source of drag. The Comet’s sink rate was another jump ahead as was its glide ratio and performance at speed. If that was not enough, UP also created a novel crossbar attachment that allowed the keel and pilot’s hang point to move ether side of the wing’s centre line thereby giving the pilot much more leverage for improved roll control, something that made the relatively taut wing flyable. Within months the Lancer IV was no longer relevant. Pacific Kites had changed hands and US sailmaker
12 A i r b o r n
Bob Schutte and friends released the Vampire, a second generation Comet, to the New Zealand market for which Flight Sails had no answer. My brother Warren had countered with a glider called the Sabre. It however did not work as hoped, it was all new territory at this point. I realised that we had to think further ahead of the Comet concept to get back into the game. After conferring with Murray Ross, one of New Zealand’s leading sailmakers, a plan was born. We decided to go to a near 100% double surface wing with ribs in the lower and upper surfaces to better sail control sail shape. We also chose to enclose the keel as well as the cross bar for further drag reduction. The nose angle was increased significantly from the Lancer, and we moved as others had to pre shaped aluminium tube ribs for the upper surface. I wanted the upper surface of the sail to fly in its own right, with the lower surface to do its job separately. The upper surface was attached to the leading edge with small pockets at each batten, so it did not rely on the lower surface to determine its fit during flight. I had noticed two things about double surface flexible wings from a
Above; A good shot of the Shark under surface Below left; Prototype Shark being test flown by Warren Below; A Pacific Kites Vampyre
