FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1957
1957 - 1814.PDF
904 FLIGHT Missiles 1957 ... ( U.S.A.—continued") carry the new weapon, and Halibut is a nuclear-propelled submarine which is being built "from the keel up" to operate with Regulus 2. Thefirst rocket-boosted launching of a production- type Regulus took place on November 13, andthe weapon is going into production at Dallas and should be operational next year. Sergeant Owing to its early conception itis only natural that Corporal should be far too large and complex for the task which it per-forms. Sergeant, which will replace Corporal, is a moden weapon carrying the same payloadfor at least an equal range with far less com- plexity, implying lower cost, better field per-formance and greater availability. Like the earlier weapon, the basic development was con-ducted at the J.P.L. of the California Institute of Technology. Numerous development roundshave been fired with singular success, and the weapon is also profiting from the fact that itspropulsion system has been extensively em- ployed in the Lockheed X-17 re-entry researchvehicle. J.P.L. announced that "the latest techniques Artist's impression of a North American G-28 SM-64A Navaho. Weighing one hundred tons, the weapon climbs vertically, riding on a 405,000 Ib-tntust rocket-boost unit (see text). in guidance, airframe design and rocket pro-pulsion are being applied to the development of this rugged weapon, which is capable ofoperating in any area." Propulsion is provided by a high-impulse solid motor developed byThiokol at Redstone and produced at the new Utah Division. Motor thrust is much greaterthan that of Corporal and the filling is a cast polysulphide plastic-base composition burningfor some 30 sec. The warhead is a product of Honeywell's Ordnance Division and the com-plete weapons system is going into production at Sperry-Rand's Utah Engineering Labora-tories at Salt Lake City. Snark Between 1943 and 1948 NorthropAircraft investigated the widespread aero- dynamic and structural problems of taillessaircraft. This configuration was finally adopted for a pilotless bomber with the U.S.A.F. desig-nation XB-62, and a number of scale models were made for tunnel and free-flight investiga-tions. This history was fully reported in our issue of March 16, 1956, and also in our 1956missile review. Development vehicles were flying in 1951 and representative configurationsof the ultimate outcome, the SM-62 Snark missile, were first launched in 1954 poweredby an Allison J71 turbojet. Numerous XSM-62 development vehicles were fired from PatrickA.F.B., a number having under the body tandem oleo legs fitted with skids supplementedby small skids at the wing tips, so that, with a braking parachute, they could be recovered.Thirteen such vehicles were lost during early testing as a result of various malfunctions, butthe solid endeavour put in at this period has now resulted in a weapon system of exemplaryreliability. In its fully developed form the SM-62 Snark is a shapely aircraft-type weaponwith a high-mounted, swept wing fitted with elevons. In conjunction with the swept fin andtiny rudder, these surfaces serve all the stability and control functions; there is no horizontaltail. As at present conceived, the SM-62 is firedfrom a zero-length launcher under the thrust of two Aerojet-General solid boost motors. Itthen climbs away on the power of a constant- speed Pratt and Whitney J57 turbojet up toan altitude of approximately 50,000ft, there- after following a cruise-climb path at Mach 0.94for a range of approximately 5,000 miles, even- tually reaching a height of some 55,000ft. Droptanks are carried under the wings and jetti- soned during the journey. Extensive aero-dynamic investigations have resulted in a con- figuration which, although it flies at what mayseem an excessive angle of attack, has the optimum lift/drag ratio and a specific rangeof better than one mile per gallon. Noteworthy parts of the structure includethe upper and lower wing skins, for which single slabs of cast magnesium alloy wereevolved, and the numerous areas fabricated from aluminium honeycombs. The powerplantgroup forms a compact package at the rear, the remainder of the lengthy fuselage beingoccupied by kerosine tanks, guidance and con- trol systems and the megaton-yield warhead.The latter is accommodated in the nose, where it is released by Bohanan force-ejection devicesin the final supersonic dive on to the target. Beneath the nose is the large radome, byZenith Plastics, which is presumably associated with countermeasures systems. The guidance,which is also a product of Northrop Aircraft, weighs approximately 1,000 lb and is anunusual and interesting hybrid device com- bining celestial (star-tracking) and inertialfunctions. Northrop originally suffered greatly from the problems of launching accelerationand in-flight vibration, but these were cured by a "reliability program" applied to theguidance system. During the past two years, a large numberof development XSM-62s and pre-production SM-62s have been tested from Patrick A.F.B.Some of the former have been flown on out- and-return flights and landed back at Patrick,but one weapon achieved notoriety in December last year when an XSM vehicle under com-mand guidance from Patrick failed to make a required turn and was written-off as "lost inthe jungle of E. Brazil." In April of this year, when a complete airframe had just completedstructural testing at W.A.D.C., an order was placed for 50 additional development SM-62s,and by June the total Northrop employment on the weapon reached 7,800. The big ques-tion of whether or not the weapon would be put into the U.S.A.F. inventory was answered the following month, when a production orderfor $73m was placed, with delivery to Strategic Air Command due to start in the second halfof FY58, i.e., between January and June next year. The former assistant defence secretary,Ruben B. Robinson, said: "it is possible to activate Snark squadrons by the end ofcalendar 1958. ... It has its disadvantages of being subsonic, but will probably have quitean accurate guidance system as is now visualized and a very good circular-error prob-ability." This seems to have been borne out by a development flight on October 30 when aSnark conducted a complete simulated mission in the face of various types of interception andcountermeasures, and struck a target at least 4,000 miles from Patrick "with unprecedentedaccuracy." This was hailed as "the first true demonstration of intercontinental nuclearcapability in the world." The complete SM-62 weapon system canbe transported in a C-124, including the launching vehicle which is towed by a tractorand carries the weapon on zero-length pivot- ing arms (originally a 29ft elevating rail wasemployed). The three launchers assigned to an S.A.C. squadron can be operated from anyreasonably flat site and can theoretically con- duct twenty firings in a 24-hr period. Lastmonth contractors were assigned to prepare facilities for the first operational sites on theAtlantic seaboard. Northrop have also pre- pared studies for an RM-62 reconnaissanceSnark for damage-assessment missions after ICBM strikes. Thor When the Wilson Memorandum ofNovember 1955 gave the U.S. Air Force com- plete control of all weapons with a range greaterthan 200 miles the U.S.A.F. instituted a "crash programme" for an IRBM (intermediate-rangeballistic missile), to compete with the U.S. Army's Jupiter. From the outset this pro-gramme has been fraught with politics, and the prime contractor—Douglas Aircraft—hashad the unenviable task of rushing through critical decisions, accelerating firing trials inthe glare of public limelight and producing a reliable weapon at the earliest moment, know-ing all the time that the final weapon might be not their own but the Jupiter, or a hybrid"Thorpiter" drawing upon both programmes. There is no parallel case of a major weaponsystem being developed in such a critical climate, or with the knowledge that it mayhave to be "married" with a quite different system—causing frustration, rather than actingas a spur to greater efforts. Be that as it may, Douglas and their sub-contractors have performed a series of miracles in producing SM-75 Thor in exactly one year.The overall weapon system, WS-315A, draws heavily upon the Atlas ICBM; it uses for pro-pulsion a unit resembling an Atlas boost motor, it has the Atlas nose cone and its guidanceinvolves equipment already largely developed for either Atlas or Titan. In contrast to themore conservative, and less-wealthy, U.S. Army, the Air Force have gone into theirIRBM programme head-long, on a maximum- risk basis. Douglas have designed Thor as aproduction weapon from the outset, and, long before a complete missile had been assembled,development XSM-75s were being produced on an assembly line using production tooling.Altogether the programme has followed Cook/ Craigie lines, in which a widespread and inten-sive programme of testing has been used to ensure that each development missile is slightlynearer to the definitive operational weapon than was its immediate predecessor. By so doing, the U.S.A.F. have made it pos-sible for Douglas to be in a position to deliver in bulk at a relatively early date; and they have-not been reluctant to use the fact that Thor is built on an "assembly line" in their bitterpolitical battle with the team developing the Army Jupiter. It is only natural that such apolicy should have led to relatively unsatis- factory progress in the early stages of flighttrials, and the Army in their turn have seized on Thor's "series of disasters" as usefulammunition for their own cause. Thor is a single-stage missile, with a light-weight airframe drawing upon the experience of such companies as Convair, North Americanand Martin. At the top is the nose cone, almost a facsimile of that evolved for the SM-65 Atla'-The nose-cone contract held by General Ele;> tric's MOSD amounts to $158m, and of thisabout $40m is probably ascribable to SM-7?- Next comes the Sandia warhead, probabsy
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
