Schweizer SGS 2-33

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SGS 2-33
300px
Role Training sailplane
National origin United States
Manufacturer Schweizer Aircraft Corporation
Designer Ernest Schweizer[1]
First flight 1965[1][2]
Status Production completed
Primary user Royal Canadian Air Cadets
Produced 1967-1981
Number built 579[1]
Developed from Schweizer 2-22
Schweizer SGS 2-33A belonging to The Winnipeg Gliding Club
File:SchweizerSGS2-33C-GRVS27.JPG
SGS 2-33A showing its semi-tapered wing planform. The tire is used to secure the wing in windy conditions
File:Royal Canadian Air Cadets Schweizer 233 A.jpg
Schweizer SGS 2-33A used for training in the Royal Canadian Air Cadets gliding program

The Schweizer SGS 2-33 is an American two-seat, high-wing, strut-braced, training glider that was built by Schweizer Aircraft of Elmira, New York.[1][2][3]

The 2-33 was designed to replace the Schweizer 2-22, from which it was derived. The aircraft first flew in 1965 and production was started in 1967. Production was completed in 1981.[1][2][3]

From its introduction until the late 1980s, the 2-33 was the main training glider used in North America.[1][2][3]

Background

The SGU 2-22 two seat training glider was introduced in 1945 and quickly became the most popular training glider in the USA.[4]

By the early 1960s it became obvious to Schweizer Aircraft that a replacement for the 2-22 was needed. At that time the single seat Schweizer SGS 1-26 was becoming very popular for one-design competition flying. The company realized that the new trainer should have similar performance to the 1-26, in order to be used as the 1-26's two seat transition trainer.[3]

SGU 2-22 production was ended at serial number 258 in 1967 to commence production of the new model.[3]

Development

The SGS 2-33, indicating Schweizer Glider, Sailplane, 2 Seats, Model 33, was designed by Ernest Schweizer. The aircraft was a derivative of the 2-22, which in turn was based on the SGU 1-7 single place glider of 1937. The 2-33 retained the 2-22 and 1-7's metal wing, single spar and single strut arrangement.[1][2][5]

The 2-33 was manufactured in three variants and remained in production for 14 years. Production was only curtailed when demand dropped off due to the import of higher-performance two-place sailplanes from Europe.[3]

The 2-33 received type certificate G3EA on 10 February 1967.[6]

A number of 2-33s were delivered as kits to the purchaser and designated as SGS 2-33AK. These were accepted by the Federal Aviation Administration as certified aircraft and not amateur-builts, subject to conditions:[6]

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Each Model SGS 2-33A glider assembled from a kit is designated Model SGS-2-33AK. These K models will be eligible for an airworthiness certificate when accompanied by an affidavit certifying that the glider is constructed in exact accordance with the approved drawings and manual, and that the parts and materials furnished by the manufacturer in the kit have been used; and further when the following inspections have been satisfactorily passed:

(a) An inspection for workmanship, materials, and conformity before any covering is applied. (All woodwork may be sealed.)
(b) A final inspection of the completed glider.

(c) Check of flight characteristics.

The 2-33 type certificate is currently held by K & L Soaring of Cayuta, New York who now provide all parts and support for the Schweizer line of sailplanes.[6][7]

Design

The 2-33 was designed to be rugged, easy to maintain and with a high degree of crashworthiness.[1][2][3][5]

The 2-33 has a welded steel tube fuselage covered in aircraft fabric. The single-spar, aluminum structure wings are tapered from mid-span and feature top and bottom balanced divebrakes. The wings are covered in aluminum stressed skin. The tailplane and elevator are made from welded steel tube covered in aircraft fabric. The vertical fin is aluminum stressed skin construction, while the rudder is fabric-covered.[1][2][5]

The 2-33 has a fiberglass nose cone and a one-piece molded front canopy. Access to the rear seat is via door on the right-hand side. Instruments are fitted in the front cockpit only. Most 2-33s have a four-position bungee trim system, with aircraft starting with serial number 500 equipped with a "ratchet-lock trim".[1][2][5][8]

Operational history

The United States Air Force Academy operated 13 2-33s as the TG-4A until they were replaced by the TG-10B (L-23 Super Blanik) in 2002. The USAFA TG-4s were all donated to other US government agencies, such as the Civil Air Patrol or to aviation museums.[1][9][10]

Under the 1962 United States Tri-Service aircraft designation system the USAF 2-33 was designated as the TG-4A. This can cause confusion with a World War II training glider made by Laister-Kauffman and used by the United States Army Air Forces from 1941 to 1947. The Laister-Kauffman LK-10B also bore the designation TG-4A, but from an earlier USAAF designation system.[11][12]

In June 2011 there were still 347 SGS 2-33s registered in the USA. These included:[13]

  • 64 SGS 2-33
  • 281 SGS 2-33A
  • 2 SGS 2-33AK

There were 91 2-33s registered in Canada as of May 2008, including:[14]

  • 15 SGS 2-33
  • 76 SGS 2-33A

Variants

SGS 2-33
The original 2-33 was certified on 10 February 1967 and includes serial numbers 1 to 85.[1][2][6][15]
SGS 2-33A
The "A" model incorporated some minor changes, including a larger rudder with an aerodynamic balance horn. It was certified on 7 March 1968 and includes serial numbers 86 and subsequent. The replacement rudder of the "A" model was available as a retrofit to earlier 2-33s and some have been upgraded to "A" status.[1][2][6][15]
SGS 2-33AK
The "AK" model was an "A" model completed by the buyer from a kit. It was certified on 19 April 1973.[1][2][6]

Operators

The SGS 2-33 remains popular with glider schools, the largest operator is the Air Cadet League of Canada with a fleet of 54 2-33s and 2-33As as of June 2011.[14]

Aircraft on display

File:SGS233AwingsMuseum.jpg
SGS 2-33A at Wings Museum, June 2007

There is a 2-33A in the Wings Over the Rockies Air and Space Museum, but none in the collection of the National Soaring Museum.[16]

Specifications

Data from Jane's All the World's Aircraft 1988-89,[17] Pre-Course Information Package for Glider Candidates[18]

General characteristics

  • Crew: one
  • Capacity: one passenger
  • Length: 25 ft 9 in (7.85 m)
  • Wingspan: 51 ft 0 in (15.54 m)
  • Height: 9 ft 3 in (2.83 m)
  • Wing area: 219.5 sq ft (20.39 m2)
  • Aspect ratio: 11.85:1
  • Airfoil: NACA 633-618[2]
  • Empty weight: 600 lb (272 kg)
  • Max takeoff weight: 1,041 lb (472 kg)

Performance

  • Stall speed: 36 mph; 57 km/h (31 kn) dual
  • Never exceed speed: 98 mph; 157 km/h (85 kn) in smooth air, rough air and aero-tow
  • Max winch-launch speed: 60 kn (110 km/h; 69 mph)
  • G limits: +4.67 -2.56
  • Maximum glide ratio: 22.25:1
  • Best glide speed dual: 45 kn (83 km/h; 52 mph)
  • Rate of sink: 187 ft/min (0.95 m/s) dual
  • Minimum sink speed: 37 kn (69 km/h; 43 mph)
  • Wing loading: 4.74 lb/sq ft (23.14 kg/m2) max

See also

Related lists

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 32. Soaring Society of America, November 1983. USPS 499-920
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 Schweizer, Paul A: Wings Like Eagles, The Story of Soaring in the United States, pages 227-327. Smithsonian Institution Press, 1988. ISBN 0-87474-828-3
  4. ↑ Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 28. Soaring Society of America, November 1983. USPS 499-920
  5. ↑ 5.0 5.1 5.2 5.3 Schweizer Aircraft: The Schweizer 2-33 Super Club Sailplane, pages 1-4. Schweizer Aircraft undated
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Schweizer Aircraft: Schweizer 2-33A Sailplane Flight - Erection - Maintenance Manual, page 1-2B. Schweizer Aircraft
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.[dead link]
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  12. ↑ Andrade, John: U.S.Military Aircraft Designations and Serials since 1909, Page 169 and 170, Midland Counties Publications, 1979, ISBN 0-904597-22-9
  13. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  14. ↑ 14.0 14.1 Lua error in package.lua at line 80: module 'strict' not found.
  15. ↑ 15.0 15.1 Lua error in package.lua at line 80: module 'strict' not found.
  16. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  17. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  18. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

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