Zombie V (oz7812)

About this Plan

Zombie V. Wakefield rubber competition model.

Quote: "RH Warring needs no introduction to our readers, his articles and designs are known wherever modellers meet. As a Wakefield designer he is in the front rank and in 'Zombie' we have the ultimate result of 5 years design and development. Those aspirants for the 1949 Wakefield Contest who wish to fly a proved design would be well advised to give this model every consideration.

IN the summer of 1944, Bob Copland and Ron Warring I both produced, quite independently, shoulder-wing slabsided 'lightweights' (actually to FAI loading) with the main idea of breaking away from the rut of high and parasol wing designs in this class and also to have a model which, when rigged correctly and trimmed, would always assemble in exactly the same way. Once trimmed, therefore, it should be possible to take the model out of the box and make a competition flight without any need for a short trimming flight. Both models, incidentally, were also about the first to carry internally-stowed, parachute-type dethermalisers. Copland used an airdraulic timer and Waning a burning fuze.

This new design layout produced many unexpected difficulties, prominent amongst which was the inherent tendency to spin. The solution to this particular problem was the result of combined effort and discussion between the two designers, extending over several months and took the form of increased fin area given by auxilliary outrigged fins. The whole problem of spiral stability as affecting rubber models and the use of outrigged or anti-spin fins to bring the centre of lateral area on approximately the same level as the centre of gravity has been dealt with in previous articles. The two models in question were the guinea-pigs which led to the development of this modern theory which has now become standard practice.

The other major problem brought out by these original designs was structural - the wing/fuselage joint. Copland has pursued the shoulder-wing slabsider layout little further.

Warring, on the other hand, adopted the shoulder-wing slabsider as the basic layout for his Wakefield designs and, in doing so, has produced the new streamlined-slabsider class of model which has a comparable overall drag figure with any full streamliner, coupled with the simpler and more robust construction of the slabsider. Similarly, all the components lock into place to ensure identical line up each time.

The tongue and box-wing fixing has proved very satis-factory and extremely reliable, once localisation of stress could be avoided. This is achieved by triangulated stub spars in the wing which distribute the maximum bending load, which would otherwise be concentrated on the mainspar at the end of the tongue, along the mainspar itself. No breakage has yet been recorded with a wing of this type, the main necessity being that the fuselage must be braced rigidly where the leading and trailing edges contact the sides, otherwise the wing will tend to break into these sides if displaced roughly as in a bad landing.

This system, and the type of fuselage box; bas remained basically unaltered throughout the series. Several forms of mainspar have been tried, the tapered 1/16 sheet spar passing through the middle of the ribs as nosi used being definitely superior. The lightest wing (1 ounce complete) had 1/16 square top and bottom spars, but was locally weak. The standard wing shown on the plan has been tested to carry a 12 ounce dead weight on the tip without failure.

The first Wakefield of the series was completed at the end of 1945 and prepared for the 1946 competition season. The basic slabsided fuselage was cleaned up considerably by employing a circular nose former and nose stringers and the propeller was fitted with a spinner enclosing the freewheel. A mono wheel undercarriage was used which, with the under-slung anti-spin fins, gave a three-point support for take-off.

Good rubber was particularly scarce at the time, but a small batch of 3/32 in. square section brown rubber was forthcoming from some quite unlikely source and showed up exceptionally well on torque test. The model was first flown in competition in the 1946 Gamage, and conditions were just about ideal..."

Update 21/07/2016: Replaced this plan with a clearer copy (patterned background removed) thanks to TonyP.

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