Schweizer SGS 1-23
Encyclopedia
The Schweizer SGS 1-23 is a United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 Open and Standard Class
Glider Competition Classes
Competition classes in gliding, as in other sports, mainly exist to ensure fairness in competition. However the classes have not been targeted at fostering technological development as in other sports...

, single-seat, mid-wing 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 original "standard" 1-23 was introduced in 1948. The aircraft quickly became the most numerous competition and performance sailplane in the USA. A total of 93 of all sub-models were built by the time production was completed in 1967.

Development

Schweizer Aircraft started construction of the 1-23 prototype in May 1948. The aircraft was completed and first flew on 5 July 1948, only nine weeks after construction had begun.

The prototype had been ordered by Bill Frutchy 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...

 and the aircraft was available for him to fly it in the second half of the US Nationals.

The first production 1-23 was ordered by E.J Reeves. The success of this aircraft lead to more orders and series production was commenced. The 1-23 was initially sold on a "factory-direct" basis, which allowed them to be sold at a lower price than through the dealer network.

The 1-23 received type certificate 1G1 on 22 November 1949.

The 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 :...

. K & L Soaring now provides all parts and support for the Schweizer line of sailplanes.

Variants

1-23
The original 1-23 model is also referred to as a "standard". The aircraft had a 43.83 foot wingspan and a glide ratio of 27:1, with a minimum sink of 2.3 feet per second.

Gross weight for serial numbers 1 to 11 was 600 lbs. Later 1-23 standards had a gross weight of 660 lbs. One "standard" was retrofitted at the factory with water ballast for Kim Scribner. There were 22 "standards" completed.

Many pilots like the faster roll and better circling characteristics of the "standard" over the later longer-winged versions of the 1-23.


1-23A
There were no 1-23As built.


1-23B
The "B" model was introduced in 1952 and incorporated a longer wing of 50 feet in span. The spars were standard 1-23 spars with a spliced section added. There was only one "B" model built. It was a custom order for Paul MacCready
Paul MacCready
Paul B. MacCready, Jr. was an American aeronautical engineer. He was the founder of AeroVironment and the designer of the human-powered aircraft that won the Kremer prize...

 specifically to fly in the 1952 World Gliding Championships
World Gliding Championships
The World Gliding Championships is a gliding competition held every two years or so by the FAI Gliding Commission. The dates are not always exactly two years apart, often because the contests are sometimes held in the summer in the Southern Hemisphere....

 held in Madrid
Madrid
Madrid is the capital and largest city of Spain. The population of the city is roughly 3.3 million and the entire population of the Madrid metropolitan area is calculated to be 6.271 million. It is the third largest city in the European Union, after London and Berlin, and its metropolitan...

, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

.

The production version of the "B" model was the "D" model. The 1-23B was not certified.


1-23C
The "C" model was also built in 1952 and, like the "B", incorporated a longer wing with a 50 foot span. The "C" had heavier wing skins and a heavier spar and, as a result, weighed 90 lbs more than the "B". There was only one "C" model built for the designer Paul A Schweizer
Schweizer brothers
Paul, William , and Ernest Schweizer were three brothers who started building gliders in 1930. In 1937, they formed the Schweizer Metal Aircraft Company. Their first commercial glider sale was an SGU 1-7 glider to Harvard University's Altosaurus Glider Club. At that time, Eliot Noyes was a...

 specifically to fly in the 1952 World Gliding Championships
World Gliding Championships
The World Gliding Championships is a gliding competition held every two years or so by the FAI Gliding Commission. The dates are not always exactly two years apart, often because the contests are sometimes held in the summer in the Southern Hemisphere....

 held in Madrid
Madrid
Madrid is the capital and largest city of Spain. The population of the city is roughly 3.3 million and the entire population of the Madrid metropolitan area is calculated to be 6.271 million. It is the third largest city in the European Union, after London and Berlin, and its metropolitan...

, Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

.

The 1-23C was not certified.

The "C" was subsequently sold to by Larry Gehrlein who modified it to a large degree. It was crashed and rebuilt with a set of 1-23D wings. It was later damaged again in an accident and rebuilt by the factory as a "D" model. In the mid-1980s it was owned by the Rochester Soaring Club.

The "C" wings were also later rebuilt and used in the homebuilt
Homebuilt aircraft
Also known as amateur-built aircraft or kit planes, homebuilt aircraft are constructed by persons for whom this is not a professional activity. These aircraft may be constructed from "scratch," from plans, or from assembly kits.-Overview:...

 Gehrlein Precursor
Gehrlein Precursor
|-See also:...

. The Precursor mounts the 1-23C wings high on a Schweizer 1-26A
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...

 fuselage
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...

 to produce an aircraft with a 53.5 foot wing span and a glide ratio of 32:1.


1-23D
The 1-23D was introduced in 1953 and incorporated the improvements tested in the "B" and "C" models at the 1952 World Championships and beyond.

The "D" has a wingspan of 50 feet and a glide ratio of 30:1 at 48 mph, with a minimum sink of 2.0 feet per second at 36 mph. The gross weight on the "D" and later models is 750 lbs.

A total of 12 "D" models were produced. The aircraft received its type certificate on 1 June 1953.


1-23E
The 1-23E has 52.8 foot wings equipped with balanced dive brakes. It has a glide ratio of 31:1 at 46 mph and a minimum sink speed of 1.95 feet per second at 40 mph.

A single 1-23E model was constructed for Paul MacCready
Paul MacCready
Paul B. MacCready, Jr. was an American aeronautical engineer. He was the founder of AeroVironment and the designer of the human-powered aircraft that won the Kremer prize...

 to compete in the 1954 World Gliding Championships
World Gliding Championships
The World Gliding Championships is a gliding competition held every two years or so by the FAI Gliding Commission. The dates are not always exactly two years apart, often because the contests are sometimes held in the summer in the Southern Hemisphere....

 held in Great Hucklow
Great Hucklow
Great Hucklow is a small village in the Derbyshire Peak District which nestles under Hucklow Edge between the villages of Tideswell and Bradwell. It has a population of about 100. The area is now mainly agricultural, but the village was formerly a centre of the Derbyshire lead mining industry...

, United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

. He flew the "E" to a fourth place finish. The aircraft was originally constructed without a wheel and used a skid for takeoff and landing. After the Worlds a wheel was retrofitted.

The aircraft was subsequently sold to Paul Bikle
Paul Bikle
Paul F. Bikle Director of the U.S. National Aeronautics and Space Administration Dryden Flight Research Facility from 1959 until 1971, and author of more than 40 technical publications, has been associated with major aeronautical research programs including the supersonic X-15 rocket plane, and...

 and he used it to set two world altitude records on 25 February 1961. In the mid-1980s it was owned by the Rochester Soaring Club. The 1-23E was not certified.


1-23F
The 1-23F was a 1-23E with the same 52.8 foot wings but was constructed with heavier gauge, butt-constructed wing skins. Only one was built.

The 1-23F received its type certificate on 12 June 1958.


1-23G
The 1-23G was the production version of the 1-23E and F. It retained the 52.8 foot wing and had the same glide ratio of 31:1 at 46 mph and a minimum sink speed of 1.95 feet per second at 40 mph. The "G" had a redesigned taller fin and top-surface spoilers only.

A total of eight 1-23Gs were constructed. The type received its type certificate on 12 June 1958.


1-23H and 1-23H-15
The 1-23H was designed by adding balanced dive brakes to the "G", designing a square fin and rudder to replace the rounded ones found on earlier models, adding removable wingtips plus other minor changes.

The "H-15" reduced the span from 52.8 feet to 49.2 feet (15.0 m) which, combined with the dive-brakes, qualified the type for the then new Standard Class
Glider Competition Classes
Competition classes in gliding, as in other sports, mainly exist to ensure fairness in competition. However the classes have not been targeted at fostering technological development as in other sports...

. With removable wingtips the aircraft could be easily converted between the standard class and open class.

In its Standard Class configuration the "H-15" has a 29:1 glide ratio at 50 mph and a minimum sink of 2.2 feet per second at 37 mph.

The type received its type certificate on 13 March 1961 and a total of 47 were built, including 39 H-15s. Production of the "H" ended in 1967, completing an 19 year production run.


1-23HM
One production 1-23H was rebuilt as an experimental aircraft
Experimental aircraft
An experimental aircraft is an aircraft that has not yet been fully proven in flight. Often, this implies that new aerospace technologies are being tested on the aircraft, though the label is more broad....

 in the "racing-exhibition" category by Sterling Starr and designated SGS 1-23HM.

The HM was built by using a stock 1-23H fuselage and tail assembly. Starr built a new set of 54 foot (16.6 m) span wings with an aspect ratio of 23.5:1. The wings took 1500 hours to construct, but the resulting aircraft has a glide ratio of 33.2:1 which is a 7% improvement over the stock 1-23H. The HM later had retractable landing gear added.

The 1-23HM was flown in the 1966 US nationals.

The aircraft is registered as N94298 and is currently owned by Vincent Grisemer. It is on loan to 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...

.

Competitions & Records

1-23Ds were flown by Paul McCready to win the 1953 US Nationals and to set a distance record of 455.5 miles (733 km) by Joe Lincoln. Lincoln was awarded the Barringer Trophy
Barringer Trophy
The Lewin B. Barringer Memorial Trophy was established by the will of Lewin Barringer in 1948. The original rules specified that the trophy would be awarded for the longest distance soaring flight from any type of launching method other than airplane tow...

 in 1960 for that distance flight.

Paul Bikle flew the sole 1-23E to a world absolute altitude record of 46,267 feet for a record gain of 42,300 feet on 25 February 1961. The records were set in the Sierra Nevada lee wave
Lee waves
In meteorology, lee waves are atmospheric standing waves. The most common form is mountain waves, which are atmospheric internal gravity waves...

 between Mojave, California
Mojave, California
Mojave is a census-designated place in Kern County, California, United States. Mojave is located east of Bakersfield, at an elevation of 2762 feet...

 and Inyokern, California
Inyokern, California
Inyokern is a census-designated place in Kern County, California, United States. Inyokern is located west of Ridgecrest, at an elevation of 2434 feet . Located in the Indian Wells Valley. The population was 1,099 at the 2010 census, up from 984 at the 2000 census...

. Bikle flew the record flights without cabin pressurization or a pressure suit. His record stood for many years.

Museum aircraft

There is a 1-23D, N91899, and the sole 1-23HM, N94298, in 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...

.

Specifications (1-23 "Standard")

External links

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