The Schweizer SGS 1-29 is an American single-seat, mid-wing, experimental laminar flow airfoil

glider Glider may refer to: Aircraft and transport Aircraft * Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight ** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of glidin ...

built by Schweizer Aircraft of Elmira, New York.Said, Bob: ''1983 Sailplane Directory, Soaring Magazine'', page 32. Soaring Society of America, November 1983. USPS 499-920 The 1-29 is a development of the Schweizer SGS 1-23 that utilizes a 1-23 fuselage and a newly constructed set of 49.2 foot (15.0 m) span wings. The aircraft was constructed to study the feasibility of producing improved boundary layer laminar flow on a metal-winged sailplane. Only one SGS 1-29 was produced and the project was not pursued further.

Background

In the mid-1950s the SGS 1-23 was in full production and through successive models was performing very well in competition. By 1957 the development of fiberglass-reinforced plastic affected the production of many sporting goods, such as boats and fishing rods. Schweizer Aircraft thought it was only a matter of time before a fiberglass sailplane was produced. This concern was borne out in 1965, when two German fiberglass sailplanes were entered in the world championships. Schweizer Aircraft evaluated the use of fiberglass for sailplane construction and rejected it for several reasons: * The high cost of demonstrating to the

Federal Aviation Administration The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic ...

that this new material could safely be used for aircraft primary structure. * Problems with crash resistance of fiberglass structures in high impact accidents. * The unknown service life of fiberglass. * The high degree of manual labor required to do fiberglass lay-ups at that time and the associated cost. The company decided to concentrate on getting the best performance from the material that it knew best,

aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...

. Schweizer created several design studies of new sailplanes in the mid-1950s. These included: *Schweizer 2-27 *Schweizer 7-28 *Schweizer SGS 1-29 Of these, only the SGS 1-29 proceeded to prototype stage.

Design and development

The 1-29 was constructed using a modified SGS 1-23G

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraf ...

. New

wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is e ...

s were built for the aircraft to determine if better laminar flow could be achieved on a metal wing. The wings were all-metal and of constant chord. The

wing ribs In an aircraft, ribs are forming elements of the structure of a wing, especially in traditional construction. By analogy with the anatomical definition of "rib", the ribs attach to the main spar, and by being repeated at frequent intervals, form ...

were identical and created from a single master die to ensure uniformity. The wing features a thick, deep

spar SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...

to reduce wing flexing and "oil-canning" that might interrupt laminar flow. The wing was assembled using flush rivets and has balanced top and bottom dive brakes. The aircraft first flew in 1958 and flight testing was reported by Schweizer Aircraft as on-going through 1959. The 1-29 program did yield positive results. The standard production model SGS 1-23H-15 with the same fuselage and wingspan as the 1-29 and a NACA 43012A airfoil, produced a best glide ratio of 29:1. With its laminar flow wing and NACA 63-618 airfoil the 1-29 recorded a 34:1 glide ratio, an improvement of 15%. The 1-29 design was never

certified Certification is the provision by an independent body of written assurance (a certificate) that the product, service or system in question meets specific requirements. It is the formal attestation or confirmation of certain characteristics of a ...

and the sole aircraft that was built is an experimental aircraft in the "racing, exhibition" class and registered as N3898A.

Operational history

The 1-29 was flown in at least three US national competitions by Paul A Schweizer, Bill Ivans and Tom Smith.

Aircraft on display

Once the 1-29 test program was complete, the aircraft was donated to the

National Soaring Museum The National Soaring Museum (NSM) 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, United States. The NSM is the Soaring Society of America's officia ...

where it is currently listed as being in storage.

Specifications

References

External links

Photo of the SGS 1-29
{{Schweizer aircraft 1950s United States experimental aircraft 1950s United States sailplanes Schweizer aircraft Mid-wing aircraft Aircraft first flown in 1958