PZL-Swidnik JK-1 Trzmiel
Single-seat open frame ultra-light helicopter with two rotor-tip mounted Wojcicki pulse-jets.
A jet-powered helicopter, the JK-1 Trzmiel, designed by J. Kotlinski, a former member of Zurakowski's design team, was completed at the I.L. (Aircraft Institute) in the spring of 1957.
A light pulse-jet-powered helicopter with a two-bladed main rotor with small two-blade servo-rotor above main rotor and two-blade tail rotor. Main rotor blades, with a steel spar in the leading edge, are filled with plastic and have sheet duralumin skin. Servo-rotor of two circular planform blades mounted on short streamline stubs. Two-blade small diameter directional control rotor at the rear end of fuselage frame. Total main disc area 38 sq.m.
The fuselage is an uncovered steel-tube structure. Power is from two 11-kg Wojcicki pulse-jets mounted at tips of main rotor blades.
First flown on 28 June 1957, the JK-1 was flight-tested hat year. Two were built.
Engine: 2 x Wojcicki turbojet, 12.5kg
Main rotor diameter: 7m
Max take-off weight: 340kg
Max speed: 131km/h