Kestrel (401)

The Open Class was quite neglected by glider pilots in Germany between 1970 and 1980.  Standard Class was the most popular, and from 1976 there was a strong influx of new gliders for the new 15 metre class. Open Class remained somewhat behind in numbers and this can clearly be seen when looking at Championship entries for this time. First and foremost, the price of the large gliders may be to blame for this development, but in many places it is probably also a question of hangarage, the problem of the launch possibility (many fields only had winch) and simply the handling on the ground.

But now they are a very sought after aircraft with a wingspan of more than 15 metres, and the Kestrel must be counted among them.

The Kestrel, whose name comes from English and means “Turmfalke” in German, was originally designed as a further development of the H-301 Libelle. However, it has almost nothing in common with it, rather the Kestrel is a fundamentally new construction, for which mainly Josef Prasser and Dieter Althaus were responsible. Like the fs-25, the fuselage with its relatively strong constriction is influenced by wind tunnel investigations carried out by members of Akaflieg Stuttgart. The vertical stabilizer has a new Wortmann profile and the horizontal stabilizer with a span of 2.85 m is mass balanced.

The cockpit of the Kestrel is quite spacious and the rear part of the canopy folds up for entry. Schempp-Hirth airbrakes are fitted on the upper side of the wing and flaps are also fitted. In addition, a brake parachute is installed.

The first flight took place on the 9th of August 1968 in Karlsruhe-Forchheim.

A total of 129 Kestrels were built at Glasflügel. Under license, the Slingsby company in England also built first the 17 m version, then mainly a 19 m Kestrel with the designation T59D.

Wingspan                         17.00 m
Surface Area                    11.58 m²
Aspect Ratio                    25
Profile                               FX 67-K-170
Profile                               FX 67-K-150
Length                              6.72 m

Empty Weight                                  280 kg
Maximum Cockpit Weight             105 kg
Maximum Gross Weight                400 kg
Maximum Ballast Weight              approximately 20 kg
Maximum Wing Loading               34.5 kg/m²

Maximum Speed                              250 km/h
Stall Speed                                         62 km/h

Minimum sink at  74 km/h              0.55 m/s
Best Glide at 97 km/h                      43