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Aviation History
1949
1949 - 1260.PDF
FLIGHT JULY 7TH, 1949 AMERICAN NOTEBOOK By " Favonius SOME CATERPILLARS FLY- DESCRIBING it as "the world's first track-tread typelanding gear for medium or heavy bombers," Boeingannounce successful completion of taxi tests with a caterpillar-track landing gear fitted to a B-50 weighing164,000 lb. This fanciful claim will be news (or stale bread upon the waters) to George Dowty, who pioneered the intro-duction of caterpillar gears for aircraft, both in England and the U.S.A., before and during the war, and even gotas far up the weight scale as a caterpillar landing gear for a Lancaster bomber. The B-50 gear follows, in fact, along the lines establishedby Dowty on an experimental Douglas A-20 attack bomber and since more fully exploited in America by Fairchild incollaboration with Firestone on the Fairchild C-82 Packet Transport. Grooved and wire-reinforced rubber belts run-ning over grooved drums and bogies, with multiple shock- absorber units, permit the gear to roll with ease over smallobstructions and turf or dirt—that is, the kind of unpaved runway that would quickly bog the modern bomber withhigh wheel-loadings. There is more truth in Boeing's claim that the B-50 gearis the largest of this type so far built. The main gear comprises a twin-track installation in lieu of the twin-wheelsystem of the standard B-50. These endless belts are each 2oin wide with a ground contact length of 46 in; iie., atotal contact area of roughly 13 sq ft is available per side of the aircraft. The nose gear, which retains the hydraulicsteering feature of the standard nose wheel, is a single-track unit measuring i6in wide by 36m long—a contact area of4 sq ft. All three caterpillar units are fully retractable, thus the speed performance of the aircraft is unchanged. Since the total " footprint" area of 30 sq ft is about three An experimental twin caterpillar landing gear for the Boeing B-50 Superfort. (The corresponding nose gear was illustrated in " Flight," June 2nd). The main units and belts were manu- factured by Goodyear, and the nose unit by Firestone. Ground " footprint " area is roughly three times that of standard 8-50 wheel-and-tyre system. times that of the standard B-50 double-tyre system, it be-comes possible to operate from a greater number and variety of improvised bases. Considerable misconceptionis prevalent in England concerning the proper sphere and functions of aircraft equipped with caterpillar landing gears,for it should be understood that they are not primarily intended for hard runways. One official apologist for thestatus quo has publicly stated that the use of track under- carriages is not worth while—presumably because theengineering snags are difficult to hurdle. Meanwhile the Americans have got their caterpillars out of the cocoonstage and into the air. -AND SO DO CRANES A GIANT twin-jet, heavy-lift helicopter is•^*- under construction (or, at any rate, design development) for the U.S.A.F. at the CulverCity (Calif.) plant of Howard Hughes. As the sketch illustration shows, it is designed as anaerial crane to pick up tanks, field artillery and suchlike heavy military equipment in muchthe same manner as the grotesque mechanical monsters used in the lumber industry, whichstraddle over a stack of boards and hoist the load between their high vertical sides. TheHughes XH-17 will settle down like a clucking hen over her eggs and, after the cargo is hookedin place, will lift it over short hauls. The 136-ft diameter rotor is jet-reaction-rotated through ducts leading up the rotor shaft and out through burners (or ramjets) at theblade tips, the thrust being supplied by a pair of Allison J-35 turbojets mounted along thevertical sides of the cargo hoist. Reports indi- An artist's conception of the Hughes XH-17 jet reaction helicopter for the U.S.A.F. Its military function is to pick up tanks, artillery, etc., and transport them over short hauls. Power plant is two Al//son J-35 turbojets driving a 136-ft rotor by je< reaction through ramjets at the blade tips.
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