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Aviation History
1964
1964 - 1360.PDF
FLIGHT International, 7 May 1964 753 Typical payload accommodation for 18 passengers and, in the forward compartment, 5001b cargo. The three fuselage cross- sections are drawn in line with the stations to which they refer PT6A-6, rated at 578 h.p., as a reported optional alternative. Seats in the W-18 will be in six rows of three—two on one side of the aisle and one on the other, with a cargo hold forward. Nor- mal cargo load with 18 passengers would be 5001b. Two further rows of seats can be installed in the forward compartment, with partition bulkhead removed, and in this configuration each seat row is still matched to a window, of which there are eight on each side. There will be a forward crew- and freight-door and passenger entry will be through an aft drop-down door with built-in steps, opposite which is a lavatory compartment. Uninterrupted interior height over the cabin will be 6ft 2in. Payload: range curves for the W-18 now being circulated by Wagner show an extreme still-air, no-fuel-reserves range, cruising at 210m.p.h. and 5,000ft, of 1,100 st miles with 18 passengers, baggage and 5001b cargo aboard, and the same range for the maximum cargo load of 4,2401b. Under the same conditions, 1,300 miles' range can be attained with 17 passengers and baggage or 3,9201b cargo. Maximum-payload range of the 24-passenger version, with baggage but with no cargo, would be an extreme 630 miles. Maxi- mum gross weight rate of climb, at sea level, with JIL and a.p.u. operating, is estimated to be 2,521ft/min. Pressurization Despite the low cruising altitude taken in the payload : range calculations, it is obviously foreseen that the W-18 will spend most of its time at greater heights, for there is a full air-conditioning and pressurization system, fed with engine bleed air. The single main- wheels will have a relatively narrow track of 134in and will retract mto wells beneath the cabin floor. The nosewheel will be forward- retracting. It is generally accepted that the local-service transport is a par- ticularly demanding specification, in which costs are—if this is possible—even more important than usual. Despite the obvious need to match STOL performance with good cruising efficiency, it15 surprising that a manufacturer should have found that the opti- mum design is one incorporating advanced BLC systems, because such equipment has so far been used only on a small number of one-off" research aircraft, and has yet to be subjected to any kind of operational service. Simpler blown-flap arrangements are used in the F-104G, Scimitar and similar high-speed military aircraft, and more complex systems (but still employing only engine-bleed Wowing) are employed in the Buccaneer and A-5 Vigilante. It is aoubtful if civil operators will be able to obtain from this experiencean y firm idea of the costs involved. Moreover, none of the military BLC systems involves combus- tion. The nearest approach to the W-18 arrangement is probably the Jet Flap configuration being flown in the Hunting H.126. The use of burning greatly increases the power of a BLC system, and efficiency is further improved by making the "suck" at one place provide the basis for the "blow" at another; but it may be expected that certification of the high-temperature installation will prove a protracted business. An accompanying drawing illustrates the basic JIL system in the W-18 wing. Surface angles are as follow: outboard, 45°, with movement limits as aileron of 25° up and 20° down measured with respect to the basic 45° angle; main suction flap A, 40° for take-off (as illustrated in inset) and 80° for landing; inboard blowing flap B, 50° for take-off and 80° for landing (inset). The Wagner W-18 seems destined to go ahead, whatever the result of the FAA-sponsored ALTA design competition may prove to be. It will be remembered that the FAA is about to let three 1100,000 contracts for preliminary design studies of a "third-level" airliner, but is not to finance development of the actual design selected. According to company president J. R. Dettman, Wagner officials see the firm interest already aroused by the W-18—with other letters of intent "unmistakably imminent"—as assistance in their efforts to make the W-18 the FAA-favoured design. Wagner W-18 Type Proposed local-service transport. Powerplant Two 600 s.h.p. AiResearch (Garrett Corp) TPE 331-22 driving three- blade propellers. Dimensions Span, 47ft; length, 50ft 8in; height, 19ft 4in; wing area, 170 sq ft; aspect ratio, 13; track, lift 2in; wheelbase, 17ft 2£in; approx length of passenger cabin, 37ft 4in (flight-deck bulkhead to centre of rear pressure dome); approx in- terior width, 79in max (two-and-one seating); approx interior height, 74in floor to ceiling. Weights (estimated) Empty (including 1,1001b wing, 2351b tail, 1,7901b fuse- lage, 1,1081b powerplant and 5971b for JIL system), 7,1801b; basic operating, 7,8801b; zero-fuel (including 3,0601b passengers (18), 3601b baggage and 5001b cargo), 11,8001b; take-off gross (including 1,7001b mission fuel), 13,5001b. Note: payload quoted is 3,9201b, but 4,2401b is possible with all-cargo. Performance (estimated) Take-off over 35ft, 985ft; rate of climb (max wt. SL, JIL and a.p.u. on, 20° flap), 2,52lft/min; service ceiling (JIL and a.p.u. on, 20° flap), 26,200ft; speeds at sea level, 325 m.p.h. (Mil power), 304 m.p.h. (max cont power); range (still air, no reserve), 1,105 miles; ferry range (with fuselage tanks), 3,530 miles; landing over 35ft, 952ft (JIL on and partial power), 2,825ft (JIL and power off). Note: in take-off, Vo is 61 m.p.h. at lift-off after 525ft run, and 75 m.p.h. from tran- sition into climb; in landing, Vo is 72 m.p.h. on approach and 63.9 m.p.h. at touch- down, ground run being 330ft.
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