Reviewed by Unique Cars and Parts
Our Rating: 5
We would guess few people have ever heard of the YAK Yeoman. The brainchild of Bob Stoodley, the concept was to build a vehicle in KD (knockdown) form, such that it could be easily assembled in just about any country on the planet that could muster a wrench and screw driver - perfect for 3rd world countries.
There were only five panel forming tools needed to produce all the aluminium body panels. The bonnet, the wings (identical front and rear and side-to-side), the side panels (again interchangeable), the front grille panel, the rear quarter panel and the tail gate.
According to the very few reports we can find on the car at release, the two-wheel drive Yak Yeoman was able to cope with slippery slopes and with deep soft sand. Like the Moke
, the YAK was a lightweight, country utility vehicle manufactured on the simplest jigs using a standard Ford engine and other easily obtained components.
Coping With A 1-in-2.5 slope Thanks To Fairey Engineering
The cross-country ability was conferred by combining two wheel drive with a locking differential, to prevent wheel spin on slippery going, and a built in winch to retrieve the YAK should the going get too difficult. Stoodley ensured the design of the car would cope with a 1-in-2.5 slope, which meant there needed to be a reduction gear.
This was cleverly incorporated in the winch specially designed by Fairey engineering. A further refinement of the Yak concept was that it should be easily manufactured and assembled by unskilled labour and was designed to be able to pack into a standard 20 foot container. To this end the chassis, fabricated from gas welded square section tubes was in four main units which could be easily bolted together by un-skilled labour.
These main components were the engine bay, which looked like a skeleton crate, and comprised the engine mountings supports for the Ford Escort McPherson front suspension
and all the ancillaries, the centre section which consisted of a stressed skin, tube-based backbone, the aluminium panel floor and the girder type side members. The other main chassis component was the rear suspension
box whic was manufactured in two halves for ease of assembly and carrieds the leaf springs and Escort live axle.
Finally there was a bolt-on cab-frame which supported the windscreen and door apertures. In keeping with the ingenious simplicity which typified the whole vehicle there were only five panel forming tools for the whole vehicle - they were for the bonnet, the wings of which were identical front and rear and side-to-side, the side panels which were interchangeable, the front grille panel and the rear quarter panel and tail gate. Panels were produced by the "Blowform
" process which required extremely simple tooling.
The end result was a functional-looking vehicle whose manufacture was, in theory anyway, economically viable because it used standard Ford components and the aforementioned manufacturing techniques. The 1300 Escort Export engine was chosen because of its low compression ratio. The 1100 Escort
was considered insufficiently powerful and the 1600 was found to be too expensive. The whole of the gearbox and drive line and springs were of Ford manufacture, and where available heavy duty items were specified, especially for the front and rear suspension
- this was not only in keeping with the "off-road" nature of the Yeoman, but also suited the environment where it was initially anticipated they would operate, that being assembley and sale in 3rd world countries.
Reduction Gearbox and Automatic Differential Lock
The only mechanical components specially designed for the vehicle were the reduction gearbox and winch and the automatic differential lock by Suredrive of Hathersage Road, Manchester. Fairey's winch was designed from scratch and was a two speed reduction gear with synchromesh
engagement and a fore-and-aft-power takeoff. A drum winch with 26 to 1 reduction was mounted on the forward power take off. This winch had a minimum 2,000 Ibs. ft. pull. Vehicle kerb weight was a claimed 1,960lb. (889kg).
Unique Cars and Parts
were not there for the original demonstration - but a handful of motoring scribes were. They claimed that the Yak's cross-country ability showed that it did all that was claimed for it. Manchester Garages pointed out at release that most cross-country vehicles needed four-wheel-drive less than five percent of the time, and when it was required it was only a marginal requirement (obviously they had not done their research in Toorak or Double Bay, where the figure would be much closer to 0%).
According to the reports we have read, the YAK demonstration vehicles were able to cope with steep, slippery slopes with the locking two-wheel drive axle although it was noticed that they were all carrying a load which gave extra adhesion. Part of the test consisted of deep soft sand which turned out to be a marginal hazard in that two of the vehicles managed to get through while one became bogged down through lack of ground clearance despite its 16 in. wheels. It easily extracted itself with the winch - so maybe this was a marketing ploy to demonstrate just how easy it was to get the YAK out of a jam.
In keeping with the general conception it was intended that the YAK be marketed with a range of options. In basic form without the differential lock reduction gearbox or power winch it was initially priced at £2,899. The reduction gearbox cost £325, and the power winch was £120 on top of that while the automatic differential lock was a further £195 - thus the cost of a vehicle in cross-country form added up to £3,539 which brought it almost into the light four-wheel-drive market dominated by the Japanese. And that was the problem.
The initial production target was for up to five thousand vehicles per year, so tooling for the aluminium body panels was justified - leastwise as far as expected production totals was concerned. The YAK could have been revolutionary in the developing nations, but it needed to be as competitively priced as it was innovative. Unfortunately, it was not.