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Aviation History
1966
1966 - 0375.PDF
232 FLIGHT International, 10 February The beautifully finished standard V/-8 built by bud and Toni Harwood of Rockford, III SPORT AND BUSINESS WITTMAN'S CONTRADICTORY TAILWIND . ., having just the right amount of "twang" in it. Some builders have even faired off the rods in the quest for performance. Engines vary from the 85 h.p. Continental with fixed-pitch propeller, through the 130 h.p. O-290 ground-power unit con- version and up to the 160 h.p. Lycoming with a v.p. propeller installation in the latest tricycle W-9L version. In general, the cowlings continue the downward sweep of the windscreen to give an excellent view over the nose. A simple extension piece to the crankshaft hub achieves the shark-snitch look now popular on Cessnas and Pipers. Most cowlings are in glass fibre and the standard version has been carefully moulded to cut down cooling drag to a reasonable figure. Some amateurs have gone even better: one nose cowl seen was devoid of the customary intakes for cylinder cooling air altogether, a com- bined carburettor and cooling intake being used in conjunction with an ejector exhaust system. With cooling drag above 120 m.p.h. eating up 10 per cent of engine power the power- plant is a fruitful area for experiment. On such installations propeller efficiency is a must, and considerable smoothing and shaving has been done by Wittman fans to achieve some really satisfying results. Tail feathers, in simple steel tube, include a small, low-set rudder extending only half-way up the fin and providing about 25 per cent of the vertical surface (Wittman asks "So why do you need more? You tell me."). The mainplanes are a homebuilder's joy, small enough for domestic construction and using simple mahogany plywood covering with no need to wrap the ply round the leading-edge radius. The use of separate top and bottom skins allows con- siderable final effort to be applied to a good leading-edge finish, with impressive performance bonus. Spars are simple planks and ribs starkly conventional. Balanced ailerons and flaps are fitted, and it is hard to overcome the suspicion that dimensionally they are but trim-tabs filched from another aircraft. One streamlined-section tube on each side of the fuselage forms a minimum-structure lift-strut bracing. Being a high-wing monoplane, the Tailwind invites its share The lash-up flight-test instrument panel of the W-9L of criticism, and in the basic design the amount of view through the smallish area of glazing leaves something to be desired by those more used to bubble canopies. Most con- structors soon put this to rights, however, and the problem is resolved to a great extent by extending the side windows and roof panels. Additionally, the leading-edge roots have the attractive cut-back reminiscent of the Puss and Leopard Moths, although this does involve a penalty due to flow separation both here and on the windscreen edge. A visit to Oshkosh Airport, where Steve Wittman is manager, provided me an opportunity to realise a 30-year-old ambition to meet the man and also fly in the latest tricycle version of the Tailwind. This particular W-9L version, registered N374, is fitted with a Lycoming O-320-BIA of 160 b.h.p. and a Hartzell constant-speed propeller. The cowling on this installation is to be improved and more m.p.h. gained as a result. Notable on 374 is the nosewheel system: a Wittman twanging rod is used, with the lower end swept round in simple hook form to carry a freely swivelling, fully trailing wheel in a simple "U" fork. For rough-ground operation a slightly inclined spade-blade style of skid-plate is mounted on the lowest part of the hook just ahead of the wheel, so that it skates it over really un- pleasant ruts and bumps—another first in the realms of simpli- fied aviation. Flying the Tailwind It was by the luck of the game that an opportunity arose to fly in, and fly, two different versions oi the Tailwind within the same week. The first of these was "Wittman's Own" N374 while the second was the product of one Bud Harwood, who had taken three months away fr°m ordinary humdrum work to produce N1111N. This latter air-
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