Dick Ohm Special (oz9543)

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Dick Ohm Special. 1/2A Pylon racer model to BMPRA rules.

Quote: "THE original purpose of 1/2A pylon racing was to establish a cheap, simple class of pylon racing in which anyone could compete who couldn't afford the more expensive forms such as Formula 1 or FAI Racing was started in this country three or four years ago by members of the Southampton MAC who formed their own set of rules based loosely on the American rules published in RCM magazine.

Originally, the fuselage size was governed by a cross sectional area rule of 8.5 sq in but this has been changed to a size of 4-1/2 in high x 2-1/4 in wide in the interests of simplicity of checking. This has, however, resulted in a certain number of weirdos similar to those seen in FAI pylon racing. The early American rules restricted the wing planform to constant chord type, but this was felt to be rather restrictive on model design and therefore the requirement was altered to 7/8in constant thickness with no limitation on planform. This means that several of the more attractive scale type models may be built.

There has been a move afoot recently to delete the undercarriage mainly by those flying off rough fields, but this does in fact, seem to defeat its own object since it causes damage to the model rather than saving damage and also tends to break the rather fragile Cox propellers which are used. At the moment, a compromise has been reached by allowing undercarriages to be removed, but a competitor cannot qualify for BMPRA championship points by using a model in this condition.

There have been several kits for 1/2A racers available in the past, most of these tending to suffer by having foam wings and being rather heavy. There is at the moment one excellent British kit available with a fibre glass fuselage as reviewed in RCM&E, November issue.

The actual layout of the model does not seem to be too important, the main thing being to ensure a fairly clean nose entry to enable the use of fairly small propellers in order to achieve the high rpm at which the motors realise their peak horse power.

Virtually all models are now flown on ailerons and elevator - originally several models appeared with rudder and elevator and while take-offs were mandatory, this did in fact, still result in a fairly competitive model in that the models with ailerons usually lost a considerable amount of ground following take-off while establishing themselves..."

Dick Ohm Special, RCM&E, February 1975.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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