HWL Pegaz

HWL Pegaz was the first Polish post-war motor glider, a single-seat mid-wing monoplane with a pusher propeller and twin tail boom, which was designed and constructed by Tadeusz Chyliński and was built in Warsaw-Goclaw Aircraft Plant 6.
Design and development.
During 1945 and 1946, Tadeusz Chyliński took part in a competition of the Civil Aviation Department for developing a training motor glider. He won first prize for his project, the HWL Pegaz motor glider. From 1946 to 1947, Tadeusz Chyliński based on an agreement with the Department of Civil Aviation ("Departament Lotnictwa Cywilnego") with the help of Bronisław Żurakowski, developed the construction plans for the "Pegaz". The motor glider was designed to train class "C" glider pilots in stand-alone (without dual-controls) motor piloting, as well as for training and pursuing aeronautic sports in inexpensive aircraft. The engine for the "Pegaz" was designed by Stefan Gajecki, who was well known for designing skimming boat motors. Construction began on the "Pegaz" at the HWL (Harcerskie Warsztaty Lotnicze - Scouts' Aircraft Works) in Warsaw. In 1948, the work was taken over by Warsaw's Gocław Aircraft Plant 6.
The motor glider (one for flying and two unassembled) was finished in spring of 1948. The engineless plane was on display at the Aviation Day in 1948. "Pegaz" was test-flown on July 16, 1949, piloted by Bronisław Żurakowski and Jerzy Szymankiewicz. The factory and certification test were conducted at the National Aviation Institute in Warsaw and completed in May 1950. "Pegaz" was in three air shows on Aviation Day in 1949, 50, 51. At first, the plan was to build 80 "Pegaz" planes for various flying clubs. "Pegaz" passed the National Approval Test with a very good rating, however it was never put into production. There was the order from the USSR to stop work on national aviation projects. The "Pegaz" was assigned the registration number SP-590 and was given to the Warsaw Aviation Club to use, piloted by many glider pilots. It has been on display at Polish Aviation Museum in Kraków since August 1964.
Features.
The "Pegaz" proved to be very safe and easy to pilot during testing and operation. It was stable in every axis with the controls released. By stalling and releasing the stick with the engine running, the motor glider was able to make about decreasing changes in velocity, going into a fixed climb rate of 1.5 m/s with a trajectoryspeed of 90 km/h. Also by stalling and releasing the stick with the engine throttled, the velocity amplitude changed two to three times, after which the aircraft went into a fixed glide at a speed of 110 km/h and a descent rate of 2.0 m/s. When stalled with the rudder released, the motor glider displayed no tendency to spin. It was hard to get the "Pegaz" to go into a tailspin. The speed necessary to go into a tailspin was 55 km/h, with an altitude loss at one spin of 75 meters. Landing speed was 130 km/h. The motor glider performed acrobatic figures with a gravity load range up to 4 g. It could do loops at a speed of 125 km/h without losing altitude and ended loops with the same speed. The "Pegaz" behaved totally normal in dives at 210 km/h.
Survivors.
The HWL Pegaz (SP-590) is preserved in the Polish Aviation Museum in Kraków, from 1964