Schweizer SGS 2-33 / TG-4A
Designed by Ernest Schweizer the SGS 2-33 two-seater is a slightly larger version of the SGS 2-22, of improved performance, developed to meet the need for a medium-priced sailplane for general soaring and training.
Of the same all-metal construction as the 2-22, the 2-33 has strut-braced aluminium alloy high-set wings of slightly greater span than its predecessor, with metal skinning and all-metal ailerons; there are aerodynamically balanced spoilers in both upper and lower wing surfaces. The fuselage is of welded chrome-molybdenum steel tubing and is covered with Ceconite fabric except for the nose, which is covered with glassfibre. Landing gear is a non-retractable Cleveland monowheel mounted just aft of the nose skid, which is mounted on rubber blocks for shock absorption; there is also a small wheel mounted under each wing tip. The tail unit is a steel tube structure covered with Ceconite fabric, the tailplane being braced. The two pilots sit in tandem, with dual controls, under a one-piece cockpit canopy hinged to port, and there is a door to starboard for the rear pilot's exit; he also has windows at the side and a transparent panel above him.
It first flew in prototype form in in 1965 and the SGS 2-33A flew for the first time in 1966, and received FAA Type Approval in February 1967. The A model, introduced in 1968, has a larger rudder, subsequently offered as an FAA-approved homebuilders kit.
Production began in January 1967 and a total of 570 had been built by January 1980; the type is also available in kit form for amateur constructors, and a production version is the SGS 2-33A.
The U.S. Air Force Academy operates 13 as the TG-4A.
1982 Standard price: US$24,450
Length: 25 ft 9 in
Height: 9 ft 3.5 in
Wing span: 15.54 m / 51 ft 0 in
Wing area: 20.39 sq.m / 219.48 sq.ft
Wing aspect ratio: 11.85
Airfoil: NACA 4301 2A
Empty Weight: 272 kg / 600 lb
Payload: 200 kg / 440 lb
Gross Weight: 472 kg / 1040 lb
Wing Load: 23.15 kg/sq.m / 4.73 lb/sq.ft
Minimum sink: 0.85 m/s / 2.8 fps / 1.66 kt / 186 fpm at 37 kt
Max speed: 85 kt / 98 mph (in smooth air)
Max aero-tow speed: 98 mph
Stall speed: 30 kt
Glide ratio (L/D): 23:1 at 44 kt
Rough air airspeed: 85 kt