Skybird (oz8793)

About this Plan

Skybird. Radio control slope soarer. 72in span full house aerobatic sloper.

Quote: "WAY BACK IN 1974 I was pressurised by my fellow Bloobirds club members to send off, in the hope of publication, the plan for the model that I had designed, and of which many replicas were flying. It was called Probe oz8883) and, to our delight the Editor saw fit to publish it. Since then, a great deal of development and flying hours have been put in and, as our flying skills have improved, so have the models. Now, would you believe, the Bloobirds are at it again, with the pressure that is, so here I go again with the latest design. Originally called Probe 5 but now renamed Skybird and, as you can see from the photographs at the time of writing, four check models are already delighting their owners.

Perhaps at this point I may be permitted to outline a brief history of how the current design has evolved. I was now striving for a perfect pattern acrobatic model, with less emphasis on pylon racing than the original Probe, which was primarily for racing, with some acrobatic potential. I thought that, to be competitive in aerobatic competitions, the model would need to have considerably more wing area, with the obvious lighter wing loading. The original shape, I felt, was the selling point, so this was retained, but the wing chord was increased to 12 in and the span to 72 in, making it necessary to increase the size of the fuselage and tailplane proportionally. The vee-tail at this stage still remained.

In this form Probe performed well for a whole season, but still lacked the little touch of magic I was searching for. So blowing the balsa dust from the drawing board, I set to once more, and Skvbird began to take shape. The large area symmetrical wing remained, but with a very thin section, giving a wing loading of only 92oz. sq. ft.

The basic fuselage shape was slimmed down and a conventional tailplane and rudder added, the change from vee-tail being made to enable the model to execute better stall turns and figure Ms without the need for complicated linkages, or electronic gadgetry. After building the prototype, it fulfilled all my expectations. Of the four so far built by my fellow club members, one is very light, at about 2-1/4 1b, and one very heavy at around 3-1/4 lb, giving wing loadings varying from 8 to 11 oz / sq ft. All will stay airborne on the slightest breeze, yet still penetrate well in winds up to gale force..."

Skybird, Radio Modeller, July 1978.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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