Born Slippy WB 120 Special. One-off built to beat the Lotus Elite. We wind test the WB 120 special, conceived in 1957 by a mathematician and a physicist to rival the best sports cars available at the time. Words Simon Duval Smith. Photography Matthew Howell.
A 60mph gale rips at our clothes and hair as we brace ourselves inside the wind tunnel at MIRA, one of the car industry’s foremost proving grounds. In front of us, parked on a turntable that will alter its angle of attack to the powerful airstream, sits a home-built special.
Called the WB 120 and first registered in 1963, the low-slung, slippery-looking sports car was intended by its creator, Dr John Best (the ‘B’ of WB), to be superior in every way to the contemporary Lotus Elite. This is because, a few years earlier when buying an Eleven kit from the Lotus factory in Hornsey, North London, Best’s suggestion to Colin Chapman that design of suspension and aerodynamics could be speeded up and improved by the use of computers had been summarily dismissed.
Unimpressed by the quality, handling and practicality of first the Eleven, and then an Elite bought subsequently, Best and his engineer partner Bob White (the ‘W’ of the company name) believed they could do better.
In a letter to Roy Campbell, present owner of the WB 120, Best said of the Elite: ‘It is an interesting car, much easier to drive than the Eleven, not much quicker on average despite the greater power, but shocking on ventilation and very irritating, unexpected and not necessarily small twitches – even on the straight – due to changing rear track with the strut suspension (which had a very marked swing-axle action). Colin Chapman, I remember, called it a heap. You could say it was a nice heap. I wanted to get something together that you could simply say was nice.’
And here, amidst the din and the blast of the wind tunnel in 2017, we’re about to discover whether Best and White’s self-belief – at least in terms of aerodynamic efficiency – was justified. Best was an unlikely car designer. He had gained a PhD in mathematics from Cambridge, then joined EMI. There, he worked on the development of TV, the first airborne radar fitted to fighter aircraft early in World War Two, as well as the design of the first computers and brain and CAT scanners. He was drawn to White as the man to turn his ideas into reality; White worked in EMI’s engineering department after the war, having been involved in installing the first TV transmitter at Alexandra Palace in 1937. He’d also worked on radar during the conflict.
Best recalls his role in the project: ‘My connection with the car was as designer and funder. Bob White had exceptionally good construction skills and performed virtually all of the building of the car, including the shaping and butt welding of the aluminium panels.’ Best says that the idea for the WB special was born after he ‘…dumped a new Lotus Eleven kit in Bob’s garage and we agreed that if he built it up, he could use it for six months’.
Having enjoyed driving the Eleven, White then rashly said he didn’t think it would be too difficult to make their own car: ‘About six weeks later, John appeared with a wad of foolscap paper covered with a profusion of maths: it was the design of a car.’ Best believed he could produce a vehicle that would behave in a calculable and predictable way. Via reams of complex mathematics, he concluded that the best results would be obtained by fitting an aerofoil; aesthetically, however, that wasn’t acceptable. So he devised a body that was itself an aerofoil in cross-section.
Best then turned his attention to the design of the WB 120’s rigid tubular chassis, and a suspension layout that would give controlledroll understeer with minimum unsprung weight at each corner (35lb using Dunlop R4 tyres).
Dry weight was planned to be around 730kg, and it came in very close to that figure when finished. Best also calculated the front wishbone design to control the roll centre and camber angles, and fully exploit the advantages of a front track that was six inches narrower than the rear, limiting changes to just three degrees of camber change and roll at 1G. For the rear, he designed unequal-length wishbones to give 1.5 degrees of negative camber at 1G.
In 1957, White started construction of the wooden buck around which the aluminium skin would be formed. Over a few years, the entire car was constructed in his garage using basic equipment but achieving very sophisticated results. Almost all parts were designed from Best’s drawings, including the suspension uprights and the aerodynamically shaped and specially cast wheels. Many of the car’s features, such as recessed wipers, eyeball cabin vents and flush glass, were well ahead of their time.
Best’s disaffection with Lotus endured, it seems, and the only Elite-related components featured on the car were the Coventry Climax FWE 1200cc engine and an Elite diff. Setting the motor far back in the frame gave good weight distribution and allowed Best to implement the WB 120’s most remarkable feature, its narrower front track. This was intended to give quick steering and stability at speed, while making the handling neutral and preventing it snapping into oversteer when approaching the limit of grip. He specified inboard disc brakes all round, the forward set being carried on a specially cast dummy differential with half-shafts running to the hubs, through bespoke cast Elektron uprights, which are also used at the rear.
When finally the car was road-ready, Best and White tested it on the newly opened (and speed limit-free) M1 motorway. Best recalls being very happy straight off, his theories and calculations being borne out in the car’s neutral handling and aerodynamic performance. He recalls: ‘I designed it to become increasingly stable above 80mph, and at 125mph [with the FWE at its 7250rpm rev limit] it felt beautiful.’
In 1967, after White had been rewarded for his efforts by driving the car for a few years, and Best had also used it regularly, they decided it could benefit from more power. So it was left with a garage in south London for a Lotus-Ford Twin Cam engine to be installed. Shortly afterwards, however, Best’s wife was killed in a road crash and his interest in cars waned.
The WB 120 passed through a few hands before present owner Roy Campbell, an electronics engineer and maker of his own brand of professional audio equipment, found it while browsing Exchange & Mart for a special. ‘I looked for specials every week, as I couldn’t afford an original sports car,’ he says. ‘I was after a new interest having been a TR enthusiast and racer for many years, and I fancied something that would give the Elites a run for their money.’
He was a bit surprised when the owner drove the WB 120 out of its lock-up; it had a badly fitted Fiat twin-cam – forcing the bonnet to be raised by two inches – rattle-can green paint, gold wheels and a gold-carpeted interior. The original paperwork confirmed that it should have an FWE engine, and Campbell knew it was going to be a long restoration: ‘I made a quick choice to carry on with the trusty TR, and parked the WB in my parents’ garden for the next 12 years!’
In the midst of starting his own electronics business, he occasionally managed to visit the car and make drawings of missing parts. However, with no cash for a Climax engine, he fitted an MG Midget motor and gearbox that a friend had discovered under the local cricket pavilion. Although the WB 120 now drove, it wasn’t until 2016 – 36 years after Campbell first bought it – that the car was fully restored, complete with a freshly rebuilt FWE engine and a Ford T9 five-speed transmission.
On the road, the WB 120 belies its age with beautifully neutral and assured handling. As the suspension loads up and the designed-in body roll adjusts the cambers and roll centre, it has tremendous grip and poise. The clever geometry allows predictable understeer to build as you push it really hard in a corner. This can be switched into very controllable oversteer and ultimately into a very well balanced – and fast – four-wheel drift. The steering is communicative and light, and the narrow front track gives instant turn-in and, of course, a tight turning circle.
The FWE engine is smooth and lusty, and the Ford gearbox complements it perfectly with a very fast change. A high fifth ratio allows cruising at any speed at which one can tolerate the breeze through the slightly draughty doors – Campbell has yet to fit seals. The brakes are tremendously powerful; no servo is fitted or needed to repeatedly pull this very light car down from three-figure speeds without fade.
The whole machine has a delicacy and lightness of touch that some of today’s sports car engineers might do well to emulate. There’s no artificially weighted steering or piped-in engine noise here; the WB120 simply feels taut and agile, without being tiresome.
And so we find ourselves at MIRA. Campbell is very keen to prove Best’s theory that the WB 120 is more slippery than an Elite. ‘I have been waiting a long time to see this test, and my gut feeling says the WB 120 is aerodynamically better – if judged only by its top speed and high-speed acceleration, which I think are better than any standard Elite’s. And, of course, it’s using the same Coventry Climax engine.’
In the wind tunnel, the WB 120 sits on special multi-part scales which measure drag, lift, side-force, yaw, and moments of roll, pitch and yaw. The scales are mounted on a turntable that allows measurements to be taken as though the vehicle is cornering; changes in forces can be considerable at even small angles of attack to the wind. Results are harvested from the scales and also by using a smoke wand to gauge the airflow over particular parts of the car, highlighting areas that can be improved.
The aerodynamic efficiency of any structure is a product of its drag-resistance – Cd – to a measured wind, and its frontal area. The product of drag coefficient and area is represented as CdA, a multiplication of the Cd value by the area. David Wain, MIRA’s full-scale wind-tunnel supervisor, starts the test by photographing the WB 120 from as far away as possible, to avoid the influence of parallax, to accurately measure the frontal area. The WB 120 is then run through several tests at up to 60mph wind speed; the results confirm the excellence of Best’s design with a Cd of 0.33. Multiplied by its frontal area of 1.44, this gives a CdA of 0.475.
A lowered racing Elite run through a wind tunnel in recent times showed a Cd of 0.295 – but it used an estimated frontal area of 1.6 to give a CdA of 0.472, which ‘beats’ the WB 120. However, Campbell’s research turned up an earlier test, when a standard Elite’s frontal area was accurately measured at 1.49. This test gave it a Cd of 0.35, thus a CdA of 0.5215 – 10% less efficient than the WB 120 and so vindicating Best’s design. Cue a delighted Campbell.
While the car is in the wind tunnel, other measurements are taken. The WB 120 exhibits fairly high levels of lift – 176lb at the rear at 60mph – but Wain comments favourably on other aspects of the design. ‘When the car is turned into the wind, it shows a very gradual increase in drag, with no sudden changes that might cause instability in fast turns. The car has an aerofoil shape that doesn’t help downforce, but this is not uncommon in most modern cars. The difference is that a new vehicle will inevitably have spoilers, splitters and so on to mitigate this.’ We can’t resist trying to improve on Best’s design, and so engineering technician Ivan Starkey tapes a 50mm x 20mm-section foam spoiler on to the trailing edge of the rear deck, reducing the Cd to 0.319 and cutting lift considerably; when he adds tape over the front grille, the figure drops to 0.298. Wain says: ‘The rear spoiler alone has changed the whole airflow distribution of the car.’
We then try a front spoiler – with the grille uncovered – that reduces Cd to 0.317 but slightly increases rear lift. Some early photos show the WB 120 with disc wheels and a different grille treatment that may have lowered the Cd, so there may be yet more aerodynamic gains to be made. Campbell is loathe to add visible spoilers.
However, after consultation with David Twohig, chief engineer on the new Alpine sports car, he may fit underbody strakes to retain and accelerate airflow already drawn under the car by the wider rear track. This could help to reduce rear lift. It’s a real testament to the integrity of Dr John Best’s original WB 120 design that, without any testing except for those 120mph-plus blasts up the M1 in 1963, it performs so well in the wind tunnel. Perhaps Colin Chapman should have listened to him a little more carefully…
‘THE WHOLE MACHINE HAS A DELICACY AND LIGHTNESS OF TOUCH THAT SOME OF TODAY’S SPORTS CAR ENGINEERS MIGHT DO WELL TO EMULATE’
Clockwise from below Super-slippery WB 120 bears out calculations of its creator both in the wind tunnel and on the road. Dr John Best (on left) and Bob White in 1965. This page and opposite Modern-day wind-tunnel testing reveals Climax-engined special’s aerodynamic qualities. WB 120’s one-off cabin is surprisingly well appointed.
TECHNICAL DATA FILE SPECIFICATIONS 1963 WB 120
Engine 1216cc inline four-cylinder Coventry Climax FWE, SOHC, twin Weber carburetors
Power 105bhp @ 6400rpm SAE
Torque 92lb ft @ 5500rpm SAE
Transmission Five-speed Ford Type 9 manual, rear-wheel drive
Steering Rack and pinion
Suspension Front: upper and lower equal-length wishbones with coil-over dampers. Rear: upper and lower unequal-length wishbones with coil-over dampers
Brakes Inboard discs front and rear, front mounted on bespoke dummy differential housing, Girling calipers
Top speed 137mph