Schweizer SGS 1-34 - Design and Development

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 velocity dive 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 (49.2 feet) wingspan.

The SGS 1-34 is of all metal aluminum 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 root transitioning 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.