Transiting from Air to Space
The North American X-15


Apart from the major problems encountered during the development of the X-15, there arose less critical items of concern, some technical, some administrative, and some financial. portions of the program were routine, but even those portions demanded time and attention if they were to remain in the routine category. For instance, the ground range presented a problem that had no connection with the selection of radars, with geography, or with building and equipping the stations. The procurement of the high-altitude tracking equipment was expedited by transferring the procurement responsibility to Patrick Air Force Base and the equipment was obtained by the modification of an existing contract. 1 The detail design and fabrication of the range was undertaken by the Electronic Engineering Company of Los Angeles, California. 2 The range was completed and ready for operation in late 1958. 3 The difficulty in connection with the ground range stemmed from the joint nature of the program and consisted of a dispute between the Air Force and NACA over the operation of the range after its completion.

As early as 7 April 1955, Brigadier General B. S. Kelsey, the Air Force representative on the Research Airplane Committee, wrote to Dr. H. L. Dryden, director of NACA, and requested that an understanding be reached on the construction and operation of the range. 4 At a meeting of the Research Airplane Committee on 17 May 1955, the NACA agreed to cooperate with WADC and the Air Force Flight Test Center (AFFTC) in planning the range; the Air Force was to be given the task of building and equipping the range, and the NACA would operate the range after its completion. 5

These decisions were not favorably received by Air Force Flight Test Center personnel, who felt that their center was ”… being relegated to the position of procurement agent for NACA. The Air Force also had some reservations about the ”… adequacy of equipment NACA had selected for the range.” 6 Despite the flight test center's lack of enthusiasm for the arrangements, an amendment of the original development directive, issued on 28 July 1955, spelled out the flight test center's responsibility for establishing the range. As neither the amendment nor the original directive assigned the responsibility for the operation of the completed range, the Air Force Flight Test Center renewed its attempts to acquire this responsibility. On 2 December 1955, Lieutenant Colonel B. H. Harris Jr., deputy chief of staff for operations at the flight test center, wrote to the commander of ARDC and formally requested that his center ”… be assigned the responsibility for operating, as well as developing, the test range.” 7

The NACA, determined to retain the responsibility for the operation of the range, simply reminded the Air Force that the matter had been settled by an agreement between Dr. Dryden and General Kelsey. As the Air Force's strongest argument was that Air Force operation would permit the use of the range during tests of such advanced fighters as the F-107, the NACA quickly agreed to make the range available for such tests – providing such use did not interfere with the X-15 program. 8

Fortunately this dispute over range operation and the similar disagreement with the Navy in relation to engine procurement were exceptions rather than the rule. The division of responsibility was usually arranged without difficulty and such disputes never offered a serious threat to the ultimate success of the project.

Another aspect of the X-15 program which occasionally caused concern was in the field of public relations. With numerous government agencies and contractors taking part in a program which was certain to arouse a great deal of public interest, there was bound to be some conflict. Each agency and each contractor had an information service or a publicity department, and it was to be expected that each such organization would seek to insure proper recognition of its own parent. Ordinarily such competition would have been considered unimportant, but after the success of the Soviet satellites in late 1957, the X-15 program became intimately associated with national prestige. The successful launchings of space vehicles made everything connected with space exploration a matter of vital interest to a world that was deeply concerned about the technological race between the United States and the Soviet Union. The X-15 ceased to be just an advanced research airplane-it suddenly became an entry in an international race.

As the roll-out of the first X-15 did not occur until 15 October 1958, most of the early publicity burden was carried by the pilots who had been selected to fly the aircraft. At one stage, the demands upon these pilots became so serious as to interfere with their training and indoctrination program. Some of those involved actually reported physical incapacitation as a result of extensive travel, irregular meals, and a lack of proper rest.

In addition to actual interference with the X-15 schedule, the publicity efforts sometimes created ill will and misunderstandings. For instance, on 13 January 1958, the Office of Information Services in the Office of the Secretary of the Air Force issued a release which stated that after company demonstrations of the X-15, the airplane would be flown by Air Force pilots and then turned over to NASA. a As an arrangement had already been made for the Air Force and NASA pilots to share in the research flights and for NASA to plan and direct the flights, the release confused the NASA and Air Force personnel at Edwards who had been planning the joint research effort and the relegation of NASA to last place displeased that agency. 9

One of the least comprehensible facets of the public relations program was the insistence that the X-15 would reach an altitude of 100 miles. The 100-mile figure was repeated in almost every article and broadcast that dealt with the X-15, and it was also used in speeches by Air Force and North American personnel. While it was more than probable that the X-15 would exceed its design altitude of 250,000 feet, the constant reiteration of a maximum altitude figure seemed very questionable public relations. The Air Force might find itself in the unenviable position of having to confess that the X-15 could not meet its advertised goals. On the other hand, if the design altitude had been used in the various releases, it is very possible the Air Force could have proudly announced that the X-15 had exceeded the goals that were set for it. The X-15 project office consistently reduced the altitude claims in its contacts with news media, but apparently the 100-mile figure was firmly established in the public mind. The inflated figure seemed particularly unnecessary in view of the fact that attainment of the design altitude would approximately double the existing record. If the X-15 failed to reach the goals announced in the preflight publicity releases, it could only result in a general impression that the project was a partial failure, or create doubts about the veracity of the information services that had persisted in publicizing the maximum performance. 10

Throughout the development of the X-15 there was a considerable body of opinion favoring an extension of the program beyond the original three aircraft. Although this opinion did not prevail, the proposals for such an extension were of more than passing interest. At one point, North American suggested the X-15 be utilized as a training vehicle and that an extensive training program be established. The company pointed out that such a program would prove useful in familiarizing Air Force pilots with rocket powered aircraft, the use of reaction controls, and some of the physical problems and sensations of space flight. Naturally such a training program would have necessitated production of additional X-15s.

Early in 1958, the NACA expressed the hope that at least one additional X-15 could be produced and that it would be devoted specifically to flight-control research. 11 However, the most serious consideration for an extension of the X-15 program came in mid-1958. On 8 April of that year, Air Force headquarters asked ARDC to consider the wisdom of investing additional funds in an expansion of the X-15 program. The letter in which the request appeared asked that ARDC weigh the cost of a possible extension against the probable value of such an extension and suggested that the requested recommendations should ”… include configuration changes, estimated costs, aircraft availability, the increased performance expected, the test results to be obtained and a brief substantiation of their value.” It also urged that the results of the extension studies be made available to Air Force headquarters at an early date--because any decision for an extension would have to be made before North American broke up the engineering team that had been assembled for the original program. 12

In response to this request for a study of extension possibilities, the X-15 project office conferred with the Directorate of Laboratories at WADC, with North American, and with the Air Force Flight Test Center at Edwards Air Force Base. Conferences with these groups took place between 17 and 21 April 1958 in an attempt to determine the future research requirements that might be met by an extension of the X-15 program. There were discussions on a possible change of structural materials of the X-15 airframe and attempts to estimate preliminary costs, design changes, production schedules, and performance figures for some of the more promising modifications that were envisioned. By 29 April, ARDC, the X-15 project office, and the Directorate of Laboratories had concluded that the best approach to an extension program would be to prove out the existing aerodynamic design and to consider the possibilities of improving performance by the use of new structural materials and the substitution of an improved rocket engine for the XLR99. The suggestion for a new engine was evidently influenced by the then-current difficulties with the XLR99; Air Force planners emphasized that any new engine should ”… be obtained as a result of across the board BMD (Ballistic Missile Division) and other effort, and not as a sole X-15 effort.” 13

On 19–20 May, the Air Force obtained verbal concurrence on the proposed extension from the Navy and NASA. The recommendation submitted to ARDC by the X-15 project office on June 13 was that the X-15 program be extended by the construction of three additional airplanes employing structural materials capable of withstanding higher temperatures than the materials utilized in the original design. ARDC approved the recommendation and forwarded it to Air Force headquarters on 16 June. 14

The urgency expressed in the original headquarters letter of April 8 had apparently evaporated, for it was not until 18 November 1958 that General Demler, director of research and development at Air Force headquarters, advised the commander of ARDC that no further consideration was to be given to an extension of the X-15 program. The Research Airplane Committee had not even met until October 31 and at that time Dr. Dryden, the NASA representative, stated that NASA had reached the conclusion that the original aircraft were adequate for the research contemplated by his agency and that any increase in program effort should be directed toward the maximum exploitation of the three X-15s already procured. He held that further development of additional aircraft was not warranted; the Navy and Air Force representatives on the Research Airplane Committee concurred with Dr. Dryden. 15

Not everyone was convinced that the decision was final, as there was still some interest in at least one additional airplane for flight-control research. However, as all three of the original aircraft were substantially completed by early 1959, it seemed most unlikely that there would ever be any additional extension proposals.

Responsibilities of the X-15 project office were many and varied. The office had to maintain close liaison with NASA on such subjects as the spherical nose being developed under the supervision of that agency. It had to make the arrangements for procuring and modifying the two B-52s that were to replace the B-36 carrier that had been contemplated originally. Other aircraft had to be scheduled for pilot indoctrination and for chase planes. Ground equipment had to be scheduled so that components could be tested and the aircraft maintained. Pilots had to be selected for the program. It was necessary to arrange for wind tunnel and centrifuge time at facilities already operating on tight schedules. Difficulties in the fabrication of some of the pressure tanks had to be considered and decisions made as to whether it was better to accept the weight penalties involved in a change of materials or the time penalties involved in further development. The decision to switch from a B-36 to a B-52 carrier necessitated that the X-15 be carried under a wing rather than the fuselage of the carrier aircraft and this change introduced new problems of sonic fatigue and flutter that had to be met and overcome. Testing revealed that some components of the stability augmentation system were 'not satisfactory and time was lost in redesign and retesting. A second industry conference, held 28–30 July 1958 at Los Angeles, had to be arranged. In addition to all of these items, routine paper work had to be accomplished, reports reviewed, and everyone concerned with the program advised of the progress. The paper work was more burdensome than usual because of the participation of two additional government agencies--the Navy and the NACA(NASA).

Two incidents, both connected with the XLR99 engine, revealed the variety of details with which the project office had to concern itself. They also illustrated the problems and frustrations that occurred when that office was not adequately or promptly informed. The first incident involved an aft-fuselage section which was furnished to Reaction Motors for 'the purpose of determining engine-airframe compatibility and the effects of engine vibration on the fuselage structure. When Reaction Motors had completed the tests, the company in accordance with existing procurement directives advised the nearest Air Force procurement office of this fact and asked for instructions as to its disposition. The Air Force office in quest£on, without consulting the X-15 project office, instructed Reaction Motors to destroy the item and the company proceeded to do so, completely unaware that the $300,000 airframe section had been scheduled for further use at Edwards.

The second incident involved the shipment of the first XLR99 engine, associated ground test equipment, and spare parts to Edwards Air Force Base. In an attempt to expedite the engine program, the project office had arranged for a military aircraft to transport the engine, the test equipment, and the spares from Reaction Motors to Edwards. Everything was ready for shipment.when the Air Force inspector noted that the boxes containing the spare parts were not labeled in accordance with regulations. The part 'numbers had been inked rather than typed on the box labels. The inspector refused to release the spares for shipment, with the result that the military aircraft proceeded to California with the engine and test equipment but without any spares. Subsequently, the project office had to arrange for shipment of the spares by commercial air freight. 16

In addition to the various technical tasks, the X-15 project office was under almost constant pressure to secure additional funds. This was because the original cost estimates for the X-15 and the XLR99 were grossly inaccurate. Initial ”planning” figures – for everything – totaled $12,000,000. Between October 1955 and the beginning of 1959, the airframe estimates rose from $50,063,500 to $64,021,146, and in the first 6 months of 1959 the estimates continued to rise, first to $67,540,178, and then to $68,657,644. 17 By 1 June 1959, North American's informal estimate of the airframe's cost had risen to $74,500,000. 18

The engine program involved even greater relative increases. In 1955, it had been estimated that the engine costs would ultimately be about $6,000,000. By the time an engine contract had been signed, the estimate had risen to $10,000,000. At the end of fiscal 1958, engine costs had risen to over $38,000,000 and expenditures in fiscal year 1959 brought the cost to $59,323,000. Estimated engine costs for fiscal 1960 were $9,050,000 – almost as much as the total estimate of 1955. As of June 1959, it appeared that engine costs would be at least $68,373,000 – over five times the original estimate for the entire X-15 program and almost a seven-fold increase over the costs contemplated when the engine contract was signed. 19 With the cost of the stable platform totaling more than $3,000,000, and with an estimated $6,000,000 needed for support costs in fiscal 1961, the total cost of the X-15 was going to exceed $150,000,000, even if no further increases occurred. (The Navy's contribution to the X-15 program totaled $6,400,000 at the end of fiscal 1959 and the project office hoped that an additional $1,000,000 could be obtained from the Navy in fiscal 1960.) 20 All the remaining funds had to be furnished by the Air Force, as NASA's contribution was in the form of wind tunnel testing and evaluation. The program was never halted by a lack of funds, but there were occasions when the funds only became available at the last possible moment; the files of the project office revealed that appeals for funds, justifications for additional funds, and the explanation of increased costs absorbed much of that office's time and energy.

Despite the technical problems, the paper work, the necessity of seeking more and more funds, and the recognition that the first flight would be several months. late, the X-15 program did move ahead.

It was still too early to predict the ultimate success of the X-15 in its research role, but the development program was rapidly drawing to a close in 1959. The airplane took slightly longer to reach the flight stage than had originally been contemplated, and the costs were far in excess of the estimates, but it would appear that the vehicle would be able to equal or surpass the performance for which it had been designed, and that it would prove to be a valuable research instrument.

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