Schweizer SGS 2-12

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The Schweizer SGS 2-12 is a United States two-seat, low-wing, training glider built by Schweizer Aircraft of Elmira, New York.Said, Bob: "1983 Sailplane Directory, Soaring Magazine", page 26. Soaring Society of America, November 1983. USPS 499-920]

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 Two. cite web|url = http://www.sailplanedirectory.com/PlaneDetails.cfm?planeID=311|title = SGS 2-12 Schweizer |accessdate = 2008-05-17|last = Activate Media|authorlink = |year = 2006]

Background

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.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]

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.

Development

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.

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.

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).

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.

The 2-12 received type certificate G-2-11 after the war was over, on 27 February 1947. cite web|url = http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/3a7256e8fd1ec9dc85256721006d5f78/$FILE/ATTWIDA4/G-2-11.pdf|title = TYPE CERTIFICATE DATA SHEET NO. GTC 5|accessdate = 2008-05-17|last = Federal Aviation Administration|authorlink = |year = 1947|month = February]

All aircraft are officially FAA certificated as TG-3As, rather than SGS 2-12s.

Construction

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

Production

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. cite web|url = http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=497|title = SCHWEIZER TG-3A|accessdate = 2008-05-26|last = National Museum of the USAF|authorlink = |year = undated]

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.

Variants

;XTG-3

:Three prototype TG-3s were constructed under the designation XTG-3.

;TG-3A

:The USAAF variant. All surplus aircraft sold at the end of the war were TG-3As. 110 produced.

;SGS 2-12

:One civil SGS 2-12 was completed.

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.

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.

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

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

In service

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.

In May 2008 there were still 29 TG-3As registered in the USA. [ cite web|url = http://registry.faa.gov/aircraftinquiry/acftinqSQL.asp?striptxt=TG3A&mfrtxt=&cmndfind.x=16&cmndfind.y=19&cmndfind=submit&modeltxt=TG-3A+|title = FAA Registry|accessdate = 2008-05-17|last = Federal Aviation Administration|authorlink = |year = 2008|month = May]

Museum aircraft

There is a 1943 model TG-3A, N61279, in the National Soaring Museum. This aircraft is displayed with its entire left side and wing revealed without fabric installed. cite web|url = http://www.soaringmuseum.org/collection.html|title = Sailplanes in Our Collection|accessdate = 2008-04-15|last = Munson|first = J.|authorlink = |year = undated] cite web|url = http://www.retroplane.net/soaring_museum/schweizer_tg-3/accueil.htm|title = Schweizer TG-3|accessdate = 2008-04-15|last = Mosson |first = Norbert|authorlink = |year = undated]

A TG-3A was restored by the Spartan School of Aeronautics in Tulsa, Oklahoma and donated to the National Museum of the United States Air Force in December 1980. [ [http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=497 USAF Museum TG-3A Fact Sheet] ]

pecifications

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span ft=54
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height m=2.44
height ft=8
height in=0
wing area sqm=22.0
wing area sqft=237
swept area sqm=
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volume m3=
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aspect ratio= 12.3
wing profile= NACA 4416
empty weight kg=390
empty weight lb=860
gross weight kg=544
gross weight lb=1,200
lift kg=
lift lb=

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max speed kmh=144
max speed mph=90
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range km=
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glide ratio= 24 at 52 mph (83 km/h)
climb rate ms=
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sink rate ms= 0.91
sink rate ftmin= 180

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ee also

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* List of gliders

References

External links

* [http://www.retroplane.net/soaring_museum/schweizer_tg-3/accueil.htm Detailed photos of the SGS 2-12 (US Army Air Force TG-3) in the NSM]