The IS-4 was a high performance glider designed by Iosif Şilimon and built in Romania in the late 1950s at the URMV-3 (Rom: Uzinele de Reparatii Material Volant-3 - Glider repair and manufacture factory) factory at Braşov.[1]
| IS-4 | |
|---|---|
| Role | Sailplane |
| National origin | Romania |
| Manufacturer | URMV-3[1] |
| Designer | Iosif Şilimon[1] |
| First flight | 5 June 1959 |
| Developed from | URMV-3 IS-3d |
Design and development
editThe IS-4 high-performance glider followed the layout of the earlier IS-3d, constructed largely of wood with plywood and fabric skinning. The high-set cantilever wings with moderate dihedral (2º 30') were built with a single main spar with a plywood covered leading edge torsion box. The ovoid section fuselage was of monocoque construction with plywood skin with a streamlined full-length cockpit canopy forward of the wings. The undercarriage consisted of a balloon main-wheel with nose and tail skids. Flying controls were largely conventional with plywood skinned fixed portions and fabric covered wooden built up movable surfaces. Pitch trim was achieved by a trim tab on the elevators and adverse yaw was alleviated through the use of differential ailerons.[1]
Very little is known of the IS-4s development or operational history.
Specifications (IS-4)
editData from The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde Volume II[2]
General characteristics
- Crew: 1
- Length: 7.1 m (23 ft 4 in)
- Wingspan: 15 m (49 ft 3 in)
- Height: 0.9 m (2 ft 11 in) at cockpit
- Wing area: 14 m2 (150 sq ft)
- Aspect ratio: 16
- Airfoil: Root:Göttingen 549, Mid Göttingen 549, Tip Göttingen 693
- Empty weight: 210 kg (463 lb)
- Gross weight: 320 kg (705 lb)
Performance
- Stall speed: 60 km/h (37 mph, 32 kn)
- Never exceed speed: 200 km/h (120 mph, 110 kn) *Rough air speed max: 150 km/h (93 mph; 81 kn)
- Aerotow speed: 120 km/h (75 mph; 65 kn)
- Winch launch speed: 90 km/h (56 mph; 49 kn)
- Terminal velocity: with full air-brakes at max all-up weight 185 km/h (115 mph; 100 kn)
- g limits: +5 -3 at 250 km/h (135.0 kn)
- Maximum glide ratio: 30 at 80 km/h (50 mph; 43 kn)
- Rate of sink: 0.64 m/s (126 ft/min) at 41.6 mph; 36.2 kn (67 km/h)
- Wing loading: 22.9 kg/m2 (4.7 lb/sq ft)
See also
editAircraft of comparable role, configuration, and era Grunau Baby Related lists List of gliders
Notes
edit- ^ a b c d Gudju, Ion; Gheorghe Iacobescu; Ovidiu Ionescu (1974). Romanian Aeronautical Constructions 1905-1974. Bucharest. pp. 318–319.
{{cite book}}: CS1 maint: location missing publisher (link) - ^ Shenstone, B.S.; K.G. Wilkinson (1963). The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde Volume II (in English, French, and German) (1st ed.). Zurich: Organisation Scientifique et Technique Internationale du Vol a Voile (OSTIV) and Schweizer Aero-Revue. pp. 192–193.
References
edit- Shenstone, B.S.; K.G. Wilkinson (1963). The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde Volume II (in English, French, and German) (1st ed.). Zurich: Organisation Scientifique et Technique Internationale du Vol a Voile (OSTIV) and Schweizer Aero-Revue. pp. 192–193.
- Gudju, Ion; Gheorghe Iacobescu; Ovidiu Ionescu (1974). Romanian Aeronautical Constructions 1905-1974. Bucharest. pp. 318–319.
{{cite book}}: CS1 maint: location missing publisher (link)