Open and 100s Classes
As stated in the F3J model description on this web site, the top performing models for both BARCS Open and 100S competitions are generally of all moulded construction. However in the many local Open competitions multiple entries are encouraged which gives an opportunity to fly models of differing classes and the challenge of competing with the F3J type models all adds to the fun. The sub classes of models are: Rudder, Elevator & Spoiler (RES), Classic, Vintage, Tail-less and 100S.
As a model definition, RES is it – no limits on span, area, weight or anything else but the model must not have more than these three functions. This makes for a reasonably simple model with minimal demands on the radio as no ailerons or wing camber changing functions are allowed. Until the advent of composite models factory produced from female moulds, the great majority of UK Open Class thermal soarers were simply RES models. A typical soarer from that era (up to the early 1990’s) was about 12 foot span and 9 or so ounces/square foot loading and a great many of these models are still about.
Classic is a class of glider intended to bridge the gap between the real “Golden Oldies” of Vintage gliders and the modern day gliders.. The cut-off qualifying date for Classic gliders has recently been brought forward and is now the end of 1990. Classic therefore covers the period 1956 to 1990. After all even 1990 will still feel pretty classic to anyone who only took up the sport within the last 15 years or so. This date encompasses a huge range of designs – all essentially built up but glass fibre fuselages were available for many gliders in that era and obechi covered foam wings were also commonplace.
Vintage gliders are those designed before the end of 1955. What therefore makes Vintage gliders quite unique is that, without exception, they were all designed before the days of radio control. Thus every single vintage design was originally intended for free flight use and a significant challenge exists in creating a radio version which is controllable and has a worthwhile soaring performance. To assist the process of converting such venerable designs to radio control some changes are allowed. Models can be scaled up (or down) in size. Thus a free flight design of an original 50 inch span can readily be doubled in size to become a 100 inch span model. The rules require basic adherence to the type of construction used in the original design, however internal, non visible modifications are allowed. For instance spruce can be used instead of balsa if the builder so chooses and even the wing section can be altered, provided the new section was also in existence in the same era. Hatches and whatever modifications are necessary to get the relevant control surfaces are also allowed.