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Vintage RC Helicopters - Schlüter Cobra
Harsewinkel 1970 and Dieter Schlüter with his semi-scale Bell Huey Cobra presented to the world the first successful Radio Controlled Model Helicopter and following this initial outing he them set world records for both duration and distance. Prototype Cobra - Technical description in Dieters own words of his model Cobra taken at the time of the world record.
Dieter was inundated with best wishes and invitations to display the helicopter flying plus he also received many requests for details or better yet finished mechanical components. The original Cobra mechanics were not really suited to mass production and the gearbox overheating problem could not be solved in production by adding the complication of a pump and cooling tank as per the prototype for the duration record. The gearbox was completely redesigned to be of the spur gear / bevel arrangement (3:1 tail rotor and 9:1 main rotor reduction) which was significantly more efficient and as such would not overheat, especially as the housing was a hand made aluminium casing which would radiate any heat generated. The rotor head also required redesigning for a simpler production method and would not incorporate the swivel. All parts were produced in dieters workshop and it became a full family affair which took over the whole house. The original kits came out late in 1970 but as Dieter still had his daytime job it quickly became apparent he needed a partner.
Later into 1971 he teamed up with the firm of Schuco-Hegi who made the fuselage kits and the mechanics were being made under his supervision in South Germany; approximately 300 of the initial version were made and it is noted that the first 50 kits were actually numbered on the gearbox. Following this production run and at the 1972 Nürnberg Toy Fair Schuco-Hegi presented the Cobra in its 'mass production' format.
The mass produced models have a number of differences to original Schlüter models, changes in the bodywork for one but the major difference was to replace the original aluminium gearbox case with one made of plastic. Whilst significantly cheaper and quicker it did prove to be a weak point in the transmission and was not fully oil tight such that it had to be checked and topped up prior to each flying session. Another revision was the rotor head and the design was changed for easier production without the 'tether' hook.
The Cobra was also produced with a fixed pitch head even though a basic design for a collective pitch head had already been developed. This was a conscious decision by Dieter as he appreciated it was going to be difficult for the first few years whilst people learned how to fly helicopters without the further complication of a collective pitch system. Cobra Kit details - Schuco-Hegi Cobra Kit details with photo's of actual kit. Cobra build manual - Schuco-Hegi Cobra Kit build manual.
Helicopters had not been reviewed before and so this is a very comprehensive review. Full technical description is given along with a comprehensive overview of all aspects of the build including techniques; so much so that it is better in many places than the supplied building instructions.
Site run by Uwe Jantzen covering the Cobra in great detail and even includes shots of the 'made under license' Kalt Cobra.
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