SZD-7 Osa
Role	Glider aircraft Type of aircraft
National origin	Poland
Manufacturer	SZD
First flight	16 August 1950
Number built	1
Developed from	IS-2 Mucha

The SZD-7 Osa was a single-seat developmental glider aircraft that was designed and built in Poland at Szybowcowy Zakład Doświadczalny (Glider Experimental Works) in Bielsko-Biała in 1950. Only one example was built.

Development

The SZD-7 or IS-7^[1] Osa (Wasp) was based on the IS-2 Mucha, with a laminar flow aerofoil section developed by Tadeusz Kostia. Little information on laminar flow aerofoils was available but Kostia was able to design the aerofoil for the SZD-7 Osa to achieve laminar flow to at least 18% chord. As well as the laminar flow wings, the Osa introduced the SZD plate-style airbrakes, which were installed aft of the mainspar. The first flight of the Osa took place at Bielsko airfield piloted by Adam Zientek on 16 August 1950.^[1] The prototype was registered as SP-1047.^[2]

Specifications (SZD-7 Osa)

Data from http://www.piotrp.de/SZYBOWCE/pszd7.htm

General characteristics

• Crew: 1
• Length: 6.8 m (22 ft 4 in)
• Wingspan: 15 m (49 ft 3 in)
• Height: 1.6 m (5 ft 3 in)
• Wing area: 14.1 m² (152 sq ft)
• Aspect ratio: 16
• Airfoil: Kosti laminar flow
• Empty weight: 237 kg (522 lb)
• Gross weight: 327 kg (721 lb)

Performance

• Maximum speed: 250 km/h (155 mph, 135 kn)
• Stall speed: 56 km/h (35 mph, 30 kn)
• g limits: +4.5 / -3
• Maximum glide ratio: 26.1 at 81 km/h (50 mph/44 kts)
• Rate of sink: 0.80 m/s (157 ft/min) at 73 km/h (45 mph/39 kts)