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Aviation History
1949
1949 - 1764.PDF
528 FLIGHT, 20 October 1949 AMERICAN NOTEBOOK By " Favonius " LIGHT-AIRCRAFT IMACINEERINCT HIS business (mixed with pleasure) of the single- seater light-aircraft can be approached from opposite ends of the design spectrum. At one end of the scale we see the cloud gamboliers debasing their sport with* auxiliary powered gliders, while at the other end we have the pylon posturists with their souped-up engines, clipped wings, and the landing characteristics of a scalded cat. In between this extreme range may be diagnosed two widely different schools of thought for tapping this relatively un- exploited—and fascinating—market. And, if we may be permitted to air a personal credo, we believe the market is there to exploit. It needs, however, the right kind of imagineering. One school of thought seeks to tap this market by hook- ing a two-cylinder pop-bottle engine to a large and crude- looking expanse of generously strutted airframe, while the other believes in adequate (but not excessive) power in affiliation with aerodynamic refinement. By adequate power we mean a minimum of four cylinders delivering between 40 and 50 h.p. combined with an efficient airscrew, not a tooth-pick in front of the kitchen stove and by aero- dynamic refinement our specification would certainly in- clude landing-gear retraction and simple slotted-wing flappery. That the latter goal is not out of the market economic- ally looks like being proved by Mooney Aircraft, Inc., of Wichita, Kansas, who have been working up the Mooney M-18 single-seater for the past couple of years. Al W. Mooney, the designer, began with that widely cherished pipe-dream—the reconversion of a mass-produced automo- bile engine already on the market. He cleverly adapted the little 25 h.p. four-cylinder liquid-cooled Cobra engine used in the Crosley baby car by fitting a belt-type airscrew reduction gear drive, plus sundry other changes for C.A.A. certification. This engine was neatly tailored into a 27ft- span low-wing monoplane with retractable-nosewheel land- ing gear, wing flaps, trimming tail and canopied cockpit— the end result being an eminently businesslike example of aircraft design in miniature. But 25 horses straining at the shaft were not enough to pull a good 700 pounds of avoirdupois out of the rough cow- pastures and range country for which this type of single- seater must be designed. Despite rapid retraction of the hand-operated counterbalance landing gear and the bene- ficial effects of geared-down airscrew and wing flaps, the initial climb off the ground was barely 400 ft/min and the take-off run somewhat sluggish. In the air, however, the M-18 was a sprightly performer with a sea-level top speed of 100 m.p.h., a normal cruising speed of 85 m.p.h., and a service ceiling just over 10,000ft. The normal fuel consumption was only 2 gal/hr and the corresponding range a comfortable 300 miles. The price, fly-away Wichita, was quoted at $1,975. Mooney now tells us that he has definitely put the Cros- ley engine project on the shelf in favour of the 65 h.p. Lycoming 0-145 flat-four. He has, in fact, converted the five original M-18 Crosley-engined "pilot" models built for demonstration and shake-down, and returned them to their owners as the M-18L model with Lycoming engine. Apparently the big jump in performance made the lower- powered model quite unattractive by comparison; also, the overall cost of the Crosley Cobra engine came out high after all the necessary conversion work had been done on it. This is borne out by the current price of $1,995 f°r the M-18L—a remarkably keen figure for a 65 h.p. light-aircraft with a retractable landing gear. Although this intriguing little job with its square-cut utilitarian lines is no aesthetic dream, it nevertheless bristles with practical engineering features. By this we do not mean unnecessary gadgetry or fancy appointments that would needlessly increase the cost, but everything possible to obtain a high degree of safety, ruggedness and utility. The tricycle landing gear, for example, is lever-suspensioned on all three wheels, the shock-absorbers being simple rubber compression discs with friction rebound-snubbers in the best de Havilland tradition. The nosewheel is steerable from the rudder pedals, while the main wheels are fitted with brakes operated by individual toe-pedals. To cap all this "grown-up" engineering, the whole lot is completely retractable by means of straight- forward mechanical linkage controlled by a simple lever in the cockpit, which shows the position of the gear at all times. A counter- weight assists the manual action of the pilot in pulling up the gear and a warning horn is tied in with the throttle; the horn continues sounding until the gear is fully down and properly locked for landing. The nosewheel folds backward into a box just forward of the. control stick, while the main wheels retract inboard into the wing—incidentally, without Aerial Cowboy. The Mooney M-I8L single-seater - light-plane with 65 h.p. Lycoming engine. Thi* ; example of light-plane engineering has a retract- able tricycle landing gear and wing flaps co-ordin- ated with a trimming tailplane. Fly-away price is just under $2,000.
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