WSK PZL Świdnik SM-4 Łątka. 1962Last change: September 2019
Kraków July 30. 2018.
179b Section 1962
WSK PZL Świdnik PZL SM-4 Łątka
The PZL SM-4 Łątka helicopter was made of metal (steel) and composites (glass laminates). Composites were made of support rotor blades, a crew cabin shell, chassis components, a tail-gate balancer and a tail rotor.
Three-blade supporting rotor. The blades had a construction made of laminate. A girder made of a laminate with a polystyrene core. Strainer parts made of honeycomb filler were attached to the core. The whole was covered with a laminate. The blades had steel fittings at the base for connection to the rotor head. Fittings were able to move vertically and horizontally for control.
Two-blade tail propeller. Made in the same way as the main rotor. A tail propeller drive shaft was placed above the tail beam. The drive shaft consisted of five sections connected by joints.
The helicopter was made of three main sections: the cabin, the middle section, the tailbone. The cabin skeleton was made of laminate. The windows are made of organic glass. The cabin was attached to a beam that was a floor and was made of duralumin. The cabin floor connected to the truss of the central part with four fittings. The central part of the helicopter was a truss made of steel pipes connected by welding. In this part there is a main transmission, a motor with a fan, a fuel tank and others. The tail beam was a truss made of steel pipes.
The chassis consisted of skids, fixed. The skids were made of dural pipes.
WN-6S piston engine, air-cooled, six-cylinder with 132 kW (180 hp) starting power.
General characteristics of PZL SM-4 Łątka (Data T-T)
Fuselage length: 9.30 m
Height 2.80 m
Diameter of the rotor: 10.00 m (32 ft 10 in)
Main rotor surface: 78.5 m2 (845 m²)
Own weight: 640-660 kg (1 455 lb)
Useful weight: 340 kg
Starting weight: 970-980 kg
Maximum take-off weight: 1000 kg (2205 pounds)
Maximum speed: 115 km / h (71 mph, 62 kn) (estimated)
Range: 300 km (186 miles, 162 miles) (estimated)
Ceiling: 3300 m (10 800 ft) (estimates)
The rate of climb: 4.4 m / s (870 ft / min) (estimate)
Flight duration: 3 hours 20 minutes (estimated)
Drive unit: 1 × WN-6S air-cooled, six-cylinder, counter-rotating piston engine, 130 kW (180 HP)
Capacity: 2 passengers
One prototype was built.
Written by Karol Placha Hetman