ITS-IVB
ITS-IV | |
---|---|
Role | High performance research glider |
National origin | Poland |
Manufacturer | ZASPL |
Designer | Adam Nowotny, Franciszek Kotowski |
First flight | 30 July 1935 |
Number built | 1 |
The ITS-IV was a
Design and development
The ITS-IV was a high performance, two seat research sailplane designed initially by Adam Nowotny to gather meteorological and airframe stress data. It was also intended to provide blind flying training. Franciszek Kotowski took over the design work after Nowotny's death in July 1934[1], producing the ITS-IVB.[2]
It was an all-wood aircraft. The two part wing had a rectangular plan central section and gently tapering trapezoidal outer panels. Each part was built around a single plywood box-spar which was widened and reinforced in more highly stressed regions; at the wing roots it extended back across almost the whole chord, narrowing linearly outwards far as about mid-wing, after which it reduced only slightly. Away from the plywood spar and tips the wings were fabric-covered, as were the differential ailerons which filled the trailing edges of the outer panels. The wing bracing was unusual, with the normal rigid struts replaced by pairs of steel ribbons on each side. The upper pair ran from a central cabane, formed from three steel tubes. to the wing and the others joined the wing to the lower fuselage. They offered less air resistance and also provided a way to measure wing loads in flight.[2][3]
The fuselage was a ply-covered semi-monocoque structure with an oval cross-section. It was unusually wide and deep in the central section, tapering away strong aft of the wings. This variation allowed an uncramped, enclosed pilot's cockpit ahead of the wing and a very generous workspace for the observer, who accessed his space via a port side door[2] and had large elliptical, celluloid-paned[3] underwing windows on each side. He also had a table which could be folded away if he needed to use the dual flight controls. A sprung landing skid was mounted below.[2]
The empennage was conventional, with a cantilever, tapered tailplane and elevators mounted on top of the fuselage[2] and a fin carrying a full, rounded, deep, rudder hinged behind the elevators. The fixed surfaces were ply-covered and the control surfaces fabric covered.[3]
Operational history
Specifications (ITS-IVB)
Data from J. Cynk (1971)[2] except where noted
General characteristics
- Crew: Two
- Length: 8.42 m (27 ft 7 in)
- Wingspan: 20 m (65 ft 7 in)
- Height: 2.2 m (7 ft 3 in) [3]
- Wing area: 24.3 m2 (262 sq ft)
- Aspect ratio: 15.8
- Airfoil: Göttingen Gö 655
- Empty weight: 254 kg (560 lb)
- Gross weight: 431 kg (950 lb)
Performance
- Maximum glide ratio: 22.5 at 73 km/h (45 mph; 39 kn) best
- Rate of sink: 0.82 m/s (161 ft/min) at 63 km/h (39 mph; 34 kn) minimum[3]