Canada Aviation Museum Exhibit
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CANADA AVIATION MUSEUM EXHIBIT DE HAVILLAND CANADA CS2F / CP-121 TRACKER RCN / CAF SERIAL 1587 / 12187 IN THE ROYAL CANADIAN NAVY Introduction The predecessor to the Canadian CS2F Tracker, the S2F, was conceived in 1950 by the Grumman Aircraft Company in response to a United States Navy (USN) Bureau of Aeronautics requirement for a twin engine, carrier-borne Anti-Submarine Warfare (ASW) aircraft. An interesting stipulation in the original (USN) specifications was that the aircraft must be small enough, with the wings folded, to operate from a relatively small CVE-105 (USN) class aircraft carrier. These smaller aircraft carriers were normally equipped with aircraft elevators located inboard on the flight deck centerline, one forward and the other aft. The dimensions of these elevators governed the size of aircraft that could be moved up and down from the hangar deck below. This elevator configuration and the respective dimensions were almost identical to those of the British built Majestic class aircraft carriers of which the Canadian aircraft carrier Her Majesty’s Canadian Ship (HMCS) Bonaventure was a derivative. This design feature was probably the single most important reason for selecting this aircraft for use in the Royal Canadian Navy (RCN). A formation of four Royal Canadian Navy CS2F-2 Trackers of VS 880 assigned to HMCS Bonaventure. (Bill Upton Collection) Cover Photo Caption: CS2F-3 Tracker, RCN serial 1587 of VS 880, prepares to trap aboard HMCS Bonaventure (CVL 22) during exercises in 1968. Sadly the Royal Canadian Navy ceased to exist in February of that year with the forced integration of all services into the newly designated Canadian Armed Forces, and the CS2F became the CP-121. (CF Photo PCN68-500) Development History The Tracker (initially called Sentinel) was designed and built by the Grumman Aircraft Corporation in Bethpage, Long Island, N.Y., as Model number G-89 towards a US Navy contract for a search and attack (“hunter-killer”) anti-submarine mission aircraft. This acquisition program would see replacement of the venerable Grumman-built TBM Avengers, which first saw duty with the US Navy in the Pacific during the Second World War, and Grumman AF-2 Guardians then in use. Assigned the US Navy designation XS2F-1, the first of two prototypes (USN BuNo 129137) performed its premier flight on 4 December 1952. Smaller, extendable AN/APS-38 radar units replaced the fixed, bulbous radomes associated with the Avenger and Guardian. The aircraft, configured with shoulder-mounted wings, was powered by two Wright R-1820 Cyclone radial engines, and was equipped with a rugged tricycle undercarriage. The design incorporated numerous advanced features to solve control problems previously associated with the operation of twin-engine aircraft aboard aircraft carriers and to provide sufficient space for a crew of four. It was large for a carrier borne aircraft in the sense that it could house a generous quantity of ASW detection equipment and anti-submarine weapons within an airframe small enough for operations aboard USN aircraft carriers and Majestic class escort aircraft carriers of the Royal Canadian Navy. Because of the foregoing, the USN S2F (informally called Stoof by its crews) became the RCN’s first choice as early as 1954, only two years after it had first flown. There was initial talk of a quantity order directly from the Grumman Aircraft assembly line, but a predisposition existed within the Canadian political community that they be built and manufactured under licence in Canada. Meetings between Canada’s Department of Defence Production (DDP) and several competing manufacturers served to establish a national plan for the production of 100 of these aircraft in Canada. Subsequently de Havilland Aircraft of Canada Limited (DHC) was selected as prime contractor and would assume overall responsibility for construction and assembly of the Tracker at a new plant located at Downsview, Ontario. Shortly after the new DHC plant opened, the overall scope of the manufacturing plan became known. It included the fabrication of components by a wide spectrum of Canadian companies. The wings would be built by Canadian Car and Foundry of Fort William. The rear fuselage, retractable radome, and MAD booms by Canadair Limited, Montreal, and the tail section by Enamel and Heating Products located in Amherst, Nova Scotia. The engine nacelles were to be produced out West by MacDonald Bros. Aircraft in Winnipeg. The undercarriage shock struts were to be made under license by Jarry Hydraulics in Montreal, the nose undercarriage and tail bumper by The first rear fuselage section, here labeled as “Unit 1”, built by Canadair Limited, is readied for shipment to DHC Dowty Equipment of Ajax and the weapons bay in July 1955. (Canadair via Bill Upton Collection) doors, hatches and covers by Fleet Manufacturing of Fort Erie. As the prime contractor, DHC would build the forward fuselage section and the pilot's compartment, assemble the aircraft, look after the installation of the electronic gear, manage the overall program and finally, test and prepare the aircraft for RCN acceptance. Even the engines were to be manufactured in Canada; in April 1954, the DDP had negotiated the building of 400 Wright Cyclone engines, under license, by Pratt & Whitney Canada (P&WC) at its Longueil, Quebec plant. This defence contract, which amounted to $100 million, was the biggest since the Second World War. In the meantime, the RCN purchased a new Grumman-built S2F-1 as a test model and a pattern aircraft to confirm DHC construction jigs and tooling. It arrived at Downsview in November 1954 painted in the standard US Navy Gloss Sea Blue scheme. As a test and evaluation aircraft it was assigned to the RCN’s VX 10 squadron. In 1955 it was painted in RCN colours and markings and assigned serial number 1500 / X500 (‘X’ for Experimental). Another Grumman S2F-1 (USN BuNo 136519) was also obtained, on a one-year loan from the US Navy, and delivered to HMCS Shearwater in September 1956 for equipment trials by VX 10. It retained its USN colours and markings during the course of the trials, then was returned to the US Navy in September 1957. The aircraft built for RCN use were to be called the CS2F-1 and retained the name Tracker. This all- weather, twin-engine, high-wing, anti-submarine aircraft was to employ the most sophisticated Grumman Tracker 1500 / X500 over the DHC plant. The electronic gear in the “hunter-killer” role and be bipolar AN/APA-69 Airborne Direction Finding Antenna set over the cabin was not used on the DHC-built capable of carrying a wide variety of weapons. It was aircraft. (CAvM Photo 28477) to be a formidable ASW aircraft indeed. Design Features The Tracker aircraft incorporated many unique design features. Particularly significant, were the measures adopted to permit the aircraft to operate on a single engine in the event of an engine failure on the opposite side. To allow the aircrew to maintain the aircraft in “balanced” flight and permit a single engine carrier approach and landing, the aircraft was equipped with a large vertical stabilizer and rudder, the latter split vertically into two sections. The forward section was hydraulically actuated during take-off and landing and was required during single engine operations to supplement the manually operated rear rudder section. The wing control surfaces included flaps, which spanned over 85% of the trailing edge; circular arc spoilers supplemented the relatively smaller ailerons. Lift was augmented by employing fixed leading edge slats. The multi-spar wings folded asymmetrically above the fuselage employing hydraulic power. This allows the wing span to be reduced from 22m (72ft 7in) with wings spread to just 8.4m (27ft 6in) when folded. Also noteworthy was the use of large under wing nacelles to house the two Wright R-1820 nine-cylinder radial engines and to provide space for the main undercarriage and rear-launched sonobuoys. The pilot/co-pilot cabin located just forward of the wings had superb visibility and the aircraft additionally included two detection systems operators later known as Air Electronic Systems Operators (AESOP). Weapon Systems Another unique feature of the Tracker was the search radar, powerful enough to detect submarine snorkels, using an antenna small enough to fit into a retractable "dustbin" radome beneath the rear fuselage. This was a big improvement (both in weight and aerodynamics) over the “Guppy” appearance of the RCN’s former carrier-based Grumman Avenger ASW aircraft. Non-acoustic submarine detection equipment included an Electronic Counter Measures (ECM) suite, which could detect any surface radio transmissions initiated by ships or submarines operating on the ocean surface. Later, wingtip UPD-501 radar emission detector “cans” would be installed to much of the fleet. A retractable "stinger", the AN/ASQ-8 Magnetic Anomaly Detection (MAD) boom allowed the aircraft to “fix” a submarine’s underwater position by measuring the variations in the earth’s magnetic field caused by The CP-121 Tracker’s brilliant searchlight is even seen to be blinding in the daylight hours. (Bill Upton Photo) large underwater metal objects. A steerable, 70- million candlepower AN/AVQ-2A searchlight to aid in illuminating nighttime targets was installed in a fairing beneath the outer section of the starboard wing. CS2F-2 Tracker 1581 lets it all hang out during this flyby. A view of the underside of CP-121 12183 during a flyby Assigned to HMCS Bonaventure (as seen by the tail shows the open weapons bay with a long-range stripes) ‘581 has the weapons bay doors open, the auxiliary fuel tank and, immediately aft of that, the “dustbin” radome deployed, and the MAD “stinger” deployed search radar antenna radome. Three weapons extended at the rear.