Designed by Leslie Schweizer, the all-metal 1-36 Sprite, the final glider model produced by the Schweizer Aircraft Corporation, was conceived as a replacement for the 1-26 one class design The SGS 1-36 Sprite single-seater is intended to be an all-round sailplane, which can be flown and soared by an inexperienced pilot shortly after his first solo, but is also easily capable of Diamond distance flights, and able to offer modern performance, handling and appearance whether as a personal, club or school aircraft. It will serve as a replacement for the veteran SGS 1-26 series, and a one-design competition class was planned.
With a cantilever mid-wing 46-foot wingspan, it has an all-aluminum structure with standard effective dive brakes, T-tail, a large cockpit, and good visibility. Two landing gear positions were offered: a forward-wheel position, which makes the ship a “taildragger,” or an aft-wheel position with a nonspring tailwheel and an aluminum nose skid. The latter is recommended for school and club operation. It has balanced top and bottom surface DFS type airbrakes with the upper surface segment set well back forwards the trailing edge of the wing. The structure is all metal, with fabric cover on rudder and elevator. Standard equipment includes tip wheels, deluxe seat cushions, headrest, and rudder pedal adjusters.
The prototype SGS 1-36 Sprite first flew on 2 August 1979.
First year built 1980.
1982 Standard price US$17,950.
SGS 1-36 Sprite Wing span: 14m / 46 ft 2 in Wing area: 13.07sq.m / 140.7sq.ft Wing Load: 24.63kg/sq.m / 5.05lb/sq.ft Aspect ratio: 15.15 Airfoil: Wortmann FX 61-163 Length: 20 ft 6 in Height: 4 ft 7.5 in Empty Weight: 215kg / 475lb Payload: 107kg / 235lb Gross Weight: 322kg / 710lb Max speed: 109 kt / 123 mph Stall speed: 31 kt Rough air airspeed: 93 kt Max aero-tow speed: 123 mph L/DMax: 31 77 kph / 42 kt / 48 mph MinSink: 0.67 m/s / 2.2 fps / 1.30 kt / 135 fpm at 36 kt / 46 mph Seats: 1 No. Built: 43
The SGS 1-35 was designed by Leslie Schweizer to 15 m racing class rules.The 1-35 is a high performance single seater which first flew in prototype form in April 1973, and completed its FAA certification programme in the spring of 1974. It was offered in two versions in addition to the standard 1-35, the SGS 1-35A Unrestricted 15m Class variant, and the SGS 1-35C, or Club-35, a simplified and cheaper version for club or syndicate ownership.
The 1 35 has removable wingtip training wheels, a skid under the nose, and an external radio antenna -features. In lieu of spoilers or air brakes, the 1 35 uses a trailing edge flap. All models use flaps for performance and approach control with -8 to +32 degrees that can be deflected beyond its normal landing setting to increase sink, with a maximum de¬flection of 80 degrees.
The structure is all-metal monocoque fuselage and single-spar, multi-stringer stressed skin wing; elevator and rudder fabric covered.
The 1-35A has a retractable monowheel forward of the cg, with a hydraulic brake, a large tailwheel and no nose skid. Interconnected flaps and ailerons are standard, and the flaps can be lowered to 80° for use as air brakes; there is provision for up to 145 kg/ 320 lb of water ballast with an empty weight of 490 pounds. The 1-35A is claimed to have the widest range of wing loadings in the FAI 15m Class, from 5.78 to 8.96lb per sq ft, enabling it to compete effectively in both weak and strong soaring conditions. Later production 1-35As have a more painted nose and improved wing root fairings.
The 1-35C less expensive has a non-retractable unsprung Cleveland monowheel aft of the eg, with a hydraulic brake, and a nose skid plus a tailskid. There is no provision for water ballast, and the maximum wing loading is 6.59lb/sq ft. The C has a 425-pound empty weight. Low profile rivets are used on the 1-35C’s rear fuselage, and its best glide ratio is 36:1 compared to 41:1 for the 1-34A. Altogether 96 1-35s of all versions had been built by January 1980. The type has cantilever shoulder wings with aluminium stressed skin and stringers, the ailerons and flaps being of aluminium torque cell construction; air brakes or spoilers are not fitted. The monocoque fuselage is entirely of aluminium, and incorporates an integral fin; the T-tail is likewise of aluminium with a fixed-incidence tailplane and fabric-covered elevator. The pilot sits in a semi-reclining position under a one-piece detachable canopy.
By 1977 72 1 35s have been built, and they were coming off the line at the rate of one per week.
Part of the price was due to the costs of FAA certification, but most competition pilots modify their ships back into the experimental category anyway.
The first 1-35 serial 001, belongs to the National Soaring Museum.
SGS 1-35A Wing span: 49 ft 2 in / 15.0 m Wing area: 9.64 sq.m / 103.8 sq ft Aspect ratio: 23.29 Wing section: Wortmann FX-67-K-170/150 Length: 19 ft 2 in / 5.84 m Height: 1.35m / 4ft 5in Max TO wt: 422 kg / 930 lb Empty wt: 199 kg / 440 lb Useful load: 510 lb Water ballast: 147 kg / 320 lb Wing loading: 5.78 lb/sq.ft Max speed: 121 kt / 223 km/h Rough air speed: 121 kt / 223 km/h Stall: 35.5 kt / 66 km/h Lift to drag: 40 @ 48 kt Min sinking: 0.54 m/sec / 1.77 ft/sec at 40 kt / 74 km/h Best glide ratio: 39 at 54.5 kt / 105 km/h Seats: 1
SGS 1-35C Wing span: 15m / 49 ft 2 in Wing area: 9.64sq.m / 103.8sq.ft Aspect ratio: 23.29 Airfoil: Wortmann FX 67-K-170/150 Length: 19 ft 2 in Height: 4 ft 5 in Empty Weight: 181kg / 400lb Payload: 118kg / 260lb Gross Weight: 299kg / 660lb Wing loading: 5.58 lb/sq.ft Max speed: 121 kt / 139 mph Rough air speed: 121 kt Max aero-tow speed: 139 mph Stall: 28 kt L/DMax: 39 88 kph / 48 kt / 55 mph MinSink: 0.61 m/s / 2.0 fps / 1.18 kt @ 40 kt Seats: 1 No. Built: 101
The SGS 1-34 high-performance single-seat sailplane was designed by Ernest Schweizer to meet Standard Class specifications and is stressed to +8.33Gs and -5.33 Gs. Design work started in 1967 and construction of the prototype began the following year.
The all-metal aluminum cantilever shoulder wings were the shoulder type with a Wortmarm FX-61-163 at the root and Wortmann FX-60-126 at the tip. The 1-34 has differential ailerons and no flaps are fitted. The SGS 1-34B features double flap speed-limiting airbrakes and an optional retractable nosewheel. The fuselage is an aluminium alloy semi-monocoque structure, and the cantilever aluminium alloy tail unit has a swept back fin and rudder, and a fixed incidence tailplane with no trim tabs. The standard nonretractable nosewheel is fitted with a Cleveland brake and is balanced by a forward skid and tailwheel.
Suitable for the low time pilot. It featured in-flight adjustable rudder pedals and a two-way adjustable seat. The pilot sits under a large one-piece canopy.Originally offered only with a fixed gear, a retractable version was added.
First flying in April 1969, the 1-34 receiving FAA Type Certification in September of that year.
By January 1978 a total of 93 production 1-34s had been completed, the 51st and subsequent aircraft being the 1-34A variant with a smoother wing upper surface through the use of bonded corrugations on the underside of the top skin. This was followed by the SGS 1-34B.
At least one example has been substantially modified when a storm damaged 1-34 was rebuilt by Bob Park with a V-tail and provision for 105 kg / 230 lb of water ballast in the wings.
SGS 1-34B Span: 49 ft 2.5 in / 15.0 m Length: 25 ft 9 in / 7.85 m Height: 7 ft 6 in / 2.29 m Wing area: 151.0 sq.ft / 14.03 sq.m Aspect ratio: 16.04 Wing section: Wortmann FX-61 -163/60-126 Empty weight: 550 lb / 250 kg Max weight: 800 lb / 363 kg Water ballast: None Max wing loading 25.88 kg/sq.m / 5.3 lb/sq ft Max speed: 135 mph / 117 kt / 217 km/h (in smooth air) Max aero-tow speed: 115 mph Min sinking speed: 2.1 ft/sec / 0.64 m/sec at 46 mph / 41 kt / 76 km/h Best glide ratio: 34:1 at 52 mph / 45 kt / 84 km/h
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.
Designed by Ernest Schweizer for training, the 2-33 was to succeed the 2-22 as something a little plusher and better performing, thereby making it easier to attract new students into soaring. One of the very few sailplanes designed to carry passengers as distinct from a second pilot under training, the high performance SGS 2-32 accommodates a pilot and one very large or two average sized passengers under a long jet fighter-type blown Perspex cockpit canopy that opens sideways; dual controls are provided, and the rear control column can be removed for the passenger’s comfort. The cockpit is of a size more usually associated with powered aircraft than gliders, and among the optional ‘extras’ are radio, special instrumentation, electrical and oxygen systems, canopy locks, map cases, cushions and small wheels mounted at the wing tips.
Of traditional Schweizer all-metal construction, the 2-32 has cantilever single-spar mid-set wings with metal covering and fabric-covered ailerons; there are air brakes in the upper and lower surfaces. The fuselage is an all-metal monocoque, and there is a non-retractable unsprung monowheel, with a hydraulic brake, and a tailskid. The cantilever tail unit has an all-moving tailplane with an adjustable trim tab in it, the fin being metal-skinned and the control surfaces fabric-covered. A special SGS 2-32 with a new wing of 67ft span with integral water ballast tanks was built in 1970 for Joe Lincoln.
The prototype SGS 2-32 first flew on 3 July 1962 and FAA Type Approval was granted in June 1964, whereupon production started at once, a total of 89 having been built by January 1978. The 2-32 has set up a number of world and national records, including womens multi-place world and national records for absolute altitude and altitude gain (10,809 m / 35,463 ft and 7,848 m / 24,545 ft), in Class D2, of 35,462ft set by Babs (Mary L.) Nott and Hannah F. Duncan of the United States at Black Forest, CO on 5 March 1975.
The SGS 2-32 was chosen by the Lockheed Missiles & Space Co as the basic airframe of their YO-3A quiet observation and reconnaissance aircraft developed for service in Vietnam through the earlier QT-2 and Q-Star, likewise based on the 2-32. The Q-Star, developed by Lockheed as a private venture, first flew in June 1968 and was powered by a 185hp dorsally-mounted Curtiss Wright RC 2-60 rotary combustion Wankel engine driving a special low speed propeller through a long prop shaft passing over the top of the cockpit.
The SGS 2-32 also formed the basis of another quiet observation aircraft, the LTV Electrosystems L450F, which first flew in prototype form in February 1970 and was powered by a Pratt & Whitney PT6A-29 turboprop derated to 680shp.
The X-26A was a Schweizer SGS 2-32 sailplane that was used by the Navy to expose novice pilots to the phenomenon of yaw/roll coupling. Conventional jet trainers reacted much too quickly and dangerously for effective instruction – an aircraft that had unusually slow roll rates and excellent recovery characteristics was needed instead. Four of the gliders were originally delivered, but accidents soon claimed three of them. U.S. Navy 157932 crashed March 1971, pilot killed. U.S. Navy 157933 crashed May 18, 1972, pilot killed. In each case the aircraft was replaced with a new one, and the training program continued, making the X-26 the longest-lived X-vehicle. USN serial were 157932-157933, 158818, 159260, and 161571.
Two Schweizer 2-32s (67-15345 and 67-15346) from the U.S. Naval Test Pilot School X-26 Program (USNTPS) were modified to QT-2 configuration (QT for Quiet Thruster) by the Lockheed Missiles & Space Co. The original X-26 glider version was then designated X-26A.
The program included the X-26A Frigate sailplane and the motorized X-26B Quiet Thruster versions: QT-2, QT-2PC, and QT-2PCII. All were based on the Schweizer SGS 2-32 sailplane.
The first 2-32, serial 001, belongs to the National Soaring Museum.
Variations: Schweizer X-26 LTV Electrosystems L450F Lockheed YO-3A
Wing span: 17.37 m / 57 ft 1 in Length: 8.15 m / 27 ft 9 in Wing area: 16.72 sq.m / 180 sq.ft Aspect ratio: 18.05 Airfoil: NACA 63(3)-618, 4301 2A Empty Weight: 377 kg / 831 lb Payload: 231 kg / 509 lb Gross Weight: 608 kg / 1340 lb Water ballast: None Wing Load: 36.36 kg/sq.m / 7.44 lb/sq.ft Max airspeed: 130 kt / 140 mph (in smooth air) Rough air speed 130 kt Max aero-tow speed: 110mph Stall 44 kt / 81 km/h L/DMax: 33 84 kph / 45 kt / 52 mph Best glide ratio: 34:1 at 59 mph / 51 kt / 95 km/h MinSink: 0.61 m/s / 2.38 fps / 1.18 kt at 43 kt / 50 mph Seats: 3 No. Built: 87
X-26A Frigate Wingspan: 57 ft 1.5 in (17.37 m) Length: 26 ft 9 in (7.92 m) Height: 9 ft 3 in (2.74 m) Wing area: 180 ft² (16.7 m²) Wing aspect ratio: 18 Empty weight: 857 lb (389 kg) Loaded weight: 1,430 lb (650 kg) Max. takeoff weight: lb (kg) Maximum speed: 158 mph (254 km/h) Wing loading: 39 kg/m² (7.9 lb/ft²) Power/mass: 0.07 hp/lb (0.12 kW/kg) Rate of sink: 0.6 m/s (120 ft/min) Crew: two
Only one 1-29 was built by Ernest Schweizer. It consists of a modified 1-23G fuselage and tail with the addition of a constant chord, laminar-flow airfoil wing and balanced dive brakes. The wing ribs are identical, made from one master die to help ensure laminar flow. It has flush, counter-sunk rivets, and the heavy, deep spar helps to reduce elastic wing deflections and minimize skin oil-canning.
1964
It was subsequently presented to the National Soaring Museum
Ernest Schweizer’s medium performance single-seat SGS 1-26 was originally designed to be marketed in kit form to homebuilders, with a wing span of 40ft 0in.
It first flew in prototype form in January 1954 and following FAA Type Certification production began in November that year of 1-26s both complete and in kit form.
To help the amateur constructor, all the complicated alignments, welding and assemblies requiring specialised tooling are undertaken by the manufacturer; included in the kit is a basic welded fuselage assembly, and parts such as a pre-formed aluminium nose cap and the moulded Plexiglas canopy. The 1-26 was reckoned to require from 300 to 600 man-hours for assembly, depending on the homebuilder’s skill and experience and, unlike the earlier SGS 1-23, it had fabric covering of the control surfaces, fuselage and tail unit.
The 1-26 once held the National Feminine Distance and Goal records at 439.8 km./ 273.28 miles and 153.1 km./ 96.5 miles set by Rose Marie Licher and Jean Arnold, respectively. A significant number of pilots have earned all three Diamond badges in 1-26’s. A significant number of 1-26’s were sold outside the U.S. notably in Canada and Indonesia.
The original (‘standard’) model was factory completed (22 built); the A was a standard kit (114 built). They were of metal/ fabric wings and tail, steel-tube/ fabric fuselage.
The prototype 1-26 had fabric-covered wings, whereas the B, which first flew in June 1956, was factory completed with all-metal covered wings increasing both empty and gross weight by 11 kg/ 25 lb. The C was the kit version of the B.
The 1-26D, which first flew in June 1968, offered a new low-profile fuselage featuring a monocoque metal nose and new one-piece canopy for better visibility, plus air-balanced double dive brakes, a new cockpit interior and an increased allowable load, with a welded chrome-molybdenum steel tube fuselage with Ceconite fabric covering, and a new fin and rudder with squared-off top and straight trailing edge, replacing the curved top and rudder trailing edge of earlier versions.
The SGS 1-26E first flew in March 1971, with an all-metal semi-monocoque fuselage. The all-metal mid-wing has fabric-covered horizontal tail surfaces, ailerons and airbrakes.
SGS 1-26E
The E model superseded the 1-26D in 1971, being the last refinement in the 1-26 series with an all metal monocoque fuselage which appreciably increased the empty weight. The 1-26E has cantilever all-metal mid-set wings of aluminium alloy, with metal skinning and fabric covered ailerons, and balanced air brakes immediately aft of the spar. The cantilever tail unit is of aluminium alloy, with fabric covering on all versions. Landing gear consists of a non-retractable unsprung monowheel with a brake, with a nose skid mounted on solid rubber blocks just ahead of it; there is also a small solid rubber tailwheel, although the early versions had a tailskid, and there is a small wheel mounted under each wing tip. The pilot sits under a one-piece moulded Plexiglas canopy, and there is provision for radio to be carried. Dick Johnson’s flight test show little difference between the earlier models and the E. The U.S. Air Force Academy operates 3 as the TG-3.
The original Standard 1-26, serial 001, was donated to the National Soaring Museum.
More than 700 1-26s of all variants had been produced by January 1980, of which about 200 were in kit form. An SGS 1-26E was to be a prototype for an electrically-powered light aircraft being studied by NASA’s Dryden Flight Research Center and the Jet Propulsion Laboratory.
Only one all metal 2-25 was built by Ernest Schweizer and was flown in the 1954 World Championships at Champhill, England and 1956 World Championships at St. Yan, France in the multiplace category. Stan Smith and R.Kidder fininished 3rd in 1954, and Kempes Trager and Gene Miller were 4th in 1956. It has triple spoilers (2 on top, 1 on bottom of each wing). The sole example was donated to the soaring program at the U.S. Air Force Academy and later presented to the National Soaring Museum. It is presently on loan to the U.S. Air Force Museum at Wright Patterson FB, Dayton, OH.
The all metal 1-24 was a spare-time cooperative project between Ernest Schweizer and Howard Burr when he worked for the company. It features a shoulder wing and an internal traveling balance weight for trimming hands-off at 80 kph/ 43 kt/ 50 mph through 129 kph/ 70 kt/ 80 mph.
Designed by Ernest Schweizer, the SGS 1-23 all-metal high performance single-seater was first flown at the 1948 US National Soaring Contest at Elmira, NY, and was based on the 1-21.
The 1-23 has mid-set single-spar cantilever wings and is of truly all-metal construction with flush riveting, there being no fabric covering at all; 75ST alloy was used in the spar ends and fuselage centre-section, and the remainder of the structure was of 24ST Alclad. In its initial form the 1 -23 had a wing span of 43ft 10in, and an aspect ratio of 12.88, and there were two sets of spoilers in the wing upper surfaces. The outside spoilers were double ones and could be locked in four positions, fully open as dive brakes or intermediately for the landing approach; the inner spoilers were single for glide control on the approach, and were coupled to the monowheel brake. There was a rubber-mounted skid forward of the non-retractable unsprung monowheel, and a small tail wheel.
The 1-23B & C were built for the 1952 World Championships held at Madrid Cuatro Vientos, Spain flown by Paul MacCready and Paul Schweizer. They both had the wing spars spliced and stretched to 15.24 m / 50 ft, and the C had thicker wing skins, a heavier spar and weighed 41 kg./ 90 lb more.
The SGS 1-23D production version of the B (Air Transport Certified), like the 1-23B and 1-23C featured a wing increased in span to 50ft 0in, with an aspect ratio of 15.58, for improved performance, and production of this version started in July 1953; the wing tips were now square-cut instead of pointed as on the 1-23, and the fin and rudder were slightly larger.
One flown by Paul MacCready won the 1953 Nationals, and another was flown 733 km / 455.5 miles by Joe Lincoln to earn the Barringer Trophy for 1960. An example belongs to the National Soaring Museum.
The single 1-23E was built for Paul MacCready to fly in the 1954 World Championships where it finished 4th. It has balanced airbrakes and originally no wheel, using the skid for takeoff and landing. The 1-23E had a wing span of 16.1 m / 52ft 9.5 in and a thicker wing skin. Paul Bikle won two world altitude records with the 1-23E (14.102 m / 46.267 ft absolute 12.894 m / 42.303 ft gain).
The one 1-23F built was an E which featured butt joints in the structure instead of lap joints. A larger fin and rudder with squared-off top distinguished the 1-23G (Air Transport Certified). The 1-23G was a 1954 production model with the longer wing of the E and F, standard spoilers and a larger vertical tail of slightly different shape.
One 1-23G was developed into the experimental 1-29, which was basically a 1-23G fitted with a new constant-chord laminar flow wing, the first Schweizer design to be so fitted; this was used to flight test new design features as well as for competition flying.
Final production versions, also with the larger vertical tail surfaces, were the 1-23H and 1-23H-15, the H, of which 8 were built, having a span of 52ft 8in and limiting speed DFS-type air brakes which replaced the double spoilers of earlier versions, as well as detachable wing tips enabling it to be converted to a Standard Class 15m span, in which form it was known as the 1-23H-15. The pilot sits over the leading edge under a blown one-piece sideways-opening Perspex canopy, and there is room behind him for a radio, barograph and oxygen equipment. The 1-23H and H-15 has a squared-off top to the fin and rudder. The more numerous H-15 version has a wingspan reduced to 15.0 m / 49.2 ft qualifying it for the FAI-OSTIC Standard Class. It was also produced with removable tips increasing the span to 16.1 m / 52.8 ft. 39 of this model were built.
On 30 December 1950, a 1-23 flown by William Ivans set a new World height record of 42,100ft above sea level at Bishop, California, gaining 30,100ft from his aero-tow release height, and on 25 February 1961 a 1-23E flown by Paul Bikle set the world height record of 46,266ft.
A total of 69 SGS l-23s of all versions have been produced.
One, which also belongs to the National Soaring Museum, was substantially modified by Sterling Starr by the fitting of a new NACA 65 (3)-618 section 16.5 m / 54 ft wing.
SGS 1-23D Wing span: 15.24 m / 50.0 ft Length: 6.25 m / 20 ft 4 in Height 1.52 m / 5 ft 0 in Wing area 14.9 sq.m / 160 sq ft Wing section: NACA 43012A/23009 Aspect ratio: 15.6 Empty weight: 190 kg / 420 lb Max weight 340 kg / 750 lb Water ballast: None Max wing loading: 22.8 kg/sq.m / 4.6 lb/sq ft Max speed: 114 kt / 212 km/h Stalling speed: 28 kt / 52 km/h Min sinking speed at 30 kt / 55 km/h: 0.61 m/sec / 1.86 ft/sec Best glide ratio at 41.5 kt / 77 km/h: 30
SGS 1-23H Span: 52 ft 8 in Length: 20 ft 10 in Wing area: 164.9 sq ft Aspect ratio: 16.9 Empty weight: 480 lb Max weight: 750 lb Max speed: 140 mph Min sinking speed: 2.05 ft/sec at 37 mph Best glide ratio: 30.8:1 at 50 mph
SGS 1-23H-15 Span: 49 ft2.5 in Length: 20 ft 10 in Wing area: 159.4 sq ft Aspect ratio: 15.12 Empty weight: 474 lb Max weight: 750 lb Max speed: 140 mph Min sinking speed: 2.15 ft/sec at 38 mph Best glide ratio: 29.2:1 at 50 mph
All Aero 