Why the turbine Lotus experiment failed to realise its potential in F1

All in all, 1971 was a strange year for Team Lotus. It should have been all champagne and silverware given its potent cocktail: the great Lotus 72, not only arguably Colin Chapman’s greatest Formula 1 car but a contender for the best from anyone, ever; young, ambitious Emerson Fittipaldi, already a winner following his astounding maiden-season breakthrough at just the fourth time of asking at Watkins Glen, 1970; financial security through its continuing (gaudy) support from Gold Leaf tobacco.

Yet instead, the result was the first winless season for Lotus since 1959. So was this car, the whooshing turbine-powered Lotus 56B, to blame for the alarming and unexpected drought? No, that’s too trite.

Even Fittipaldi has dismissed the notion Chapman’s most ‘out-there’ innovation was a distraction. The problem, as is usually the way in Formula 1, was multi-faceted.

First, it didn’t help that Fittipaldi was derailed by a mid-season road accident – all in the wake of Jochen Rindt’s terrible demise at Monza the year before that led to his ghoulish epitaph as F1’s only posthumous champion. Meanwhile, the 72 – which had swept Team Lotus to its fourth constructors’ world championship in the wedge-shaped model’s maiden season – was briefly thrown off course by a fundamental F1 development: the introduction of slick tyres.

Unprecedented levels of grip shone an unforgiving light on the 72’s too-flexible suspension. Chapman’s chief designer, Maurice Phillippe, was forced into a redesign and by the time the 72 was back on track the season was more or less over.

As for the 56B, Fittipaldi’s view on the car has mellowed. The two-time world champion and double Indianapolis 500 winner once described it as the worst he ever drove, yet he’s also adamant it’s worthy of respect, beyond its status as a beacon for Chapman’s always restless trademark desire for discovering the next big thing. “Potentially it could have
been a winner,” Fittipaldi asserts.

The distinctive Lotus 56B, originally conceived for Indycar racing, had a short-lived F1 career in 1971

Photo by: James Mann

Unique in F1 terms, it looks astonishing today and must have appeared like something from another planet when it was new. A remarkable feat of engineering, nevertheless in sporting terms it’s a mere footnote in the Lotus and F1 story – a car that started just three world championship grands prix, each with a different driver.

So why the B in 56B? Because first there was simply the 56, and it was designed solely to win the Indy 500. We can’t think of too many other grand prix cars derived from an IndyCar rather than the other way round.

The story of turbine power dates back as far as the mid-1950s. Experiments were undertaken for Firestone tyre tests with a Boeing 502 turbine-powered Kurtis Kraft roadster in 1955, and a year later Boeing engineer Len Williams made such a convincing case on how a turbine car could out-drag conventional Offenhauser power out of the corners that John Zink commissioned a turbine car for the 1961 Indy 500.

Regulators always frowned on turbines, which is what ultimately made this power source a cul-de-sac at both Indy and later in F1

‘Trackburner’ was delayed until 1962, then fell 1mph short of qualifying, driven by Dan Gurney. Andy Granatelli, charismatic businessman, chief of the STP fuel additive company and an Indy 500 addict, took note.

The turbine headaches revolved around wheelspin and throttle lag, both getting on the gas and coming off it. In terms of wheelspin, two-wheel drive with hard, narrow tyres was tough to overcome – which is why Granatelli’s shift towards four-wheel drive changed the game.

Stirling Moss sparked the revolution, with tales of his all-wheel driven Ferguson P99 in which he’d won the non-championship 1961 Oulton Park Gold Cup – itself a unique feat in F1. At first 4WD was a wheelspin solution for Granatelli’s Novi V8 power.

The subsequent Ferguson-built P104 Novi V8s ran at Indy between 1964 and 1967, by which time Granatelli had latched on to turbines. And he came a $6 gearbox bearing failure away from winning racing’s biggest prize with one.

Parnelli Jones had come close to winning the 1967 Indianapolis 500 with a turbine, demonstrating to Champan the benefits of pursuing its novel approach

Photo by: LAT Photographic

The STP Paxton turbo car was the Lotus 56’s forerunner. Designed by Englishman Ken Wallis and built by Granatelli’s brothers Joe and Vince in Santa Monica, California, it was powered by a Pratt & Whitney ST-6 industrial version of the PT-6 turbine built by United Aircraft of Canada. The ST6B-62, as it was dubbed, delivered 550bhp at 6230rpm, although power reduced as air temperatures rose.

At five feet long, yet weighing in at only 260lb bare, the turbine required a novel side-mounted installation. Too late for 1966, the Paxton was an odd-looking contraption – but it proved its worth in the summer of love. Parnelli Jones led most of the race in 1967, until the infuriating gearbox bearing failed barely 10 miles short of the chequered flag. Still, Chapman was inspired and, encouraged by Granatelli, waded in with the Lotus 56.

But the regulators always frowned on turbines, which is what ultimately made this power source a cul-de-sac at both Indy and later in F1. In Indianapolis, the USAC rules committee had been spooked early on by another turbine racer, the Jack Adams Aircraft Special, featuring a GE T58 engine fitted in the nose of a 1961 Watson roadster.

It had 1350bhp on acceleration, hit 200mph and handled terribly
(if at all). That led the rules committee to limit turbine power to around 600bhp, among other restrictions. It didn’t stop
the Paxton’s Indy near-miss in low temperatures in 1967, so USAC took further action to limit the whoosh factor. Granatelli took legal action – and lost. But by now
Chapman had the bit between his teeth.

The regulatory skirmishes didn’t diminish the Lotus 56’s potency, at least in 1968. Culled of ultimate power, it represented a victory (of sorts) for chassis handling. Maxed out on top speed along Indy’s main straightaways, Chapman and his ally Phillippe understood their turbine racer’s speed through the turns could make all the difference. Just as well.

Once United Aircraft had responded to USAC’s measures, by removing two of the engine’s three axial compressor stages preceding the main centrifugal compressor, power had been reduced to 490bhp – compared with the 600-700bhp of the turbocharged Drake-Offenhauser 2.8-litre engines. The key now was to ensure the 56 cut through the air – and stuck itself to the track. That’s where the wedge shape concept came from, which Phillippe then adopted for his epochal 72.

Lotus was already grappling with an uncomfortable reality that its cars sat lowest when they were stationary, thanks to aerodynamic lift. The wedge shape was designed to compress the car into the road. Sitting beside the ungainly Paxton, the 56 looked ultra-modern, imposing, sleek – and fast.

Now the Pratt & Whitney turbine was slung out back in conventional fashion rather than tagged on the side. Given the dimensions of the turbine, that made the Type 56 long – 14ft 2in from nose to tail compared with the 12ft 6in of Jim Clark’s 1965 Indy-winning 38. Never mind. Extra body length just increased scope to chase the new elixir: downforce.

The Lotus 56 IndyCar was given its first public outing in 1968, to astonishment of contemporary journalists

Photo by: David Phipps

The monocoque hull was formed around a large, low and light 16-gauge aluminium-sheet tub, with initially kerosene fuel cells fitted within the side pontoons – although gasoline was found to improve throttle response. A box structure at the front housed the steering, front-drive cross shaft, brakes and suspension, while at the rear a massive fabricated bridge arched over the rear drive unit and oil tanks.

The car featured identical suspension members all round, with fabricated double wishbones actuating inboard coil/damper units by top cantilever arms. The brakes were massive: 10¼in diameter Girling ventilated discs which were 1¼in thick, the calipers clasping from underneath in a bid to keep the centre of gravity as low as possible.

Power was delivered to each wheel through Lotus-Ferguson half-shafts, then transmitted through same-sized tyres developed specially by Firestone. The Ferguson centre differential, located offset to the left, originally promised a symmetrical 50/50 torque split until it was decided a 45/55 bias to the rear was preferrable. Steel torsion shafts fed ZF spiral-bevel final drives at both ends. The car weighed in at 1350lbs – 400 less than the Paxton. Very Lotus.

Turbine power had come a hair’s breadth from Indy glory, not once but twice in successive years. Could the concept be adapted to work on road courses, and for F1?

The Type 56 was launched to general astonishment at Hethel with a demo by Graham Hill in mid-April 1968 – by which time Lotus’s world had been turned on its head by Clark’s shocking death at Hockenheim on 7 April. The Scot had been due to race a 56 beside Hill, and now intriguingly Jackie Stewart was listed to take his place.

Stewart in a Lotus? A wrist injury sustained in a Formula 2 crash in Spain scotched that possibility. A narrow escape, as it turned out. Instead, Mike Spence, who’d driven for Team Lotus in F1 as team-mate to Clark in 1964-65, took the drive.

Back in March the car’s initial tests had resulted in modest speeds limited to 161mph, which would have missed the qualifying cut for the 1967 race. But come May Spence began to find his groove. On 3 May, Parnelli Jones rejected a repeat campaign in the Paxton which, thanks to USAC, was now deemed uncompetitive. On the same day Spence lapped at 164.239mph. Progress. Four days later, on 7 May, he was up to 169mph consistently, with a best lap at 169.555mph.

Then late in the afternoon Spence was called upon to shake down the 56 entered by Granatelli for Greg Weld. Running high on to some dust at Turn 1, Spence attempted to kiss the wall at a mild angle. The Lotus struck almost broadside, lost its right-side wheels and sustained very little damage to its hull. But the front wheel hurtled back and hit Spence directly on the head. He died four and a half hours later in hospital without having regained consciousness.

An injury for Stewart forced him to withdraw from the 1968 Indy 500, and Spence took his place with tragic consequences

Photo by: LAT Photographic

It was all too much for Chapman. “I am filled with grief at the loss of my long-time friend and associate Jimmy Clark, and the additional loss, just a month later to the day, of Mike Spence,” he announced. “As an understandable result I want nothing more to do with the 1968 Indianapolis race. I just do not have the heart for it.”

Granatelli pressed on regardless. Weld was stood down, while Hill was joined by Joe Leonard and Art Pollard to maintain a three-car campaign. The 56 set a record pace through the turns and Indy’s short chutes, even if it ran out
of power on the main straightaways. Leonard secured pole
at 171.559mph (compared with 168mph for Mario Andretti
a year earlier), with Hill second and Pollard on row four.

But in the race there was more near-miss heartbreak for Granatelli. Hill lost a wheel and crashed out, but Leonard appeared destined for victory – until lap 192 of 200.

Following a yellow flag, both Pollard and Leonard slowed with identical snapped fuel pump driveshafts. Lotus had made them from steel, but Pratt & Whitney – angered by the change – insisted Granatelli switched back to the phosphor-bronze shafts used in the aircraft industry. They were claimed to be fail-safe.

Indy’s turbine adventures were at an end. Hostile to the whooshing threat, the National Championship Car Owners Association petitioned USAC for further turbine limitations and more restrictions were pushed through for 1969, then for 1970 both 4WD and gas turbines not made purely for automobile use were banned in all USAC competition.

Still, Chapman kept the faith. Turbine power had come a hair’s breadth from Indy glory, not once but twice in successive years. Could the concept be adapted to work on road courses, and for F1? The thought took hold when Hill turned a rapid pace in a Type 56 in a post-Indy 1968 USAC round at Mosport.

The problem was slowing for tight corners and then overcoming throttle lag on exits. The turbine required a disconcerting style of maintaining a consistent throttle even through the turns, hence the need for those mighty brakes – and a huge brake pedal. Chapman – a dog with a bone, as usual – commissioned Pratt & Whitney to produce a 3-litre equivalent of its Indy turbine to fit F1.

For a US company with no interest in European racing, it was never a priority, hence the delay before the Type 56B was eventually wheeled out. To Chapman’s delight, the engine was ready by the end of 1970.

Pratt & Whitney produced a three-litre version of its gas turbine engine to fit the 56B for the 1971 season

Photo by: Rainer W. Schlegelmilch / Motorsport Images

The first turbine F1 car made its debut in Fittipaldi’s hands at the non-championship Brands Hatch Race of Champions in the spring of 1971, while Reine Wisell and Dave Walker gave 56B further outings at the British and Dutch Grands Prix. The turbine’s whistle and whine was a novelty among the shrieks of Cosworth DFVs and V12s, but after Monza – where the car ran in a striking gold and black livery in the hands of Fittipaldi, the experiment ran out of gas.

“The turbine was another of Colin’s incredible projects,” says Fittipaldi today. Although more than half a century ago his initial excitement at the sight of the thing quickly turned to fear on first contact at Hethel.

John Miles, respected for his test and development capabilities, had headed out first in freezing conditions, with Fittipaldi entranced to hear tyre scrub over engine noise. Then Miles lost the brakes heading for the hairpin, went straight over the fence and into the fields beyond. Upon his return, a pale Miles wished Emmo the best of luck with his run.

"You had to calculate looking into the corner when to put the power on. But yes, if we had continued the development it could have worked"
Emerson Fittipaldi

“It had these huge brakes, calipers and pads, because the engine always continued, unlike a conventional engine,” says Fittipaldi. “I had to brake the car and the engine. When the power came, big acceleration.

“The problem was working with the throttle delay on the turbine. I had to hold the brake and power against each other because there was this delay on the turbine. That was the most difficult thing and it took some time.

“We always tried to cut the injection of fuel. The delay in the beginning was a second and a half, two seconds. You had to calculate looking into the corner when to put the power on. But yes, if we had continued the development it could have worked.”

Fittipaldi felt that potential first time out at the Race of Champions, although in the race it bottomed out badly at Brands and that broke the rear suspension. Wisell ran as high as fifth at Oulton Park for the Gold Cup, before a tyre burst and damaged the suspension again.

Fittipaldi was back in the 56B for the International Trophy and qualified on the front row at flat-out Silverstone, but again suffered suspension trouble early in the first heat. Still, it finished third in the second.

Rear suspension failure spelt the end of Fittipaldi's Race of Champions hopes, on the turbine's debut in 1971

Photo by: LAT Photographic

Walker was entered for the Rindt Memorial at Hockenheim in June. High inter-turbine temperatures at Silverstone had led to an engine rebuild back in Canada, but during practice at the German circuit it broke up and Walker’s entry was scratched.

A replacement was sourced for the Dutch GP and at Zandvoort Walker was up to 10th from the back of the grid when he lost the car on the brakes at Tarzan. Wisell was in for the British GP, but 56B lost power and he was unclassified.

At the end of the summer Lotus wheeled its turbine racer back out for the other flat chat GP, at Monza. Fittipaldi was back in, under an entry named World Wide Racing in the wake of Italian legal ramifications a year on from Rindt’s death. Ambient temperatures proved too high for the turbine to produce peak power, but Emmo brought it home eighth.

The new gold and black colour scheme was a sign of things to come. “The gold colour was a test for John Player Special,” explains Fittipaldi. “They didn’t know if it was going to be black or gold. But gold didn’t look good on TV so they decided to go black.” One of F1’s most evocative liveries, JPS black and gold would adorn the Type 72s from 1972.

Type 56B signed off back at Hockenheim at the Preis der Nationen Formula 5000 race a week later. Fittipaldi stuck it on the front row and finished second after setting fastest
lap.

“I raced it at Hockenheim against the F5000s and I
was leading the race,” he recalls. “It was really good. We
knew it had potential. Colin injected more fuel into the turbine, it was giving a lot of fire behind my head… When
I put the power down, big flames.”

But that was it for turbine power. F1 followed USAC’s lead and banned it. At Team Lotus, full focus was trained on the 72 and something of a fresh start for the next season, when Fittipaldi was crowned as the then-youngest world champion. The whoosh had been silenced. But for those who saw 56B race, it will never be forgotten.

F1 banned turbines after Fittipaldi's appearance at the 1971 Italian GP in the 56B with a striking Gold Leaf livery

Photo by: Rainer W. Schlegelmilch / Motorsport Images

Race record

Starts: 3
Wins: 0
Podiums: 0
Pole positions: 0
Fastest laps: 0
Championship points: 0

Specification

Chassis: Aluminium monocoque
Suspension: Double wishbones with inboard coil springs/dampers
Engine: Pratt & Whitney STN76 gas turbine
Power: 500bhp
Gearbox: Manual single-speed direct drive, four-wheel drive
Brakes: Steel discs
Tyres: Firestone
Weight: 600kg
Notable drivers: Emerson Fittipaldi, Reine Wisell, Dave Walker

The 56B is today regarded as a footnote in the Lotus F1 story

Photo by: James Mann