The Avro Canada CF-105 Arrow was a delta-wing interceptor aircraft, designed and built by Avro Aircraft Limited (Canada) in Malton, Ontario, Canada, as the culmination of a design study that began in 1953. Considered to be both an advanced technical and aerodynamic achievement for the Canadian aviation industry, the CF-105 held the promise of Mach 2 speeds at 50,000 ft+ altitude, and was intended to serve as the Royal Canadian Air Force's interceptor for the 1960s and beyond.
Following the start of its flight test program in 1958, the Arrow, and its accompanying Orenda Iroquois jet engine program, were abruptly cancelled in 1959, sparking a long and bitter political debate. The Arrow is still the subject of controversy, almost 50 years after it was cancelled.
Recognizing that the delays that impacted the development and deployment of the CF-100 could also impact its successor, and the fact that the Soviets were working on newer jet-powered bombers that would render the CF-100 ineffective, the RCAF began looking for a supersonic, missile-armed replacement for the Canuck even before it had entered service. In March 1952, the RCAF's Final Report of the All-Weather Interceptor Requirements Team was submitted to Avro Canada.
Instead, aerodynamicists employed a swept-wing design to "trick" the airflow into behaving as though it was flowing over a long, thin wing. Almost every fighter project in the postwar era immediately applied the concept, which started appearing on production fighters in the late 1940s. Avro engineers had previously explored swept-wing and tail modification to the CF-100 known as the C103, which had proceeded to wooden mock-up stage, and offered transonic performance with supersonic abilities in a dive. However, the basic CF-100 continued to improve through this period, and the advantages were eroded. When Janusz Żurakowski broke the sound barrier in a dive, interest in the C103 waned.
Another solution, picked up by the Avro engineers, was the delta-wing design. The delta-wing had many of the same advantages of the swept wing in terms of transonic performance, but offered much more internal room and overall area. This providing more room for fuel, an important consideration given the thirsty engines of the era, and the large wing area provided lift at high altitudes. The disadvantages of the design were increased drag at lower speeds and altitudes, and especially higher drag while maneuvering. For the interceptor role these were minor concerns, as the aircraft would be spending most of its time flying in straight lines at high altitudes and speeds, mitigating these disadvantages.
In the words of designer James C. Floyd,
Further proposals resulted in two versions of the design known as C104: the single engine C104/1, and twin-engined C104/2. The designs were otherwise similar, using a low-mounted delta-wing and powered by the new Orenda TR.9 engines. Armament featured a battery of Velvet Glove missiles, (a Canadair Aircraft product based on CARDE design work), stored in an internal bay. It would be crewed by a single pilot guided by a completely automatic weapons control system to track and attack the target, similar to the system utilized in the F-86D. The primary advantages of the twin-engine C104/2 version was that it was larger overall, with a much larger weapons bay, and that it provided twin-engine reliability. The proposals were submitted to the RCAF in June 1952.
Intensive discussions between Avro and the RCAF examined a wide range of alternative sizes and configurations for a supersonic interceptor, culminating in RCAF Specification AIR 7-3 in April 1953.
AIR 7-3 called specifically for:
An RCAF team led by Ray Footit visited U.S. aircraft producers and surveyed British and French manufacturers before concluding that no existing or planned aircraft could fulfill these requirements.
Avro submitted their modified C105 design in May 1953, essentially a two-man version of the C104/2. A change to a "shoulder-mounted" wing allowed rapid access to the plane's internals, weapons bay, and engines. The new design also allowed the wing to be built as a single structure sitting on the upper fuselage, simplifying construction and improving strength. The wing design required a long main landing gear that still had to fit within the thin delta wing, presenting an engineering challenge. Five different wing sizes were outlined in the report, from 1,000 to 1,400 square feet (93 to 130 m²). The 1,200 square-foot (111 m²) version was eventually selected. Three engines were considered as well: the Rolls-Royce RB.106, the Bristol B.0L.4 Olympus, and the Curtiss-Wright J67 (a license-built version of the Olympus). The RB-106 was selected, with the J67 as backup.
The weapons bay design was larger than the original C104/2 design, situated in a large thin box on the bottom fuselage, running from a point adjacent to the front of the wing to the middle of the fuselage. The weapon system originally selected was the Hughes MX-1179, which was a pairing of the existing MA-1 fire-control system with the AIM-4 Falcon missile of both radar-guided and heat-seeking variants. This system was already under development for proposed use in the USAF's WS-2011954 interceptor (dating from 1949, which would lead to the F-102 Delta Dagger). The Velvet Glove radar-guided missile had been under development with the RCAF for some time, but was considered unsuitable for supersonic launch, and further work on that project was eventually cancelled in 1956.
In July 1953, the proposal was accepted and Avro was given the go-ahead to start a full design study. In December, $27 million was provided to start flight modeling. At first, the project was limited in scope, but the introduction of the Soviet Myasishchev M-4 Bison jet bomber and the Soviet Union's testing of a hydrogen bomb dramatically changed Cold War priorities. In March 1955, the contract was upgraded to $260 million for five Arrow Mark 1 flight-test aircraft, to be followed by 35 Arrow Mark 2s with production engines and fire-control systems.
In order to mitigate risks, a massive testing program was started. By mid-1954, the first production drawings were issued and wind tunnel work began. In a related program, nine instrumented free-flight models were mounted on solid fuel Nike rocket boosters and launched over Lake Ontario while two additional models were launched from Wallops Island, USA, over the Atlantic Ocean. These models were for aerodynamic drag and stability testing, flown to a maximum speed of Mach 1.7+ before intentionally crashing into the water. Ongoing efforts have been made to search for the models in Lake Ontario, and, to date, two have reputedly been found, along with one Nike booster and another for a Velvet Glove.
Experiments showed the need for only a small number of design changes, mainly involving the wing profile and positioning. To improve high-alpha performance, the leading edge of the wing was drooped, especially on outer sections, a dog-tooth was introduced to control spanwise flow, and the entire wing given a slight negative camber which helped control trim drag and pitch-up.
The area rule principle, made public in 1952, was also applied to the design. This resulted in several changes including the addition of a tailcone, sharpening the radar nose profile, thinning the intake lips, and reducing the cross-sectional area of the fuselage below the canopy.
The aircraft used a measure of magnesium and titanium in the fuselage, the latter limited largely to the area around the engines and to fasteners. Titanium was still expensive and not widely used because it was difficult to machine. The construction of the airframe itself was fairly conventional, however, with a semi-monocoque frame and multi-spar wing.
The Arrow's thin wing required aviation's first 4,000 pounds per square inch (28 MPa) hydraulic system to supply enough force while using small actuators and piping. A rudimentary fly-by-wire system was employed, in which the pilot's input was detected by a series of pressure-sensitve transducers in the stick, and their signal was sent to an electronic control servo that operated the valves in the hydraulic system to move the various flight controls. This resulted in a lack of control "feel", since, because the control stick input was "disconnected" from the hydraulic system, the variations in back-pressure from the flight control surfaces that would normally be felt by the pilot could no longer be transmitted back into the stick. To re-create a sense of "feel", the same electronic control box rapidly responded to the hydraulic back-pressure fluctuations and motivated actuators in the stick, making it move; this "artificial feel" was also a first. An advanced stability augmentation system was added as well, recognizing long, "thin" aircraft have a number of coupling modes that can lead to departure from controlled flight if not damped out quickly. Since the center of lift moved with speed, the flight control system also assisted stability and manoeuvre.
In 1954, the RB.106 program was cancelled, necessitating the use of the backup J67 instead. In 1955, this engine was also cancelled, leaving the design with no engine. At this point, the Pratt & Whitney J75 was selected for the initial test-flight models, while the new TR 13 (soon PS-13 Iroquois) engine was developed at Orenda for the production Mk 2s. Ultimately, only the rejected Bristol Olympus engine would actually go into production.
In 1956, the RCAF demanded additional changes, selecting the advanced RCA-Victor Astra fire-control system firing the equally advanced US Navy Sparrow II in place of the MX-1179 and Falcon combination. Avro objected on the grounds that neither of these were even in testing at that point, whereas both the MX-1179 and Falcon were almost ready for production. RCAF planners felt the greatly improved performance of the Sparrow was worth the gamble.
The Astra proved to be problematic as the system ran into a lengthy period of delays, and when the USN cancelled the Sparrow II in 1956, Canadair was quickly brought in to continue the Sparrow program in Canada, although they expressed grave concerns about the project as well.
In June 1957, the Liberals lost the election, and a Progressive Conservative government under John Diefenbaker took power. Diefenbaker, from the Canadian west, had campaigned on a platform of reining in what they claimed was "rampant Liberal spending." The debate was politically presented as an east versus west divide, with the Conservatives campaigning on a platform of eastern Canada using money from across the country to fund their "industrial welfare" projects. The Arrow was not the only major industrial project targeted during the campaign, others such as the "million dollar monster" postal sorting computer from Ferranti Canada were singled out for additional political scorn.
In August 1957, the Conservative Diefenbaker government signed the NORAD (North American Air Defense) Agreement with the United States, which required the subordination of the RCAF Air Defence Command to American command and control. The USAF was in the process of completely automating their air defense system with the SAGE project, and insisted that the RCAF had to use it as well. One aspect of the SAGE system was the BOMARC nuclear-tipped anti-aircraft missile, which when intercepting bombers over Ontario and Quebec would be exploding over major Canadian cities. This led to studies on basing BOMARCs in Canada in order to push the line further north, away from the cities.
Storms of Controversy revealed a top secret brief prepared for George Pearkes, then Minister of National Defence, for his July 1958 meeting with U.S. officials. The brief states,
"The introduction of SAGE in Canada will cost in the neighborhood of $107 million. Further improvements are required in the radar… NORAD has also recommended the introduction of the BOMARC missile… will be a further commitment of $164 million… All these commitments coming at this particular time… will tend to increase our defence budget by as much as 25 to 30%…"
Pearkes was also concerned about funding defence against ballistic missiles. The existence of Sputnik had also raised the spectre of attack from space, and, as the year progressed, word of a "missile gap" began spreading. An American brief of the meeting with Pearkes reported Pearkes "stated that the problem of developing a defence against missiles while at the same time completing and rounding out defence measures against manned bombers posed a serious problem for Canada from the point of view of expense… In a document written after the cancellation, Pearkes noted, "We did not cancel the CF-105 because there was no bomber threat, but because there was a lesser threat and we got the Bomarc in lieu of more airplanes to look after this It is also said Canada could afford the Arrow or Bomarc/SAGE, but not both..
In a later interview in the 1990s, Pearkes discussed these problems and revealed he was advised by an American official, while en route to Colorado, Canada did not need to build aircraft because the US had plenty and could make them available at any time. Pearkes states this is when he made his decision to cancel the Arrow. His dilemma was how to fill in the defence gap from cancellation of the Arrow to the time when Bomarc bases would be operational. He revealed he struck a deal to allow American training in Goose Bay (Labrador) and Cold Lake (Alberta) in exchange for protection.
By 11 August 1958, Pearkes requested cancellation of the Arrow, but the Cabinet Defence Committee refused. He tabled it again in September, and recommended installation of the Bomarc missile system. The latter was accepted but, again, the CDC refused to cancel the entire Arrow program. The CDC wanted to wait until a major review in 31 March 1959, to better examine world conditions. They did, however, cancel the Sparrow/Astra system in September 1958. Efforts to continue the program through cost-sharing with other countries were then explored.
Worldwide, the Arrow was not the only heavy high-speed interceptor design cancelled at that time; the Republic Aircraft XF-103 and the North American Aviation XF-108 Rapier, designed to have higher performance specifications than the Arrow, were cancelled in the mock-up stage of development at approximately the same time.Even the Convair F-106 Delta Dart was very nearly terminated. In the UK, the ramifications of the 1957 Defence White Paper led to the cancellation of almost all manned fighter aircraft development.
From 1955 onwards, the UK had shown considerable interest in the Arrow; in April 1956, the UK's Air Council recommended a purchase of 144 Arrows for the RAF to serve alongside the Saunders-Roe SR.177 mixed power interceptor, instead of the "thin-wing" Gloster Javelin then under study. The CF-105 would serve as a stopgap until the UK's F.155 project came to fruition. However with the F.155 due in 1963 and the Arrow not likely to reach the RAF before 1962, there was little point in proceeding, even if the costs of acquisition had not been so high. The infamous 1957 Defence White Paper, prompted by a general lack of funds, foretold an end to manned fighters and completely curtailed any likelihood of a purchase. In January 1959, the UK's final answer was no – with an offer to sell Canada the English Electric P.1 (the aircraft that would become the English Electric Lightning). The French government was prepared to buy some 200 Iroquois engines, but cancelled their order in 1958, being advised by persons unknown that the Arrow was going to be cancelled.
The US Air Force had already developed three aircraft with performance intended to be broadly similar to the Arrow, originally as part of their "1954 Interceptor" project -- the McDonnell F-101B Voodoo, Convair F-102 Delta Dagger and Convair F-102B (later Convair F-106 Delta Dart). Additionally, two more advanced interceptors (the Republic XF-103 and North American XF-108) were under development, although both would ultimately be cancelled in the early design and mock-up phases. Nevertheless it appears the USAF was concerned about the effect the cancellation would have on Canada's defence industry. In 1958, Avro Aircraft Limited President and General Manager Fred Smye had elicited a promise from the USAF to "supply, free, the fire control system and missiles and if they would allow the free use of their flight test center at Muroc Lake in California (now known as Edwards AFB)".
An attempt was made to provide the completed Arrows to the National Research Council of Canada as high-speed test aircraft. The NRC refused, noting that without sufficient spare parts and maintenance, as well as qualified pilots, the NRC could make no use of them. A similar project initiated by the Royal Aircraft Establishment (Boscombe Down) had resulted in Avro Vice-President (Engineering) Jim Floyd, preparing a transatlantic ferry operation. This proposal, like others from the United States, was never realized.
Along with the five flying test models and production aircraft, blueprints and other materials were destroyed leading to the creation of a piece of Canadian mythology. The rushed destruction incited a number of conspiracy theories alleging American culpability for the Arrow's demise. There remains an enduring but fanciful legend that one of the prototypes was spirited away after the cancellation and remains intact, but continues to be the basis of an urban legend.
Following the Canadian government's cancellation of the Avro Arrow project in 1959, CF-105 Chief Aerodynamicist Jim Chamberlin led a team of 25 engineers to NASA's Space Task Group to become lead engineers, program managers, and heads of engineering in NASA's manned space programs—Projects Mercury, Gemini and Apollo. This team would eventually grow to 32 Avro engineers and technicians, and become emblematic of what many Canadians viewed as a "brain drain" to the US. Many other engineers, including Jim Floyd (whose design studies at Hawker Siddeley (Avro Aircraft's UK parent) on the HSA.1000 SST design studies were ultimately influential in the design of the Concorde) found work abroad in either the UK or the United States.
In 1961, the RCAF obtained 66 CF-101 Voodoo aircraft, one of the American designs the RCAF originally rejected, to serve in the role originally intended for the Avro Arrow. The controversy surrounding this acquisition, and Canada's acquiring nuclear weapons for the Voodoos and Bomarcs eventually contributed to the collapse of the Diefenbaker government in 1963.
Although nearly everything connected to the CF-105 and Orenda Iroquois programs was destroyed, the cockpit and nose gear of RL-206, the first Mk 2 Arrow, and two outer panels of RL-203's wings were saved and are on display at the Canada Aviation Museum in Ottawa, alongside an Iroquois engine.
With specifications comparable to then-current offerings from American and Soviet design bureaus, at the time of its cancellation, the Arrow was considered by one aviation industry observer to be one of the most advanced aircraft in the world.
Go-ahead on the production was given in 1955, with series production taking place in Assembly Bay One. The rollout of the first CF-105, marked as RL-201, took place 4 October 1957. The company had planned to capitalize on the event, inviting more than 13,000 guests to the formal occasion. Unfortunately, the media and public attention for the Arrow rollout was dwarfed by the launch of Sputnik the same day.
The J75 engine was slightly heavier than the PS-13, and therefore required ballast to be placed in the nose to return the center of gravity to the correct position. In addition, the Astra fire-control system was not ready, and it too, was replaced by ballast. The otherwise unused weapons bay was loaded with test equipment.
RL-201 first flew on 25 March 1958 with Chief Development Test Pilot S/L Janusz Żurakowski at the controls. Four more J75-powered Mk 1s were delivered in the next 18 months. The test flights went surprisingly well; the aircraft demonstrated excellent handling throughout the flight envelope. Much of this was due to the natural qualities of the delta-wing, but an equal amount can be attributed to the Arrow's stability augmentation system. The aircraft went supersonic on only its third flight and, on the seventh, broke 1,000 miles per hour (1600 km/h) at 50,000 feet, while climbing and still accelerating. A top speed of Mach 1.98 was eventually reached at three quarters throttle, even with these lower-powered engines.
No major problems were encountered during the testing phase, though some minor issues found with the landing gear, flight control system, and the stability augmentation system needed considerable tuning.
The former problem was partly due to the tandem main landing gear (two wheels and tires: one in front of and one behind the gear leg) being very narrow, in order to fit into the wings. The leg shortened in length and rotated as it was stowed. During one landing incident, the chain mechanism (used to shorten the gear) in the Mark 1 gear jammed, resulting in incomplete rotation. In a second incident with Arrow 202 on 11 November 1958, the flight control system commanded elevons full down at landing. The resulting reduction in weight on the gears reduced the effective tire friction, ultimately resulting in brake lockup and subsequent gear collapse. A photograph taken of the incident proved inadvertent flight control activation had caused the accident.
The stability augmentation system was a matter of tuning, tuning and more tuning. Although the CF-105 was not the first aircraft to use such a system – the Arrow used this system for all three axes, other aircraft did not – it was one of the first of its kind, and was consequently problematic. By February 1959, the five aircraft had completed the majority of the company test program and were progressing to the RCAF acceptance trials.
Top speed would have been limited by frictional heating but, “The aluminum alloy structure which we favoured was good for speeds greater than a Mach number of 2.
The Avro Museum of Calgary began a Replica Arrow Project Theirs is a 0.6-scale piloted replica aircraft being built for public flight demonstration — construction started in September 2000 following eight years of research. Built of modern-day composite materials under Canadian Recreational Aircraft Legislation, construction is expected to take five years of volunteer labour and cost a half-million dollars in materials and parts.
The Toronto Aerospace Museum, located at the former CFB Downsview features a full-size replica Arrow built by volunteers with assistance from local aerospace firms. With a metal structure, the replica features many authentic-looking components including landing gear constructed by Messier-Dowty (the original Arrow main landing gear sub-contractor). Painted in the colours of Arrow 25203, the Arrow replica was rolled out for a media event on 28 September 2006 and was on public display on 8-9 October 2006 to commemorate the original aircraft's rollout in 1957. It will be permanently displayed beside an Avro Lancaster bomber (currently under restoration) built at the same Malton plant that produced the Arrow. The museum ultimately hopes to acquire an Avro CF-100 and obtain the first Avro VZ-9-AV Avrocar (the company's last aviation project) on a long-term loan from the National Air and Space Museum, in Washington, D.C., to be exhibited alongside the Arrow replica and Avro Lancaster.