Around and about: comment on the racing and club scene, August 1971
Wind tunnel
Little more than ten years ago Peter Jackson was trying to persuade racing car manufacturers to build their car bodies in glass fibre reinforced plastics rather than from the then almost universal aluminium sheet. Since then the British racing car industry has grown enormously, and one of the biggest success stories of all is that of Jackson.
Now he controls a labour force of over fifty from a sumptuous executive suite at his spacious new 21,000 sq. ft. factory on the Huntingdon Industrial Estate. His firm moved there in 1961 from a dingy collection of sheds in South-East London, and since, racing car chassis manufacturers Arch Motors plus car constructors Charles Lucas Engineering and Lola Cars, soon to be joined by Royale, have also moved on to the same estate. It is quite a haven for the racing car enthusiast.
These pages have already related the story of Jackson and his firm, Specialised Mouldings Ltd., but recently a new chapter in the firm’s expanding history was opened when their wind tunnel was commissioned. I was unfortunately unable to attend the opening function, but recently I made a trip to the factory to see just how they were getting on with this exciting venture.
This wind tunnel is the first to be operated as a fully independent commercial unit in Britain. Previously, racing car constructors, and smaller British road car manufacturers, have had to wait until free time was available at University tunnels if they wanted to study the highly complicated art of aerodynamics, of which so little is really known. In fact the SM tunnel may also be of use to civil engineering firms for investigating wind loading on high chimneys, and so on.
The tunnel, which cost £20,000, and undoubtedly would have cost much more had the firm not constructed and designed most of it themselves, is built mainly from glass fibre. The working section is five foot by four foot, and the maximum wind speed is in the region of 100 ft. per second, which is suitable for the majority of subsonic testing. The 70 ft.-long glass fibre tunnel is of the open circuit, closed working section type, whereby the semi-cylindrical corrugated iron building in which the tunnel is housed acts as the return circuit for the air.
An initial problem was that of the air still being turbulent on re-entry into the mouth of the tunnel despite grilles to prevent this, so a ventilated brick wall was just being completed in front of the mouth to eliminate the problem.
Air is sucked through the tunnel by a six-bladed, eight foot diameter fan which is driven by a 1,700-c.c. Volkswagen engine. Both Charles Lucas Engineering and Lola Cars assisted in the design and construction of the transmission which is actually through a VW gearbox. The fan duct, fan, and engine/transmission unit are insulated from the main structure to minimise vibration and noise.
To obtain a simulation of ground effect of a vehicle on the road, a suction grille is positioned in “the road surface” about three car lengths up stream of the model to draw-off the boundary layer down from a thickness of about 2 1/2 in. to 1/4 in.
The heart of the tunnel is the balance installed under the centre of the working section, upon which the quarter-size model is fixed on the four-point mounting, these being the four tyre/ground contact points. The traditional strain-gauged support arm has given way to a complicated six component strain gauge balance to measure drag, lift, side force, pitching force, yaw and roll and is accurate to 0.5%. The forces/moments are computed for digital display on a console in the control room. There were a few minor problems with this complicated bridge, but these have now been ironed out. Pressure measurements and various flow visualisations techniques are also used in the operation of the tunnel.
SM are able to offer manufacturers a package deal whereby they design a body, make a model, test it and finally produce the finished product in quantity, but are quite willing to offer any part of the service separately. One of the first projects has been on the distinctively shaped new Can-Am Lola body, while a road car manufacturer is presently working with the firm.
All this sounds very impressive and exciting, and indeed looks it, but nothing can he done without a man to operate the tunnel and draw conclusions from the result. That very important man is a young aerodynamist by the name of Peter Wright. Aged 25, Wright joined BPM direct from. Cambridge with a mechanical engineering degree and worked closely with Tony Rudd, of whom he has a tremendous admiration, on both chassis design and aerodynamics. He left BRM at the same time as Rudd and joined Specialised Mouldings as the Resident Aerodynamicist. The tunnel has been very much his “baby” ever since, and now he is starting to benefit from its installation.
Wright feels that the tunnel could, in the long term, play an important part in completely altering the shape of racing cars. But he also added that the tunnel will have many other more mundane uses like testing the flow through touring car radiators and so.
Readers will remember that recently we published a series of photographs showing the very different thinking of racing car designers for the nose sections of Formula One cars. While wishing Peter Jackson and Peter Wright every success with their forward thinking and worthwhile venture, let us hope the time will not come when their efforts will completely standardise the racing car body into one ultra-wind cheating shape.
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•Following the success of the Rally team run in Scandinavia by the GM Dealers’ Association, the British Vauxhall Dealers have formed together to run a racing and rally team. The nucleus of the teams formerly run by Bill Blydenstein in racing and Coburn Improvements in rallying will be retained and expanded. Over 1,000 Vauxhall dealers have contributed to this racing and rallying programme which will initially include two Vivas in both racing and rallying, first at club level and later in Internationals. Later Vauxhall Firenzas will be used and all the cars will compete under the title Dealers’ Team-Vauxhall. Gerry Marshall, who has done great things for Vauxhall with the Shaw & Kilburn Viva GT, will lead the racing team and other drivers will have been appointed before the team makes its debut late in July.
•Silverstone Circuits Ltd. have failed to come to an agreement with the Nottingham Sports Car Club regarding the club running their very successful club meetings at the track after the end of 1971. Thus it has been announced that Silverstone has invited its own parent body, the British Racing Drivers’ Club, to undertake the organisation of Bank Holiday and certain other meetings from the beginning of 1972 onwards. Commenting upon the arrangement BRDC Secretary Anthony Salmon said “I welcome the opportunity for BRDC to become directly associated with the organisation of races catering particularly for the up and coming driver of tomorrow.”
Meanwhile it is possible that the Notts Sports Car Club are banking on Torn Wheatcroft having the Donington circuit, in some form, ready for next season and will swop their meetings to this exciting venue. Silverstone have also announced special arrangements for organising clubs wishing to run purely amateur meetings at the circuit. From next year a club can have the use of the circuit free of charge providing the club undertakes that the meeting will not be given a commercial name and that no outside sponsorship will be received.
•Motor racing sponsorship seems to be catching on in a big way with more and more companies who have previously had no motor sporting connections tieing themselves to a racing team. In the last month the nasal decongestent people Contac 400 have announced a strong backing of the Ensign F3 driven by Steve Thompson (see last month’s “They Make Racing Cars”) while the Cona coffee firm has also announced sponsorship of the little one-off Rawlson sports racer driven by a chap called Mike Yeomans. Another press release tells us that a firm called Crookes Anestan Ltd., are particularly happy with their sponsorship of a lady racing driver, Alison Davis, who drives a Ginetta G15. The product?—Femfresh!