Paradox (oz7910)

About this Plan

Paradox. Radio control powered glider for .15 to .20 engines. Winspan 105 in, wing area 1086 sq in.

Quote: "By dictionary definition, a glider is 'a form of aircraft similar to an airplane, but without an engine.' The Paradox is a glider with the exception that it has an engine enabling it to reach the necessary altitude to glide. The last sentence is a paradoxical statement, meaning 'seemingly contradictory but possibly true.' Thus, my reasoning for giving this model, aircraft, glider, whatever, the name - the Paradox. The term 'powered glider' is, in the English language, what is called an oxymoron, 'the bringing together of incongruous contradictory ideas.' The glider purist would probably consider this a better name for the aircraft and the designer - so much for the name and English lesson.

Previous to this model, I built several 2-meter .049 powered gliders, oops aircraft. The results were not what I would consider satisfactory. The engines were always a problem, flying characteristics were unpredictable. etc, etc. For practical purposes, I also consider taking a long length of string with a big rubber band, or winches, to sling-shot a model a few hundred feet off the ground impractical, and electrical aircraft inefficient. It does not make sense to me to build an aircraft as light as possible and then turn around and use heavy electric motors and batteries to make the model fly. The bottom line is a large glider-designed aircraft with an
internal combustion engine to propel it to the desired height, thus enabling the model to glide. But then I concede: different strokes for different folks.

The basis of the Paradox design is from a 2-meter electric glider enlarged 1.33. Since it is a large model. I wanted to get the design on as little print paper as possible to save the cost of the plans. Consequently, all wing rib spacing is the same, 2-1/2 inches. Tip panel has the leading and trailing edge of equal taper. Root panels are just reversed. Wing airfoil is a computer-generated Eppler Selig S3021094 with a slightly thicker tip to accommodate construction with approximately 1/4 in washout.

An unusual feature, optional, is the inboard spoiler-ailerons. They assist in trimming and turning in conjunction with the rudder; theyalso pop up to act as air brakes. A very efficient flying tail is used, as there is considerable difference in trim setting under power and that glide. The fuselage is straightforward.

With a 105 in wingspan, it is obviously necessary to build the wing in two sections. What was not so obvious is the best way of assembling the two wing panels to the fuselage. One day, while in a sporting goods store. I noticed a large number of Easton XX75 Cameo Hunter (XX75 Autumn Orange will also do) aluminum arrow shafts and immediately thought that they would make excellent wing joiners..."

Supplementary file notes

Article pages, text and pics, thanks to hlsat.

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