Polish Aviation Museum

31-864 Kraków,
al. Jana Pawła II 39
phone: (12) 640 99 60,
(12) 642 40 70
e-mail: info@muzeumlotnictwa.pl

a cultural institution of the Malopolska Region

Małopolska – Kraków Region

Mecenas Muzeum

Kraków Airport

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Patroni Medialni

Skrzydlata Polska

Glider: IS-1 Sęp bis

IS-1 Sęp bis
high performance glider

  • Technical data

Span 17.5 m (57 ft 4 in)
Length 7.5 m (24 ft 7 in)
Wing area 17 sq m (183 sq ft)
Empty weight 276 kg (608 lb)
Take-off weight 353 kg (778 lb)
Glide ratio 27 at 72 kph (45 mph, 39 kt) optimum  speed
Sink rate 0.74 mps (2.42 fps) at 67 kph (42 mph, 36 kt) economy speed
Minimum speed 50 kph (31 mph, 27 kt)
Max. diving speed 225 kph (140 mph, 121 kt)


A single-seat all-wooden high performance glider of a high wing cantilever configuration. The wings are equipped with divided flaperons, flaps, aerodynamic brakes and interceptors.

In 1945, the group of gliding enthusiasts decided to re-activate the Silesian Glider Workshops, which were established before the Second World War. As a result of this initiative, the Gliding Institute was established in 1946. Its goal was to design new gliders, using Polish experience in this field.

The Sęp (vulture) was the first after-war Polish construction designed at the Gliding Institute in Bielsko Biała. The initial design was carried our by engineers: Józef Niespał and Władysław Nowakowski. Despite hard times the prototype was flown on 2nd June 1947and already in July of the same year, the Sęp flown by Adam Ziętek represented Poland on the International Gliders Competition in Samedan, Switzerland. It came eight. The Polish glider was the only new construction there. The other participants flew the pre-war or the captured German gliders.

A few minor changes in the wings construction and the cockpit equipment were introduced in subsequent examples. The modified version bore the designation Sęp bis. The total production number (together with prototypes) was six gliders, the last one was still flying at the beginning of 1960's Flying the Sęps, the Polish glider pilots set several domestic and world records.

The IS-1 Sęp bis on display bearing the SP-552 markings was in service from 1948 until 1960, and took part in many different championships. In 1949 Irena Kempówna established two world speed records: over a triangular course of 100 km and over a straight distance of 100 km to a declared goal. In 1964 the glider was handed over to the museum.


Dofinansowano ze środków Ministra Kultury i Dziedzictwa Narodowego
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