TMC Costin

— a return to a theme

We recently had an opportunity to drive the TMC Costin which has been designed by Frank Costin, is built by the Thompson Manufacturing Company in the Irish Republic and which is shortly to be marketed in Britain by Polaris of Petworth. In essence, the TMC is a return to the theme first essayed by Costin in 1959 when he produced the cycle-winged Marcos. Then, as now, his aim was to produce a superior rival to the Lotus Seven, the concept of which he greatly admires. Both the Costin cars are light, stiff and aerodynamically efficient but the styling is not to all tastes.

Whereas the Marcos featured a revolutionary wooden monocoque, the TMC uses a spaceframe which, Costin claims, breaks entirely new ground. The main problem with a spaceframe designed for a road-going car is maintaining rigidity around the cockpit area while leaving space for doors. Costin’s solution is a frame which basically is three modules, a rectangular structure to hold the engine and front suspension, a shallow triangular section where the occupants sit (imagine the angle of a pair of legs when one is sitting very low in a car), and a tall triangular section which supports the roll bar. It works on the basis that “if two torsionally stable systems are pin-jointed together at any two nodes, torsional continuity continues”.

The body is made largely of fibreglass but with aluminium side panels and under tray and features an unusual approach to weather protection. The top and rear sections of the body are open and are enclosed simply by the attachment of an oblong PVC panel which contains a rear window.

Another interesting feature of the body is the boot which can hold up to 16.5 cu ft of luggage or, alternatively, one may buy a section fitted with two rear-facing seats which are suitable for small children.

As with most of Costin’s cars, the mechanical layout is fairly conventional with adjustable equal wishbones at the front, together with Girling discs, while at the rear there are drum brakes and a live axle located by long (23 in) parallel radius arms together with a long Panhard rod. Spax shock absorbers are standard wear but the company recommend optional Koni hydro-pneumatic self-levelling dampers which have been specially re-valved by Koni for the TMC’s bare 1400 lbs kerb weight.

Similar Konis were used on the Costin Amigo of the early Seventies, and they give the car consistent handling regardless of payload or road conditions. The TMC has a very smooth ride yet throw it into a corner and the handling becomes more taut the harder you dare go. It never gave me a moment’s anxiety and it would take a brave man to explore the roadholding to its limits.

Most of my driving was done in a car fitted with a standard Ford Kent engine, giving 84 bhp, and driving through a four speed gearbox. Even so, 60 mph was reached in under nine seconds with a maximum speed of just over 100 mph. With the CVH engine, the company claim a 0-60 mph time of 6.7 seconds and a top speed of about 120 mph. “My” car felt dreadfully underpowered for the chassis is designed to take up to 300 bhp with a safety factor of two (i.e. it could, it is claimed, handle 600 bhp).

That is a claim which has yet to be put to the test, but the car felt as though it was hungry for a well-tuned BDA or, perhaps, the turbo-Pinto engine which will form the basis of the new Formula Turbo Ford.

The TMC comes either as a kit for around £3,000 in which case the customer provides his own running gear, trim, instrumentation etc, or fully assembled for about £6,500 (Ford Kent engine) or around £8,000 (Ford CVH engine plus extras). The final price is dependent not only on the customer’s specification but also on the exchange rate of the Irish Punt against sterling. Once an order is placed, though, the price is fixed.

The seats are very wide and are fixed (the pedals are adjustable) and though they look rather basic they are comfortable and hold one in well. There is a seven instrument dashboard, clearly visible through the 13 inch, thick, steering wheel. Both doors have sliding perspex windows and, though they fold forward flat against the body, neither entry nor exit is an excercise to be easily undertaken by, for example, a lady in an evening dress.

The TMC Costin is a great little car which is a lot of fun. Does it, however, live up to its designer’s intention of being a superior alternative to the Caterham Seven? This is a question I have to dodge because the only Caterham Seven I have recently driven was fitted with a very special twin cam engine, so one would hardly be comparing like with like. The TMC scores in practicality and ride, as a car which could be used for travelling long distances with a passenger and luggage.

The Caterham Seven’s strong points are its looks, its pedigree, its competition history and its perceived image. To seriously challenge the Seven’s position, the TMC must appear on the circuits and prove itself. It has already done so in Ireland, and won first time out at Mondello Park despite having been completed only hours before the race. If it is successful on the tracks, then it will acquire the image necessary for its long-term commercial success. We shall watch the progress of this newcomer with a great deal of interest. — M.L.