Flight, March 1923
SOME CZECHO-SLOVAK GLIDERS
REFERENCE has been made in FLIGHT on several occasions to the way in which Czecho-Slovakia is taking a keen interest in aviation, realising that geographically Prague is destined some day to become a great aviation
centre. Lately this interest has been extended to gliding and the construction of gliders, and we are able to publish photographs this week of three new gliders designed and built in Czecho-Slovakia.
The firm "Aero," of Prague, of which the chief designer is Mr. A. Husnik, has produced a cantilever monoplane of somewhat unusual design. This machine is shown in two of the accompanying photographs, which we reproduce by courtesy of our Czecho-Slovak contemporary Letectvi. In one form the machine has the rear portion of the fuselage covered in, while in the other, intended for school work and ease of repair, the girder is left uncovered. In the latter type, diagonal wing struts can be added so as to give extra strength for school work.
The cantilever monoplane wing has a single spar, with spruce flanges and three-ply side webs. It is built in three sections to facilitate transport. The centre-section is held down by four bolts, so arranged as to allow of a slight shifting of the wing in a fore-and-aft direction for trimming purposes. The leading edge over the centre-section is covered with three-ply to give extra stiffness, the rest of the wing being fabric covered.
The fuselage is very deep in front, and is of triangular section, the materials used being steel tube in front and wood longerons and struts in the rear portion. The pilot sits in front, beneath the wing, and the lower longeron is extended forward to form a central skid. The controls are of usual type, but on the left is a lever by means of which the angle of incidence of the wing can be altered during flight. When the machine is used for school work this lever can be locked, so that the pupil uses the machine as an ordinary fixed-wing monoplane. The span of the "Aero" glider is 14 m. (46 ft.) and the wing area 16 sq. m. (172 sq. ft.).
The "Praha" glider was designed and built by Group II of the "Aero" works, and is somewhat similar to the "Aero," although its fuselage is of rectangular section. The machine was built in such a way as to facilitate repairs, and is stated to have fulfilled this requirement admirably. As in the "Aero," the "Praha" has a central skid projecting out in front, and the pilot's seat is placed above this. The wing is supported by a single strut on each side, sloping up to the single wing spar from the central skid. The wing ribs are flexible, and the wing can be warped for lateral control, as well as having its angle of incidence changed in conjunction with the elevator for longitudinal control. The span is 14 m. (49 ft. 2 ins.) and the chord is 1 m. in the centre, tapering considerably towards the tips. The overall length is 4.5 m. (14 ft. 9 ins.), which seems rather short for the span. It is stated, however, that the machine has proved to be very stable.
The "Mura" was designed and built by Group I of the "Aero" works, and is a monoplane of more orthodox type, with rigid wing and aileron controls. It has a two-skid undercarriage, incorporating rubber shock-absorbers, and later it is intended to fit a small auxiliary motor. The span is 12 m. (39 ft. 5 ins.) and the wing area 15.2 sq. m. (164 sq. ft.). The weight is stated to be 61 kgs. (134 lbs.). The wing, it will be seen, is slightly swept back.