Author Topic: 'Dis week I are mostly....  (Read 1855 times)

Big Al

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'Dis week I are mostly....
« on: June 11, 2014, 08:15:31 AM »
sorting out Mk12 Invalid Carriages.

Interesting construction. The floor is based on a large section tube for to aft. The flat sheet floor is placed on folded steel outriggers on top of this. The edge of the floor has brackets for the suspension to hang off. The rear hinging as a trailing arm. The engine and suspension tops are held in by a set of bars bolted to the main spar and the top of the coil over dampers. This is rigid enough for the GRP shell to be pretty much unstressed. Indeed it would be possible to create a driving bodiless Mk12.  This construction is thus made using cheap materials, de-mounts to flat pack and bares only passing similarity to the very much more complex Type 70 construction. Yet the dimensions are not that different, so body changes occurred in sequence as the Mk12A to E gave way to the 14 and 15, both of which look like a Type 70 but have modified Mk12 and then the better front end prior to the switch the Type 70 and triple the power if the twin Steyr Puch engine is tuned correctly. This covers a period of 1964 to the end of production some 14? years later.

Interesting that investment funding saw continued alterations to improve the vehicles. Just what did not happen to cash strapped small manufacturers prior to the Mk12 appearing. Of course the public purse was deeper than a small businesses. Villiers engines were used after Villiers had failed, taking down Scooter, and other manufacturers, with them, with the rights bought out from the failed company. So it might be argued that the Mk12 is the heir to British Microcar thinking as it continued to use much of the older technology common on the by now defunct Microcars. Villiers engines, dynostarters, black boxes. The construction was a bit different but weight was always an issue as was carrying capacity, minimalism and many ancillaries and controls are very familiar. Its almost as if Burt Grieves had raided the old stock of previous small car manufacturers.

The Villiers engine itself fits uncomfortably on top of the central spar in a cradle of tube steel bars and frame. It has the fan to the left and a steel sheet cooling shroud. The dynastarter is the reversing type. Beneath the engine and attached to the gearbox is the enormous enclosed drive gear bringing down the speed. This gear has one short double jointed drive shaft powering the NS rear wheel only. The drive shaft would be instantly recognizable to any Berkeley owner. THe Black Box lives on the 'parcel' shelf behind the drivers neck, thus most of the electrics are inside the cab. That is dominated by an large rectangular box with numerous controls sprouting out of it at all angles, not always the same either as each car could be adapted for a range of disabilities. Not an easy assembly to work on, but fortunately I do not have to yet as these cars are being prepared to travel to their new owners.

Given a complete car these machines offer a relatively simple restoration project. I have now had experience of perhaps half the more common types of carriage. All seem to be a mix of clever engineering using good materials and the stunningly crude. All a learning experience to add to little cars I have pulled about over the years.

Messerschmitt set, Goggo Darts, Heinkel 175, Fiat Jolly, Autobianchi, Fairthorpe Electron Minor, Borgward, Isuzu Trooper
Citroen BX 17TZD & GTI 16v
Held - MG Magnette ZB & 4/44
For sale - Vellam Isetta, Bamby, AC Type 70, Velorex, Church Pod, Reliant Mk5, KR200,  Saab 96, Bellemy Trials, Citroen BXs

Stuart Cyphus

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Re: 'Dis week I are mostly....
« Reply #1 on: June 11, 2014, 12:14:31 PM »

...and bares only passing similarity to the very much more complex Type 70 construction. Yet the dimensions are not that different, so body changes occurred in sequence as the Mk12A to E gave way to the 14 and 15, both of which look like a Type 70 but have modified Mk12 and then the better front end prior to the switch the Type 70 and triple the power if the twin Steyr Puch engine is tuned correctly. This covers a period of 1964 to the end of production some 14? years later.


 But of course, as befits the world of the invalid three-wheeler, things were a little bit more complex than that.  Although Invacar Ltd & AC Cars Ltd were the Ministry's two most favored manufactures into the 1960s, it was usually AC who were commissioned by the Ministry to undertake most of the "official" research and development projects for whatever detail amendments would be made to the Standard Specification of Invalid Three-wheelers, which affected every manufactuer and every vehicle. Very often Bert Greeves and Invacar Ltd, despite having always been the true innovators and creative genius behind the post-war industry, would not be consulted as to any mods, but told "From X-date you will do this, this and this to your vehicle" and never mind if it conflcted with how the vehicle was put together in the first place, often causing big headaches for the production line.  Little wonder that Bert began to take more and more of a back seat in his own company through the late 1960s until he announced his retirement in 1973 and sold the company.

 But anyway; as fans will note, there are six varents of the basic Invacar Mk 12, being Mk 12, (1960-63) Mk 12A (1963-66), Mk 12B ('66-'67) Mk 12C ('67-'68), Mk 12D ('68-'69) and the Mk 12E ('69-'71)

 The AC Acedes ran from 1957 to 1971 and reached Mk 15 in 1968. The final two variants, Mk 14 & Mk 15 are the fibreglass ones which look like the Model 70. 

 The AC Acedes Mk 14 & 15 were not developments of the Invacar Mk 12. They were produced concurrently and were not related, being products of two unrelated companys who very often did not talk to each other despite the similarity of their products and the common "good" of the Invalid Vehicle Service.

 As mentioned earlier, the Ministry favored AC to come up with official modification and the most noticeable of which at this time was the front suspension, as AC had developed their double parallelogram system which gave a softer ride than the old "Cee-tube formely used. In 1969, Invacar were ordered to copy the AC suspension design and the result was the Invacar Mk 12E.

 The Model 70, appearing in the summer of 1971 and replacing both the AC Acedes and Invacar Mk 12 models, was another example of the Ministry blanking Invacar Ltd, the whole research and development project from 1967 to 1971 being signed to AC Cars Ltd solely for their experience in building "real" cars. Indeed, Invacar Ltd were completely frozen out of all development of the Model 70 and were not even permitted to SEE a prototype until 1970, despite the fact they were going to be ordered to make nothing but this vehicle in less than a year's time. Sometimes the high-handed attitude of the Ministry towards their manufactures could defy description and belief! 

 So, although Model 70's were made by AC and by Invacar, the design is enterly the responsibility of AC Cars Ltd. Therefore one could say that the last pure Invacar, (before AC Cars Ltd interference becomes stronger and stronger) is the 1967-69 Invacar Mk 12D....

Big Al

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Re: 'Dis week I are mostly....
« Reply #2 on: June 12, 2014, 12:55:13 AM »
What did AC do to upset you? Anyway there you have more facts than 25 microcar related forum items in two entries. Brilliant.
Messerschmitt set, Goggo Darts, Heinkel 175, Fiat Jolly, Autobianchi, Fairthorpe Electron Minor, Borgward, Isuzu Trooper
Citroen BX 17TZD & GTI 16v
Held - MG Magnette ZB & 4/44
For sale - Vellam Isetta, Bamby, AC Type 70, Velorex, Church Pod, Reliant Mk5, KR200,  Saab 96, Bellemy Trials, Citroen BXs