The 1980 Sigma was the first offering from Southdown Sailwings. It follows the basic concept of the Chargus Cyclone by appealing to the more experienced pilot for use in competition and cross country flying.
The Sigma is a crosstube-less bowsprit design. The machine has a high aspect ratio with a tight sail and drooped tips which lock up at the minimum desired angle of attack to aid pitch stability. Rigging is straightforward and quick, the longest operation being fitting the flexible battens. The Sigma came in two sizes, 11 sq m and 12 sq m.
The 1979 Southdown Sailwings Sigma had to be flown all the time, and if you did not get the push out right in turns, then don’t bother with light ridge lift. The nose would drop on landing.
In 1979 Southdown Sailwings made the first 12 Sigma 12m. Alan Garard and Rod Stuart from NZ test flew all 12 gliders and loved them. Stuart’s Sigma hangs in the transport museum in Wanaka, New Zealand.
The Sigma was followed by the 1981 Sigma Floater.
The Sigma Floater is an open cross boom design glider, this is different from the first Sigma which used a bowsprit design. This type of glider was more appealing to novice or intermediate pilots for use in coastal flying. Rigging is straightforward but slower than the Sigma.
The Sigma Floater was priced at £937.00.
Sigma 12 m
Span 38 ft
Sail area 188 sq ft
Aspect ratio 7.5
Nose angle 140 deg
All Aero 