Avro Canada CF-105 Arrow

 
Before giving the green light to Avro, the RCAF sent a top level evaluation team to assess all the countries in the Western alliance to find out if anyone was working on a craft that met their requirements. No one was. The Arrow was to be a twin-engined aircraft with a crew of two, a supersonic interceptor to destroy any enemy threat in the next decade or beyond, and was expected to fulfill a grueling performance specification issued by the RCAF in 1953.

It was a spec that Jim Floyd, Vice President of Engineering at Avro Canada's Malton headquarters and the man responsible for the development of the Arrow, described as "overkill". It called for a manoeuvre capability of at least 2 G at Mach 1.5 at 50,000 feet at full weight with all combat missiles aboard. This daunting list of requirements, which can scarcely be exceeded by combat aircraft today,was the reason the Arrow was to be powered by enormous engines especially designed for it, and had to stow all missiles inside for maximum drag reduction.

The Arrow was designed as a delta winged craft without a tail plane, an "inevitable compromise between aerodynamic, structural and aerolastic efficiency," as Floyd put it. The range of the new craft was specified at 200 nautical miles, which included five minutes of combat, at Mach 1.5.

Avro, however, considered this too little, and designed the aircraft for ranges of up to a 650 n.m. radius. A subsequent reconnaissance version of the Arrow was planned which would have a range of 2000 n.m.

While Avro's Gas Turbine Division (later to become Orenda Engines) was working on the powerful Iroquois engine that was to be used on the Mark 2 series, test flights went underway using an interim engine, the Pratt and Whitney J75 engine. When test flights began, the craft easily met all guarantees, according to Jack Woodman, the RCAF evaluation pilot assigned to the project. By the third test flight it broke the speed of sound, eventually reaching speeds as high as Mach 1.98.

With the new Iroquois engine, which delivered considerably more power, the Arrow was expected to break world speed records. Indeed, projected versions of the plane were to go as fast as Mach 3. But on the 20th of February, 1959, days before the new Mark 2 series bearing the Iroquois engine was about to be tested, the bad news broke -- the Arrow was to be cancelled.

Avro was instructed to immediately halt all work, and to destroy all prototypes and plans. Employees were sent home, and 14,000 people lost their jobs. The cancellation is widely credited with contributing to the growing Canadian brain drain of the period - NASA grabbed up many of the key people displaced by the move, as did the Concorde and other projects.

The cancellation was a contentious affair, and its justification or demonization has been the subject of considerable debate. At the time, the threat that inspired the formidable characteristics of the Arrow, namely that of manned Soviet bombers emerging from across the polar regions, was perceived to be diminishing. The new menace of the day was believed to be from nuclear missiles, and missiles were to be the means of defense.

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In February 1998, Claude Sherwood was invited - by Robin Murray, then CEO of the Museum - to come to the TAM to discuss how he might help with the planned project to build a full-size Replica of the Avro CF105 Arrow.   After their first meeting, Claude outlined on paper his thoughts on how this major project could be accomplished.   This initial concept report was well received, and subsequently evaluated by Bombardier structural engineers, who concurred with the conceptual fabrication methods.   Later that month, they discussed starting the project, which Robin would undertake to direct while Claude would be the Chief Engineer.   And so the TAM Replica Arrow Project was born.

 
Replica Specifications
The Arrow Replica was to be a full scale, non-flying, accurate replication of Arrow #25203, with no active systems, and the structure segmented for ease of fabrication.   The outside shape and details were to be replicated to museum quality, with wheel wells and cockpit areas fully detailed for visual accuracy.   The Replica was to be made from squared steel tubing for the basic structure, with aluminum sheet as skins and some fibreglass components, as required.

Over time, additional design criteria were added.   For example, some thought the control surfaces should be functional for realism, so, as a compromise, the control surfaces were made as separate components, but frozen to the structure, which could later be freed and modified for operation, if desired.   Later still, it was felt that it would enhance the static display if some dynamic features could be included.   Hence it was decided to have a simulated Sparrow II Missile deployed from the Weapons Pack, with the access doors and missile positioning arms activated by electrical actuators controlled from a floor console.

The finish for the Replica was to include the overall gloss white colour, with the various areas in day-glo and flat black paint. The many markings, symbols and signs were to be created and applied.

Engineering Features
Owing to the unfortunate lack of the original Arrow drawings, many small scale reference drawings, published and unpublished (i.e. donated) were used to derive the shapes and details to accurately replicate the Arrow. Some of these drawings provided different dimensions for similar details and this gave rise to ‘judgement calls’ on which to use. Photographs were also invaluable in providing proportions and minute details for the accuracy we were seeking.

The structure was originally intended to make use of squared mild steel tubing, to be cut, shaped and welded.   However, Associated Tube Industries, of Markham, Ontario, generously indicated they had available a quantity of 1" x 0.6" and 1" x 0.3" stainless steel tubing which we could have for the project.   This donation was enormous, for it dramatically influenced design details and, most importantly, allowed work on the project structure to begin immediately.

Alcan Aluminium Limited offered us some sample sheets to determine our exact specs. for the aluminum skin materials. Further, they followed through with ALL the aluminum sheet materials needed for the Replica.

The intended fabrication technique was to use blind countersunk rivets to fix the aluminum skins directly to the shaped stainless steel structure. There were a lot of rivets needed, but, again, corporate generosity came through when Avdel-Textron of Canada, a prime source for aircraft fasteners, provided the project with 100,000 of the exact rivets we needed.

As fabrication continued, additional urgently needed TIG welding equipment was supplied by Lincoln Electric Company of Canada Ltd..  Other good corporations made available materials and equipment and services - such as Praxair Canada Ltd., Toronto, providing welding supplies, Bombardier Aerospace [Downsview] providing tools and equipment; The Metal Place Inc., Mississauga, providing steel plate and heavier steel tubes; Samuel, Son & Company, Mississauga, provided 0.016" stainless steel sheet used for shear webs on spars and ribs in the outer wings and the fin.  The heavier, 0.030" galvanized steel sheet needed for the critical inner wing spars and ribs was donated by Dofasco.  Associated Tube Industries also provided 3" strip stainless which was used for the many joint gussets for the various structural parts.  In all, over 30 corporations were involved in supporting our on-going efforts.

The Replica is constructed in separate sections to facilitate ease of assembly and potential disassembly.   The Fuselage is made in five sections: Nose Section, Centre Section, Duct Section, Engine Section, and Tail Section. The large wing has four major components - Left & Right Inner Wings, joined at the centreline, and Left & Right Outer Wings; then the large Fin and Rudder is a separate assembly. All of these components were constructed in the ‘Project Hanger’ at the TAM.

Other important components include the Landing Gear, which Messier-Dowty of Canada kindly offered to manufacture for us.   Dowty also designed and built the original Arrow Main Landing Gear.

Stress analysis was another extremely important consideration, to ensure the Replica would have a sound structure with no possibility of failure for any movement of the display.   A colleague of Claude, Stan Porter, another retired engineer with design experience on the Arrow and other aircraft, made a multitude of calculations for the design loading conditions and the resulting structural details at all connections throughout the Replica.   Most of the wing design details were established by Stan.

The internal structure was simply a space frame of tubes welded at their joints with frequent use of gussets to strengthen the joints.

The Nose Section was started first, as it was the most complex and curvaceous.   Its initial sub-assembly was a separate component called the “Cockpit Tub”, which would slip into the section structure before skinning.   The full section structure was established as a space frame sized to take profiled aluminum forms on which the skins were applied.   The Radome was fabricated in fiberglass over a shaped foam mold. The Centre section was designed to have the upper main structure separate from the Weapons Pack. The Duct and Engine Sections followed in sequence and the completion of the fuselage by the Tail section included the Stinger structure and Tailpipes.  

Each fuselage section was designed with a central box structure that followed its centreline with a truss configuration between frames at the break points. This approach allowed the sections to be fabricated separately and then bolted together.   It also allowed stress loadings to be efficiently distributed throughout the replica.

The Outer Wing components underwent considerable design development to achieve the best method of construction as well as ensuring required joint strength in such a thin structure, it being very important that these cantilevered wings not droop, even under a heavy load.   The resulting design utilized stainless tubes as load-bearing caps and stainless sheet shear-web for the spars and ribs.   Gussets and welded joints completed the connections to make a very strong structure.   The leading edges were made with aluminum forms to maintain their correct airfoil shape. Skinning of the wing surfaces involved, initially, smoothing the shape of the spars and ribs with auto body filler, then fitting and riveting the large aluminum panels.   The skinning of the leading edge was more complicated since the nose radius of the skin had to be pre-bent to ensure the correct contours.   Aileron panels were built as separate units, attached with a large piano hinge and heavy steel arms fixed to the structure, thereby ensuring they are ‘frozen’ controls.   In future, should control movement be desired, these steel arms can be removed and an actuator installed.   Fiberglass blister forms were replicated to cover these external 'actuator' parts.

The Inner Wing panels are the ‘backbone’ of the Arrow structure, since they sustain all flight and standing loads.   As a result, more robust steel was used for these components.   Standard square steel tube 1"x1" with a 0.10" wall thickness was used for the primary spars and ribs.   Secondary structural members were made with smaller stainless tube.   Joints were also more robust in design using 0.25" steel plates inserted into milled slots on the adjacent heavy steel tubes, fillet welded for strength.   Skinning was somewhat easier since these wing areas were quite flat, allowing larger panels to be used.   Handling these rather heavy panels presented a challenge, but volunteer ingenuity prevailed.

The Fin, to which the large rudder panel is attached, is a structure of similar size and design to an Outer Wing panel.   It too is a very thin cantilevered structure, and was designed to withstand 20 mph wind loadings if necessary.   The stainless steel tubes again were used as caps and 0.02 stainless sheet formed the shear webs to give it strength and integrity.   As with the ailerons, the rudder is attached with 1" piano hinge sections and held ‘frozen’ by rods and pins.

Production Features
From the Toronto Aerospace Museum's beginning, a Replica Arrow was desired as a central display of this great Canadian technological achievement.   To accomplish this a full-sized Replica Arrow had to be produced.   Many individuals and organizations had talked about doing exactly this - but little or no actual work had been started.   So it was, that in February ‘98, a decision was made to move on with a concept of an ‘all-volunteer’ production, rather than wait for a windfall of money to manufacture an Arrow.

Production of the Replica Arrow started in August 1998, with a team moving quickly to fabricate the “Cockpit Tub”.   Under the leadership of Joe Foster, a local practicing dentist and aircraft enthusiast / builder, the first team of volunteers got to work.   This component needed a stable wooden assembly frame, on which the metal formers and sides, making up the shape of the “tub”, were fastened together with rivets.   This sub-assembly of the Replica Arrow progressed nicely over time and was a featured display in the TAM Booth, at the 1999 CNE.

The next major component to get started was the Nose Section structure, including the radome, pitot tube, electronics bay, cockpit and intake structures.   In November 1999, Bruno Quattrin, a retired electrical contractor, and his colleague Issidora Spinato, a retired machinist, became dedicated volunteers whose efforts, averaging three days each week, fabricated the Nose Section with all of its curves and complexities.   The “Cockpit Tub” was installed and the entire Nose Section was placed on a mobile transporter, to allow for convenient movement.  This first collective assembly gave a big push to morale and our progress.   With the expert help of Peter Allnut, a retired Air Canada staffer, and a dedicated crew of volunteers, the skinning operation on this section gave life to the ‘bones’ of the Replica. Finishing touches, which are always fussy details, were completed by Ted McLellan, a TTC technician, and John Trollup, a retired craftsman. Also during this period, the Intake entry shapes were developed , by Bernard Dodd, a retired aircraft worker; the Radome was fabricated, by Peck Duff, a retired mechanical engineer. Careful surface finishing and painting of these fiberglass components was ably done by Michael Lord, an auto repairer and detailer. Cockpit canopies, shaped in fibreglass on foam, were completed and installed by Joe Foster. So impressive was this section that it was taken by transport [free] to be displayed at the 2000 CNE. [The first “flight” of the Replica]

On the return of the Nose Section, the detailing of the cockpit areas was started. Peter Uus and Ben Mucke performed their ‘magic’ and produced a simulated pilot’s cockpit outfitted with a realistic instrument panel, side panels for switches, fuses, radios and controls. Similarly, they outfitted the navigator’s cockpit with its realistic installations. As the cockpits are intended for public viewing, their extraordinary volunteer effort will be enjoyed by all Museum visitors.

In late 2000, work started on the remaining Fuselage sections and again Bruno and Issy were the prime movers on the Duct and Engine sections structures. The Centre Section framing and assembly, which included the separate Weapons Pack, was led by Carlo Bonfiglio and Neil Dellandrea. For each of these fuselage sections a new skinning crew of Bob Jones and Elvis Bidinot started. They established an efficient process of shared talents to ensure skinning operations kept pace with the structural assembly.

The Weapons Pack was built with stainless tubing welded into frames and beams that were later assembled for final welding operations.   Since the Replica was to have a dynamic display of a Sparrow II missile being deployed, doors were needed and a full-scale missile constructed. The fabrication of the missile doors was undertaken by John Trollup and Ted McLellan, who produced finely finished moveable doors. The hardware to allow the model Sparrow missile to be deployed was built by Wilson Baker, of Sackville N.S.. These many parts were mounted and electro-mechanical actuators, to lower and retract the doors and missile, was skillfully installed by Bruno Quattrin.

The Outer Wing panels spars and ribs were fabricated, initially under the leadership of Mike Dias.  After Mike was accepted for Pilot training the task was taken up by Conrad Mancuso.  Conrad and his team assembled a number of specially leveled wooden tables, providing a stable surface to hold the components in place for welding and subsequent skinning operations.  Welding and skinning were completed by a team headed by Alan Stummer.

The Tail Section, which included the Tail Pipes and the 'stinger', the structure between the Tail Pipes, were built by a number of eager volunteers. Initially, a team of Bombardier engineer trainees worked on the curvaceous 'stinger' part. Conrad and others laid down the framework for the Tail Pipes which were finished by Peck Duff.   These components were fabricated with aluminum skins, but were treated by Michael Lord with a paint composition to give them the blackened appearance of the real parts.

The Inner Wings were constructed from robust 1" square steel tubes.   Special milling operations were required for the many 1/4" steel joining plates used for the Inner Wing panels and also joining them to each Outer Wing.   Since these wing panels were the ‘backbone’ of the Replica, serious stress analysis was undertaken by Stan Porter. The resulting calculations allowed Stan to design joint connections to sustain the highest loads estimated for the Replica.

A number of smaller parts were also undertaken by interested ‘out-of-town’ volunteers, who represent the best of volunteering, since they worked generally alone with very sketchy drawings and yet willingly produced parts that were necessary for the completion of the Replica.

Other small parts, such as simulated hydraulic actuators, control valves and brackets were produced by Jim Michin and Alan Green, both retired machinists in areas around Toronto.

Painting of the finished sections of the Replica was provided by workers at Bombardier Aerospace within the Bombardier paint shops, as another volunteer effort. These operations were co-ordinated through Dave Pollock, the manager of Bombardier’s paint shops. All of the paint to be used on the Replica was donated by SICO Inc. [Paint Division], through their representative Jeff Snyder. We are truly indebted to ALL these people for their expertise and dedication on this project.

Funding for any such undertaking is essential to purchase various supplies when they are needed and not have to wait for another benevolent donor.   Some donations were gathered in “boxes” at the Museum from those who were visiting and had some spare coins. Still other donations came through the mail from folks who lived far away and just wanted to help. Our biggest cash donation came as a grant from the Federal Government’s Canadian Millennium Partnership Program. A grant of $35,000 was made available to the Replica project based on the fact that it was a significant project to celebrate Canadian technical achievements in the last millennium and that other donor partners would be found to support this project.

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