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Avro Arrow

From Academic Kids

The Avro CF-105 Arrow was a delta-wing interceptor aircraft, designed and built in 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.

Contents

The plane

Raison d'Ítre

Missing image
AvroArrow1.jpg
Avro Arrow

In the post-World War II period, the Soviet Union was developing a fleet of long-range bombers capable of delivering nuclear weapons to North America and Europe. Western countries began the development of interceptor aircraft which would engage and destroy these bombers before they reached their targets, to counter this threat. (Of course, the West was also developing similar bombers, and the Soviet Union, the equivalent interceptors).

Avro's first interceptor project, the Avro CF-100 Canuck, had not entered RCAF service in 1951, when Air Force planners started looking for its replacement. Lead times in getting new designs into service appeared to be growing rapidly; designs like the P-51 Mustang were in service only three years after development began, but the CF-100 had been in development for six years. Similar problems were occurring with designs around the world; it was not just with the CF-100. Unless a new design effort started immediately, the CF-100 would have no replacement by 1960 when it would be outdated. In March 1952, the RCAF's Final Report of the All-Weather Interceptor Requirements Team was submitted to Avro.

Information about World War II era research on swept-wing designs in Germany started reaching design teams around the world in the late 1940s. The simple solution of sweeping the wings to the rear dramatically reduced the drag of a wing as it approached the speed of sound (the so-called wave drag), making trans-sonic and supersonic aircraft powered by then existing jet engines a real possibility. 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 was not worth the extra development costs.

For the new project, the engineers instead turned to another piece of German wartime research, Alexander Lippisch's thin delta-wing designs. This planform had a number of advantages in high speed flight, notably at high altitudes, because the leading edge of the wing stayed clear of the shock wave from the nose of the aircraft (which adds drag). In addition it had a number of practical advantages too, including large chord at the root (making it strong), excellent internal space for any given drag (allowing more fuel storage), and a good performance at high angles of attack (good for landing). However, it also had a number of disadvantages, primarily high drag at lower speeds, and a behaviour known as "pitch-up" due to much of the wing being behind the center of gravity: if the wing stalls the lift suddenly moves forward, forcing the nose up.

Delta wing flight test data started flowing out in the early 1950s, and along with it a debate on the merits of the delta design. The delta proved to have all of the promised qualities at high speeds and high altitudes, but at lower speeds and altitudes the performance was considerably worse than conventional planforms. Avro's designers took advantage of all of this research and conducted a great deal of their own, in American wind tunnels. They selected the tail-less delta based primarily on its excellent high-speed, high-altitude performance, the flight characteristics of greatest importance to an interceptor.

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. The results were submitted to the RCAF in June 1952.

Design is finalized

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 a twin-engined aircraft, since no single engine then available would be able to 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 fight at Mach 1.5 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 an altitude of 50,000 feet (15,000 m) and a speed of Mach 1.5 was to be less than five minutes. The 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 only one pilot. An RCAF team led by Ray Footit visited US and European aircraft producers and declared 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 internals of the plane, weapons bay, and engines. The high-wing on this 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 needed 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 the pairing of the existing MA-1 fire-control system, firing AIM-4 Falcon missiles 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 Convair F-102 Delta Dagger). The Velvet Glove radar-guided missile 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 starts

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 are 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-Cragie system. 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. The downside of Cook-Cragie is that changing jigs is expensive, so if the number of changes needed is large, it is more expensive than the hand-built prototypes. If there is a high confidence that the plane will enter production largely as designed, it can save considerable time and money, but if the design is wrong, it can be very expensive.

Because of this factor, it is somewhat surprising that the Cook-Cragie system was selected for the Arrow program. The plane was Avro's first delta, first supersonic, and practically no parts of the aircraft design (weapons, fire-control or engines) existed when work started. The chance that something would go wrong and the Cook-Cragie system would backfire was great.

In order to have any confidence in an advanced design like the Arrow, a massive testing program was started. By mid-1954, the first production drawings were issued and wind tunnel work began. In another program, nine large, instrumented free-flight models were mounted on solid rockets and launched over Lake Ontario for aerodynamic drag and stability tests, approaching Mach 2 before intentionally crashing into the water. (An effort was made by military divers in July of 2004 from the two Canadian Navy ships HMCS Kingston and HMCS Glace Bay to recover the submerged models from the lake, but none were found).

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.

Further data on the area rule became available during the design stage, and several changes were made to the layout of the plane to incorporate this. These are visible in the design of the rapid narrowing of the cockpit spine (which originally ran the length of the plane) and the addition of a tailcone in order to make it "pointy" at both ends.

The aircraft used a large measure of magnesium and titanium in the fuselage, the latter limited largely to the area around the engines and for fasteners. At the time titanium was an expensive material 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 two-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. This 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, this 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 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 US Navy eventually cancelled all work on the Sparrow II in 1956. This left the Arrow weaponless, although Canadair was quickly brought in to continue the Sparrow program in Canada.

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 Convair F-106 Delta Dart), so this was selected for the Arrow as well.

Mark 1

Go-ahead on the production was given in 1955, and the rollout of the first prototype, RL-201, took place in late 1957.

The J75 was slightly heavier than the PS-13, which required ballast to be placed in the nose to move the center 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.

Missing image
AvroArrow2.jpg
Avro Arrow

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.

Major problems were encountered during the testing phase -- the landing gear tended to "skid," and the stability augmentation system needed considerable tuning.

The former problem was due to the gear being very thin, in order to fit into the wings. To do this they consisted of two tires in front of and behind the gear leg, and the leg retracted in length and twisted as it was stowed. Under some circumstances the tires could hit the ground slightly twisted, and would start to skid. Because of this, two landings resulted in accidents.

The stability augmentation system was a matter of tuning. Although the Arrow was not the first plane to use such a system, it was one of the first, and the concept had not yet developed into the science it is today.

Mk.2

The primary differences between the Mk.1 and Mk.2 were the fitting of the Iroquois engine and the planned fitting of the Astra fire control system. Nevertheless, the Astra was still not ready when the Iroquois reached the flight-testing stage, so the decision was made to go ahead with flight tests with the new engine anyway. The first plane of this Mk.2 run, RL-206, was almost complete in 1959, when the project was cancelled. The Mk.2 would have been faster than the Mk.1, with the upgraded and superior Orenda engines, and would likely have offered better acceleration and climb performance.

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 -- 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.

The politics

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.

It was around 1955 that the notion began to surface, not only in Canada but most of the western world, that the era of the manned interceptor was over, and that the age of guided missiles had arrived. Britain and the US both scaled back most of their interceptor development programs, leaving only one in Britain (the English Electric Lightning) and only two in the US (the Convair F-102 (and F-106) and the recently started North American F-108 Rapier). Yet by 1956 the British were very interested in the Arrow and tried to buy 200 of them, while cancelling the Thin Wing Javelin since the Arrow was promising to be a superior performer. This purchase was cancelled, along with many of the projects under way in the British aviation industry, in Duncan Sandy' infamous White Paper of 1957.

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 the Liberals lost the election, and a Conservative government under John Diefenbaker took power.

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 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 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. The Canadian politicans seemed to come to the conclusion that they could not afford SAGE, Bomarc and Arrows.

But perhaps the most fateful event in the Arrow project was on its day of triumph on October 4, 1957, when it was first rolled out to a crowd of 12,000 in front of the Avro plant. That same day Sputnik 1 was launched. Now the age of the missile was clear even to the public, and soon the outcry over the cost of the project was reported in the press. The Arrow program was already the most expensive in Canadian history, representing a considerable fraction of all government spending, and was seen by many outside Ontario as an industrial welfare program.

In 1958, the Department of Defence Production estimated that $300 million had been spent on the Arrow, and that a further $871 million would need to be spent to have it enter service in 1962. The number of aircraft to be produced was dropped to 169 from 500 and later, under US advice, to 60, at a price of $12 million each. This last price included lifetime spare engines, runway construction and improvement, simulators, ground support equipment, weapons and other items.

In-fighting soon reached the top of the military, as both the army and navy required new equipment of their own. Even groups within the air force were worried that the introduction of the Arrow would leave no money for a new tactical aircraft, desperately needed for use in Europe. In August 1958 the CSC advised the government to cancel the Arrow, and buy two squadrons of Bomarc missiles and 100 interceptors from the US, as well as constructing two SAGE control installations in Canada.

A review of the minutes of meetings of the Canadian Cabinet in late 1958 and early 1959, now declassified, reveals that the Arrow program was effectively cancelled in September 1958. There was much discussion over the impact the cancellation would have on Canadian morale. Nevertheless, on February 20, 1959 Diefenbaker announced to the Canadian House of Commons that the Arrow and Iroquois programs were to be immediately cancelled.

The head of Avro, Crawford Gordon, had long argued with Diefenbaker, and was known to make snap decisions out of spite. That day he did both, and laid off the entire staff of the main plant, over 14,000 workers. Defence Minister George Pearkes and Minister of Defence Production Raymond O'Hurley had repeatedly given his assurance to management that the program would not be cancelled.

Two months later a wrecking crew moved into the largely abandoned Avro plants and starting sawing the six existing airframes apart. They were trucked away and melted down. All plans, engines, parts and even notebooks were also confiscated and destroyed. The blame for this action has long been placed on Diefenbaker and his cabinet, but this appears to be untrue. Several attempts were made to sell (or even give) the five completed aircraft to various parties, but in the end, none accepted. With no-one willing to accept security for them, and the government clearly unwilling to do so politically, the aircraft were destroyed by the defense minister. Diefenbaker denied any involvement or knowledge to his death.

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 National 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.

There is a belief, held by many people, that one lone Arrow was flown away before it could be destroyed, and is now stored in some remote location in Canada. This is, most likely, a myth, kept alive by the wishes of those who would like to have seen the project continue.

Since the early 2000s, a group of volunteers at the Avro Arrow Museum in Calgary, Alberta have been constructing a scaled-down recreation of the Arrow based upon original plans and designs. This reconstruction, which will be large enough to carry a pilot, is scheduled to fly within the next few years.

The controversy

The Avro Arrow aircraft program, many say, was cancelled by short-sighted political leaders. Many Canadians consider these leaders to have had little vision or understanding of the technological world unfolding at the time.

Reality is less clear on the fate of the Arrow. As the defense world had expected, the strategic bombing role was passed onto the missile. The interceptors designed to fight a potential Soviet bomber attack were all retired in the 1980s. Today the only remaining pure interceptor is, ironically, the Soviet MiG-31, built to counter a USAF bomber attack. Nevertheless the Arrow would have filled an important role in the 1960s before the bomber finally passed away.

Many have also suggested that the aviation industry in Canada was destroyed with the cancellation of the Arrow. This claim is rather suspect, considering that Canada is currently the 3rd largest aircraft producer in the world (behind the US and France). It is true that design of fighter aircraft in Canada ended with the Arrow, but the same is true for most countries of similar means. The rapidly rising costs of fighter aircraft have led to rationalisation in the industry, and there are now only a few companies in the Western world designing military aircraft today, when at the time there were dozens.

Avro's design and production teams dispersed, and their talents were used by other countries in the aerospace field, mostly in the United States and Britain. Some of the principal members of the Arrow design and engineering teams headed programs in the Mercury, Apollo and Space Shuttle programs with NASA, others worked for the Anglo-French Concorde project and some for American aircraft companies.

CBC Docu-drama

In 1997, the CBC broadcast a two-part "docu-drama" about the Arrow program, which remains one of the most-watched television programs in Canadian history. The program was noteworthy for the use of computer animation for the flying and action scenes, and the use of a nearly full scale mock up of the Arrow for ground scenes (the model can be distinguished from the genuine Arrows that appear in vintage film clips by its drooping wing tips). The program heavily fictionalized the history of the Arrow program, verging on outright fantasy in some sequences. Despite this, the docu-drama is misunderstood by many to be an accurate portrayal of the history of the project, and is often marketed to schools and the public as such.

Arrow replicas

The replica used in the CBC docu-drama was largely built by Allan Jackson of Wetaskiwin. 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 about Jackson's replica, which was then about 70% complete, and offered to finish it if they could use it for the movie. Unfortunately, when Jackson got the replica back, he found that it had also been used for the final scenes of the movie, where the aircraft is brutally dismantled with torches.

Undaunted, Jackson spent months putting his replica back together, finally exhibiting it at the Abbotsford Airshow in British Columbia's Fraser Valley, in August, 1997. The replica then found a home on the grounds of the Reynolds-Alberta Museum in Wetaskiwin where Jackson lives, which houses about 70 historical aircraft as well as Canada's Aviation Hall of Fame. Unfortunately, there was no room to house the replica indoors, and the harsh weather once again broke it into pieces. Since then, however, the Arrow replica has been moved into a newly-built, giant warehouse with other aircraft and vehicles awaiting display space, and Jackson is once again restoring it.

An additional full-sized replica has been under construction since 1998 at the Toronto Aerospace Museum [1] (http://www.torontoaerospacemuseum.com), located at the former CFB Downsview. It is made of metal, and will be painted in the colours of Arrow 25203 [2] (http://www.airforce.forces.gc.ca/equip/grfx/equip_gallery/historic_gallery/wallpaper/arrow5.jpg). When completed, 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.

See also

Further reading/viewing

  • Ron Page, Richard Organ, Don Watson and Les Wilkinson, Avro Arrow: The Story of the Avro Arrow From Its Evolution To Its Extinction (Boston Mills Press 1979, reprinted Stoddart, 2004). Probably the best book on the subject of the Arrow program. It concentrates on the technical aspects of the program, and eschews the politics. Outstanding selection of plans, photos, diagrams, etc.
  • Peter Zuuring, The Arrow Scrapbook (Arrow Alliance Press, 1999). Uncovers a lot of previously unknown information about the program.
  • Randall Whitcomb, Avro Aircraft and Cold War Aviation, (Vanwell, 2002), also available through Arrow Recovery Canada. (http://www.avroarrow.org)
  • Chris Gainor, Arrows to the Moon: Avro's Engineers and the Space Race (Apogee, 2001) also has a great deal of material about the Arrow.
  • Dateline - There Never Was an Arrow broadcast on the CBC in March 1980 (Available as an extra on the Arrow Docu-Drama DVD). Excellent, balanced documentary on the program, includes lots of interesting film clips, and interviews with key decision makers in the Arrow program. Clips from the program can be seen at [3] (http://archives.cbc.ca/500f.asp?id=1-75-275-1416&wm6=1)

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