Dalesman (oz1804)

About this Plan

Dalesman. Class B Team racer. July 1960 Aeromodeller.

Quote: "IN ORDER TO GIVE the reader some idea of how the development of this model has been approached, a short history of its career will provide a guide for young enthusiasts who may be wishing to examine the possibility of class B team racing with a view to serious competition flying.

For a number of years members of the Wharfedale Club have been interested in Class B team racing, but it was not until 1958 that a measurable degree of success was achieved. With the advent of the ETA 29 Mk. V came the first 'Dalesman', this combination together with the newly developed two-cell tank system, produced a Class B model which up to that time had no equal in the North. Final times of 8 mins for 10 miles were easily attained even with the necessity of five pit stops.

In February 1959, development of the engine had produced an increase in the possible lappage that could be expected and the time for the 10-mile race was reduced to 7:40. At this point the record of the Dalesman models was introduced, fitted with a standard ETA 29 Mk. VI, this model proved to be faster than the original, giving a speed of 105 mph on its maiden flight.

As the crew became more familiar with the new model and the motor began to come on to peak power the speed increased to 108 mph. This performance was sufficient to enable the model to win at the Woodford rally of that year. By the time of the 1959 Nationals, both the machinery and crew were on peak form. At this meeting the performance had risen to 113 mph for 30 laps, a creditable show which took the model to third place in the Davis Trophy Class B.

After this meeting the engine was rebuilt by the manufacturers after which the model secured a performance which we have yet to surpass namely 115 mph for 35 laps.

The model conforms to the engine manufacturer's recommended method of engine mounting and thus produces a racer of very rigid structure. When choosing the wood for this model, be sure to select medium hard balsa for the wing and main fuselage sides (-0- in. and A. in. respectively).

If the model is constructed correctly, fatigue failures will not occur, tests have shown that the design limit speed is around 130 mph and all components are sufficiently strong to take the model up to this speed without structural failure should at any time engine development produce the necessary power.

After close inspection of the plan it will be realised that this is no beginner's model in regard to building, although it flies like a trainer and with very little alteration, it would be possible for junior enthusiasts to build and fly a model based on this design.

While many of the features shown are conventional practice in Class B design, there are a few ideas which considerably improve the racing characteristics of this model. For example, the angular cut for the removable engine/ tank cowling, which distributes landing stresses with a less drastic change in section than could be achieved with a vertical cut. Also, note the special positioning and construction of the U/C which has saved many a race by completely eliminating the possibility of prop. breakage on rough landings and in line tangles.

The use of simple tin plate electrical terminals provide for the use of any type of accumulator connections to be used and dispenses with the need to standardise on a particular plug and socket (which are usually heavy and cumbersome to say nothing of being difficult to install correctly). The operating efficiency of the model is enhanced by the removable cowl top. This provides access to all the main working parts except the control system, this is constructed entirely of steel and thus requires no maintenance other than periodic lubrication..."

Update 9/1/2016: added article, thanks to RFJ.

Supplementary file notes

Article.

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