M.Simons The World's Vintage Sailplanes 1908-45

THE SCHWEIZER SGS 2-8, TG-2

  Three American brothers. Paul, Ernest and William Schweizer, built their first glider, a primary trainer, in 1930 and followed this with several more ‘utility’ types. In 1935 they formed themselves into a small manufacturing company based at Peekskill in New York State, on the Hudson about 60 km north of Manhattan. The brothers were convinced that for the American market, metal structures were preferable to wood.
  The largest gliding club in the New York area was the ‘Airhoppers’ Club, with their site on Long Island. The group began to feel the need for a two-seater with dual controls. The ‘Airhoppers’ approached the Schweizers who promised to design and build for them a two-seater with a good enough performance for cross-country flying yet still robust, and easy to fly and maintain. Realising that they were in a good position to capture the market for two-seat sailplanes in the Eastern States, the Schweizers planned a small production run and tooled up accordingly.
  They settled on a moderate wingspan and an aspect ratio of 12.6. With a wing loading about 19.5 kg/sq m (4 Ibs/sq ft) the soaring performance would be quite good.
  The fuselage, with cockpits in tandem, was a robust framework of chrome-molybdenum steel tubing, with gas welded joints. For ease of ground handling a wheel was fitted in a position close to the centre of gravity when the aircraft was unloaded. A skid was provided under the belly forward of the wheel. The front pilot’s seat was ahead of the wing but the rear cockpit was behind the mainspar. This position, near to the centre of gravity, would allow the glider to be flown solo quite safely from the front seat. A transparent canopy, made up of curved plastic sheets bent and riveted to a light steel tubular frame, enclosed both cockpits, which had bucket seats with ample room for parachutes. The wing was mounted at shoulder level on the fuselage. The instructor’s head came above the wing so he had a very restricted view. To alleviate this, large windows were placed in the fuselage sides below the wing. Dual controls were fitted. Light aluminium tubes, clipped on to the steel frames beneath, gave a good aerodynamic form for the fabric covering which was stretched over them, then doped and painted.
  The NACA 4412 aerofoil was chosen. To prevent excessive mainspar weight with this thin wing, an external strut was added, with an extra brace to stiffen it against lateral, secondary failure. In accordance with usual glider practice, a single mainspar with a torsion-resisting ‘D'-nose wing was used, but in metal rather than wood. The spar was built up from angle extrusions of light alloy with a thin plate web; onto this spar were riveted the pressed alloy ribs. The metal skin was riveted to ribs and spar flanges. Aft of the spar the wing was fabric covered. The planform was of constant chord over the centre panels, with tapered tips. Four degrees of washout were built in to prevent tip stalling. This proved inadequate and later models had the washout increased to six degrees.
  Fittings were welded up from chrome-molybdenum steel and bolted to the spars. There were three attachment points to the fuselage, the mainspar, a rear diagonal drag-torsion spar, and an auxiliary front attachment.
  The machine’s initial flights in 1938 pleased everyone and the SGS 2-8 took part in the Nationals at Elmira in the same year. Schweizers received an order from the Soaring Society of America for another 2-8 for demonstrations and promotional purposes. This aircraft was delivered at Elmira in 1939, and the local people pressed the brothers to establish themselves at Elmira aerodrome, which they did in December. Several more 2-8s were built, and at the 1940 Elmira meeting, Robert Stanley set a new two-seat distance record of 347 km and in August of that year, Lewin Barringer climbed 4560 metres in a wave in Idaho.
  When the US military began its glider pilot training programme Schweizers were asked to produce two-seat training gliders. Soon their production line was in full swing. The 2-8 was re-numbered the TG-2, or Training Glider 2, of which 57 were built. As the US aircraft industry began to absorb huge quantities of metal alloys for operational aircraft, Schweizers were instructed to redesign their two-seater using wood. This was the end of the production run on the TG-2, which was soon replaced by the SGS 2-12, or, as it was known, the TG-3. This was the only wooden glider type they ever built. It was much heavier than the TG-2.
  After the end of the war the military TG-2s were sold very cheaply. There were, until 1974, still about twenty in service. One at least has been restored to its full military coloring and condition.

  Technical data:
  SGS 2-8, TG-2: Span, 15.85 m. Wing area, 19.94 sq m. Aspect ratio. 12.6. Empty weight, 204 kg. Flying weight, 390 kg. Wing loading, 19.56 kg/sq m. Aerofoil, NACA 4412.