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Schweizer SGS 2-12

SGS 2-12, TG-3
TG-3A preserved at the National Museum of the United States Air Force
Role Training sailplane
National origin United States
Manufacturer Schweizer Aircraft Corporation
Designer Ernest and Paul A Schweizer
First flight 1942[1]
Number built 114

The Schweizer SGS 2-12 is a United States two-seat, low-wing, training glider built by Schweizer Aircraft of Elmira, New York.[2]

The 2-12 was a development of the Schweizer 2-8 two place training glider, with an all-wooden wing. It was designed especially for a US Army Air Force requirement to train glider pilots for air assault missions in World War II.[2][3]

Design and development

When the US entered World War Two in 1941 none of the US services had a glider program. The German use of glider-borne attack on the Belgian fortress of Eben-Emael and their use in the Battle of Crete convinced the US military that they would need glider-borne forces of their own.[4]

Initially the USAAF contracted Schweizer for the construction of the existing SGS 2-8, which entered service as the Army TG-2 and the US Navy and US Marine Corps LNS-1. The 2-8 was a good glider trainer, but had fabric-covered aluminum wings. Aluminum was designated as a "strategic material" and its use was to be avoided in training aircraft to conserve it for combat aircraft. Schweizer was therefore asked to design a new glider that would not use aluminum.[1][2]

Work began on the new model SGS 2-12 in the winter of 1941/42 as production of the 2-8 was getting under way.[1][2][3]

The 2-12 had a wooden wing, replacing the aluminum wing on the 2-8. Since the wing was being redesigned, several other improvements requested by the USAAF were incorporated into the design, including simplifying the design for mass production.[1][2][3]

The new wing was 2 feet greater in span, giving it a slightly better glide ratio than the 2-8. The greater span also helped make up for the additional weight of the aircraft. Typical empty weights were almost double that of the 2-8 at 860 lbs (390 kg).[1][2][3]

The wing was also thicker in section, with a thicker spar, which allowed the elimination of the struts that the 2-8 had used, while permitting a higher redline speed. The wing was also moved from a mid-wing position to a low-wing, to improve the instructor's visibility from the rear cockpit. The new wing also incorporated balanced top and bottom surface divebrakes, replacing the 2-8's top surface spoilers.[1][2][3]

The 2-12 has a welded steel tube fuselage covered in aircraft fabric. The wood wings are also covered in aircraft fabric.[2][3]

The 2-12 received type certificate G-2-11 after the war was over, on 27 February 1947. All aircraft are officially FAA certificated as TG-3As, rather than SGS 2-12s.[5]

Operational history

A total of 113 TG-3As were built for USAAF use, including three XTG-3 prototypes. One TG-3A was constructed by Air Glider as part of an order for 50 TG-3As, but that company's contract performance was not acceptable to the USAAF and further orders were cancelled.[1][2][6]

All remaining military TG-3As were sold to gliding schools and individuals at the end of the war. One civil SGS 2-12 was completed by Schweizer for factory use at the very end of the military TG-3A production line, bringing the total completed to 114.[1]

The SGS 2-12 is a large and heavy glider. It is also difficult and time-consuming to remove the wings for trailering or storage. After the war, when many were in civil service these factors resulted in many being tied down outside, rather than being protected in trailers. The wooden wings on many suffered deterioration as a result of exposure to the weather.[2]

Records

The 2-12 was a rugged sailplane capable of high-altitude flight and was much sought after following World War Two. 2-12s were used to set several records.[2][3]

On November 4, 1945 Frank Hurtt and Paul A. Schweizer broke the multi-place duration record in a TG-3A. The flight was flown at Harris Hill in ridge lift and lasted 9:17 and was the first post war record set in the USA.[1]

In 1950 Harland Ross set a new altitude record with a 2-12 flight to 36,100 feet (11,003 m)[2][3]

Betsy Woodward set the feminine altitude record in a 2-12 as well.[2][3]

Variants

XTG-3
Three prototype TG-3s were constructed under the designation XTG-3.[2]
TG-3A
The USAAF variant. All surplus aircraft sold at the end of the war were TG-3As. 110 produced.[2]
SGS 2-12
One civil SGS 2-12 was completed.[1]

Aircraft on display

Survivors

In March 2011 there were still 29 TG-3As registered in the USA.[14]

Specifications (TG-3)

Data from Jane's all the World's Aircraft 1947[15]

General characteristics

  • Crew: 2
  • Length: 27 ft 7 in (8.4 m)
  • Wingspan: 54 ft 0 in (16.47 m)
  • Height: 8 ft 0 in (2.44 m)
  • Wing area: 237 sq ft (22.0 m2)
  • Airfoil: NACA 4416
  • Empty weight: 820 lb (372 kg)
  • Gross weight: 1,200 lb (544 kg)

Performance

  • Stall speed: 38 mph (61 km/h, 33 kn) *Aerotow max speed: 100 mph (87 kn; 160 km/h)
  • Never exceed speed: 100 mph (160 km/h, 87 kn)
  • Maximum glide ratio: 24:1 at 52 mph (45 kn; 84 km/h)
  • Rate of sink: 180 ft/min (0.9 m/s)
  • Wing loading: 5.15 lb/sq ft (25.1 kg/m2)

See also

References

  1. ^ a b c d e f g h i j Schweizer, Paul A: Wings Like Eagles, The Story of Soaring in the United States, pages 79–94. Smithsonian Institution Press, 1988. ISBN 0-87474-828-3
  2. ^ a b c d e f g h i j k l m n o Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 26. Soaring Society of America, November 1983. USPS 499-920
  3. ^ a b c d e f g h i j Activate Media (2006). "SGS 2-12 Schweizer". Archived from the original on 8 August 2007. Retrieved 17 May 2008.
  4. ^ Schweizer, Paul A: Wings Like Eagles, The Story of Soaring in the United States, page 78. Smithsonian Institution Press, 1988. ISBN 0-87474-828-3
  5. ^ Federal Aviation Administration (February 1947). "Type certificate data sheet no. gtc 5" (PDF). Retrieved 17 May 2008.
  6. ^ a b National Museum of the USAF (16 April 2015). "Schweizer TG-3A". Retrieved 16 June 2018.
  7. ^ Flugsafn Íslands - Akureyrarflugvelli (2009). "TF-SBA Schweizer TG-3A (SGS 2-12) (Icelandic language)". Archived from the original on 22 July 2011. Retrieved 3 November 2009.
  8. ^ Svifflugfélag Akureyrar (May 2008). "Sagan samansett (Icelandic language)". Archived from the original on 13 July 2011. Retrieved 3 November 2009.
  9. ^ Íslands, Flugsafn. "TF-SBA Schweizer TG-3A (SGS 2-12)". Flugsafn Íslands.
  10. ^ Munson, J. (n.d.). "Sailplanes in Our Collection". Archived from the original on 16 May 2011. Retrieved 15 April 2008.{{cite web}}: CS1 maint: year (link)
  11. ^ Mosson, Norbert (n.d.). "Schweizer TG-3". Retrieved 15 April 2008.{{cite web}}: CS1 maint: year (link)
  12. ^ "Airplanes – Western Antique Aeroplane & Automobile Museum". Waaamuseum.org. Retrieved 9 July 2013.
  13. ^ US Southwest Soaring Museum (2010). "Sailplanes, Hang Gliders & Motor Gliders". Retrieved 26 May 2011.
  14. ^ Federal Aviation Administration (March 2011). "FAA Registry". Retrieved 16 March 2011.
  15. ^ Bridgman, Leonard, ed. (1947). Jane's all the World's Aircraft 1947. London: Sampson Low, Marston & Co. p. 289c.
Quelle: http://en.wikipedia.org/wiki/Schweizer_SGS_2-12