Avro CF-105 Arrow

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The Avro CF-105 Arrow was a delta-wing interceptor aircraft, designed and built in Malton, Ontario, Canada by Avro Canada during a short period of time in the 1950s. The design was entering the middle stages of testing when it was cancelled in 1959, after a long and bitter political debate. The prototypes were then destroyed, and the blueprints were burned, creating an enduring piece of Canadian mythology. Many of the workers moved to the United States in a massive "brain drain" to become lead engineers, program managers, and heads of engineering in NASA's manned space programs - Projects Mercury, Gemini and Apollo. There is a legend that one of the prototypes was spirited away after the cancellation and remains intact, but there is no evidence to support this.

Contents

1 Development

1.1 Initial design
1.2 Final design

2 Production
3 Variants and design stages

3.1 Mark 1
3.2 Mark 2
3.3 Other versions

4 Cancellation
5 CBC Docu-drama
6 Specifications (Arrow Mk.1)
7 References
8 Further reading and viewing
9 External links
10 Related content

Development

In the post-World War II period, the Soviet Union began developing a fleet of long-range bombers capable of delivering nuclear weapons to North America and Europe. To counter this threat, Western countries began the development of interceptor aircraft which could engage and destroy these bombers before they reached their targets.

A. V. Roe Canada Limited had been set up as a subsidiary of Avro in 1945, initially handling repair and maintenance work for aircraft at the local Malton Airport (today known as Pearson International Airport, Toronto's main airport). The next year, however, the company started the design of an all-weather interceptor for the Royal Canadian Air Force, the Avro CF-100 Canuck. The Canuck would become one of the first jet-powered aircraft in its class, and one of the most enduring, flying into the 1980s.

However, it was not until 1953 that the Canuck entered squadron service. The long delay was not unique; similar projects were suffering lengthy delays around the world as engineers came to understand the problems inherant in jet power and high-speed flight. Nevertheless, a seven year wait for any project was a worrying prospect, notably when the state of the art was progressing so rapidly. Even before the Canuck entered service, designers had moved onto a newer generation of missile-armed supersonic designs of much greater capability.

Recognizing the similar delays would likely affect the Canuck's replacement, and considering that the Soviets were working on newer jet-powered bombers, the RCAF began looking for a supersonic 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.

Initial design

The CF-100 was a very conventional design, similar to most World War II heavy fighters in layout, with the exception of the introduction of jet engines mounted close to the fuselage. This sort of design encounters a strong form of drag in the transonic speed range, wave drag, as air "piles up" on the leading edge of the wing. Overcoming this drag proved to be difficult given conventional designs, and led to the concept of a "sound barrier".

German research during WWII identified a number of solutions to this problem. It was known that the onset of the drag was greatly reduced by using thinner airfoils with much longer chord, but these were impractical because they left little internal room in the wing for weapons or fuel. Instead they introduced the swept-wing design, which "fooled" the airflow into believing it was flowing over a long, thin wing. Almost every fighter project in the post-war era immediately copied the concept, which started appearing on production fighters in the late 1940s.

Avro engineers had already explored a number of paper projects on modifications to the CF-100 using swept wings (and tail) as the C-103. Although it theoretically bettered the CF-100 in terms of performance, the small performance gain given that it would use the same engines was not worth the extra development costs.

To meet the new RCAF requirements, the engineers considered the delta. The delta offers many of the same advantages (and disadvantages) as the swept wing, but is much larger, allowing for more internal storage. The only downside to the design, compared to the swept wing, was that at low speeds it suffered from much greater drag. This was of little consequence for an aircraft which would primarily be flying at high altitudes and speeds.

In the words of designer Jim Floyd, "At the time we laid down the design of the CF-105, there was a somewhat emotional controversy going on in the United States on the relative merits of the delta plan form versus the straight wing for supersonic aircraft…our choice of a tailless delta was based mainly on the compromise of attempting to achieve structural and aeroelastic efficiency, with a very thin wing, and yet, at the same time, achieving the large internal fuel capacity required for the specified range." (Floyd, James, Journal of the Royal Aeronautical Society, December 1958.)

They created two versions of a design known as the C-104: the C-104/1 with a single engine, and the C-104/2 with twin engines. The planes were otherwise similar, using a low-mounted delta-wing, powered by the new Orenda TR.9 engines, armed with Velvet Glove missiles (an RCAF design) stored in an internal bay, crewed by a single pilot, and guided with a completely automatic interception system that would track down and attack the target after it was selected by the pilot (similar to the F-86D). The primary advantage of the twin-engine /2 version was that it was larger overall, including a much larger weapons bay, and had the advantage of twin-engine reliability. The results were submitted to the RCAF in June, 1952.

Final design

Intensive discussions between Avro and the RCAF examined a wide range of possible sizes and configurations, culminating in RCAF Specification AIR 7-3 in April 1953.

AIR 7-3 called specifically for twin engines, since no single engine then available could lift the fuel load needed for the long-range missions the RCAF demanded. This was to be 300 nautical miles (556 km) for a normal low-speed mission, and 200 nautical miles (370 km) for a high-speed interception mission. It was to fly at Mach 1.5, cruise at an altitude of 50,000 feet (15,000 m), and be able to pull 2 g in maneuvers with no loss of speed or altitude under those conditions. The time from a signal to start the engines to the aircraft's reaching 50,000 feet (15,000 m) and Mach 1.5 was to be less than five minutes. Turn-around time on the ground was to be less than ten minutes. The new specification also called for a crew of two, as it was considered unlikely that even a fully automated system would reduce pilot workload enough to allow a lone pilot. An RCAF team led by Ray Footit visited US aircraft producers and concluded that no existing or planned aircraft could fulfil these requirements.

In response to the updated requirements, Avro returned their modified C-105 design in May 1953, a two-man version of the C-104/2. It was decided to move the wing to the upper part of the fuselage from its former low-mounted point, in order to improve access to the plane's internals, weapons bay, and engines. The high-wing design also allowed the wing to be a single structure across the plane, which simplified construction and added strength. However this also required long landing gear that still had to fit within the thin delta-wing — an engineering challenge. Five different wing sizes were outlined in the report, from 1,000 to 1,400 ft² (93 to 130 m²). The 1,200 ft² (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 a backup.

The weapons bay was larger than the 104/2, situated in a large thin box running from the front to the middle of the wing. 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 radar-guided and heat seeking variants. This system was already under development for proposed use in the US's WS-201 1954 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 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 modelling. At first the project was limited in scope, but the introduction of the Soviet Myasishchev M-4 Bison jet bomber and their testing of a hydrogen bomb dramatically changed priorities. In March 1955, the contract was upgraded to a $260 million contract for five Arrow Mark 1 flight-test aircraft, to be followed by 35 Arrow Mark 2s with production engines and fire-control systems.

Production

Most aircraft designs start with the construction of a small number of hand-built prototypes. These are test-flown, and the inevitable problems are discovered and fixed. Once satisfactory results are achieved, a set of jigs for production construction is laid out in the assembly hall. This is a slow and expensive process, but a safe one.

For the Arrow project it was decided to adopt the Cook-Craigie plan. Developed in the 1940s, Cook-Cragie skipped the prototype phase and built the first test-airframes on the production jigs. Any changes could be incorporated into the jigs while testing continued, so production started as soon as the test program was complete. As Jim Floyd noted at the time, this was a risky approach but together with the RCAF, “…it was decided to take the technical risks involved to save time on the programme…I will not pretend that this philosophy of production type build from the outset did not cause us a lot of problems in Engineering. However, it did achieve its objective..” (Floyd, Journal of the Royal Aeronautical Society, December 1958).

In order to mitigate the risks, a massive testing program was started and by mid-1954, the first production drawings were issued and wind tunnel work began. In another program, 9 instrumented free-flight models were mounted on solid Nike rockets and launched over Lake Ontario while 2 more were launched across Wallops Island in the United States. These models were for aerodynamic drag and stability testing and achieved 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 but none have been found to date. What has been found is a Velvet Glove booster and possibly a Nike booster but not the scale models themselves.

Experiments showed the need for only a small number of changes to the design, mostly involving changes to the wing profile and positioning. In order to improve high-alpha performance the front of the wing was drooped, especially on the outer sections, a dog-tooth was introduced to control spanwise flow, and the whole wing was given a slight negative camber to help control trim drag and pitch-up.

The area rule principle was also applied to the design. This resulted in several changes including the addition of a tailcone, sharpening the radar nose, thinning the intake lips and reducing the cross-sectional area of the fuselage below the canopy. (James Floyd, Royal Aeronautical Journal.)

The aircraft used a large 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 demanded aviation's first 4000 lb/in² (28 MPa) hydraulic system that could supply enough power while using small actuators and piping. Use of a rudimentary fly-by-wire system resulted in the problem of the lack of control "feel" for the pilot, and to solve this the control stick input was "disconnected" from the hydraulic system. The pilot's input was sensed by a series of force transducers in the stick, and their signal was sent to an electronic control servo that operated the valves on the hydraulic system to move the various flight controls. In addition, the same box fed pressure back into actuators in the stick itself, making it move. This happened quickly enough that it appeared as if the pilot were moving the stick directly. An advanced stability augmentation system was added as well, as long, thin aircraft have a number of coupling modes that can lead to departure from controlled flight if not damped out quickly. Since the centre of lift moved with speed, the flight control system also assisted stability and manoeuvre.

In 1954 the RB.106 program was cancelled, so plans were made to use the backup J67 instead. In 1955 this engine was also cancelled, leaving the plane with no engine. At this point the new 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. Eventually it was only the rejected Bristol Olympus design that would actually go into production.

In 1956, the RCAF demanded an additional change, the use of the advanced RCA-Victor Astra fire-control system in place of the MX-1179, firing the equally advanced US Navy Sparrow II in place of the Falcon. Avro objected to this choice 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. The RCAF planners felt that the greatly improved performance of the Sparrow was worth the gamble.

The Astra proved to be a serious problem in the Arrow design. The system ran into a lengthy period of delays, and the United States Navy eventually cancelled all work on the Sparrow II in 1956. Canadair was quickly brought in to continue the Sparrow program in Canada, but they expressed their concerns about the project as well.

A rush study looked at alternatives, including resurrecting the Velvet Glove for use with the Astra, or the use of the original MX-1179 system with its Falcons. Even the MX-1179 had run into difficulties, and the F-102 eventually settled on the older MG-1 system originally used in the F-86D. Work was continuing on the MX, however, as it was planned to be used in the upgraded F-102B (later renamed as the F-106 Delta Dart), so this was selected for the Arrow as well.

Variants and design stages

Mark 1

Go-ahead on the production was given in 1955, and the rollout of the first prototype, RL-201, took place October 4 1957, quite an achievement for a company that had never built a supersonic aircraft. Unfortunately, the roll-out was dwarfed by the launch of Sputnik on the same day.

The J75 was slightly heavier than the PS-13, and therefore required ballast to be placed in the nose to move the centre of gravity back 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. This makes the Arrow one of the few aircraft to actually grow lighter during service entry.

RL-201 first flew on March 25, 1958. Four more J75-powered Mk.1s were delivered in the next two years. The test flights went surprisingly well; the plane demonstrated excellent handling at all extremes of the flight envelope. Much of this is due to the natural qualities of the delta-wing, but an equal amount is due to the stability augmentation system. The aircraft flew supersonically on only its third flight and on its seventh flight, achieved a speed of over 1,000 miles per hour at 50,000 feet, while climbing and still accelerating. A top speed of Mach 1.98 would eventually be reached at three quarters throttle.

No major problems were encountered during the testing phase. There were some issues with the landing gear, flight control system, and the stability augmentation system needed considerable tuning.

The former problem was partly due to the gear being very thin, in order to fit into the wings. In order to achieve gear stowage upon retraction, the landing gear was of the tandem arrangement (two tires); one in front of and one behind the gear leg. The leg shortened in length and twisted as it was stowed. During one landing incident, the chain mechanism used in the Mark 1 gear jammed, resulting in incomplete rotation of the gear. In a second incident, the flight control system commanded elevons full down at landing, resulting in little weight being on the main landing gears and ultimately resulting in brake lockup and gear collapse.

The stability augmentation system was a matter of tuning, tuning and more tuning. Although the Arrow was not the first plane to use such a system – the Arrow used this system for all three axes, other aircraft did not – it was one of the first, and the concept had not yet developed into the science it is today.

Mark 2

The Mk.2 version was to be fitted with the Iroquois engine. The Astra/Sparrow fire control system had been terminated by the government in September 1958 and all aircraft were to have the Hughes/Falcon system installed. At the time of cancellation of the entire program, the first Arrow Mk.2, RL-206, was nearly complete. It was expected to break the world speed record but never had the chance.

Top speed would have been limited by frictional heating but as Jim Floyd has said, “The aluminum alloy structure which we favoured was good for speeds greater than a Mach number of 2…” (Floyd, Journal of the Royal Aeronautical Society, December 1958).

Other versions

Avro Canada had a wide range of Arrow derivatives under development at the time of project cancellation. Frequent mention is made of an Arrow that could have been capable of Mach 3, similar to the Mikoyan-Gurevich MiG-25 – this was not the production version, but one of the design studies, and would have been almost a completely different aircraft from the Arrow Mk.1 and Mk.2, featuring revised engine inlets, and extensive use of stainless steel or titanium to withstand airframe heating.

Cancellation

Until 1955, the Arrow project had been quite cost effective. Only $27 million had been earmarked for the studies, and $260 million for the initial production line. However in September 1955 Avro told the Canadian Cabinet that it needed an additional $59 million to keep the program on schedule. In December 1955, Cabinet limited Avro to eleven prototypes and put a spending cap on the overall program of $170 million over three years. In February 1957, the Cabinet ordered the spending cap increased to $216 million. There is some evidence that the Liberals were losing faith in the project, but it would be impossible to cancel it in an election year.

In June 1957 the Liberals lost the election, and a Conservative government under John Diefenbaker took power. Diefenbaker, from the Canadian west, had campaigned on a platform of reigning in what they claimed was "rampant Liberal spending". Much of this was poised as an east/west divide, with 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 scorn.

In August 1957 Diefenbaker signed the NORAD (North American Air Defence) 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 defence 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 right 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 officials from the US. From the brief, "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 a defence against ballistic missiles. The onset of Sputnik had also raised the spectre of attack from space and as the year wore on, word of a "missile gap" began spreading. From an American brief of the meeting with Pearkes, "He [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…" Eisenhower Library, File: DDE Trip to Canada, Memcons, July 8-11, 1958, Canada-U.S. Defence Problems. 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." Department of National Defence, Directorate of History, File 79/469 Folder 19.

In a later interview in the 1990s, Pearkes discusses these problems and then reveals that he was advised by an American official, while en route to Colorado, that Canada did not need to build aircraft because the US had plenty and could make them available at any time. Pearkes states that 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 that he struck a deal to allow American training in Goosebay, Labrador and Cold Lake in exchange for protection.

By August 11 1958, Pearkes requested cancellation of the Arrow, but the Cabinet Defence Committee refused. He tabled it again in September, and recommended installation of Bomarc etc. 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 "save" the program through cost-sharing with other countries were then explored.

Canada tried to sell the Arrow aircraft to the US and Britain but had no takers. It appears that the USAF was concerned about the effect the cancellation would have on Canada's defence industry. Donald Putt of the AFRDC wanted to purchase the Arrow for the American inventory, but the Secretary of the Air Force said no, as did John Foster Dulles at the Paris summit in 1958. 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.

On February 20 1959 Diefenbaker announced to the Canadian House of Commons that the Arrow and Iroquois programs were to be immediately cancelled, and telegrams send to Avro stated that all work should stop on reception. This left the Avro no choice but to lay off some 14,000 workers in one afternoon. In total, some 30,000 were laid off due to cancellations of contracts with various subcontractors. Declassified records show Avro was caught unprepared by the suddeness of the announcement by the government, while they were aware that the program was in jeopardy, they expected it to continue at least until the March review.

An attempt was made to provide the completed Arrows to the National Research Council of Canada. The latter refused, noting that without a company to provide spare parts and maintenance, as well as pilots, the NRC could make no use of them. As a static test bed, the NRC could not guarantee security around the aircraft.

Within two months, all aircraft and engines, production tooling and technical data, were ordered scrapped. This was apparently in response to RCMP fears that Soviet "mole" had infiltrated Avro, and with a scale-down in progress it would be easy to remove materials and plans to be sent to the USSR. This was later confirmed to some degree in the Mitrokhin archives. Although almost everything connected to the program was destroyed, the forward fuselage and some sections of the wings and control surfaces of the first Mark 2 Arrow were saved and are on display at the Canada Aviation Museum in Ottawa.

In 1961, the RCAF purchased 66 CF-101 Voodoo aircraft to serve in the role originally intended to be filled by the Arrow. The controversy surrounding this acquisition, and Canada's acquiring nuclear weapons for the Voodoos and Bomarcs eventually led to the collapse of the Diefenbaker government in 1963.

CBC Docu-drama

In 1997, the CBC broadcast the two-part docu-drama The Arrow about the Arrow program, which remains one of the most-watched television programs in Canadian history. The docu-drama used a combination of archival film, remote-control flying models, and computer animation for the flying and action scenes. The flying models were built by Doug Hyslip of Calgary, but a full-scale replica of the Arrow was used in ground scenes. The docu-drama was intended as entertainment rather than a literal history, and the script differs considerably from the historical record. It should not be considered a canonical re-telling of the Arrow story, although it is frequently marketed as such.

Allan Jackson of Wetaskiwin was the original designer of the replica used in the CBC docu-drama. He had originally hoped to work on the original Arrow project, until it was cancelled. Years later, in 1989, he began building a full-scale replica of the Arrow. In 1996, the producers of the Arrow miniseries learned of Jackson's replica, then about 70% complete, and offered to finish it if they could use it for the movie. After several public appearances at air shows the Jackson replica was donated to the Reynolds-Alberta Museum in Wetaskiwin where it is being stored until it can be refurbished for display.

The Toronto Aerospace Museum, located at the former CFB Downsview has had another full-size replica Arrow under construction. Made of metal, it will be painted in the colours of Arrow 25203. It is scheduled to be completed and rolled out on October 4 2006. It will be displayed with an Avro Lancaster bomber built at the same Malton plant that produced the Arrow. The museum ultimately hopes to acquire an Avro CF-100 to be exhibited alongside the Arrow replica and Lancaster.

Avro Museum of Calgary also has a [Replica Arrow Project]. Theirs is a 0.6-scale piloted replica aircraft being built for public flight demonstration — construction started in Sept/05 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.

Avro CF-105 Arrow

Development

Initial design

Final design

Production

Variants and design stages

Mark 1

Mark 2

Other versions

Cancellation

CBC Docu-drama

Specifications (Arrow Mk.1)

References

Further reading and viewing

External links

Related content