Schweizer SGS 1-29
|Paul Schweizer's 1-29 at the 1963 US Soaring Championships at Harris Hill, Elmira, NY|
|Role||Experimental Standard-class sailplane|
|National origin||United States|
|Manufacturer||Schweizer Aircraft Corporation|
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.
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 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.
Design and development
The wings were all-metal and of constant chord. The wing ribs were identical and created from a single master die to ensure uniformity. The wing features a thick, deep spar 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%.
Aircraft on display
- Crew: One
- Wingspan: 49 ft 3 in (15.00 m)
- Wing area: 154 ft2 (15.3 m2)
- Aspect ratio: 15.75
- Wing profile: NACA 63-618
- Empty weight: 465 lb (224 kg)
- Gross weight: 750 lb (340 kg)
- Maximum glide ratio: 34 at 52 mph (83 km/h)
- Rate of sink: 123 ft/min (0.63 m/s)
- Activate Media (2006). "SGS 1-29 Schweizer". Archived from the original on 2007-08-08. Retrieved 2008-05-27.
- Schweizer, Paul A: Wings Like Eagles, The Story of Soaring in the United States, pages 159-209. Smithsonian Institution Press, 1988. ISBN 0-87474-828-3
- Said, Bob: 1983 Sailplane Directory, Soaring Magazine, page 32. Soaring Society of America, November 1983. USPS 499-920
- Smithsonian Institution (2004). "Directory of Airplanes". Retrieved 2008-05-13.
- Federal Aviation Administration (May 2008). "FAA Registry". Retrieved 2008-05-27.
- Munson, J. (n.d.). "Sailplanes in Our Collection". Archived from the original on 2011-05-16. Retrieved 2008-04-15.
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