Avro increased. In an internal NAE memo dated September 29, 1953, the following is noted: “[O]ur opinions differ in various ways from those of the Company or the RCAF, and this has given rise to argument and possibly to some ill feeling, even to the opinion that the NAE is anxious to hinder the straightforward development of the aircraft. Nothing could be further from the truth.”18
While the NAE saw itself as a legitimate scientific watchdog over a very complex project, its tone may have suggested otherwise; more than one official at Avro and the RCAF recalls that the NAE may have taken the role of honest broker just one step too far. The RCAF finally requested a meeting between the NAE, the DRB, and the U.S. National Advisory Committee for Aeronautics (NACA, later NASA) to discuss the differences between the NAE estimates of performance and those of Avro. At the time, it was believed that the best aeronautical minds were at NACA. The group published the “Joint Report on an RCAF-DRB-NAE Visit to NACA Langley Laboratories to Discuss Aerodynamic Problems of Avro CF-105 Aircraft,” dated November 19, 1954.
The NAE had made its points, for on December 20 and 21, 1954, Avro was called to the carpet. A second meeting was held at NACA headquarters in Washington, with Avro engineers taking centre stage to explain the reasoning behind their more favourable performance figures. Jim Floyd and Jim Chamberlin were among those present from Avro. Items discussed included the NAE criticisms of drag calculations, use of wing negative camber rather than positive camber, and perceived problems with pitch-up, engine intakes, and overall stability.
On the crucial issue of drag, NACA backed Avro, stating, “It was basically agreed … provided that (a) the intake and ramp bleed area is investigated and cleaned up where necessary, and (b) the afterbody is well faired in after the nozzles, the zero lift drag at Mach 1.5 may be as low as .020…. The Avro estimate from area distribution and skin friction considerations was .0184. The configuration is considered to be generally reasonable with respect to drag.”
Avro had proposed the use of negative wing camber rather than the traditional positive camber, which caused the NAE some consternation. Again, NACA concluded in favour of Avro: “It was agreed that there is little to be gained by conical positive camber for the particular mission of this aircraft…. Avro’s reasons for going to negative camber were also understood and appeared reasonable.”
The NAE thought the aircraft would be susceptible to pitch-up in supersonic flight. NACA stated, “It was agreed that the notch or leading edge extension proposed by Avro should alleviate pitch-up.” Similarly, with respect to engine 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
