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Aviation History
1956
1956 - 0593.PDF
FLIGHT, 11 May 1956 AERO ENGINES 1956 . . . 593 Pratt and Whitney J57-P/F-I3. Fighter turbojet with short afterburner. Nine- stage low-pressure compressor driven by two-stage low-pressure turbine, seven- stage high-pressure compressor driven by single-stage high-pressure turbine eannulor combustion system containing eight individual annular flame tubes each carrying six fuel injectors, short (1,800 deg K) afterburner with 24 injectors and eight pneumatically actuated propelling-nozzle restrictors. Height, 45 6in- width, 40.7in; length, 232in; dry weight, 5,170-5,525 Ib according to materials !iT£te?ri?d:«l5<S«fl.?Wl 172lb/sec; pressure ratio, 12.5:1; maximum thrust, 10,500- 10,900 Ib (12,500 Ib wet) at 8,000 low-pressure r.p.m. with s.f.c. of 0.80 (with afterburning, 14,500 Ib with s.f.c. of 1.95). Other models give up to 17,200 Ib thrust. flew for 15 minutes in 1951, believed to be an unbeaten endurance forthis type of motor. A promising form of helicopter tip-drive booster ramjet has beendeveloped during the past four years under Wright Air Development Center contract. It is a two-dimensional unit, one form having asliding shutter over the leading-edge intake and a propelling nozzle consisting of a spanwise slit between flexible upper and lower skinswhich form extensions to the blade surface. Within the duct are nozzles fed with fuel from the main tankage, together with an ignition plug anda flame-holder comprising a toothed channel. One model extends 15in along the span, with 16.5in chord and 2.5in maximum depth;this size provides 401 Ib thrust, and three (for a three-blade rotor) more than double the payload of a 6,400-lb helicopter. Supersonic Ramjets. A basic unit designed for the surprisingly lowMach number of 2.5 is now in a production state, with a sophisticated double-shock intake, a fuel system capable of operating over an extremerange of altitudes, and a particularly efficient flame-holding assembly. Engines of this general pattern are in production for various missiles,the most important contract being that for the twin-engined Boeing IM-99 Bomarc long-range intercepter missile. Powerplants for thisapplication are designated RJ43, and Marquardt recently received a £1,875,000 contract to cover preliminary flight-rating tests of thisramjet. Last month the U.S.A.F. also placed a contract for the pro- duction of a 36in-diameter supersonic ramjet which may, in fact, bethe RJ43. The photograph is the first to illustrate a supersonic-ramjet productionline. The engines are for the U.S. Air Force and are of the type shown in the drawing. New alloys used in these units include HK31 (magnesium-thorium-zirconium), A-110AT (titanium alloy) and 6A1-4V (heat-treated titanium alloy). The combustion chamber is lined with a heavy coatingof aluminium oxide. An unusual form of ramjet has been evolved for installation on thewing-tips of manned fighters; at the start of each mission these ramjets can be covered by nose and tail fairings and employed as additionalfuel tanks. Mechanical details of Marquardt supersonic engines are withheld, although the company claim that they have "establishedrecords in speed, altitude, distance and endurance for air-breathing engines." Pratt and Whitney: propelling nozzle of J57 afterburner. McCULLOCK. McCulloch Motors Corpn., 6101 West CenturyBlvd., Los Angeles 45, Cal. The speciality of this West Coast firm is the production of simple, lightweight, two-stroke piston enginesoperating on a 10 : 1 mixture of 115/145-grade fuel and lubricating oiL Very large numbers of such engines, mainly flat-fours, have been de-livered for use in target drones of the U.S.A.F. and Navy. The most recent powerplant is described below. O-150-4 (6318). Developed under the sponsorship of the U.S. Navy,this unit has six horizontally opposed cylinders; like its predecessors there are no valves, mixture being admitted at "medium pressure" tothe crankcase. A new feature, however, is an exhaust-driven turbo- supercharger, which has an automatic waste-gate control. No pro-vision is made for throttling, the maximum (i.e. standard) rating being 120 h.p. at sea level at 4,100 r.p.m. with an s.f.c. of 0.85, the powerreducing to 103 h.p. at 15,000ft and 86 h.p. at 30,000ft. The specified weight of the complete engine-change unit is under 153 lb. Provisionis made for repeated recovery from the sea. The new engine is being developed for a Beech target, and flight tests are expected to beginin September. McDONNELL. McDonnell Aircraft Corpn., Missile Engineeringand Helicopter Divisions, Lamben-St. Louis Municipal Airport, St. Louis 3, Mo. This aircraft company is active in the propulsion ofseven missiles, including the production of ramjets for the Bendix Talos, a supersonic ground-to-air missile. Since 1944 the company hasworked in the field of ramjets, helicopter pressure-jets and (until 1952 only) afterburners. NORTH AMERICAN. North American Aviation, Inc., RocketdyneDivision, Canoga Park, Cal. This famous aircraft company is now heavily engaged upon the development and production of rocket motorswith a potential horsepower as great as that of any man-made engine. The first firing of a motor of N.A.A. design of greater thrust than thatof the German V-2 took place in 1949. Production contracts are now held involving the development of multiple liquid-propellant motors(totalling over 1,000,000 lb thrust) for the first stage of the Atlas I.C.B.M. Very large motors are also in production for the Chrysler Redstonemissile and for launching of the company's own SM-64 Navaho. Last October the company was chosen to build the X-15 rocket-propelledpiloted research aircraft intended to explore altitudes up to 520,000ft. This is a continuation of a U.S.A.F.-Nayy-N.A.C.A. programme andthe aircraft may fly next year. N.A.A. designs of rocket motor may also be manufactured in Britain as a result of a recent licence-agreement withRolls-Royce. For many years the company have operated an enormous rocket-testing establishment in the Santa Susana mountains close to the San Fernando Valley. The director of aerophysics at this establishmentstated in April 1954 that N.A.A. led the nation in large-rocket tech- nology and was "rapidly achieving the same position in the field ofsmall rockets." At the beginning of 1955 the U.S.A.F. started to finance the new rocket-propulsion centre to be operated by N.A.A. in theSan Fernando Valley itself, approximately ten miles from Santa Susana. When complete, the new installation will provide a working space of322,000 sq ft. A further £600,000 rocket-calibration and test building was brought into use last year. North American are also conducting a large programme of nuclearresearch, the staff for which are being transferred from Downey to a new ad hoc establishment at Canoga Park (San Fernando Valley), wherethe Rocketdyne Division have their H.Q. The first sodium-graphite reactor financed jointly by N.A.A. and the A.E.C. is at Santa Susana andis delivering 20,000 kW. Also in operation are two solution-type reactors, one at Downey and the other at the Livermore research laboratory. PRATT AND WHITNEY. Pratt and Whitney Aircraft, Divisionof United Aircraft Corpn., 400 Main Street, East Hartford, Conn. During the past two years the world's largest aero-engine companyhave delivered more than 3,000 advanced rurbojets of their own design, nearly all being J57s. Although piston-engine production has shrunkrapidly since 1954 the R-2800 will remain in production for at least two more years. Meanwhile the company is advancing technically on a very broadfront in solid, conservative steps. Very large and efficient turbojets are coming into production; equally large and efficient turbopropsare advanced in development and will soon fly; ramjet work is impres- sive, although subject to strict security; and the company is a leaderin aircraft nuclear propulsion. J42. Out of production since 1953, this Nene-derived engine hasthe longest allowed overhaul time of any Navy turbojet. For two years the figure has been 1,000 hr. Rated thrust, however, is now up to5,750 lb. J48. Originally based on the Rolls-Royce Tay, this Navy centrifugalturbojet has been steadily developed at Hartford and several thousand have been delivered to the U.S.A.F. as well as to its sponsors. During1954 the performance was markedly improved (from 6,250 lb dry to 7,250 Ib, or 8,500 Ib with water injection) by raising the mass flowto 130 lb/sec and increasing the top temperature, the latter being permitted by a change to Pratt and Whitney's "Waspaloy"—a cast,vacuum-melted blade alloy—in the turbine rotor. In October 1954
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