Miles M20 (oz16101)

About this Plan

Miles M20. Radio control scale model. Wingspan 44.5 in, for .20 - .30 engines.

Quote: "Here's a 43.5 in (1126mm) span sport-scale model with a great R/C performance on only two function R/C and .20 - .30 motors. Miles M20, by Neil McHardy.

By the middle of 1940, Hitler's advance through the low countries made it quite obvious that the next target for invasion would be Britain and if the Luftwaffe gained supremacy in the air war, then a full scale invasion would undoubtedly follow. The RAF had considerably fewer fighters than its opponent and, in spite of a rate of attrition which favoured the 'home team' there was a danger that fighter production would be unable to keep up.

With this in mind, Miles Aircraft Company proposed production of a simple-to-build fighter plane utilising many unitary components from other production aircraft and to use non-essential materials, mainly wood. The plane was in keeping with the vogue at the time, to be 'utility' - that is to say, something for which any joiner's shop could produce components.

With fixed undercarriage, the plane had no hydraulics, which rendered it fairly uncomplicated and with 21% thick wings, the available fuel tank capacity was enormous, as was the room for guns and ammunition.

Flight testing revealed the M.20 to be actually a fairly competent machine, being somewhat faster than the Hawker Hurricane and posessing a longer range and higher fire power than the Supermarine Spitfire. The power plant was the same version of the Rolls Royce Merlin unit as used in the Bristol Beaufighter and utilised the same fixing as that aircraft, making the engine totally interchangeable with it.

At first glance, this might seem the answer to the maiden's prayer, but the project was beset with various problems which eventually caused its demise as the crisis over fighter production and essential war materials did not really materialise when the Battle of Britain went in our favour.

Nevertheless, the resultant aircraft was a paragon of simplicity and taught its manufacturer many lessons in construction techniques. It was an aircraft with considerable potential, but neither the time nor the effort could be afforded to follow it through to its logical conclusion, and the prototypes were scrapped by 1943.

The lines of the M.20 make it look as though it has been dipped into the gene pool of many other aircraft, which in essence it has. To my eye, it has the look of a Hawker Typhoon which has been simplified by a draughtsman, who has only a ruler and no french curves! This fact, along with fixed undercarriage, made me think of it as an ideal candidate for a quick-to-build little sports model, so here it is.

Construction of the M.20 is simplicity itself - there is hardly a compound curve in it. Cut out two sides and add the ply doublers and the triangular stock. The fuselage is parallel from the front engine bulkhead to former E, so lay one side on the board and add formers C, D and E, noting the downthrust on C. Pull the tail end together and add the rear underside and the formers, ensuring symmetry as one does so. Bind with tape to hold in place as the glue dries.

You should now have an accurate base on which to work. Fit the top spine at the front and loose fit the tail assembly to ensure that all is aligned accurately. I built up 'runners' to guide the tail feathers back into place when they are glued finally in.

At this stage, fit the control snakes and the fuel tank, which is arranged to slide in and is secured with a blob of silicon. The sides of the engine cowl are built up from soft sheet using former B as a guide and the bottom piece added. If an invented engine is to be utilised, the air exit must be built in at this stage. Plank the top decking- in soft 1/8 balsa and sand up smooth. The soft block and sheet which forms the cowl underside and the front air intake can be added now and the whole fuselage finish sanded to shape.

Cut off the engine cowl and test mount the engine. I intended to use an inverted mounting, but in the end, elected to hang it out the side as I was not sure of my ability to deal with engine management in such an installation. I'm sure all you old lags won't have such trepidation.

The wings are very simple veneered foam, with the undercart mounted on hard points which are buried in the wing, so that the spanwise component is buried in slots below the surface. These can be simply 'filmed' over. I hate to see these merely 'clagged' on the surface like some afterthought. What the resultant surface mount must do to the aerodynamics, I hate to think. The front location is by a 1/4 in dowel and the rear hold-down by a wing bolt..."

Miles M20 from Aviation Modeller International, May 1998.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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