A Yeoman effort
One of the most interesting agricultural aircraft to have seen operations in New Zealand is about to be restored to flying condition.
Craig Dowden of Waikoikoi is a sheep farmer with a strong interest in aviation. He is the holder of a CPL and his father, Bill Dowden, was one of the few pilots to fly Yeoman Cropmaster ZK-CTX. Bill flew almost 4000hr out of Gore airfield at Charlton in four of the six Cropmasters imported from Victoria, Australia, including CTX.
Yeoman YA-1 Cropmaster 250 R series 2 ZK-CTX c/n 120 was registered to Southern Aviation Ltd of Gore on 30 May 1967. Withdrawn from use in April 1971, it was cancelled from the register on 13 November 1973.
Dismantled at that time, it was until recently stored in a shed in Gore. Craig Dowden had an interest in this pile of parts because of the strong family connection, and he bought it with restoration to flying in mind.
On making an inventory of the parts he found several of the key components were missing, including the fibreglass nose cowling, tail fin, main instrument panel and, very importantly, the airframe logbook. Craig believes these are still in the Southland area and is anxious to retrieve them for the restoration.
However, he has started the long (planned 10yr) process of restoration. Joanne, Craig’s wife, is equally enthusiastic about the project, and this timeframe may well be shortened as they are aiming to have the aircraft fully restored to airworthy status as soon as possible.
The first stage of restoration has already been undertaken — the overhaul of the strong steel Cropmaster airframe by Southair Ltd at Taieri, near Mosgiel. The New Zealand aviation industry is still relatively small and it was fitting that the work on the airframe was completed under the direction of aviation engineer David Patrick. In 1967 he was an apprentice with Southair, a member of the team that assembled ZK-CTX when the parts arrived in the country.
The refurbished airframe is now back at Waikoikoi, near Tapanui, where Craig and Joanne are planning the next stage of the restoration of their historic aeroplane.
There has been renewed interest in the Yeoman Cropmaster among New Zealand aviation enthusiasts (see also “Good aeroplane, bad timing”, August 2012 Aviation News), driven by not only the rarity of the type but also its interesting development. It is one of the few links between the aviation industries of Australia and New Zealand in the days of their development.
In 1938 war clouds were gathering over Europe and also over the Pacific as the Japanese government adopted an increasingly bellicose attitude towards Australia and the United States. The Australian government of the day, while paying lip service to the protection offered by Mother England, began to make plans for its own defence. This involved the indigenous design and construction of military aircraft, including the Wirraway, a development of the North American NA-16.
As production of the Commonwealth Aircraft Corporation (CAC) Wirraway trainer and general purpose military aircraft began in 1938–39, Lawrence Wackett, CAC manager and designer in Port Melbourne, produced a new design for the CA-2 Wackett primary trainer in response to a 1938 Air Board request.
This small machine was intended to provide basic monoplane instruction to service pilots before they flew the more advanced Wirraway. The de Havilland Moth Minor, designed in the UK but with production transferred to Australia, was also considered for this role. The CA-2 cockpit instrument layout was similar to the Wirraway’s and even had an undercarriage retraction control although the undercarriage was fixed. The CA-2 featured a steel tube fuselage structure with an all-wood wing and tail. The engine was intended to be a 130hp Gipsy Major, later changed to a 200hp de Havilland Gipsy Six.
Two prototypes were flown in 1939–40 using Gipsy Six engines removed from Tugan Gannets held by CAC. Now designated the CA-6 Wackett Trainer, the aircraft was ordered into production in 1940, but as supply of the Gipsy Six engine could not be secured from Britain the American 165hp Warner Super Scarab radial engine was substituted. Delays with development and priority given to Wirraway production meant Wackett Trainer production did not begin until early 1941 and concluded in 1942 after 200 were made. Wings and tail assemblies were built by General Motors-Holden at Fishermen’s Bend.
The Wackett was mostly used by the RAAF at the Wireless Air Gunner Schools (WAGS) at Ballarat, Victoria and Maryborough, Queensland. Some service pilots disliked them intensely due to their lack of power, and RAAF pilot and author Geoffrey Dutton referred to the Wackett as “a horrid little aircraft” in his autobiography Out in the Open.
The surviving Wackett Trainers were quickly retired by the RAAF after the end of the war in 1945, with many being acquired and civilianised by J T Brown & Co. About 45 were sold to the Netherlands East Indies post-war.
Most Wacketts were flown by private owners and four were converted to KS-3 agricultural aircraft by Kingsford Smith Aviation Service Pty Ltd. A considerably more modified crop spraying version with metal wings and 250hp Continental O-470 engine was put into limited production as the Yeoman YA-1 Cropmaster between 1964 and 1966.
Craig Dowden says it is generally agreed that the Cropmaster was “wildly overbuilt”, mainly because Kingsford Smith Aviation Service had not drawn fresh specifications for the aircraft but had simply used those for the Wackett. This resulted in the big wooden wings and some other smaller parts of the Wackett being substituted by aluminium wings to the same pattern.
Six Cropmasters were exported to New Zealand and today only one of these is still flying — ZK-CPW which was also imported by Southern Aviation in Gore, registered in 1966, one year before ZK-CTX.
ZK-CPW, now owned by Lindsay McNichol and flown by Dennis Hartley, demonstrated aerial topdressing at the Warbirds Over Wanaka airshow during Easter weekend last year. Many of those present were aware of how privileged they were to be present on such an historic occasion.
In the meantime, Craig and Joanne Dowden are determined to carry on the restoration of Yeoman Cropmaster CTX.
- Report by Peter Owens
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