Schweizer SGS 2-33
Encyclopedia
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
two-seat, high-wing, strut-braced, training glider
Glider (sailplane)
A glider or sailplane is a type of glider aircraft used in the sport of gliding. Some gliders, known as motor gliders are used for gliding and soaring as well, but have engines which can, in some cases, be used for take-off or for extending a flight...
built by Schweizer Aircraft
Schweizer Aircraft
The Schweizer Aircraft Corporation is a manufacturer of sailplanes, agricultural aircraft and helicopters located in Horseheads, New York. It was incorporated in 1939 by three Schweizer brothers , who built their first glider in 1930...
of Elmira, New York
Elmira, New York
Elmira is a city in Chemung County, New York, USA. It is the principal city of the 'Elmira, New York Metropolitan Statistical Area' which encompasses Chemung County, New York. The population was 29,200 at the 2010 census. It is the county seat of Chemung County.The City of Elmira is located in...
.
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.
From its introduction until the late 1980s, the 2-33 was the main training glider used in North America.
Background
The SGU 2-22 two seat training glider was introduced in 1945 and quickly became the most popular training glider in the USA.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
Schweizer SGS 1-26
The Schweizer SGS 1-26 is a United States One-Design, single-seat, mid-wing glider built by Schweizer Aircraft of Elmira, New York.The SGS 1-26 enjoyed a very long production run from its first flight in 1954 until 1979, when production was ended. The 1-26 was replaced in production by the...
was becoming very popular for one-design
One-design
One-Design is a racing method where all vehicles or boats have identical or very similar designs or models. It is also known as Spec series. It is heavily used in sailboat racing. All competitors in a race are then judged based on a single start time...
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.
SGU 2-22 production was ended at serial number 258 in 1967 to commence production of the new model.
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 1-7Schweizer SGU 1-7
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single place glider of 1937. The 2-33 retained the 2-22 and 1-7's metal wing, single spar and single strut arrangement.
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.
The 2-33 received type certificate G3EA on 10 February 1967.
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
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...
as certified aircraft and not amateur-builts, subject to conditions:
The 2-33 type certificate is currently held by K & L Soaring of Cayuta, New York
Cayuta, New York
Cayuta is a town in Schuyler County, New York, United States. The population was 545 at the 2000 census.The Town of Cayuta occupies the southeast corner of the county and is northeast of Elmira, New York.- History :...
who now provide all parts and support for the Schweizer line of sailplanes.
Design
The 2-33 was designed to be rugged, easy to maintain and with a high degree of crashworthiness.The 2-33 has a welded steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
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
Tailplane
A tailplane, also known as horizontal stabilizer , is a small lifting surface located on the tail behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed wing aircraft such as helicopters and gyroplanes...
and elevator
Elevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. In simplified terms, they make the aircraft nose-up or nose-down...
are made from welded steel tube covered in aircraft fabric. The vertical fin is aluminum stressed skin construction, while the rudder is fabric-covered.
The 2-33 has a fiberglass
Fiberglass
Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
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
Bungee cord
A bungee cord , also known as a shock cord, is an elastic cord composed of one or more elastic strands forming a core, usually covered in a woven cotton or polypropylene sheath...
trim system, with aircraft starting with serial number 500 equipped with a "ratchet-lock trim".
Operational history
The United States Air Force AcademyUnited States Air Force Academy
The United States Air Force Academy is an accredited college for the undergraduate education of officer candidates for the United States Air Force. Its campus is located immediately north of Colorado Springs in El Paso County, Colorado, United States...
operated 13 2-33s as the TG-4A until they were replaced by the TG-10B (L-23 Super Blanik
LET L-23
-See also:-References:*...
) in 2002. The USAFA TG-4s were all donated to other US government agencies, such as the Civil Air Patrol
Civil Air Patrol
Civil Air Patrol is a Congressionally chartered, federally supported, non-profit corporation that serves as the official civilian auxiliary of the United States Air Force . CAP is a volunteer organization with an aviation-minded membership that includes people from all backgrounds, lifestyles, and...
or to aviation museums.
Under the 1962 United States Tri-Service aircraft designation system
1962 United States Tri-Service aircraft designation system
The 1962 United States Tri-Service aircraft designation system is a unified designation system introduced by the United States Department of Defense on 18 September 1962 for all the U.S. military aircraft. Prior to this date, each armed service used their own nomenclature system...
the USAF 2-33 was designated as the TG-4A. This can cause confusion with a World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
training glider made by Laister-Kauffman and used by the United States Army Air Forces
United States Army Air Forces
The United States Army Air Forces was the military aviation arm of the United States of America during and immediately after World War II, and the direct predecessor of the United States Air Force....
from 1941 to 1947. The Laister-Kauffman LK-10B also bore the designation TG-4A, but from an earlier USAAF designation system.
In June 2011 there were still 347 SGS 2-33s registered in the USA. These included:
- 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:
- 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.
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.
SGS 2-33AK
- The "AK" model was an "A" model completed by the buyer from a kit. It was certified on 19 April 1973.
Operators
The SGS 2-33 remains popular with glider schools, the largest operator is the Air Cadet League of CanadaAir Cadet League of Canada
The Air Cadet League of Canada is a volunteer organization that provides financial support and oversight to the Royal Canadian Air Cadets. The Air Cadet League owns all of the aircraft used in the Air Cadet Gliding Program...
with a fleet of 54 2-33s and 2-33As as of June 2011.
Aircraft on display
Wings Over the Rockies Air and Space Museum
The Wings Over the Rockies Air and Space Museum is located on the former grounds of Lowry Air Force Base in Denver, Colorado. The museum, which opened in 1994, is housed in the Hangar #1 built in 1939. The museum preserves the history of Lowry AFB's operations from 1938 to 1994 in its...
, but none in the collection of the National Soaring Museum
National Soaring Museum
The National Soaring Museum is an aviation museum whose stated aim is to preserve the history of motorless flight. It is located on top of Harris Hill near Elmira, New York, USA.The NSM is the Soaring Society of America's official repository...
.