ISF Mistral-C
The Mistral -C in 1974, was one of the first gliders, which was designed according to the rules of the then new competition class Club class. It is based on the Strauber Mistral, but received a new wing geometry with a lower aspect ratio, damped horizontal tail, built with modern composite materials. Both aircraft were designed in Germany. In total, more than 75 Mistral - C were prepared.
History
The immediate precursor of the Mistral -C was the standard class sailplane Strauber Mistral, which was designed by Manfred Strauber, Alois Fries, Hartmut Frommhold and Horst Gaber. Construction began in January 1970 and the first flight of the Mistral took place in July 1975. Series production of the original Mistral was not planned.
In October 1974 Strauber and Frommhold began under the name Engineering Office Strauber - Frommhold GmbH (ISF ) with the construction of a new aircraft model, the Mistral -C. This aircraft should meet one of the first rules of the then newly launched FAI Club Class. The first flight took place on 21 October 1976.
By the beginning of 1980 by the ISF 25 aircraft have been built. The number of after renaming the Mistral aircraft built up to the first half of 1981 aircraft is unknown. Valentin aircraft manufactured by the beginning of 1984 in the work of Mistral Mistral -C 50 additional aircraft.
Construction
Strauber Mistral
The Strauber Mistral was a shoulder-wing monoplane made of glass fiber reinforced plastic (GRP ) with 15 - meter wingspan and a T-tail. The wing area was 9.4 m at an aspect ratio of 23.9. The wing had a sweepback of 0.4 ° with 1 /4 of the tread depth. The V- position was also 0.4 ° . As wing profiles were at the root Wortmann FX -66 -S -196 and on the surface ends FX -66 -S -161 used. As the material for the wings a GRP balsa sandwich was used, the ailerons were made of fiberglass in conjunction with polymethacrylimide (PMI ) foam. The Schempp- Hirth airbrakes aluminum imports from only upward. Also PMI - filled fiberglass was used for the floating elevator. The semi-monocoque fuselage of the Mistral consisted of a GRP balsa sandwich, the hood was in one piece. The one-wheeled landing gear was einziehbahr, a tail skid was used at the rear. The best glide ratio of Strauber Mistral was 39:1, minimum sink at 0.6 m / s
Mistral -C
The main differences in Mistral -C relate to the wing and the materials used. The wing area was the same span increased, so that aspect ratio and thus the power has been reduced. The new wings were made of other Wortmann profiles, the sweep was 1.0 ° and the dihedral 4.30 °. Add wings and tail of the GRP balsa sandwich was replaced by a GRP - PVC foam sandwich, the ailerons and the fuselage were made entirely of fiberglass. Instead of a pendulum tail a dim tail was used. The hood is hinged at the side. The later produced by Valentin Mistral -C were nearly identical, only from a slightly lower dihedral of the wings is reported.
Use
In 2010, 54 civil registered Mistral -C there was in Europe, 2012, there were another 3 in the United Kingdom registered.