Author Topic: Canso: A Stranraer Story  (Read 325 times)

Offline apophenia

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Canso: A Stranraer Story
« on: May 08, 2022, 10:12:21 AM »
Part 1

Origins - From Vancouver to Victoria (via Argentina)

In 1932, Canadian Vickers Limited proposed two derivatives of its Vancouver patrol flying boat to Canada's Department of National Defence. One was the Vancouver III photo-survey amphibian, the other was a coastal defence flying boat to be named Venomous. Both were to be powered by Pratt & Whitney Wasp radials. Neither type was ordered by DND ... which caused some soul-searching at Canadian Vickers. The firm's previous Chief Engineer had advocated pursuing Private Venture design to avoid the endlessly-shifting requirements associated with projects for the RCAF. This now seemed a good direction to go in.

New Chief Engineer R.P. Key and project engineer R.J. Moffett decided to further refine their Venomous concept. Two roles were envisioned - a light passenger transport for export to the British West Indies and a military patrol flying boat. An updated version of the Vancouver III's twin rudders would be adopted to ensure reasonable engine-out handling. [1] The upper wings were extended - for an overall span of 65 feet. [2] Most dramatically, the pilots' cockpit would now be enclosed and faired into a new dorsal 'hump' containing additional fuel. But, in most respects, this new Venomous was true to its Vancouver roots.

Initial Success Abroad - the Argentine Veneno hidroavión

As expected, the RCAF had no interest in the new type. However, Argentina was willing to be the launch customer - if trials with the prototype met expectations. They did, fortunately. In Comando de la Aviación Naval Argentina service, the Canadian boats would augment the expensive-to-operate Dornier Do Js and entirely replace the worn-out Felixstowe F.5L fleet. To the COAN, the new flying boats would be the Venenos (Spanish for 'venom') but, in service, were often referred to as the 'Cormorán' ('cormorant'). The six Canadian Vickers Venenos - serialled B-24 to B-29 - would serve on until finally replaced by US-supplied PBY-4As in early 1947.

Bottom Canadian Vickers Veneno of COAN's Escuadrilla de Patrulleros operating from the slips at Base Naval Puerto Belgrano outside of Bahía Blanca in late 1936. Note the 4-bladed Canadian Vickers-made propellers (later replaced by metal 2-bladers). Argentina aircraft had their Alclad sheeting covered with over-all grey anti-corrosion paint.

When the hidroavión argentino illustrated the front cover of Canadian Aviation Magazine in January 1936, RCAF leadership was not best pleased. But poking at the 'brass' had been precisely the Aviation League of Canada's intention. Canadian industry had produced a new military aircraft ... but it had entered service with a nation located 5,600 miles away. In short order, DND's Chief Aeronautical Engineer would be called up in front of the Minister of National Defence to account for the RCAF's lack of support for Canadian industry.

Vic-torr-iiia, Vic-torr-iiia ... (Using best Ray Davies Impression)

MND Ian Alistair Mackenzie was an imposing former Seaforth Highlander. But Group Captain E.W. Stedman, OBE, was more than able to stand his ground. The RCAF had experienced difficulty in finding a suitable role for the Canadian Vickers Vancouver flying boats - they had served in forestry and then mail carriers before finally becoming Vancouver Mk.II patrol aircraft. Thus, the RCAF was not short of Canadian-made coastal patrol types and had no immediate need of Vancouver Mk.II replacements. If there were political motivations for such a purchase, Cabinet must be prepared to increase DND's procurement budget accordingly. In Mackenzie's view, 'national reconstruction' from the Great Depression was at stake. The money would be found.

At that West Block meeting, the MND and Ernie Stedman plotted out the procurement. G/C Stedman would write the specification and Ian Mackenzie would find the funds to purchase new flying boats to replace the RCAF's existing Vancouver IIs. Specification C/2/36 covered the procurement of five Vancouver II replacements based on the Canadian Vickers Veneno. In place of the Veneno's 450 hp Pratt & Whitney Wasp SC1s, the RCAF machines would have more powerful Wasp S3H1 radials [3] driving 3-bladed Hamilton Standard variable-pitch propellers. The nose profile was also refined. Additional RCAF-specific equipment was specified but, otherwise, the new RCAF aircraft would be identical to the Argentine Venenos.

Top Canadian Vickers Victoria in service with No. 4 (Bomber Reconnaissance) Squadron based at RCAF Station Jericho Beach in late 1940. Markings on the Victoria fleet were never brought up to wartime standards. In early 1941, Victoria 902 was transferred to No. 3 Operational Training Unit. [4]


[1] on the Vancouver III, this involved a central vertical fin and triple rudders matched with a biplane horizontal tail.

[2] The wings now had a NACA 3411 section - a slight variation on the Vancouver's original Clark Y airfoil.

[3] The Wasp S3H1s were each rated at 550 hp (at 2,200 rpm) to 5,000 feet but had 600 hp (at 2,250 rpm) available for takeoff. A three-bladed Hamilton Standard variable-pitch propeller was used.

[4] No. 3 OTU was transferred to Pat Bay on Vancouver Island in 1942 but, by then, the surviving four Victorias were all being employed as ground instructional airframes.
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Offline ericr

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Re: Canso: A Stranraer Story
« Reply #1 on: May 08, 2022, 09:51:16 PM »

Offline Old Wombat

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Re: Canso: A Stranraer Story
« Reply #2 on: May 08, 2022, 10:22:20 PM »
"This is the Captain. We have a little problem with our engine sequence, so we may experience some slight turbulence and, ah, explode."

Offline GTX_Admin

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Re: Canso: A Stranraer Story
« Reply #3 on: May 09, 2022, 01:37:32 AM »
All hail the God of Frustration!!!

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But you can make the Bastard work for it.

Offline apophenia

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Re: Canso: A Stranraer Story
« Reply #4 on: May 09, 2022, 04:38:17 AM »
Part 2

Sometimes Less is More ...

By the time that his Victoria flying boat was in RCAF service, R.P. Key had already departed from Canadian Vickers. He was replace as Chief Aeronautical Engineer by his former assistant, R.J. Moffett. It was readily apparent to 'Dick' Moffett that the Vancouver/Victoria lineage had no further development potential. It was also obvious that Canadian Vickers alone could not bear the costs of developing a modern all-metal flying boat. No help was forthcoming from Ottawa but the parent firm was pitching Supermarine Stranraer flying boats for patrol use by the RCAF. When the Government of Canada awarded a contract in 1936, it was stipulated that the Stranraer be built by the Canadian Vickers subsidiary.

That contract was welcome news on the Montreal factory floor. But 'Dick' Moffett and the design office were less thrilled. Canadian Vickers was already assembling a single-engine photo-reconnaisance aircraft for the RCAF. These licensed Northrop Delta monoplanes were far more advanced than the biplane Stranraer (which was effectively a Southampton modernized for metal construction). Surely with its new and hard-won facility with all-metal stressed-skin construction, the Canadian Vickers design office could do better than the lumbering Stranraer. [1] On the upside, Canadian Vickers top management had approved the construction of a larger factory space at Cartierville outside Montreal to build the new flying boats.

With production space at a premium at Hythe, Stranraer jigs, tooling, and equipment was already being packed up for shipment by sea from Southampton docks to the Port of Montreal. Things began moving quickly, once Stranraer jigs and components began arriving at the semi-finished plant at Cartierville. The first of six Cartierville-assembled Stranraers (RCAF serials 700-705) was delivered to the RCAF in 1938. But, what was viewed as a victory by Accounts and Canadian Vickers brass, was preached against from the design office. In doing so, 'Dick' Moffett was making himself very unpopular with top management.

Unpopular or not, it was becoming obvious to all that biplanes were not going to play a major part in the future war which was brewing. If Canadian Vickers was to make a useful contribution in aviation, monoplane designs were needed. Approval was finally given for Moffett and team to submit a monoplane flying boat study - but one with very tight reigns on the budget. So, neither an entirely new design nor a complete redesign of the Stranraer was in the cards. This quickly narrowed options to a monoplane design based upon the existing Stranraer hull. Eventually, that led to a cooperative relationship with the US firm of Sikorsky Aviation Corporation of Stratford, Connecticut.

The Sikorsky S-43 'Baby Clipper' transport amphibian - a parasol monoplane was approximately the same size and weight as the biplane Stranraer. The US military was in the process of buying or ordering S-43s, which gave the type additional credibility. Canadian Vickers and Sikorsky agreed to a work up a co-operative offering to the RCAF. This would consist of the militarized S-43C transport amphibian and the CVS-304 'Stranraer Monoplane' patrol aircraft. [2] The latter, in simple terms, combined the hull and tailplane of the Supermarine Stranraer with the pylon and wings from the Sikorsky S-43. It was anticipated that any RCAF order would be powered by Bristol Pegasus X radials while Wright GR-1820-G2s would be offered for export variants.

The prototype 'Stranraer Monoplane' was the seventh hull assembled from British parts mated to Sikorsky-supplied wings. This aircraft flew from the Saint Lawrence Seaway in June 1938 with American engines. Despite the lower-powered Pratt & Whitney R-1690 Hornet radials, performance gains were immediately obvious. On the 750 hp R-1690-52s, the 'Stranraer Monoplane' was 30 mph faster in flight than its biplane progenitor. That speed would increase by another 10 mph once the 920 hp Bristol Pegasus X engines were installed. 'Dick' Moffett appeared to be vindicated. [3] DND and the RCAF requested that all further production work on the Stranraer be halted.

The second batch of six RCAF Stranraers (RCAF serials 906-911) was cancelled with this order transferred to the new 'Stranraer Monoplane' - which DND dubbed the Canadian Vickers Canso. [3] A second order followed for another half-dozen Canso Mk.IAs with changes to armament and equipment (912-917) The most obvious changes were a refined nose/bombardier's station and an enclosed tail gun position. Consideration was also given to adopting alternative, American powerplants - the 950 hp Wright R-1820-G5. Eighteen American-engined Canso Mk.IIs were procured (RCAF serials 918-935). However, no immediate threat to the supply of British-made Pegasus engines was anticipated and no further orders were placed for the Mk.II. A final order was placed for a half-dozen Pegasus-powered Canso Mk.IIIs (936-941) with improved crew accommodations. And with that, Canso production ended at Canadian Vickers.

Although the monoplane Canadian Vickers Canso proved superior to the biplane Stranraer, both types were outshone by the American Consolidated PBY flying boat. Ordered for both the RAF and RCAF as the Catalina, it was decided to license-build the Consolidated boat at Cartierville. As a result, both the Canso and its biplane forebearer played fairly obscure roles in Canada's war effort. By the Summer of 1942, all remaining Cansos and the four surviving Stranraers had been transferred to Western Air Command on the Pacific coast. But that is the beginning of a different story ...

( Fin )


[1] Even British Air Ministry had been underwhelmed by the Stranraer - preferring its competition rival - the Saunders Roe A.27 London.

[2] At the time, the RCAF saw no application for an amphibian transport (it would take the outbreak of the War in the Pacific to make the usefulness of such aircraft apparent). So, no RCAF orders for the Sikorsky S-43C were forthcoming. As will be seen, the CVS-304 'Stranraer Monoplane' was another matter. To parent firm, Vickers-Armstrong, this type would be known as the Supermarine Type 304M - despite the Southhampton design team playing no part in the final design.

[3] In the end, the battle must have been too frustrating. In July 1940, as Canso orders peaked, 'Dick' Moffett left Canadian Vickers to became the general manager of Federal Aircraft.

[4] The Canadian Vickers Canso was named after Cape Canso in Nova Scotia. Canadian Vickers had proposed the name Vigilant but this suggestion was rejected by DND.
"Hey! Hey! Careful, man! There's a beverage here!"

Offline robunos

  • Can't afford the top wing of his biplanes...
Re: Canso: A Stranraer Story
« Reply #5 on: May 09, 2022, 05:27:35 AM »
Oohh nice !     :smiley:
And you should be able to see why I didn't go for the Parasol type with my version . . .   ;)

By the pricking of my thumbs, Something Whiff-y this way comes . . .

Offline apophenia

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Re: Canso: A Stranraer Story
« Reply #6 on: May 09, 2022, 11:19:56 AM »
... And you should be able to see why I didn't go for the Parasol type with my version ...

Yup. Easy enough in pixels but there is a surfeit of struttery on any parasol   :P
"Hey! Hey! Careful, man! There's a beverage here!"