US Army Corporal Type 1 Fact Sheet:
The CORPORAL Type I (XSSM-A-17 to XSSM-G-17) program was initiated in 1949 while the CORPORAL-E firing tests were still under way. The Type I missile system utilized some HERMES components and a DOVAP type transponder, but with the exception of the propulsion system it left something to be desired in the way of a tactical weapon. This fact eventually led to development of the Type II CORPORAL, which will be described later.
Type I firings were carried out from January 1951 through December 1954. A total of 64 Type I rounds were fired, including 20 in the Engineer-User testing program and 44 by JPL in its contractor testing, evaluation and development programs. A reliable propulsion system was developed. Malfunctions in the propellant shutoff mechanism, encountered frequently in the earlier tests, eventually were solved by redesigning components. A right azimuth bias, observed repeatedly in the early tests, was effectively removed by incorporating accelerometer control in azimuth.
The Type I CORPORAL was 45 feet long, 30 inches in diameter and weighed 11,400 pounds. The propulsion system, with a burning time of 63 seconds, developed 20,000 pounds of thrust. The fuel was liquid aniline, with inhibited red fuming nitric acid (IRFNA) as the oxidizing agent. Capable of carrying a 1,500-pound payload at ranges of 50,000 to 120,000 meters, or 25 to 75 nautical miles, the Type I system was fired from a mobile ground installation. It was designed to fly a series of standard trajectories.
The range of the missile was controlled primarily by terminating thrust at a velocity, determined by a shutoff computer, that would minimize the range error at impact. So that the missile would be in the proper region of position-velocity space at shutoff, an elevation computer system guided the missile along a predetermined trajectory from 22 seconds to shutoff. Range error was further reduced by determining, on the basis of measured position and velocity, the predicted impact error, near the peak of the trajectory, and by programming a terminal maneuver to compensate for this error. The azimuth error was controlled by commands calculated to keep the missile heading on target from 22 seconds to impact minus 10 seconds. The missile was controlled to fly close to the standard trajectory by means of yaw and pitch programs, and by autopilot control. Deviations were determined by a combination of Doppler and radar data. These data were transmitted to the missile as commands.
Type I Contractors
The first Type I CORPORAL missiles were fabricated by the Douglas Aircraft Company, Santa Monica, California. During 1949, Douglas built seven CORPORAL airframes under Contract W-04-200-ORD-1504. Propulsion and guidance were added by the Jet Propulsion Laboratory. During 1950 and early in 1951, Douglas built an additional 20 rounds (Rounds 12 through 31) under Contract DA-04-495-ORD-21. The Douglas rounds were used in the R&D flight testing program. Production information also was generated under these contracts.
Even before the demonstration of guidance feasibility, the Department of Defense ordered the CORPORAL into production. Thus, in the summer of 1951, several companies were invited to submit bids for the initial Type I production contract.
In October 1950, the Office of the Director of Guided Missiles had been established in the Office of the Secretary of Defense, and Mr. K.T. Keller had been appointed to this office. On 15 March 1951, the Department of the Army had recommended to Mr. Keller an industrial program calling for the procurement of CORPORAL missiles, spare parts and ground equipment. Upon approval of the Secretary of Defense, bids for production of 200 missiles, plus spare parts and manuals, were solicited from several selected companies. A Board of Awards met at Redstone Arsenal on 29 June 1951 and selected the Firestone Tire and Rubber Company as the successful bidder. A letter order in the amount of $6,888,796 was placed with the Firestone Company on 17 July 1951. This was replaced, when funds became available for the Fiscal Year 1952 program, with Contract DA-04-495-ORD-159, dated 10 December 1951, in the amount of $13,695,592. In June 1952, implementing another program approved by the Secretary of Defense, this contract was supplemented to call for production of 120 additional missiles, at a cost of $9,000,000, or $75,000 per unit. This brought the total to be produced under the ORD-159 contract to 320 Type I CORPORAL missiles.
Type I Evaluation Program
The first Firestone-manufactured CORPORAL,which incorporated all the significant features of CORPORAL-E Round 11, was fired at White Sands Proving Ground on 7 August 1952. Two more Firestone missiles were launched during the month of August. These missiles were incomplete with reference to guidance equipment -- the radar command unit and the range correction unit had not reached a satisfactory production stage and could not be used in the production flight tests. However, all rounds manufactured by Firestone under the initial contract were delivered to JPL, where they were dismantled, inspected, reassembled and preflight tested before shipment to WSPG for flight testing. As a result of this preflight evaluation program, JPL was able to submit suggestions to Firestone to assist in expediting factory production of acceptable rounds.
Various difficulties were encountered during the Type I flight evaluation program, which continued in 1953 and 1954. The most flagrant of these involved the propellant shutoff circuit, which affected the range control mechanism. The missiles were fired at ranges of 30, 50 and 70 statute miles. This system showed a greater dispersion in range than in azimuth, and the Type I program demonstrated a CPE of approximately 500 meters.
This was considered satisfactory in view of the fact that many unique experiments were being conducted during this phase, and these experiments were more likely to cause errors or failures than would be the case in normal tactical operations. While these experiments themselves did not necessarily result in improvement of the overall accuracy record of the Type I CORPORAL, they were necessary during the design and development stage of such a new weapon system.
Corporal missile launch on Oct. 25, 1955
Type I Engineer-User Program
As early as the spring of 1952, planning was under way for the CORPORAL Engineer-User program. The first E-U missile, scheduled to arrive in September 1952, was delayed until early January 1953.
Concerning the E-U testing program, a JPL report said:
"Past conventions have usually dictated that any new weapon development be given engineering tests by that arm of the Army which has had responsibility for the particular weapon program. These tests have then been followed by tests of the weapon under operational conditions, as conducted by the using arm of the service. This practice was somewhat altered insofar as the CORPORAL was concerned. In the interests of conserving time, money and manpower, a joint team of Army Ordnance Corps and Field Forces personnel was formed as an Engineer-User team for the CORPORAL missile.
This team was organized at White Sands Proving Ground; the testing program initially used missiles which had been modified by the Jet Propulsion Laboratory preparatory to release to the Engineer-User team. This team also used ground guidance and handling equipment which was obtained by this Laboratory and subjected to various modification prior to the release for Engineer-User tests."
Fourteen rounds were fired in the E-U program from 30 January 1953 through 22 January 1954. CORPORAL EU-1 (Firestone Serial No. 1247), fired on 30 January 1953, impacted 70.61 meters right and 6,629.6 meters short of the target, after 165.8 seconds of flight. Propellant shutoff occurred four seconds prematurely, causing the range correction system to operate at an improper time. An extra high trajectory also contributed to the shortness of range. After 23 seconds of flight, the missile was 200 meters above the standard trajectory. This was to be the largest deviation from a standard pitch program of any of the 14 rounds, but was not considered excessive as the elevation system was capable of compensating for at least 600 meters.
CORPORAL EU-2 (Firestone 1251) was fired on 26 February 1953 and impacted 6,936 meters right and 84,072.3 meters long after 183.18 seconds of flight. The Doppler unit transmitted the fuel shutoff signal at the proper time, 54.05 seconds, but the missile failed to respond. It burned until the fuel was exhausted, accounting for the extremely long range. Evaluation of the flight data indicated that the Doppler shutoff signal from the ground was not acted upon by the shutoff circuitry of the missile Doppler transponder.
Round 3 (Firestone 1261), launched on 23 March 1953, impacted 3,606.94 meters right and 1,351.2 meters long after 171.59 seconds of flight. In this round, the missile responded properly to the shutoff signal. The missile achieved a satisfactory flight and flew a trajectory that deviated only slightly from the standard.
Of the remaining 11 round fired in the Engineer-User program for the Type I CORPORAL, only Round 8 on 13 August 1953 and Round 14 on 22 January 1954 were evaluated as complete failures. However, only Rounds 7, 12, 13, fired on 4 August 1953, 15 December 1953 and 12 January 1954 respectively, were fully successful. These three rounds averaged approximately 170 seconds of flight time each and achieved an average range of around 64 kilometers (40 miles). Miss-distance ranged from 25.6 meters right and 548.7 meters long for Round 7 to 12,960.7 meters left and 7, 799.8 meters short for Round 13.
Round 4, on 14 May 1953, was shut off by Range Safety at 68 seconds because it entered a heavy overcast of clouds and was lost by the radar and optical trackers. It traveled only 23.7 kilometers. Round 5, 8 June 1953, was late in reaching range correction velocity -- 170 seconds instead of 116 seconds as programmed -- but flew for 183.5 seconds and impacted 45.22 miles from the launcher. An error in the shutoff equation sent to Round 6 during flight, on 7 July 1953, resulted in a large miss-distance, but the missile flew for 205 seconds and achieved a range of 82.3 kilometers. After Round 8 was fired, the central power system failed and the forward and aft sections of the missile broke apart at 30.5 seconds, terminating thrust. The aft section impacted 61.14 seconds later, 7.029 miles from the launcher. The nose section followed a shorter trajectory and impacted 2.34 miles from the launcher.
Rounds 9 (1 October 1953), 10 (13 October) and 11 (27 October), all had large miss-distances due to malfunctions in the range correction systems, but otherwise were satisfactory tests. Ranges averaged more than 52 kilometers, and flight times averaged about 160 seconds.
A dense cloud of smoke was seen pouring from the side of Round 14 just before takeoff. Post flight studies indicated that this vaporization probably was caused by an aniline leak, and that it had no apparent effect on the function of the propellant system. At takeoff plus one second, the missile yawed hard to the right. At nine seconds, it began to roll. It continued in a northeast direction for five more seconds, then impacted only 3,070.21 feet from the launcher, just 14.2 seconds after takeoff. Data indicated that a failure of the north servo system, due to intense vibration during the count-down and takeoff, caused the hard right yaw. The roll was caused by abrupt action of the south fin in response to the yaw-right error signal.
An evaluation of this 14-round Engineer-User program indicated: (1) that accuracy of the azimuth system met military requirements; (2) that accuracy in range could not be determined; (3) that component malfunctions occurred approximately 54 percent of the time; (4) that the majority of the malfunctions occurred in the missiles; (5) that malfunctions in components during preparations for missions caused excessive increases in preparation times, and (6) that operating personnel for the CORPORAL system would have to be extremely well trained.
After the firing of E-U Round 14 on 22 January 1954, the Engineer-User team suspended firings for a few months. In March 1954, the Jet Propulsion Laboratory conducted a school on the CORPORAL system, attended by 14 E-U personnel including officers, enlisted men and civilians. The course continued for three months and covered all aspects of firing and check out of the missile.
E-U Rounds 15 and 16 were fired jointly by the Engineer-User team and JPL personnel in May 1954. In June 1954, a high altitude shoot employing extensive instrumentation for the Ballistic Research Laboratories was highly successful.
From August until November 1954, at the request of the Chief of Ordnance, the E-U team conducted various climatic tests with the CORPORAL missile. One phase involved extreme cold and extreme heat, ranging from 60 degrees below zero to 180 degrees above zero, Fahrenheit. The other phase involved temperature variations and humidity tests. These E-U tests were conducted in addition to the JPL firing schedule and resulted in extra efforts on the part of firing crews, who used the same check out equipment for both regular firing and the climatic tests.
Field Forces Program
Late in 1953, after troops had been trained at the Guided Missile School at Fort Bliss, Texas, three CORPORAL Field Artillery Missile Battalions -- the 246th, 247th and 259th -- were activated. These units were still receiving items of basic equipment as late as mid 1954, when field firing operations were under way at Red Canyon Range Camp on White Sands Proving Ground.
Initial flight tests in the Field Forces program were considered unsatisfactory for a variety of reasons. A fact finding conference was held at Fort Bliss on 29 June 1954. It was attended by representatives from WSPG, Fort Bliss, the Office of the Chief of Ordnance, Redstone Arsenal, Jet Propulsion Laboratory, Firestone and Gilfillan Brothers. A committee was appointed to establish the facts and make recommendations to the agencies involved. This committee determined that supplies of spare parts were deficient and that usable information about the CORPORAL system was not being distributed freely to those having a need for it at the lower operating levels. Over a period of time, these difficulties were rectified. JPL began publication of a biweekly newsletter for the exchange of pertinent information among the contractors, training schools, user troops, test agencies and administrative organizations. The committee produced detailed instructions concerning operating and maintenance procedures, resulting in standardization in all phases of the program. An office for technical consultants was opened and staffed at Fort Bliss, to provide direct engineering field service and consultation for user units.
Late in 1954, the 259th Field Artillery Missile Battalion fired four successful training rounds in the Field Forces program at Red Canyon Range Camp, on White Sands Proving Ground. In January 1955, the 259th was deployed to Europe with full Type I CORPORAL field equipment. It was accompanied by an Ordnance support company.
Early in 1955, the British government decided to integrate the CORPORAL missile into its field program, providing a missile potential until such time as the British could design, test and produce similar weapons of their own. As a result, 113 CORPORAL missiles and several sets of guidance and handling equipment were ordered for the British Army. British troops were brought to Redstone Arsenal and the Fort Bliss - White Sands area later in 1955 for technical training. Field firing experience for these troops was scheduled at White Sands Proving Ground.
Conclusion of Type I Program
Starting in 1954, a new type of CORPORAL missile had begun to replace the Type I system among deliveries from the Firestone plant at Los Angeles. Phasing of this newer design into the flight testing program began, although a number of Type I rounds were still available. These subsequently were used by Jet Propulsion Laboratory, the Army Field Forces and the Chemical Warfare Service as test vehicles for the new Type II program. The last Type I round was fired at WSPG in December 1954.
Gross mass: 5,400 kg (11,900 lb).
Height: 14.00 m (45.00 ft).
Diameter: 0.76 m (2.49 ft).
Thrust: 89.00 kN (20,007 lbf).
Apogee: 50 km (31 mi).