View source for Schweizer SGS 2-33

{{Short description|American training glider}}
<!-- This article is a part of [[Wikipedia:WikiProject Aircraft]]. Please see [[Wikipedia:WikiProject Aircraft/page content]] for recommended layout. -->
{{Infobox aircraft
 | name = SGS 2-33
 | image = Schweizer2-33C-GRVS.JPG
 | caption = 
 | type = [[Trainer aircraft|Training]] sailplane
 | national_origin = [[United States]]
 | manufacturer = [[Schweizer Aircraft Corporation]]
 | designer = [[Ernest Schweizer]]<ref name="ActivateMedia">{{cite web|url = http://www.sailplanedirectory.com/PlaneDetails.cfm?planeID=314|title = SGS 2-33 Schweizer|access-date = 2008-05-31|last = Activate Media|year = 2006|url-status = dead|archive-url = https://web.archive.org/web/20080625231055/http://www.sailplanedirectory.com/PlaneDetails.cfm?planeID=314|archive-date = 2008-06-25}}</ref>
 | first_flight = 1965<ref name="ActivateMedia"/><ref name="SoaringNov83">Said, Bob: ''1983 Sailplane Directory, Soaring Magazine'', page 32. Soaring Society of America, November 1983. USPS 499-920</ref>
 | introduction = 
 | retired = 
 | status = Production completed
 | primary_user = [[Royal Canadian Air Cadets]]
 |produced = 1967-1981
 | number_built = 579<ref name="ActivateMedia"/>
 | developed_from = [[Schweizer 2-22]]
 | variants = 
}}

[[File:Schweizer2-33C-GWCV01.JPG|thumb|right|Schweizer SGS 2-33A belonging to The Winnipeg Gliding Club]]
[[File:SchweizerSGS2-33C-GRVS27.JPG|thumb|right|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|thumb|right|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 (sailplane)|glider]] that was built by [[Schweizer Aircraft]] of [[Elmira, New York]].<ref name="ActivateMedia"/><ref name="SoaringNov83"/><ref name="Schweizer">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}}</ref>

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.<ref name="ActivateMedia"/><ref name="SoaringNov83"/><ref name="Schweizer"/>

From its introduction until the late 1980s, the 2-33 was the main training glider used in North America.<ref name="ActivateMedia"/><ref name="SoaringNov83"/><ref name="Schweizer"/>

==Background==
The SGU 2-22 two-seat training glider was introduced in 1945 and quickly became the most popular training glider in the USA.<ref name="SoaringNov832-22">Said, Bob: ''1983 Sailplane Directory, Soaring Magazine'', page 28. Soaring Society of America, November 1983. USPS 499-920</ref>

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.<ref name="Schweizer"/>

SGU 2-22 production was ended at serial number 258 in 1967 to commence production of the new model.<ref name="Schweizer"/>

==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 [[Schweizer SGU 1-7|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.<ref name="ActivateMedia"/><ref name="SoaringNov83"/><ref name="Pamphlet">Schweizer Aircraft: ''The Schweizer 2-33 Super Club Sailplane'', pages 1-4. Schweizer Aircraft undated</ref>

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.<ref name="Schweizer"/>

The 2-33 received type certificate G3EA on 10 February 1967.<ref name="G2EA">{{cite web|url = http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/6ae4e0e921eb7d16862573b1005bb659/$FILE/G2EA.pdf|title = GLIDER DATA SHEET NO. G2EA |access-date = 2008-05-31|last = Federal Aviation Administration|author-link = Federal Aviation Administration|date=September 2007}}</ref>

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 [[home-built aircraft|amateur-builts]], subject to conditions:<ref name="G2EA"/>

{{cquote|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.) <br />
(b)  A final inspection of the completed glider. <br />
(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.<ref name="G2EA"/><ref name="K&L">{{cite web|url = http://klsoaring.com/|title = K & L Soaring, LLC|access-date = 2008-04-05|last = K & L Soaring |year = n.d.}}</ref>

==Design==

The 2-33 was designed to be rugged, easy to maintain and with a high degree of [[crashworthiness]].<ref name="ActivateMedia"/><ref name="SoaringNov83"/><ref name="Schweizer"/><ref name="Pamphlet"/>

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 (aircraft)|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.<ref name="ActivateMedia"/><ref name="SoaringNov83"/><ref name="Pamphlet"/>

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 cord|bungee]] trim system, with aircraft starting with serial number 500 equipped with a "ratchet-lock trim".<ref name="ActivateMedia"/><ref name="SoaringNov83"/><ref name="Pamphlet"/><ref name="SGS233">Schweizer Aircraft: ''Schweizer 2-33A Sailplane Flight - Erection - Maintenance Manual'', page 1-2B. [[Schweizer Aircraft]]</ref>

==Operational history==
The [[United States Air Force Academy]] operated 13 2-33s as the TG-4A until they were replaced by the [[Blanik TG-10|TG-10B]] ([[LET L-23|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.<ref name="ActivateMedia"/><ref name="USAFA">{{cite web|url=http://www.usafa.af.mil/tu/306ftg/94fts/tg-4a.cfm |title=TG-4A |access-date=2008-05-31 |last=United States Air Force Academy |author-link=United States Air Force Academy |date=May 2008 |url-status=dead |archive-url=https://web.archive.org/web/20070825080923/http://www.usafa.af.mil/tu/306ftg/94fts/tg-4a.cfm |archive-date=August 25, 2007 }}</ref><ref>{{cite web | title = TG-4 Sailplane | publisher = Global Security.org | url = http://www.globalsecurity.org/military/systems/aircraft/tg-4.htm | access-date =  2007-02-28}}</ref>

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 TG-4|Laister-Kauffman LK-10A]] also bore the designation TG-4A, but from an earlier USAAF designation system.<ref name="ActivateMediaLK">{{cite web|url = http://www.sailplanedirectory.com/PlaneDetails.cfm?planeID=200|title = LK-10A Laister-Kauffmann|access-date = 2008-05-31|last = Activate Media|year = 2006|url-status = dead|archive-url = https://web.archive.org/web/20070608195510/http://www.sailplanedirectory.com/PlaneDetails.cfm?planeID=200|archive-date = 2007-06-08}}</ref><ref name="Andrade">Andrade, John: ''U.S.Military Aircraft Designations and Serials since 1909'', Page 169 and 170, Midland Counties Publications, 1979, {{ISBN|0-904597-22-9}}</ref>[[File:Sgs 2-33b sn286 5 20231004 1274531989.jpg|thumb|Long Island Soaring 2-33B being built at K&L Soaring]]There were 254 SGS 2-33s registered in the US as of November 2017, including:<ref>{{cite web|title=Make/Model Inquiry Results Schweizer SGS 2-33|url=http://registry.faa.gov/aircraftinquiry/AcftRef_Results.aspx?Mfrtxt=SCHWEIZER&Modeltxt=2-33&PageNo=1|website=registry.faa.gov|publisher=[[Federal Aviation Administration]]|date=20 November 2017|access-date=20 November 2017}}</ref>
*47 SGS 2-33
*206 SGS 2-33A
*1 SGS 2-33AK
*2 SGS 2-33B

There were 93 SGS 2-33s registered in Canada as of November 2017, including:<ref>{{cite web|title=Civil Aircraft Registry - Schweizer SGS 2-33|url=http://wwwapps.tc.gc.ca/Saf-Sec-Sur/2/CCARCS-RIACC/RchAvcRes.aspx?m=%7c%7c&cn=%7cSCHWEIZER%7c&mn=%7c233%7c&sn=%7c%7c&wf=0&wt=1000000&iy=%25%25&aac=3&ne=%25%25&ce=%25%25&rp=%25%25&fr=%25%25&in=%7C%7C&ay=%25%25&ac=%25%25&sc=%25%25&on=%7c%7c&tn=%7c%7c&c=%7c%7c&r=%25%25&p=%25%25&pc=%7c%7c&mo=A&print=y|author=Transport Canada|author-link=Transport Canada|work=wwwapps.tc.gc.ca|date=20 November 2017|access-date=20 November 2017}}</ref>
*15 SGS 2-33
*78 SGS 2-33A

==Variants==
;SGS 2-33
:The original 2-33 was certified on 10 February 1967 and includes serial numbers 1 to 85.<ref name="ActivateMedia" /><ref name="SoaringNov83" /><ref name="G2EA" /><ref name="POH">{{cite web|url = http://www.illinigliderclub.org/poh/2-33_poh.pdf|title = The 2-33 Sailplane Fight-Erection-Maintenance Manual|access-date = 2009-06-06|last = Schweizer Aircraft|author-link = Schweizer Aircraft|url-status = dead|archive-url = https://web.archive.org/web/20110726172914/http://www.illinigliderclub.org/poh/2-33_poh.pdf|archive-date = 2011-07-26}}</ref>
 
;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.<ref name="ActivateMedia" /><ref name="SoaringNov83" /><ref name="G2EA" /><ref name="POH" />
[[File:SGS233AwingsMuseum.jpg|thumb|SGS 2-33A at [[Wings Over the Rockies Air and Space Museum|Wings Museum]]]]
;SGS 2-33AK
:The "AK" model was an "A" model completed by the buyer from a kit. It was certified on 19 April 1973.<ref name="ActivateMedia" /><ref name="SoaringNov83" /><ref name="G2EA" />
:
;SGS 2-33B
:The B model has an extra 5 inches in the rear seat, a ratchet trim system, a nose wheel, and 40 extra pounds of gross weight. This new 2-33 was certified on 2 February 2022. As of March 2024, two have been delivered. One to Haris Hill Soaring and one to the Long Island Soaring Association.<ref>{{Cite web | title=Home | url=https://www.klsoaring.com | archive-url=https://web.archive.org/web/20080718034802/http://klsoaring.com:80/ | access-date=2025-01-11 | archive-date=2008-07-18}}</ref>
:

==Operators==
The SGS 2-33 remains popular with glider schools, the largest operator is the [[Air Cadet League of Canada]] with a fleet of 79 2-33s and 2-33As as of 2022.<ref name="TC">{{cite web|url = http://wwwapps2.tc.gc.ca/Saf-Sec-Sur/2/ccarcs/aspscripts/en/quicksearch.asp|title = Canadian Civil Aircraft Register|access-date = 9 June 2011|last = Transport Canada|author-link = Transport Canada|date = June 2011|url-status = dead|archive-url = https://web.archive.org/web/20110718042755/http://wwwapps2.tc.gc.ca/Saf-Sec-Sur/2/ccarcs/aspscripts/en/quicksearch.asp|archive-date = 18 July 2011}}</ref><ref name=SAC.ca>{{cite web |url=https://www.sac.ca/index.php/en/documents-en/info-general/694-canadian-glider-fleet-february-2022/file |title=Canadian glider fleet 2022 |last=Burton |first=Tony |date=July 2022 |website=SAC.ca |publisher=Soaring Association of Canada |access-date=16 November 2022 |quote=}}</ref>

Caesar Creek Soaring Club operates 2 2-33A's as of 2024.

The [[Indonesian Air Force Academy]] received 3 2-33As in 2009.<ref>{{Cite web |url=https://tni.mil.id/view-14009-3-pesawat-glider-perkuat-terbang-layang-terla-akademi-angkatan-udara.html |title=3 Pesawat Glider Perkuat Terbang Layang (Terla) Akademi Angkatan Udara |website=tni.mil.id |date=29 May 2009 |access-date=10 April 2025|language=ID}}</ref>

==Aircraft on display==
There is a 2-33A on display at the [[Wings Over the Rockies Air and Space Museum]].<ref name="NSM">{{cite web|url = http://www.soaringmuseum.org/collection.html|title = Sailplanes in Our Collection|access-date = 2008-05-19|last = Munson|first = J.|url-status = dead|archive-url = https://web.archive.org/web/20110516142717/http://www.soaringmuseum.org/collection.html|archive-date = 2011-05-16}}</ref>

==Specifications==
[[File:Schweizer SGS 2-33A two-seat glider colour 3-view drawing.jpg|thumb|Schweizer SGS 2-33A 3-view drawing]]
{{Aircraft specs
|ref=Jane's All the World's Aircraft 1988-89,<ref name=JAWA88-89>{{cite book |title=Jane's All the World's Aircraft 1988-89 |year=1988 |publisher=Jane's Information Group |location=London |isbn=0-7106-0867-5 |editor=John W.R. Taylor|page=642}}</ref> Pre-Course Information Package for Glider Candidates<ref name=package>{{cite web | publisher=Regional Gliding School (Pacific) | title =Pre-Course Information Package for Glider Candidates | year =2005 | url =http://www.cadets.net/pac/support/pdf/pre_study_glider05.pdf | access-date =2007-01-01 | url-status =dead | archive-url =https://web.archive.org/web/20110716201619/http://www.cadets.net/pac/support/pdf/pre_study_glider05.pdf | archive-date =2011-07-16 }}</ref>
|prime units?=imp
<!--
        General characteristics
-->
|crew=one
|capacity=one passenger
|length m=7.85
|span m=15.54
|height m=2.83
|wing area sqm=20.39
|aspect ratio=11.85:1
|airfoil=[[NACA airfoil|NACA 63<sub>3</sub>-618]]<ref name="SoaringNov83"/>
|empty weight kg=272
|max takeoff weight kg=472
|max takeoff weight note=
|more general=
<!--
        Performance
-->
|stall speed kmh=
|stall speed mph=
|stall speed kts=31
|stall speed note=dual
|never exceed speed kmh=
|never exceed speed mph=
|never exceed speed kts=85
|never exceed speed note=in smooth air, rough air and aero-tow
*'''Max winch-launch speed:''' {{convert|60|kn|kph mph|abbr=on}}
|g limits=+4.67 -2.56
|roll rate=
|glide ratio=22.25:1
*'''Best glide speed dual:''' {{convert|45|kn|kph mph|0|abbr=on}}
|sink rate ms=0.95
|sink rate ftmin=
|sink rate note=dual
*'''Minimum sink speed:''' {{convert|37|kn|kph mph|0|abbr=on}}
|lift to drag=
|wing loading kg/m2=23.14
|wing loading lb/sqft=
|wing loading note=max
|more performance=
|avionics=
}}

==See also==
{{aircontent
<!-- include as many lines are appropriate. additional lines/entries with carriage return. -->
|see also=
|related=<!-- related developments -->
|similar aircraft=<!-- similar or comparable aircraft -->
|lists=<!-- related lists -->
* [[List of gliders]]
}}

==References==
{{Reflist|30em}}

==External links==
{{commons category|Schweizer SGS 2-33}}
*[https://www.youtube.com/watch?v=L2UiOSmWiM0 2-33 takeoff video]
*[https://www.youtube.com/watch?v=Rf8vZrxwzlQ 2-33 takeoff video - cockpit view]

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[[Category:1960s United States sailplanes]]
[[Category:Schweizer aircraft]]
[[Category:Glider aircraft]]
[[Category:High-wing aircraft]]
[[Category:Aircraft first flown in 1965]]