Graeme Bird’s hang gliders
The New Zealand sail-maker’s work that advanced the state of the art
Graeme Bird, a New Zealand boat sail maker by trade, started hang gliding in 1974 with a Flexi Flyer standard Rogallo from California, which he attempted to improve by modifying the sail. The performance of the resulting glider matched that of the Seagull 3s popular in New Zealand at the time, but…
…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 beach and I managed to land safely.
That was a lesson that several pilots of the early Rogallo wings discovered. Not all survived the loss of pitch stability in a dive if the wing had insufficient reflex. (See Luff in the time of cholera for more about the phenomenon known as the luffing dive.)
In 1975, together with Rob Beresford, Graeme built the Skua, which featured the curved leading edges of the Seagull. (See Semi cylindrical Rogallo in Rogallo wing definitions and diagrams.) He added a raised shaped keel pocket with reflex for pitch stability.
In the early days I learned a lot from my friend Rob Beresford not only on how to fly but how to think about a hang glider. Rob built all his gliders in his garage and he made everything except the sails.
In late 1975, pilots from Christchurch turned up with a radical new glider from Australia: The SK2, a small glider designed by Steve Cohan with a fully shaped and ribbed sail, “…just like two Aussie skiff sails joined together.” In response, in 1976 Rick Poynter of Pacific Kites made two airframes and Graeme Bird made two sails, based on the SK2, but larger and “…a fully battened skiff type sail design and a full airfoil shaped keel pocket.” They called it the Lancer.
See film of this glider flying at the 1976 world championship in Kössen, Austria, and see a photo of an SK2 flying in England, both under External links later on this page.
The 1976 Hiway Scorpion also featured a similar ventral fin. See the related topics menu Hiway of Sussex, England, and Abergavenny, Wales.
Back in New Zealand there was now a race for the next best hang glider inspired by what had been seen at Kössen and US hang gliding magazines.
The result of that inspiration was the Lancer II of 1977 with a raised and shaped keel pocket to provide the wing with more anhedral for improved handling. In addition, to improve dive recovery, based on what Bill Moyes (Australia) had done, lines were added lines from the top of the king post to the rear of the inboard-most rib each side of the keel. The result was that, in an extreme dive situation, the trailing edge curved upward, acting as an up-elevator (in conventional aircraft controls) as the following photo illustrates by inference:
As well as being among the safest hang gliders to fly in turbulence up to that time, the Lancer II also gained a reputation for its performance and handling, being a nimble and well balanced glider to fly.
In 1977, led by the British Gryphon bowsprit-rigged wing (see the related topics menu Miles Wings Gulp and Gryphon) and others that followed with similar structures, Graeme Bird and Rick Poynter developed the Lancer III. Instead of cross-tubes, it used a bowsprit with cables attached to the leading edges to hold the wings spread. (The cables are not visible in this photo.)
Being a hang glider designer brings with it some ‘small print’ in the unwritten contract implicit in that calling. Graeme describes how their bowsprit-rigged project ended:
…on a day that my brother Warren and I were out sailing, a close friend Dave Pearce took the largest of the two gliders for a flight at Muriwai. From accounts, the bowsprit folded near the nose plate and the wing collapsed and fell to the rocks below. This was the lowest point I ever experienced with hang gliding.
The Lancer IV, also known as the Santana, featured a wider nose angle than that of the Lancer II, a shorter root chord, and broader tip chord. ‘Blow down’ tubes were added near the wing tips to improve the pitch stability, augmenting the reflex bridles in dive recovery.
On a light wind day at Fort Funston near San Francisco in June 1978, Graeme soared the Lancer IV, performing 360s and wangs, while all other gliders that launched — except one — sank to the beach. The exception was a large Ultralight Products Dragonfly that was more or less ‘parked’ 50 feet above the cliff top. That one day launched the Lancer IV in the U.S.A. (1)
However, the Santana (Lancer IV) was designed for New Zealand conditions; windy coastal sites with grassy rigging areas where you rig the glider flat on the ground. (Just like in Britain.) In California, light wind, dirt, and spiny bushes conspired to cause Americans to prefer rigging gliders with the control frame extended, keeping the wing off the ground. With Flight Designs of Salinas, California, Graeme developed the Americanized Super Lancer with a cleaned up leading edge sail pocket and modified frame.
The Lancer IV gained a world-wide reputation as the glider to beat. If you were manufacturing hang gliders at this time, your latest design had better at least look like a Lancer.
Then, in 1979, the La Mouette Atlas (made in France) with permanently curved alloy battens rendered previous flex-wings obsolete. And in 1980, the Ulralight Products Comet revolutionized flex-wing design further by successfully implementing the enclosed crosstube double surface wing.
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 control sail shape. We also chose to enclose the keel as well as the cross bar for further drag reduction.
*Not to be confused with British hang glider designer Murray Rose
The new double surface wing incorporated many innovations, the most revolutionary of which, arguably, was an under-surface detached from the upper surface at its trailing edge.
Technical: Graeme noticed that the under-surface and upper surface of a sail were subjected to different forces, so it seemed logical to detach the two at the trailing edge (of the under-surface). The two surfaces were not completely detached, however.
In the tip region the lower surface was not attached to the upper surface except for a strap that picked up the tip batten of the lower surface, allowing it to move separately to, but not away from, the upper surface.
— Graeme Bird (1)
Another innovation commonplace on modern (2021) flex-wing hang gliders that might have been first introduced by Graeme is a transverse trailing edge batten near the tip, bridging the two chord-wise battens where the anti-dive strut is situated.
It spreads the up-elevator effect of the strut in a ‘blow down’ situation across more sail area, improving its effectiveness. That allows the strut to be set at a lower angle, delaying the onset of its effect to a lower angle of attack, which results in the glider achieving a greater top speed.
Graeme felt uneasy about the absence of a stand-up keel pocket, so he raked the king post rearwards and added a fin. They called the new glider the Shark. Comparing the Shark to the Comet and its clones, Graeme writes:
The Shark… had a lot of shape cut into the sail at each batten. When the leading edge flexed at speed the heavily shaped sail lost little trailing edge tension, resulting in a wing that retained much of its efficiency at speed.
After winning the open class of the 1981 world championship (in Japan) flying a Shark modified with spoilerons to improve its turning ability(2), Graeme fractured his neck during flight testing back home in New Zealand. A subsequent crash — in front of his wife — during development of an easier to fly development of the Shark caused Graham to stop flying and move on to other things.
Bennett delta wing in Hang gliding mid 1980s for a photo of the Bennett Streak, which also featured a detached under-surface
Lightnings, Comet clones and pod people in Hang gliding early 1980s part 1 for the Southdown Sailwings Lightning of 1980, which had a similar fin to that of the Shark
Rogallo versus Quicksilver in colour in Hang gliding 1974 part 2 for Rick Poynter’s early involvement with hang glider manufacture
Tom Price’s flying machines: Tom Price was another early adopter of the raised shaped keel pocket.
Ultralight Products of California and Utah related topics menu for the UP Comet
Lancer 1 launching at the 1976 world championship in Kössen, Austria (very short clip): 1976 Kössen 1 de 3 15 min starting at 11 minutes 25 seconds (digitized film on YouTube)
Lancer 1 approach and landing at the 1976 world championship: 1976 Kössen 2 de 3 15 min starting at 3 minutes 33 seconds
SK2 flying in England photo on Flickr by Don Liddard
1. Of Lancers and Sharks Part 2: Double-surfaces, Vampyres and Sharks, Graeme Bird, SkyWings (BHPA magazine) January 2021
2. Spoilerons: Steve Pionk’s article following Graeme’s in SkyWings, January 2021