In 1980 Sven-Olof Ridder and Harald Undén start a hobby project which was intended to become a very light self-launching glider. During 1983 the Windex wing section developed and tested in wind tunnel. During 1985 Windex 1100 (unpowered) flies and work have started on moulds for powered version with 12 m. span, Windex 1200 C.
In 1986 all Windex 1200 C moulds burn in a factory fire after only 2 sets of laminates have been produced but during 1987 the Windex 1200 C prototype was shown at the Paris Air show.
During 1990 new moulds were being produced for kit production model, Windex 1200 C, fully aerobatic, with carbon fibre spars.
The Windex 1200 C prototype took part in Aerobatic World Championships 1991 for Gliders in Poland. Bronze medal in 2 categories.
10 “pilot-builders” in Sweden and abroad tested kit parts, drawing, manual etc during 1993. During 1992-1995, intensive kit development work, product testing took place with 2 factory prototypes under construction.
The first amateur-constructed kit Windex 1200C flew in 1996.
In 1999 Windexair AB took over the Windex 1200C project from RADAB.

Windex 1200 C is primarily a high-performance sailplane, but has a low-drag fin-mounted engine installation and a variable-pitch propeller turning it into an efficient touring aircraft with a cruising speed of 210 km/h (130 mph) and self-launching capability.
The airframe of Windex 1200 C is stressed for aerobatic manoeuvres and designed to JAR 22 (A). It’s a powered high-performance sailplane that can be easily handled on the ground by one person. Even with engine nacelle, propeller and a 20% smaller span it has a soaring performance equal to or better then a 15-metre Standard Cirrus glider. It also has a climb rate of approximately 2.5 metre/sec (685 fpm), under power.
The specially designed 17% thick airfoil section has comparatively low drag and a wide low drag bucket that is further expanded by a 22.5% chord trailing edge flap. The basic airfoil has very docile stall characteristics in both smooth and rough condition.
The carbon fibre spar has been successfully proof tested at 2175 kgs each side. That gives a useable load factor of +9 g and -7 g (with added safety factor of x 1.725). The König SC-430 3-cylinder engine, used in the Windex 1200C is manufactured in Canada. A displacement of 430 cc gives a take off power of 20 hp at 4200 rpm. Weight of the König engine is 13.8 kg (30.4 lbs). Starting is electric and it uses gasoline of types 100LL, 80UL and mogas98.
The variable-pitch propeller unit for the König engine has been built and
successfully tested to JAR 22 standards. The pilot control pitch from the cockpit, fine pitch to fully feathered.
The JAR tests include 50 hours running and 500 control movements
with engine running. After that the propeller unit is dismantled, searched
for damage, tolerances checked and finally function checked again.
The unit has come through bench testing without problems.

The Windex 1200 C Fuselage kit consist the following:
Laminate parts:
Upper and lower fuselage shells, vertical tail with engine nacelle, left and right, spar for vertical tail, upper and lower stabiliser shells, including spar caps moulded-in, spar web stabiliser, reinforcement module including seat and backrest, cockpit frame left and right, wheel housings for main- and tail wheel fairings, housing, ventilation channel with mechanism mounted, stick mechanism cover, fwd push rod cover aft rudder line covers and rudder pedal assembly.
Plexiglas canopy cut to size with ventilation window (Mecaplex). Main wheel with tire. Tail wheel, complete. Miscellaneous tubing, electrical wiring, switches, fuel lines, etc.
All metal parts are pre made.
All hardware, bolts etc., is AN-quality.
(With a few stainless steel exceptions)
5-Point (aerobatic) harness. Tow hook. Full scale templates for bulkheads, etc. All necessary drawings. Building manual (English language)
Epoxy, fibreglass, adhesives.
NOT INCLUDED: Instrument, paint, abrasive paper and similar materials. Wood, chipboard etc. for building cradle and jigs.
Wing kit
All internal wing fittings, hinges, spoilers, push rods, fuel tanks and wing spars are fitted. Wing is closed to eliminate wing jig and to considerably save building time
Metal parts:
All metal parts are pre-made.
Wing spar pin bolts, bolts for rear and fwd attachment. AN aircraft hardware. Push rods for ailerons and spoiler. 2 x aluminium fuel tanks each 17 litres. Associated couplings and hardware.
All necessary drawings and templates. Building manual. Epoxy, fibreglass, adhesives,
NOT INCLUDED: Paint. Abrasive paper and similar materials. Wood, chipboard etc. for jigs.

The span is 39′ 8″ and best L/D is 38:1. They also offered a fast build kit version for $5l,890 that saves approximately 300 hours from the normal 1000 hour build time. The glider is stressed for aerobatics and has enough fuel capacity and a variable pitch propeller for efficient powered cruising up to 3 hours. The Windex uses preimpregnated composite materials and an autoclave cure process for high strength to weight ratio in the structures. No other current sailplane uses this fairly expensive process. The prize of the kit was US$39,000 in 1997. Windex also offered a building assistance program in Sarasota, Florida for $870 per month and will provide qualified helpers for $40 per hour.

ARACO were the US agents for the Windex.

Windex 1200C
Engine: Konig 2 cycle, 24 hp.
HP range: 18-24.
Wing span: 12.1m / 39.7ft
Wing area: 7.41 sq.m / 79.8 sq.ft
Aspect ratio: 19:8.
Height: 3.7 ft.
Length: 16.1 ft.
Empty Weight: 150 kg/331 lb
Payload: 160 kg/352 lb.
Gross Weight: 310 kg/683 lb
Wing Load: 41.83 kg/sq.m / 8.56 lb/sq.ft
Stall: 45 mph.
Seats: 1
L/D max: 38 at 100 kph / 62 kt / 71 mph
Aspect ratio: 19.75
Min sink: 0.70 m/s / 2.3 fps / 1.36 kt
Airfoil: Radab
Structure: CFRP/GFRP
Load limit: +9/ -6g
Landing gear: fixed single wheel and tail.

AB Radab Windex 1200
Engine: Konig 430, 24 hp
Wing span: 12 m
Wing area: 7.34 sq.m
MAUW: 310 kg
Empty weight: 150 kg
Fuel capacity: 34 lt
Max speed: 240 kph
Cruise speed: 200 kph
Minimum speed: 71 kph
Climb rate: 3 m/s
Seats: 1
Kit price (1998): $39,000