The Schweizer SGS 1-34 is a United States StandardClass, single-seat, high-wing glider built by Schweizer Aircraft of Elmira, New York. The 1-34 was designed over a number of years in the mid-1960s and first flew in 1969. By the time the 1-34 was introduced it was no longer competitive in the Standard Class, but has proven very successful as a club aircraft.
Design and development
The 1-34 was designed over several years to spread out the development costs. At the time the design work on the aircraft was started the Standard Class was new and described a very simple aircraft with terminal velocitydive brakes, fixed landing gear and no water ballast. By the time the 1-34 had flown in 1969 the Standard Class rules had changed to allow essentially unrestricted sailplanes with a 15-metre wingspan. The SGS 1-34 is of all metalaluminum semi-monocoque construction. All surfaces are aluminum covered, with the exception of the rudder which is covered in aircraft fabric. The 1-34 has the originally specified terminal velocity dive brakes, that limit the glider to below redline speeds in a vertical dive. Developing and testing these proved expensive and time-consuming and this also extended the aircraft's development time. The 1-34 was the first Schweizer design to depart from using a NACA airfoil. The 1-34 has no wing washout and instead uses a Wortmann FX 61-163 airfoil at the wing roottransitioning to a Wortmann FX 61-126 airfoil at the wing tip. The tip airfoil stalls at a higher angle of attack, ensuring that the wing root stalls first. The one company concession to the changing Standard Class rules was the development of a retractable landing gear version of the 1-34, designated as the SGS 1-34R. The 1-34 also features in-flight adjustable rudder pedals and a two-way adjustable seat to accommodate pilots of different heights. The 1-34 was flown in Standard Class competitions, but was out-performed by the new fiberglass European gliders, such as the Glasflügel H-201 Standard Libelle. During the protracted development process, Schweizer Aircraft was aware that the 1-34 would be overtaken by the changes in class rules and also by the performance of the newer European fiberglass sailplanes, but continued development of the SGS 1-34 anyway. The company identified that there was demand from private owners and especially clubs and commercial operations for a simple, rugged single seat glider with greater performance than the 1-26. In service the 1-34 has proven to be a popular club aircraft and ideal for the completion of badge flights. If a greater number of 1-34s had been built, Schweizer indicated that it would have become another one-design class, similar to the 1-26. The 1-34 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.
Operational history
At least two 1-34s have been highly modified. Bob Park's 1-34R, registered N17974, was damaged when a hurricane passed through Georgia and resulted in a hangar collapse. The 1-34R was rebuilt with a V-tail and ballast tanks mounted in the wings that hold 230 lbs of water. The aircraft was subsequently registered in the experimentalRacing - Exhibition category. A modified SGS 1-34 airframe with tricycle landing gear and powered by a Lycoming TIO-360piston engine was used as the basis for the pilotless Martin Marietta Model 845 prototype, an entry in the early 1970s USAF Compass Dwell enduranceUAV program. In May 2008 there were still 63 1-34s and six 1-34Rs registered in the USA and 5 SGS 1-34s in Canada. The USAF designation for the SGS 1-34 is TG-6.
