The Brabham BT46B – higher often called the fan automotive – solely raced as soon as in Method 1. However it made a profound influence and is well known to today as a beacon of technical ingenuity.
Most F1 followers know the fundamental story of Gordon Murray’s automotive, which received the 1978 Swedish Grand Prix within the palms of Niki Lauda on its sole racing look. As a solution to the ground-effect innovation of Workforce Lotus, a fan hooked up to the rear of the Brabham created an identical impact by sucking air out from the underfloor of the automotive, pulling it nearer to the bottom with the facet skirts sealing the perimeters of the ground.
However there’s much more to the story than that, in addition to some legends about it that are not fairly correct. So we now have picked out some information in regards to the fan automotive that you could be not have recognized.
Alfa Romeo made the fan automotive essential
Workforce Lotus first ran a floor impact automotive in 1977, however it wasn’t till 1978 and the Lotus 79 that everyone realized the potential of such ideas. It triggered a rush for rivals to create their very own floor impact designs.
However Brabham had an issue. Its automotive was powered by the chunky Flat 12 Alfa Romeo ‘boxer’ engine. The structure meant any try to create typical floor impact venturi tunnels was basically compromised – primarily due to the cylinder heads being in the way in which. This led to the consideration of a twin-chassis design, which proved too heavy, after which the concept of the fan automotive.
“Gordon Murray was and is a really high-quality technician,” mentioned Alfa Romeo engine boss Carlo Chiti.
“Because it was not possible to create a floor impact car due to the boxer engine, he produced the concept of posterior air flow, which assured the identical bodily benefits because the Lotus, fitted with its skirt.”
The fan was hidden with dustbin lids
Whereas information acquired out in regards to the fan automotive lengthy earlier than it appeared, Brabham had performed its testing in personal at Manufacturers Hatch and Alfa Romeo’s Balocco proving floor and wished to maintain particulars of its design hidden even at Anderstorp. The end result was the followers had been coated.
However whereas right this moment’s groups would manufacture their very own custom-fitted shroud, Brabham’s mechanics discovered a a lot less complicated resolution and located dustbin lids that occurred to suit completely over the fan.
It prices round 30bhp
The fan was not pushed by its personal motor, in contrast to the Chaparral 2J ‘sucker automotive’ of 1970 that pioneered the fan automotive idea in racing in Can-Am. As an alternative, by an advanced system that related the fan to the decrease shaft of the gearbox and included a minimum of 4 clutches, it was powered by the Alfa Romeo engine.
That meant round 30 brake horsepower went to the fan relatively than to the wheels.
However that was a suitable trade-off as a result of the downforce and corner-speed achieve had been price considerably extra lap time.
The fan actually was primarily for cooling…kind of
Whereas the fan was clearly to create downforce by sucking air from the underfloor, which was sealed by the facet skirts, this might not be its major function in keeping with the principles. That is due to the way in which the rules had been worded.
In a change for 1978, the rule banning moveable aerodynamic gadgets, included a caveat. This acknowledged that moveable aerodynamic gadgets had been permitted if their major function was not aerodynamic.
There have been two results of the fan on the Brabham. One was to assist to suck the automotive to the bottom, however the different was to extend the effectivity of the water radiator mounted horizontally on the highest of the Alfa Romeo engine.
To fulfill the rules, all Brabham wanted to do was present that greater than 50% of the impact was cooling.
As anticipated, 5 groups launched protests even earlier than the race began in Sweden – Williams, McLaren, Lotus, Tyrrell and Surtees. The premise for these protests involved not solely the first operate but additionally whether or not the skirts weren’t fitted solely to the sprung a part of the automotive because the rules demanded.
The Fee Sportive Internationale had dominated the automotive legally earlier than the occasion and did so once more in face of this protest, discovering that the skirts had been mounted to the sprung a part of the bodywork. And, crucially for the fan, the first operate was cooling despite the fact that the aerodynamic impact was recognised.
Measurements obtained when the CSI visited Brabham’s headquarters established that greater than 55% of the facility of the fan was for cooling.
Though clearly, Brabham’s major motivation for introducing the fan was aerodynamic, a part of the genius of the automotive was producing it in a means that glad this regulation by the way in which it impacted the cooling.
It included tank elements
The fan itself options seven blades and requires an unlimited quantity of labor to get proper. Initially, the hope was that the automotive could be prepared for the Monaco Grand Prix in early Could relatively than for Sweden six weeks later. A thermodynamics specialist, David Cox, was engaged to work on the traits of the fan.
The fan elements themselves initially got here from a tank. Initially plastic, then glassfibre-reinforced nylon, these needed to be beefed up considerably with solid magnesium blades.
As Gordon Murray explains within the wonderful e book – One Method, 50 Years of Automotive Design – the hub of the fan was additionally reproduced on the final minute in stable aluminum following one other catastrophic failure.
“In the course of the first take a look at, we had a catastrophic fan failure and tried totally different supplies, which appeared to work,” mentioned Murray. “However with simply weeks to go, we had one other fan-blade failure, so I had them solid in magnesium, which made them considerably heavier.
“With only one week to go earlier than Sweden, we had one other catastrophic fan hub failure. I had simply sufficient time to machine two hubs from stable aluminum and the ultimate meeting went off to Sweden untested.”
However regardless of the dearth of testing of the ultimate model of the fan, it proved dependable sufficient for Lauda to win at Anderstorp.
Lauda and Watson certified on full tanks
Brabham drivers Niki Lauda and John Watson had been below strict directions to not reveal simply how sturdy the fan automotive was. That included being warned about how a lot they revved the engine within the pits given it visibly sucked the automotive to the bottom.
However it additionally meant that, on the directions of Brabham crew proprietor Bernie Ecclestone, they ran on a heavy gas load in qualifying to ballast what Niki Lauda known as ‘the vacuum cleaner’ in his well-known e book, To Hell and Again.
“The vacuum-cleaner was prepared in time for the Swedish Grand Prix in Anderstorp, and our greatest fear was giving the sport away by demonstrating its plain superiority,’ mentioned Lauda.
“John Watson and I drove the qualifying laps with full tanks and did our degree greatest to keep away from pole place.”
That explains why Mario Andretti took pole place for Lotus with a bonus of round seven-tenths of a second over the 2 Brabhams, with Watson qualifying second forward of Lauda.
Within the race, Lauda mentioned he “performed cat and mouse” with Andretti earlier than overtaking him simply and profitable with what he known as “embarrassing ease”.
It wasn’t banned in 1978
It is usually mentioned that the fan automotive was banned after its one and solely race, however this is not strictly true despite the fact that Brabham withdrew it from competitors.
The CSI evaluation of the automotive concluded that it was authorized in keeping with the rules, with the wording adjustments solely coming in for 1979. And whereas the CSI tried to border it as a ban, there was extra to the story.
Brabham crew proprietor Bernie Ecclestone understood that his place inside FOCA – the Method One Constructors’ Affiliation that he headed and that was the inspiration of his rising energy in F1 – was compromised by the fan automotive’s dominant efficiency and the potential value implications of rivals being closely beat and having to reply.
So he was persuaded to drop it, creating what might be offered as a ban for the remainder of 1978 despite the fact that the automotive remained authorized for the remainder of the yr.
There was a second fan automotive design
The Brabham BT46B was solely Gordon Murray’s first try at a fan automotive. It was successfully a lower and shut job, adapting the prevailing BT46 to take advantage of the idea.
However Murray was already engaged on a bespoke fan automotive, the Brabham BT47. That automotive by no means speeded, in actual fact it was by no means constructed, given the rule adjustments that outlawed such designs for 1979.
There have been two key adjustments within the nascent design. Firstly, the pace of the fan can be variable, as Murray explains within the e book One Method 50 Years of Automotive Design.
“We had been taking a look at a variable-pitch fan that was pushed by automotive pace and on the straight they might feather, principally, and the automotive would not get sizzling sufficient with decreased cooling in that brief time,” mentioned Murray. “Then, once we acquired to a nook, the fan would come again on once more. The automotive was far more boxy, so for a similar suction, we’d have had much more downforce.”
This could enable it to generate floor impact downforce within the corners however not sap a lot energy on the straights. Secondly, the world of the underfloor was elevated to maximise downforce.
As an alternative, Murray penned the Brabham BT48. Unreliable and compromised by the chunky Alfa Romeo engine regardless of Chiti producing a brand new V12, Brabham managed solely eighth within the constructors’ championship.
The fan automotive competed twice
Whereas the fan automotive solely raced as soon as, it did additionally compete in a time trial occasion at Donington Park on June the third 1978. This was truly the aggressive debut for the automotive.
It was one among simply 5 vehicles entered for the non-championship Gunnar Nilsson Memorial Trophy. That wasn’t sufficient for a race, however the vehicles ran in what was successfully a glorified qualifying session.
Nelson Piquet drove the automotive and completed fourth in an occasion received by Williams driver Alan Jones. James Hunt (Wolf), Mario Andretti (Lotus) and Rupert Keegan (Arrows) had been the opposite rivals.
The Brabham BT46B fan automotive stays some of the exceptional vehicles in F1 historical past, with Murray’s genius permitting a sublime resolution to the issue posed by the success of the Lotus 79 and the restrictions he needed to work inside to reply.