The appearance and the evolution of the third generation Hang glider occurred during the years 1977-1979. It was a time of fierce competition between manufacturers. McBroom, at least, was one of the personalities who left the manufacturing scene at this time. As is usual during competitive eras the various companies' designs began to move in the same direction. If one designer introduced a significant technological improvement, then the others had rapidly to follow suite with a similar design or be bypassed by pilots eager to be flying 'the best'. As always some eccentric looking products made their way to the hills but generally poor or almost non-existent sales ensured that only ' the best' and it's clones survived.
If there is one design feature which might be said to have marked out this generation of hang glider it would undoubtedly be the multiple deflexer. The reason for the triple deflexer was that in general the light and flexible airframes of the earlier generations were being required to bear flight loadings which were beyond their capacity, therefore the tubes required extra bracing to avoid excessive flexing. Too much flexing of the airframe allowed the sail to deform and lose efficiency. Along with the cloud of post and wire around the leading edges there were significant advances in the sail making field which led to increased performance. Radial tips emerged as the accepted format and the art of sail cambering and shaping developed rapidly in response to every increasing aspect ratios and deflexer induced leading edge stiffness. A raised keel pocket was introduce and coupled with this the adoption of larger diameter tubing for keels and leading edges heralded the next generation of glider.
General Specification of third generation gliders
Aspect ratio 5.0-7.0.
Nose angle 110-120 degrees.
Sail planform Transition to flying wing.
Tail either vestigial or none-existent.
Leading edge pockets broader, sometimes inflated.
Tips either truncated, droop, radial or defined.
Sail shaping Wide variety of methods. Early models relied more on wire bracing to force shape, but dog-leg and broadseaming introduced as type progressed.
Keel and leading edges Keel chord reduce dramatically to make most of higher aspect ratio. Raised or shaped keel pocket introduced in later model.
Cross tubes Exposed, and two-piece for ease of transport.
Sail slackness 1.0-3.0 degrees billow.
Top rigging Kingpost always.
Battens Full length chordwise battens across entire wing, occasionally preformed.
Pitch stability From keel reflex and planform.
Duration of type 1977 to early 1979. Examples Hiway Scorpion, Birdman Moonraker, Chargus Midas, Skyhook Sunspot and Flexiform Vector.