|Année du premier vol
(ou de design, si seul projet)
|Pays||Afrique du Sud|
|Designer(s)||BEATTY, Patrick James|
|Premier constructeur||Patrick James BEATTY (SA)|
|Profil aile||Eppler 1001, à cambrure variable|
|Masse à vide||--|
|Taux de chute mini||--|
|Structure||Composite fibre de verre|
|Infos techniques||Panneaux extérieurs d'ailes rétractables|
|Histoire résumée||The B-5|
Although Pat recognised that the Fowler flapped glider had reached the end of it's competitive era, it didn't prevent him from exploring further possibilities for variable geometry.
Now working without the assistance of Fritz Johl, the B-5 was designed to be a truly innovative glider; perhaps radical is a better description! In order to reduce interference drag, the wings were mounted virtually at the front of the fuselage, and swept back slightly . To get the center of gravity far enough forward, two streamlined balance weights were mounted on arms in front of the wings. The camber of the wing could be adjusted in flight, by moving the wing upper surface up or down. The wings could thus be made thicker and more cambered for climbing, or thinner and less
cambered for high speed cruise. To further enhance low speed flying, the wing span could be extended from 15 meters to 19 meters by means of a telescopic wing tip!
The B-5 was first flown in 1979, but only once in this configuration - a very nasty oscillation encountered on its maiden flight persuaded the designer/builder/pilot to abandon the wing mounted balance weights in favour of a single conical balance weight mounted on the nose. Version 2 of the BJ-5 was soon replaced by Version 3, which discarded the nose-mounting for the wing in favour of a pylon, fitted just behind the cockpit. The objective was still to reduce interference drag. In fact, Version 3 had an all-new fuselage, a very slender body of revolution. The fuselage was
constructed from moulded glass fibre. It eventually became clear that the camber- and span changing mechanisms did not produce the hoped-for advantages. Amongst other problems, the geometrical constraints of variable span resulted in spanwise load distributions that were unacceptably poor.
|Liens personnalités||BEATTY Patrick (Afrique du Sud) |
|Liens WEB||Site : Google Groups . Texte. ()|
Site : ICAS . Variable geometry airfoils as applied to the Beatty B-5 and B-6 sailplanes. Texte + plan 3 vues. (2016-11-13 CL)
|Livres||Pas de livre référencé.|
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