The Avro CF-105 Arrow

v1.0.4 / 01 jan 02 / greg goebel / public domain

* Avro of Canada had made a significant contribution to the air defense of North America with its CF-100 "Canuck" interceptor of the early 1950s, and hoped to follow it with a truly advanced aircraft, the Avro "CF-105 Arrow".

The Arrow was a huge, twin-engined delta-winged interceptor that in completion would have been able to attain Mach 2.5, but costs and changing mission requirements kept it from ever leaving the prototype stage. Nonetheless, this impressive machine represented the highest ambition of Canadian aircraft design and remains a romantic ideal for Canadian aviation enthusiasts.

This document outlines the history of the CF-105 Arrow.



* During World War II, Avro of Britain built some production of their Lancaster bomber at the Victory Aircraft factory in Canada. In late 1945, British Avro bought the plant from the Canadian government and established Avro Canada. The Canadian government took over Avro Canada in 1954, organizing the company into an aircraft division and an engine division, later known as Orenda Engines.

Of the postwar aircraft produced by Avro Canada, the most important was the Avro CF-100 "Canuck", a big twin-engined straight-winged jet interceptor. 692 were built between 1950 and 1958, and the aircraft proved reliable and useful.

With the rapid improvements in aircraft performance after World War II, the success of the CF-100 led to consideration of a more capable replacement. Initial concepts were of modified CF-100s with swept wings, and then the designs evolved to delta winged aircraft.

In April 1953, the Royal Canadian Air Force (RCAF) presented a requirement for a twin-engined, two-seat interceptor with a maximum speed of Mach 2, a maximum ceiling of 18.3 kilometers (60,000 feet), and a combat radius of 370 kilometers (200 nautical miles). It would have a fast rate of climb and would be able to maneuver at two gees at high speed and altitude, an extremely difficult requirement to meet.

The new aircraft would be armed only with missiles stored in an internal weapons bay, and would use a sophisticated radar fire-control system to allow collision-course intercepts, rather than tail-chase pursuit. The result was the Avro CF-105 Arrow.



* The Arrow was conceived in response to the threat posed by fleets of Soviet nuclear-armed bombers, then believed to be under construction, cruising into North American airspace from over the poles. It seemed crucial to have a weapon that could intercept and destroy these intruders over the empty northlands before they reached Canadian and American cities farther south.

The RCAF requirements implied a big aircraft. The final design had a boxy fuselage and a slightly drooping high-set delta wing, with a sweep of 60 degrees and a "dogtooth" leading edge.

Key parts of the airframe were made of titanium to withstand the heat of high-speed flight, and an environmental control system was provided to protect the crew against flight temperatures, as well as the extreme cold of the Canadian north.

The high wing led to long landing gear, with main gear legs some 3.65 meters (12 feet) in length. The nose gear had twin side-by-side wheels, while each of the main gear had four wheels, arranged in a 2 by 2 configuration. Delta winged aircraft tend to be "hot" on landing, and so a drag chute was fitted in the tail cone.

The RCAF had originally requested two hand-built engineering prototypes, but decided that the project was too urgent and that flight tests would be done on a handful of preproduction prototypes. Since this meant expensive production tooling would have to be in place before the Arrow ever flew, this requirement stepped up the pressure on the design team, who were forced to implement extensive preflight testing to ensure that the preproduction prototypes operated as intended.

Wind tunnel tests were used to refine the aircraft's aerodynamics, which were tuned by the application of the "area rule" contour. This scheme was devised by an American, Richart T. Whitcomb, then at the US National Advisory Committee for Aeronautics' (NACA, one of the precursors of NASA) Langley Research Center. The principle behind area ruling was to minimize abrupt changes in aircraft cross section. In practice, it dictated a "Coke bottle" streamlining to a fast aircraft's fuselage.

11 free-flight models of the Arrow were launched on Nike boosters from the end of 1954 to the beginning of 1957 to validate the aircraft's design. Two of these flights were conducted at the NACA facility at Langley Field, Virginia, in order to use NACA's sophisticated tracking and telemetry equipment. The others were conducted in Canada over Lake Ontario, and in recent years Arrow enthusiasts have been searching the waters of the lake to find some of the flying Arrow models that were lost there.

After much consideration of alternatives, the Orenda PS-13 Iroquois engine was chosen as the powerplant. Since this engine would not be ready in time for initial flight tests, an alternate engine was needed for early flight testing. The Avro team originally selected the new Rolls-Royce RB.106, but development of that engine was delayed in turn, and the Pratt & Whitney J75 was chosen to power the preproduction prototypes, which were designated Mark 1. Prototype development would in principle then evolve to the Iroquois-powered Mark 2, resulting in an aircraft that would be capable of Mach 2.5. The production model would be designated Mark 3.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                15.24 meters        50 feet
   length                  25.3 meters         83 feet 
   height                  6.25 meters         20 feet 6 inches

   empty weight            22,250 kilograms    49,000 pounds
   max loaded weight       31,100 kilograms    68,600 pounds

   maximum speed           3,200 KPH           2,000 MPH / 1,740 KT
   service ceiling         18,300 meters       60,000 feet
   operational radius      480 kilometers      775 MI / 675 NMI
   _____________________   _________________   _______________________

The J75 had a dry thrust of 5,700 kilograms (12,500 pounds), and an afterburning thrust of 8,400 kilograms (18,500 pounds). The Iroquois was the most powerful engine in North America, with a dry thrust of 8,400 kilograms (18,500 pounds) and an afterburning thrust of 11,800 kilograms (26,000 pounds). It had an unprecedented 5:1 thrust to weight ratio, achieved partly to the extensive use of titanium.

The Iroquois was ground-tested in 1955. In 1957, the US Air Force loaned a B-47E Stratojet bomber to the Canadians for a flight-test platform. The engine was bolted to the side of the aircraft, near the tail. The lopsided bomber was apparently something of a handful to fly. Some snags were encountered in testing, but in general the engine development effort went well.

The Orenda was removed from the B-47E after the completion of trials, and the bomber was returned to the United States. However, its airframe had apparently warped by the asymmetric thrust of the Orenda, and the aircraft was scrapped. Interestingly, this particular B-47E was the only American strategic jet bomber that was ever operated by a foreign country.

The Arrow's two crewmen sat under clamshell-type canopies. Visibility was not the best, particularly for the back-seat radar operator, who only had small window panels on either side, but the cockpit layout was superb. Martin-Baker ejection seats were provided. An Automatic Flight Control System (AFCS) was developed that could operate in several modes, and in principle could even land the Arrow automatically or compensate for severe damage to the aircraft. Control surfaces were hydraulically operated and electronically controlled; the Arrow was one of the first "fly by wire" aircraft ever built.

The armament system was devised as a replaceable pack that could be plugged into the aircraft's big weapons bay, which was 5.5 meters (18 feet) long. This allowed different weapons systems or fuel tanks to be fitted as required, with all armament carried internally.

However, the greatest weakness of the Arrow project was to prove to be the armament system. At the beginning of the project, the CF-105 was specified to use the American Hughes MX 1179 fire control system, directing eight Hughes AIM-4 Falcon air to air missiles carried in a huge internal weapons bay. The Falcons were available and, in principle, proven technology, though experience in the 1960s with air-to-air missiles would show the confidence of 1950s designers in their guided weapons to be somewhat misplaced.

However, in 1955, the RCAF changed their minds and decided that they wanted new technology, in the form of the RCA-Victor Astra radar and fire control system, and an advanced version of the Raytheon Sparrow, the Sparrow II. The Arrow would carry four Sparrow IIs as well as the eight Falcons.

While the RCAF had been dithering about the weapons fit to the point where Avro engineers had simply designed the fire-control system as a modular pack that could be upgraded, the engineers nonetheless protested at such a drastic change in plans while their program was well under way, as well as at the adoption of completely unproven technology. Their fears were justified. The Astra fire control system was complicated and its development was to be full of problems.

Sparrow II was even more unrealistic. The existing Sparrow I was a semi-active radar homing (SARH) missile, meaning it homed in on radar reflections from a target illuminated by the launch aircraft's radar. Sparrow II was to have its own radar transmitter and would be, in modern terms, a "fire and forget" missile.

The Sparrow II was an attempt to build a radar-guided fire-and-forget missile in a Sparrow airframe, essentially the same requirement that produced the Advanced Medium-Range Air-to-Air Missile (AMRAAM) in the late 1980s. AMRAAM's development would prove troublesome enough. Attempting to build such a weapon in the 1950s was out of the question. The US Navy cancelled Sparrow II in 1956, but the RCAF revived the project, with Canadair working with Douglas, the original contractor on the program.



* While the Arrow's development seemed to be going well, astute observers could see the program was running out of steam. Missiles seemed to be the way of the future for both defense and offense.

Improved anti-aircraft missiles seemed able to deal with Soviet bombers, which American intelligence, through the use of the new U-2 spy plane, had discovered were by no means as numerous as had been thought. In any case, the development of intercontinental ballistic missiles (ICBMs) made visions of squadrons of such bombers streaking in over the Arctic obsolete, since ICBMs could not be intercepted by any technology available at the time.

In 1957, the new Conservative Canadian government under Prime Minister John Diefenbaker cut the number of Arrows planned down to 100, escalating unit cost. Nonetheless, the first Arrow Mark 1, Number 201, was rolled out on 4 October 1957, and flew for the first time on 15 March 1958.

The day of the initial roll-out, 4 October, was by coincidence the same day that the Soviet Union launched the first artificial Earth satellite, Sputnik I, hinting that the threat that the Arrow had been designed to deal with was moving to a higher ground. Nonetheless, the aircraft had fine handling characteristics, and exceeded Mach 1.5 on its 7th flight.

On its eleventh flight it suffered a landing gear failure and ended up performing a belly landing, but damage was relatively minor, and Number 201 was flying again by early October. Four more Mark 1s were delivered between August 1958, and January 1959.

Despite these milestones, the program was falling apart. In late September, the Astra radar and associated Sparrow II missiles were cancelled, to be replaced by a combination of the Falcon and a pair of nuclear-armed unguided Genie missiles. This was a hint of things to come.

In August, the Canadian government sent a mission to the US Air Force to sell them on the Arrow, but the USAF wasn't interested. They countered by promoting the range Boeing BOMARC-B anti-aircraft missile, with a range of over 700 kilometers, that seemed perfectly able to defend against intruding bombers, though the BOMARC program would prove to have problems of its own, with an unreliable guidance system and other troubles. The Diefenbaker government bought on to the BOMARC, while tentatively hanging on to the Arrow program at the same time.

However, Canada was in a recession, and the Arrow had become the most expensive single defense project the country had ever taken on. The Canadian Army and Navy were reluctant to sacrifice their own programs to support the aircraft. RCAF Air Marshall Hugh Campbell understood the politics, and told the Defense Ministry that he would accept cancellation of the Arrow if he could obtain an alternate high-performance interceptor.

On 20 February 1959, Prime Minister Diefenbaker cancelled the CF-105, with the order taking effect immediately. The prototype Arrows had completed 66 flights, for a total of 70 hours of flying time. The first Mark 2 prototype was almost ready for flight tests, with four more Mark 2s virtually complete. All the Arrows built or in production were scrapped, and design documentation and production tooling was generally disposed of, apparently as a security measure. None of the Iroquois-powered Mark 2s ever flew.

Avro ended up laying off 14,000 workers. The layoffs were a massive shock to Canada's aircraft industry, and the day of the Arrow's cancellation has been known as "Black Friday" ever since. Air Marshall Campbell obtained 66 surplus F-101 Voodoo supersonic interceptors from the United States to handle his air-defense requirements. They weren't Arrows by any means, but at least they were affordable.



* As noted, Canadian aviation enthusiasts hold the Arrow near and dear to their hearts, and in the minds of some it has become cherished as a Lost Cause. The wisdom of and motives behind its cancellation remain hotly debated.

The facts in the case seem remarkably convoluted, and given their complexity it is unlikely there is any one person who was in a position to have an objective understanding of them at the time or later.

The Diefenbaker government is often singled out as irrationally hostile to the Arrow, insisting on its cancellation out of ignorance of the facts. The destruction of Arrow prototypes, components, tooling, and documentation is sometimes blamed on Diefenbaker himself, but it appears that was not the case.

The high costs of the Arrow are given by some as a compelling reason for the government to cancel the aircraft, while others maintain that costs were inflated by unrealistic assumptions. The absence of any mention of a particular champion for the Arrow within the Canadian government makes the consideration even murkier.

Others accuse the Americans of deliberately sabotaging the Arrow program. Again, the issues here are murky. The Americans were pushing compatibility with the SAGE (Semi-Automated Ground Environment) continental defense system. The Arrow did not fit into that scheme. American promotion of the BOMARC is described by some as overbearing.

However, the Americans had also been supportive of the Arrow program in many ways, and in fact at the eleventh hour had offered to donate the weapons-control system to the program and even fund the purchase of some Arrows for the RCAF. This suggests that there was no particular American policy on the Arrow, with some defense factions taking actions hostile to it and others taking actions favorable to it while in pursuit of their own agendas.

There is little doubt that the Arrow would have been a magnificent aircraft, and it was certainly a shame the Orenda-powered prototypes never flew, but on the same coin it is apparent that the program was extremely ambitious and risky. The RCAF requirements were gold-plated, and the aircraft was based on almost entirely new technology, including the airframe, engine, fire control system, and missiles.

The mission focus was also specialized by modern standards, with the aircraft sold almost entirely as an interceptor, and by the time the Arrow prototypes were flying the Soviet bomber threat seemed less substantial. The combination of circumstances was more than enough to give a government with a relatively modest defense budget reason to reconsider the project.

Interestingly, while the Canadians were working on the Arrow, the Americans were working on a conceptually similar long-range, high-performance interceptor, the North American "F-108 Rapier". The Rapier never got beyond the mockup stage, being cancelled in September 1959. The same logic that worked against the Arrow worked against the Rapier, with the same results.

The actual truth of the matter could be debated in at length in detailed documents, each citing sets of facts to prove one point of view or another. However, it is unlikely such documents would have a wide readership.

Whatever the case, it is hard not to sympathize with those who dream of the CF-105 thundering on patrol over Canada's snow-covered north.

* Sources include:

The Canadian Broadcasting Company did a TV movie on the development of the Arrow, starring Dan Ackroyd. I haven't seen it, but to no surprise it is said to emphasize the conspiracy theories surrounding the cancellation of the project.

* I wrote the first edition of this document as a quick study. I try to produce aviation documents on a monthly basis, and being a little behind schedule one month, I decided to write something short and easy on an interesting and attractive aircraft to meet my deadline.

This turned out to be something of a mistake, since although the Arrow had a short and sad life, it remains controversial. Trying to sort through the controversies has been a pointless and painful exercise in trivia over something I don't care about that much one way or another. Aircraft that never made it out of prototype stage are little more than curiosities, and discussing the might-have-beens of history is an idle game.

I have better things to do. I get Arrow fanatics emailing me every rare now and then, throwing down the gauntlet for battle. I end up sanitizing the text a little to dodge the controversies, and think: "It's dead, people, get over it."

* Revision history:

   v1.0   / 01 nov 97 / gvg
   v1.1   / 01 jul 98 / gvg / Cosmetic rewrite, minor update.
   v1.2   / 01 aug 98 / gvg / Cleaned up some typos.
   v1.3   / 01 may 99 / gvg / Minor cosmetics and sanitization.
   v1.0.4 / 01 jan 02 / gvg / Minor cosmetic update.