Zlin 226 (oz9806)

About this Plan

Zlin 226. Control line stunt model for .35 power.

Quote: "'Pop' Warburton maintains the family tradition with another fine semi-scale stunt controliner and introduces new ideas in this 51 in. lightweight for the popular .35 size engines

THE IDEA of building a ZLIN as a semi-scale stunt model must have occurred to innumerable modellers. I first looked into a year or two ago (thanks to the Editor, for the suggestion and appropriate information). It is an excellent subject which really flies and looks equal to the very best. The ZLIN family makes regular winning appearances in the World Aerobatic Championships for full size aircraft and this makes it an attractive model to build. It also gives one a chance to put some further theories of model stunt building into practice. One was to try and prove that this type of aircraft with a large two-seater 'glass-house' cockpit canopy can be made to execute the stunt schedule just as well if not better, than a sleek fighter or jet appearance layout. It does just that, and moreover it is very good in all weathers, from wet and windy to dry and still air.

One of the latest items included is the fully adjustable lead-out positions in the wing tip. The function of these is to enable one to find the ideal lead-out position. All models seem to vary in flying performance and line tension no matter how careful two same type models are built. Adjustable lead-outs allow a wider scope of finding similar flying characteristics. They also give a variation of line tension for very windy to calm condi-tions. However this adjustable lead-out trick does not eliminate the vital necessity of a correct bell-crank position. Top stunt men have said that the bell-crank position is not as critical as the lead-out location. Both are of equal importance and any builder is recommended to ensure that the bell-crank is positioned carefully to plan, when building this ZLIN.

Another factor in this effort to get the best from this model was to go back to the smaller wing span and low total weight to give better wing loading. The .35 size of motor is chosen because it is the most popular, the price generally lower and there is a good choice of silencers and fittings. This motor size in turn called for a wing span of 50 in. — 52 in. (50,i in. chosen). Careful selection of wood and a few lightening tips have in this instance kept the weight down to 38 oz. This layout is also cheaper than the .45 size in initial cost of motor, materials used in building and fuel used when practising yet it will give just as good a stunt pattern!

At this stage, it must be emphasised that the 'building in' of exact trim is most important. This applies to any stunt model. First the thrust line, wing line (wing incidence) and tailplane (tail incidence) although at different levels in the fuselage must all be neutral (zero incidence), i.e. all horizontal with each other. The gluing of the wing to fuselage sides is perhaps the most difficult to line-up at zero. Perseverance here in setting-up correctly with the engine bearer line is one of the 'musts' for an accurate flying model. Next trim check is with the model held up and looking from the front the wing leading edge must have the tail leading edge line from tip to tip exactly parallel. If it isn't parallel on the finished model, one or two faults will reveal themselves in flight..."

Zlinn 226, Aeromodeller, February 1969.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ

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