The Avro CF-105 Arrow

v1.1.3 / 01 sep 17 / greg goebel

* 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. This impressive machine represented the highest ambition of Canadian aircraft design and remains a romantic ideal for Canadian aviation enthusiasts. This document provides a history and description of the CF-105 Arrow.

Avro 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, after a year of analysis by Avro, 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, instead of 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. Although most of the airframe was made of magnesium, key parts were made of titanium to withstand the heat of high-speed flight, and an environmental control system was provided to protect the crew against high 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 retracted forward, while the main gear hinged in the wings to retract towards the fuselage. The nose gear had twin side-by-side wheels, while each of the main gear had two wheels, arranged in a tandem configuration to allow storage in the wing. Delta winged aircraft tend to be "hot" on landing, and so a drag chute was fitted in the tail cone.

Avro CF-105 Arrow

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 that 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 in Virginia. The principle behind area ruling was to minimize abrupt changes in aircraft cross section to improve transonic handling. In practice, it dictated a fuselage with "Coke bottle" streamlining.

Eleven 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. For whatever reason, the Nike boosters were fitted with a large tailfin and a wide-span tailplane. 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; 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.

Arrow model on Nike booster

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, used on the Republic F-105 Thunderchief and Convair F-106 Delta Dart, 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
   wing area               113.80 sq_meters    1,225 sq_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      660 kilometers      410 MI / 355 NMI
   _____________________   _________________   _______________________

The J75 had a dry thrust of 76.5 kN (7,800 kgp / 17,200 lbf) and an afterburning thrust of 109 kN (11,110 kgp / 24,500 lbf). The Iroquois was the most powerful engine in North America, with a dry thrust of 82.4 kN (8,400 kgp / 18,500 lbf) and an afterburning thrust of 115.8 kN (11,800 kgp / 26,000 lbf). It had an unprecedented 5:1 thrust-to-weight ratio, achieved partly by 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 Iroquois was removed from the B-47E after the completion of trials, and the bomber was returned to the United States. However, apparently its airframe had been warped by the asymmetric thrust of the Iroquois, 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.

The armament system would prove to be the greatest weakness of the Arrow project. 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 (AAMs) carried in a huge internal weapons bay. The MX-1179 was in development; it would emerge later, after some difficulties, as the MA-1 fire control system for the F-106. The Falcons were available and were in principle proven technology, though experience in the 1960s with AAMs would show the confidence of 1950s designers in their guided weapons to be somewhat misplaced.

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 still 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" missile, with a guidance seeker that only included a receiver system that tracked emissions from the launch aircraft's radar. That meant that the launch aircraft had to keep the target "illuminated" all the way to missile impact. Sparrow II was to have a complete, compact radar system with both transmitter and receiver; it 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, much 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 absurd. The US Navy canceled 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, perceptive 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 effectively 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 higher ground.

Number 201 continued its test flights, demonstrating fine handling characteristics, and exceeding 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 it was straightforward to repair the damage, 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 disintegrating. In late September, the Astra radar and associated Sparrow II AAM were canceled, to be replaced by a combination of the Falcon and a pair of nuclear-armed unguided Genie missiles. That 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. The Americans countered by promoting the Boeing BOMARC-B anti-aircraft missile, with a range of over 700 kilometers (435 miles) -- which seemed perfectly able to defend against intruding bombers, though the BOMARC would prove to have problems of its own, suffering from 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 alternative high-performance interceptor.

On 20 February 1959, Prime Minister Diefenbaker canceled 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. 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 F-101B/F Voodoo supersonic interceptors from the United States to handle his air-defense requirements. The F-101B/F was a perfectly state-of-the art aircraft for the time, capable of Mach 1.5, having gone into USAF service that same year, 1959. The Voodoos were delivered in 1961 and 1962; they were taken from USAF stocks, but they had very low flight hours. They were updated in Canadian service to keep them current, to be generally phased out of service in the early 1980s.



* 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, at least among the fringe. The facts in the case seem remarkably complicated, and it is unlikely there is any one person who was in a position to have a clear 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 Arrow was highly advanced secret technology, and it was all destroyed since keeping the program materials and data under secure lock and key would have been troublesome. Nobody wanted to bother with the expense.

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. In fact, this assertion has evolved into a full-blown conspiracy theory, given widespread exposure north of the border by a two-part TV movie released in 1996 by the Canadian Broadcasting Company (CBC) on the development of the Arrow, starring Dan Ackroyd. The movie apparently features scenes such as one where US President Eisenhower pressures Prime Minister Diefenbaker to cancel the Arrow and "buy American". The movie was labeled as a "work of fiction" and had elements that were clearly inventions of scriptwriters, but it apparently did much to convince people that the conspiracy theory is an indisputable fact.

In reality, the Arrow conspiracy theory, like all good conspiracy theories, is long on emotions, contrived arguments, and assertions, but short on honest evidence. Conspiracy theorists claim the US defense secretary told his Canadian counterpart that Canada would be better off to drop the Arrow and purchase US hardware, while one Diefenbaker cabinet member much later insisted that the US was highly supportive of the program, calling the conspiracy theory "nonsense".

The US did try to sell the Canadians on BOMARC, but at the same time the Americans were clearly involved with and supportive of the Arrow program from its early days -- with NACA providing test support, a B-47 provided to help test the Iroquois engine, and US hardware like the J75 engine fitted to the prototypes. After all this time, the conspiracy tale seems tiresome, but it seems to remain one of the major Canadian conspiracy theories. Incidentally, in 1980, the CBC did produce a documentary show on the Arrow that was much less sensationalistic than the movie.

There is little doubt that the Arrow would have been a magnificent aircraft, and it was certainly a shame the Iroquois-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 entirely as an interceptor, and by the time the Arrow prototypes were flying, the Soviet bomber threat seemed less substantial since ICBMs were clearly going to be in service soon. 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 canceled in September 1959. The Americans did continue work for a time on a Mach 3 interceptor design, the Lockheed "YF-12A", derived from the SR-71 reconnaissance aircraft, but though prototypes were flown it, too, was canceled. The strategic threat had shifted to ICBMs, and an expensive Mach 3 interceptor was simply not worth the cost. Whatever the facts of 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.

Avro Arrow replica

* It seems that a number of nonflying CF-105 replicas have been built for museum displays, including at least one full-scale replica built by a Canadian named Allan Jackson that was used in the Dan Ackroyd movie; that replica was cut up at the end of the film and the owner got it back in pieces, much to his distress. Apparently there had been a miscommunication and Jackson was compensated for the screwup, but it took him some time to get the replica back into shape again. It has since had other ups and downs. Work is underway to build a subscale flying replica, which would certainly be an interesting airshow demonstrator.

* I originally wrote 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 attractive and interesting aircraft to meet my deadline.

It turned out to be much more troublesome than I thought. No matter what I write, it turns out, some conspiracy theory will jump out of it. I'm really learning to hate such things, because the game of a conspiracy theorist is based on the obvious fact that it is easy to invent wild assertions, but exhausting to disprove them. Oh well, I used to think that wild conspiracy theories were a uniquely American lunacy. It's reassuring to find out that folks elsewhere can be just as crazy.

The enthusiasm for the Arrow at least has led to more interesting creativity than conspiracy theories, with artwork produced of "what if" Arrows, such as nuclear strike or electronic warfare variants. Other concepts have focused on follow-ons, with features such as modified wings and canards.

Arrow Mark IV waverider

* As concerns copyrights and permissions for this document, all illustrations and images credited to me are public domain. I reserve all rights to my writings. However, if anyone does want to make use of my writings, just contact me, and we can chat about it. I'm lenient in giving permissions, usually on the basis of being properly credited.

* Sources include:

* Revision history:

   v1.0   / 01 nov 97 
   v1.1   / 01 jul 98 / Cosmetic rewrite, minor update.
   v1.2   / 01 aug 98 / Cleaned up some typos.
   v1.3   / 01 may 99 / Minor cosmetics and sanitization.
   v1.0.4 / 01 jan 02 / Review & polish.
   v1.0.5 / 01 dec 03 / Review & polish.
   v1.0.6 / 01 sep 05 / Review & polish.
   v1.0.7 / 01 mar 06 / Cleaned up some minor errors.
   v1.0.8 / 01 feb 08 / Review & polish.
   v1.0.9 / 01 jan 10 / Review & polish.
   v1.1.0 / 01 dec 11 / Review & polish.
   v1.1.1 / 01 nov 13 / Review & polish.
   v1.1.2 / 01 oct 15 / Review & polish.
   v1.1.3 / 01 sep 17 / Review & polish.