Bringing the Glory back to Goodwood
A Spitfire hurtled low over the straight, the crackling roar of it's 12 cylinder Merlin momentarily drowning the engines of the powerful racing cars below.
Those cars - ex-works Jaguars, Aston Martins, Ferraris and BRM's in a parade lead by Lord March at the wheel of a Bristol, were gathered at a great celebration to mark the revival of Goodwood motor racing circuit.
Lord March drove the very same Bristol, used by his grandfather on the day 50 years before when Goodwood first opened. That was the day the 19-year-old Stirling Moss won his first race. Moss and other names from legend such as Roy Salvadori, Innes Ireland, Jim Clark and Graham Hill raced regularly at Goodwood throughout the 40's and 50's. Now the Goodwood estate headed by Lord March has invested several million pounds in reviving the famous circuit - providing modern racing conditions behind a facade virtually indistinguishable from the 1948 original.
Needless to say noise has been a major issue, with Goodwood being required by the Local Authority to minimise environmental impact and to devise - with the aid of AAD - a sophisticated system to monitor noise conditions at the site on a round-the-clock basis. So sophisticated is that system - Goodwood is now the most closely noise-monitored motor racing circuit in the world - excess noise can be immediately detected and action taken. There's a steep learning curve being negotiated, but the Local Authority and Goodwood are working in close liason, developing essential familiarity with the new technology.
Noise and motor racing go together like Christmas and cold weather. The Goodwood circuit closed to racing in the mid 60's, partly because it was difficult to meet the safety requirements of faster and faster cars requiring larger run off areas and partly because of a noise notice served by Chichester Council limiting use of the circuit to only five vehicles at any one time.
The circuit passed into a twilight period, being used only for testing and sprinting, which requires just five cars on the track. Lord March, however, was determined to revive the circuit and launched an ambitious program to achieve that objective. Safety has been greatly improved and pits and paddock house modern facilities, while remaining visually as close as possible to the original. Large earth banks have been erected at critical sectors of the circuit to minimise noise breakout and to provide additional spectator viewpoints - grandstands are erected for racing days on a need-to-see basis.
To achieve planning consent and lift the noise notice over 100 separate issues had to be considered, not least being the installation of the permanent noise monitoring system to local authority requirements.
AAD were engaged as consultants for this phase of the project, bringing to the professional team unrivalled experience in the monitoring of noise from cars and aircraft and the type of acoustic issues affecting motor racing circuits.
AAD's basic brief was to design a noise monitoring system that never sleeps. To fully appreciate the sophistication of the technology, however, one must understand the ways in which the newly revived Goodwood circuit will be used.
On five days a year the circuit can be used with no noise limit giving an opportunity for racing the great cars of yesteryear - eleven Ferrari GTO's on one grid are not unknown!
For a further 90 days the circuit is designated for use as "Goodwood Days" with a maximum of five cars on the circuit and a maximum drive-by of 101dBA and an 82dBA half hour Leq.
Second noise limit affects "Road Traffic Days" - a period of 170 days in which a maximum of 10 cars can be used (normally in road going trim). Maximum drive-by limit for these occasions is 96dBA with a 78dBA half hour Leq. To ensure that these conditions are observed, AAD developed a purpose-designed system based on three noise measuring stations located 10 metres from the sideline of the track at the Chicane, Madgwick and St. Mary's locations.
These three stations, specified, designed, built, tested and installed by AAD transmit noise data in digital form to a central processing unit with purpose written software located in the pit lane. No cables were required - all three microphone stations transmit data by radio waves.
Special software algorithms - developed by AAD engineers and proven on the basis of digital recordings of drive-by noise measurements made on site long before the circuit re-opened - compiles the information at high speed. At any one moment the circuit manager has access to dBA Leq for last 5 minutes and "previous half hour" intervals, plus a "predicted half hour" dBA Leq with two levels of visual on-screen warning if the latter is likely to approach, or exceed the preset limits.
Armed with this information the circuit manager can simply pull any noisy cars off the track. Precautions are taken, however, to ensure that excessively noisy vehicles never turn a wheel in anger. Every car and bike is subject to a static noise test before it can be taken on to the circuit. Measurements are conducted at 0.5m from the exhaust outlet for reference against the pre-set limits which are 98 dBA at 3/4 max. rpm for Road Traffic Days, 105 dBA at 3/4 max. rpm on Goodwood Days.
Modem links have been established to mobile computers supplied by AAD to Chichester District Council, giving them both real time and stored data access to noise conditions at the Goodwood circuit.
All the features of the system - which includes automatically triggered digital tape recorders to prove that noise from 'planes using the nearby airstrip is aeronautical and not automotive - were presented to both local authority and Goodwood circuit staff at a special training seminar held by AAD's own Dr. Bob Peters.
Some readers will already have calculated that five limitless days plus 90 Goodwood days and 170 Road Traffic days adds up to only 265. As for the other 100 days a year, in the words of Hamlet "the rest is silence".