Schweizer SGS 1-35

By the early 1970s competition in the open, standard and 15 meter classes was dominated by fiberglass sailplanes. Schweizer Aircraft evaluated the use of fiberglass for sailplane construction but 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. One of the factors that convinced the company there was a market for a US-made competition sailplane was the loss of value of the United States Dollar in the early 1970s which had made European sailplanes prohibitively expensive to US buyers. ==Development==

Schweizer Aircraft started construction of the 1-35 prototype in late 1972 and it first flew in April 1973. The company carried out side-by-side comparisons with fiberglass sailplanes as part of 50 hours of flight evaluations before making the decision to proceed with manufacturing the design on 10 May 1973. The 1-35 received type certificate G4EA on 25 April 1974. The type certificate is currently held by K & L Soaring of Cayuta, New York. K & L Soaring now provides all parts and support for the Schweizer line of sailplanes. ==Variants==

;1-35 The original 1-35 model has water ballast and retractable landing gear ;1-35B There was no 1-35B model ;1-35C The "C" stood for "Club" as this model was intended to be a high-performance sailplane for recreational, as opposed to competition, flying. It was designed to appeal to private owners, commercial rental operations and gliding clubs. The "C" has fixed landing gear and no provisions for water ballast. 41 built. ==Competition use==

The 1-35 was only competitive for a very short period of time in the early 1970s before European sailplanes such as the Schempp-Hirth Mini-Nimbus and the Glasflügel Mosquito, both introduced in 1976, out-classed it. The metal wing, while of good quality construction, just could not be made to hold an airfoil profile to the same accuracy as a fiberglass wing. The SGS 1-35 would mark the last attempt by the company to produce a competition sailplane. The 1-35 quickly found a home as a club and personal glider and, other than in national or world-class competition, has proved popular due to its rugged metal airframe and aesthetic appeal. ==In service==

As of May 2025 there were still 55 1-35s registered in the USA including: • 27 SGS 1-35 • 2 SGS 1-35A • 26 SGS 1-35C There are also five SGS 1-35s registered in Canada. ==Museum aircraft==

The prototype SGS 1-35, N17900 is on display in the National Soaring Museum. A SGS 1-35, N135V is hung from the ceiling inside the UTA Engineering building in Arlington, Texas. ==Specifications==