During the World Gliding Championships at Lüsse, Sunday 10th August was partly devoted to a demonstration of several self-launching gliders. After long periods under development, they are apparently now considered ready for display at gliding meetings. Whether there will be sufficient interest in the sailplane market for them to be produced in large numbers, remains to be seen.

A large biplane self launcher, believed to be of Russian origin, attracted a great deal of attention. It may seem that sailplane designers have neglected this type of layout, which has much to offer in terms of weight saving and structural integrity. Despite its great wingspan, unfortunately, the aerodynamicists can show that the performance of this aircraft with the power off will not be satisfactory for a modern gliding contest. The two wings tend to interfere with one another and there are four powerful wing tip vortices instead of the more common two. No tip winglets are fitted but may be available as an option. The many struts and wires, used for bracing, increase drag very seriously. These ought to be eliminated. The engine, despite the clever circular cowling, must create excessive drag when the engine is shut down for soaring. The propeller is incapable of being feathered. A fully retractable power unit should be developed. There is ample space in the fuselage for this. The undercarriage also should be re-designed. A thorough review and re-thinking of the fundamentals is required.

A very interesting innovation, rarely seen before in a glider, was the self-motivated anthropomorphic ballast packages. These are stored in the fuselage, rather than in bags in the wings, as is more usual. On the pilot's command they move under their own power to the ejection port and jettison themselves. This was demonstrated very effectively over the airfield at Lüsse. Four units of ballast, totalling about 420 kg, were jettisoned successfully. The packages were not damaged in the drop and were able to retrieve themselves automatically for re-use.

As this photograph, shows, the large span biplane self-launching glider aroused a lot of attention.

The SLG presented by Junkers was, our reporter understands, developed from some earlier designs which, while satisfactory in many ways, were thought to be in need of refinement before being offered to glider pilots. Instead of one motor, three are used here. They are not retractable when shut down, and the propellers cannot be feathered to reduce drag in the glide. No doubt the designers will turn their attention to these matters when the main concept has been proved. The ingenious use of corrugated metal skins undoubtedly adds strength and stiffness with no increase in weight. OSTIV aerodynamicists, unfortunately, consider that there can be little or no chance of laminar boundary layer flow over surfaces built in this way. Power off, the glide ratio will suffer. The use of camber changing flaps across the entire span, coupled with the ailerons, was thought highly commendable. The method of suspending these hinged surfaces on outriggers, however, with a gap between wing and flaps, should be investigated thoroughly and may need to be changed. Winglets will also be needed. As with the biplane described above, the fixed undercarriage would best be replaced with a retractable system.

There is very ample space inside the fuselage for the self motivated ballast and much more can be stored than in the Russian aircraft. Viewing ports all along the fuselage enable the pilot to check the ballast weights easily before entering the cockpit. There was no demonstration of the ejection procedure at Lüsse but photographs of it in use are probably available.

The Junkers glider exhibited a very respectable rate of climb during the launch.

The general reaction to the third self-launching glider was much more favourable although most of the pilots who looked at it were found to be considering its possibilities as a light touring aeroplane or even a glider tug, rather than a sailplane. Once these sinful thoughts were corrected, it was agreed that the aerodynamic design had been very well thought out, doubtless influenced by the designer's early experience on the Wasserkuppe with gliders such as the Messerscmitt S -12 and -13. The general shape is very good but for soaring, engine off, the wing span and aspect ratio are disappointingly low and, again, there are no tip winglets. The engine cannot be retracted, but it is very nicely cowled and faired into the lines. At least the undercarriage is retractable. With an accurately made laminar flow wing of much greater span, this could become a very efficient single seat motorised sailplane.

The Messerschmitt self-launching glider

This photograph shows the small span and low aspect ratio of the Messerschmitt self launcher.

Finally, a self launching sailplane with a small, full retracting turbojet motor was exhibited and flown. Designated the ASW 20CL, this aroused so much attention that, after it had landed, our reporter was unable to approach near enough to make any useful comments except that it has winglets. It apparently has much to offer and may well be seen again.