Comment on historic aviation by the chief executive of the UK’s Light Aircraft Association
It was recently suggested that there are three truly inspiring sounds in the heritage world; a vintage racing car at full chat: a hard-working steam locomotive, and the sound of a Rolls-Royce Merlin at take-off power. I certainly agree, feeling airshows are as much an aural feast as a visual one.
Sadly, the past years have seen one or two of our leading soloists silenced. It is highly unlikely we’ll ever again experience a sustained rendition of the awe-inspiring ‘Vulcan howl’ when all four Rolls-Royce Olympus engines reach full power on a take-off run. The best we might hope for is a second or two of an audio sample at the start of a fast taxi by one of the running survivors, should those examples at Doncaster, Southend or Wellesbourne perform in that way again. Another sound we haven’t heard for a while is the spine-tingling ‘blue note’ emanated by the armed variants of the Hawker Hunter.
The deep howl is apparently specific only to certain marks, either created by inlet duct resonance on Avon 200- powered aircraft and, more frequently, by airflow around the gun ports of the cannonarmed versions. Here’s hoping we might one day be able to savour this sound again, from a suitable Hunter on the British air display circuit.
While not quite the ‘blue note’, you might hear a similar noise from a hardmanoeuvring North American P-51 Mustang. As with the Hunter, the sound comes from the airflow over the guns; connoisseurs tell me it is only created when the aircraft is pulling around 3g or more, as it is the offset airflow that sets up the resonance in the 0.5in Browning machine gun barrels.
The nearest analogy is the old schoolboy trick of blowing across the top of milk bottles to create a similar note.
The rasp of the rotaries fitted to many of Shuttleworth’s WW1 aircraft, combined with the ‘blipping’ of the engines to reduce power, is one of the great noises of a bygone era
At displays this summer, listen out for the contrast between the softer sound of the single-speed, single-stage supercharged Merlins fitted to the early-model Spitfires compared with the later marks, which have a more aggressive exhaust note from their high-compression, two-stage, two-speed supercharged units. Griffon-powered Spitfires, of course, have a different soundtrack again.
Interestingly, the loudest of the Rolls-Royce V12 engines are the earlier Kestrels, which power the Hawker biplanes of the 1930s. Their stub exhausts give out a real crackle, which perfectly complements the beauty and grace of perhaps the most evocative aircraft of the 1930s.
Another sound which sums up the earliest era of flying is the ‘wind in the wires’, created by the airflow through the bracing wires of vintage biplanes. This was a feature from the very earliest days of flight. Perhaps the most suitable place to enjoy it is in the air. If you are fortunate to take a Tiger Moth flight, in its final stages listen out for the whistle when the throttle is closed and the tractor-like bark of the exhaust diminishes to a series of gentle ‘pop-popping’ noises as the aircraft approaches to, one hopes, a perfect three-point arrival.
To experience ‘wind in the wires’ from the ground, one of the best places to go is the series of summer airshows at the Shuttleworth Collection at Old Warden. Perhaps the ultimate example is the Bristol Fighter, which produces a beautiful thrumming tone seemingly in harmony with the low rumble of its Rolls-Royce Falcon engine.
At Shuttleworth, the ‘wind in the wires’ is often combined with another emotive sound: the rasp of the rotary powerplants fitted to many of the World War One aircraft in the collection. That, combined with the distinctive ‘blipping’ of the engines to reduce power, is one of the truly great noises of a bygone era.