Designer's First Drive

Iain Robertson, designer of the 21, takes his vision onto the road for a solo run
The rain had stopped. The vast roller door is climbing and Caterham technical director Jez Coates gives the final thumbs-up.
I've sat here a thousand times - sculpting the dashboard, checking dimensions, arranging instruments and switchgear - but this time it's for real.
This is N998 BKR, Caterham's first production specification 21 prototype - the car I sketched almost exactly two years ago.
Securely strapped in to the lightweight leather driving seat, I turn the key and the 1.6-litre K-series powerplant bursts into life with a deep throaty burble - I'm grinning already.
Lights on, nudge the short-shifting six-speed gear-lever into first, release the tiny tunnel-mounted handbrake, engage the clutch and we roll slowly into the night and out of sight.
Visually, the 21 is a million miles from its classic 39 year-old stablemate. Where the Super 7 is clothed in a minimalist function- exposing aluminium skin, the 21's high-waisted composite body envelopes the driver and mechanicals in flowing aerodynamic curves. The cockpit feels much bitter too, thanks to the extra shoulder room, enlarged footwells and dramatic visor-like windscreen.
But as I blast along Kent's sinuous A25, the family lineage is impossible to ignore. In fact, to my delight, dynamically and aurally the 21 is virtually indistinguishable from the benchmark Super 7.
Overall width is identical and perfect for swift backroad progress. The steering is light, direct and accurate. The rim, slightly larger in the 21, is alive with information from the road. The precise finger-tip controls give the same unique intimicy between driver and machine.
All round visibility is superb and even top-down at speeds approaching the national limit, the cockpit is calm - the aerodynamically optimised windscreen and removable side windows eliminating the uncomfortable buffeting that normall afflicts high-performance roadsters. Incidentally, this prototype has been tested at more than 120mph - with just 115bhp on tap from its standard Rover engine.
Psychologically the 21 feels bigger and heavier than the track car-like Super 7, but that impression vanishes at the first corner. The familier race-proven suspension - de Dion at the rear, double wishbones up-front - and ultra-low profile 16-inch rubber inspires total confidence even in these slippery conditions. And despite the 21's extra 90 kilos, there is no hint of added inertia as I slingshot from the exit with a whisper of opposite lock.
About 30 miles and as many minutes from Caterham's Dartford factory, I turn in to Jez Coates's gravel driveway, mission accoplished.
Driving Caterham's 21 prototype for the first time is, quite literally, a dream come true. I won't forget the thousands of hours spent shaping, engineering, testing and perfecting every aspect of its featherweight two-seat structure. But it's the memory of my first drive that I will treasure longest.

21 Tech by Jez Coates

Hood

Not all spects of the 21 project could be dealt with simultaneously. The hood was one of the items which had not been resolved in time for the British Motor Show in October 1995, and, understandably, it was the biggest single itme of customer concern at the show. Ever since then it has been the subject of intense engineering effort.
Firstly there has been an exhaustive analysis of past and current designs. Then design targets were set: It should wdigh less than 10kg complete with its frame, and be significantly easier to erect then the Seven hood, preferably from the driver's seat. It should be capable of folding away below the composite hood cover without requiring any bodyshell modification, and, of course, it should be watertight.
Literally hundreds of hours of work has taught us that this combination of criteria are extremely difficult to meet, but now we have a diesign which is capable of achieving them.

Fuel cell

It has always been the intention for the 21 to develop the theme of the saddle tank, first seen on the J.P.E.
Show cars were built with fabricated aluminium tanks but these were prohibitively expensive for the production car. The answer was to mould the tank in polyethylene. This involves very expensive tooling, so it was vital to get the shape right from day one.
The trouble is that the material shrinks by 3% during the moulding process, so the mould was actually to big to test fit to the car! I am glad to say the first tank has been delivered, and it fits. What's more it holds 13.5 gallons (61 litres).

Prototype testing

Dynamic pre-production cars have completed 1,000s of miles of tests on a variety of road surfaces and traffic conditions. Results so far have been extremely encouraging in terms of ride, handling and performance. Caterham has already established that the 1.6 litre K-series engine can propel the car to 120mph with the hood up - some 12mph faster than the Seven. This is despite the heavier weight of the vehicle.
The weight of the running prototypes is lower than expected and development car 003, although not complete in every detail, is well under 650kgs, making it less than 90kg heavier than the Seven - easily meeting its design target of 100kg.

Windscreen wipers

On the face of it thw wipers should not provide a problem, but life is never that simple. The problem was that we ere using a Vauxhall column stalk to operate a Fiat wiper motor which incorporated a delay wipe. Two slow speeds and a fast, or two intermittent and a fast speed were easy to achieve, but one intermittent, one slow and one fast and a park function, which consistently tucked the blade away correctly, was very illusive. Eighteen hours and one relay later, Bingo! A problem solved.

New Premises for Sales Team

Caterham Cars has acquired a new - and bigger - premises in Caterham, within the main part of the town. Perviously a Vauxhall dealership, the building will provide room for an enhanced sales operation as well as on-site workshops.
"Although we have been looking for new premises for some time. we didn't want to sever our connections with town," said Gahame Nearn, Caterham Cars' Managing Director. "We were therefore delighted when this showroom came onto the market."

Return to the Caterham 21 Register page.