Storms of Controversy. Palmiro Campagna
intakes, “It was generally agreed that the amount and the diffusion angle involved at the intake were not excessive.”
Finally, on stability, Avro was proposing the use of artificial electronic stabilization, a radical departure from conventional design. According to the NAE, it was necessary to afford stability by making the aircraft inherently stable without the use of artificial electronic means. NACA stated:
It was generally agreed that while artificial lateral stabilization is undesirable in itself, the obvious aerodynamic [nonelectronic] cures such as a large increase in fin area could be unacceptable so far as performance of the aircraft is concerned. A concentrated test programme was recommended…. It was noted that problems of this type are not peculiar to the CF-105 configuration but appear to be associated with the mass distributions of modern high performance fighters.19
Avro had been vindicated on all counts by the NACA specialists. Floyd would later write, “If the NAE had been right, the Arrow would never have flown supersonically.” Furthermore, NACA was affirming that the problems Avro was encountering were to be expected in supersonic aircraft design.20
Although many may not fully appreciate the technical significance of the arguments presented, they have been included because they have remained secret for so long, fuelling the speculation in some circles that the aircraft was technically flawed. Also, they demonstrate the technical expertise of the Avro team.
With the NACA experience behind them, the Avro team went back to work. Wind-tunnel testing continued. In all, 17 scale models ranging in size from one-eightieth to one-sixth scale were tested in the NAE facilities in Ottawa, the Cornell Laboratories in Buffalo, the NACA facilities in Langley Field, Virginia, and the NACA Lewis Laboratory in Cleveland, Ohio.
Due to the limitations in wind-tunnel testing, a complementary program of free-flight-model testing was carried out from 1954 to 1957. Eleven one-eighth-scale models of the aircraft were mounted atop Nike rocket boosters of 45,000 pounds thrust and launched into the sky. At altitude the boosters would separate, allowing the model to continue flying. (The separation technique known as drag separation had been developed by NACA. Essentially, after expending its fuel, the heavier booster would decelerate faster than the model, thereby separating from it.21 )
The models themselves were a mix of crude and highly accurate representations of the aircraft designed to provide dynamic stability and control data. Each was fitted with a series of transducers and an FM telemetering system using standard radio broadcast frequencies. The models were tracked using radar and theodolites as well as film cameras. Nine models were launched from the Canadian Armament Research and Development Establishment (CARDE) at the range in Point Petre near Picton, Ontario. Two more were fired from the Wallops Island Range of the NACA Pilotless Aircraft Research Division in Virginia. Presumably, all of these models, constructed primarily of stainless steel, remain to this day under the waters where they splashed down decades ago. They were considered expendable, so no attempts were made to retrieve them.22
Augmenting the scale-model effort, Avro also built a series of mock-ups and test rigs. For example, an engineering wooden mock-up was built to check tolerances and sizing for the engine and armament packs as well as to examine cable and wire runs. To demonstrate pilot visibility during taxiing and ground handling, a mock-up of the front cockpit was mounted to a truck, simulating the height and attitude the pilot would experience. A test rig simulating the aircraft’s electronics was added, as were others to simulate the landing gear and hydraulics. Finally, the most powerful digital computer then available, the IBM 704, was rented from IBM to handle the theoretical computations fed to it by a staff of 30 mathematicians, technicians, and operators.23
Free-flight rocket models of the Arrow were instrumented and then launched to obtain flight data for the Arrow design. (Jim Floyd)
In four short years, outstanding even by today’s standards, the most modern aircraft in the world was ready for rollout. Along the way, Floyd had become vice-president, engineering, and Chamberlin, chief of technical design. Chief engineer was now Robert N. Lindley, with Guest Hake as project designer. But despite the technical design and production achievement, the aircraft had yet to fly. Would it meet the stringent performance specifications? Would flight testing prove otherwise? Would other countries purchase it?
In a memo dated February 22, 1957, the RCAF officially named the CF-105 the Arrow.24
The Arrow Dream Team. Left to right: Bob Lindley, Jim Floyd, Guest Hake, and Jim Chamberlin. (Jim Floyd)
If they were in our position, what would be their view in continuing or abandoning the project?
— Question from the RCAF to the USAF During a
Meeting from October 31 to November 1, 19551
With all of the activity being carried out with NACA and Avro Canada’s liaison with Hawker Siddeley in the United Kingdom, it is logical to assume that both the United States Air Force (USAF) and the Royal Air Force (RAF) in Britain would have observed what was going on in Canada with great interest. In the case of the United States, General Nathan F. Twining, chief of staff, USAF, had advised the Canadian chief of the air staff, Air Marshal Roy Slemon, that the USAF was interested in a long-rage interceptor and had initiated a design competition among American manufacturers.
It was June 1954, and General Twining was expressing a specific interest in the CF-105, so much so that he had requested the Air Research & Development Command (ARDC) in the United States to evaluate the specifications of the Canadian plane with those in the design competition. On July 15, 1954, Air Marshal Slemon replied and forwarded a copy of A.V. Roe’s design study. He also stated he was pleased to open this exchange of information with the Americans. It was in keeping with the doctrine of requiring “the enemy to compete in the technological field with the combined brains and resources of the English-speaking Allies rather than three components thereof … [because] such collaboration would be superior to the individual and in some cases overlapping efforts.”2 Slemon pointed out that approval to proceed with the CF-105 was based on the knowledge that neither the United States nor the United Kingdom had or were planning to develop a similar aircraft.
The exchange of letters resulted in a team of RCAF and Avro officials providing a briefing to the ARDC on August 26, 1954. The briefing was well received, and later in 1955, when USAF assistance was requested in arranging for special wind-tunnel testing at facilities not available in Canada, help was provided without hesitation.
Despite the progress Avro was making and its vindication at NACA headquarters the previous year, Air Marshal Slemon, together with Dr. Omond Solandt, chairman of the DRB, decided an independent evaluation of the project was needed. A high-level technical delegation of USAF personnel was invited to visit Avro and study the program between October 31 and November 1, 1955. The USAF team was headed by Major General G.E. Price, director of requirements and deputy chief of staff (development). It included members from ARDC and the propulsion and fighter branches of USAF headquarters.3
The American team was told by the RCAF that increasing costs had led to a reappraisal of the project, that the defence budget was limited, and that, therefore, continuation could lead to elimination of other desirable programs. The USAF was requested to provide an opinion as to the “essentiality of the 105 Project to the defence of North America” and was asked flat out if it would abandon the program under similar circumstances! The defence of Canada had expanded to include the defence of North America, and it is probable that the Canadians were hoping to interest the USAF in eventual acquisitions. Still, it is inconceivable that the question of continuing or abandoning the project would be put so bluntly, especially when one factors in the “Buy American”