The IS-4 Jastrząb (Instytut Szybownictwa – gliding institute) was a single-seat aerobatic glider designed and built in Poland

Poland

Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...

from 1949.

Development

The IS-4 was built for aerobatics with a high structure strength and a very high maximum speed which could not be achieved in a vertical dive. Due to the pilots sitting position and the arrangements of the controls it was difficult for pilots to exceed the 8g loading limit. During high speed flight it was possible for the air-brakes to be sucked out violently so most pilots ensured that they remained closed by holding the airbrake control.

Variants

• IS-4 Jastrząb – two prototypes built in 1949.
• IS-4 Jastrząb bis – Thirty-five production aircraft, three of which were exported.

Specifications (IS-4 Jastrząb bis)

External links

• http://luftfahrtmuseum.org/htmi/itf/is4.htm
• http://www.piotrp.de/SZYBOWCE/pis4.htm
• http://kionastore.com/plan-1530.html
• http://www.vintagesailplanes.de/szd__4.htm