Infos techniques | The B-7
The introduction of a 750 kg weight limit for the open class prompted the design of the B-7. First flown in 1984, the B-7 retained the B-5/B-6 fuselage, but an entirely new wing of 19.5 m span was fitted. The pylon mount was initially retained, but later discarded in favour of a relatively conventional, but high, 'shoulder' mount. The beautiful wing is of all-metal construction, with an elliptical leading edge. To allow a straight aileron and flap hinge line whilst retaining the elliptical plan form, the trailing edge is also slightly curved. Because of the very high aspect ratio, compound curvature of the wing skins is relatively small, and the wings were constructed by bonding the skins to closely spaced glass fibre ribs and stringers. Small countersunk sheetmetal screws were used to pull the skins down. Although the B-7 almost appears conventional, compared to Pat's other innovative designs, there are some subtle
innovations. For example, the plain flaps also split differentially, to assist circling flight. The B-7, which still flies occasionally, performs well, and like all the successful Beatty and Beatty-Johl designs, is competitive under strong thermal conditions. |