Slope Swallow (oz9239)

About this Plan

Slope Swallow. An economical ab inition soarer that looks something like a glider. 6ft and 9ft versions.

Quote: "An economical ab initio soarer that looks something like a glider! 6ft. or 9ft. versions. Slope Swallow, by BA Manners.

WITH the increasing availability of reasonably priced radio outfits, I feel that many more free-flight modellers will be converting to RC via slope and thermal soaring, as many have done already. However, a low-cost type of model is going to be required to complement the low cost radio equipment, if the would-be, but impecunious, enthusiast is not to be deterred.

The background on the Slope Swallow is that I obtained a second-hand Metz 10 outfit, by dint of selling my single channel gear and free-flight models, and decided to design my own glider for this. I first drew up my own list of specifications, as follows.

1. Must be economical to build.
2. Easy to construct.
3. Have docile charac-teristics and stability.
4. Be of semi-scale appearance.
5. Have a reasonable wind-speed range.
6. Be rugged and durable.
7. Be easily transportable.

Some of these aims may seem a little naive to the seasoned experts but not, I imagine, to those thinking of their first RC glider.

The Metz equipment is pretty heavy by today's standards, so a model of at least 6ft span was called for. This was to be my windy weather version, with a wing loading of about 20 oz/sq ft. The light wind version was to have 3 ft centre section extension giving a span of 9ft and a wing loading of about 15 oz/sq ft. This may still seem rather highly loaded, where probably the 'national average' for slope soarers is around 10 oz/sq ft, but for a model of this type and size it proved very satisfactory. Perhaps we get stronger prevailing winds in the Derbyshire hills.

Construction. Wings, As already described, wingspans of 6 ft and 9 ft were decided on, and this was primarily because these make the best use of stock wood sizes, the wings being made in panels 3ft long. The wing section chosen was flat undersurfaced and fairly thick, for ease of building and for strength. The wing platform, spars and leading edge are all tapered so that the tips are light - always a good idea, but especially so for a model being turned by rudder rather than ailerons. The wing section, rigging and construction are interconnected..."

Slope Swallow, Radio Modeller, October 1973.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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