Detuner (engine)

The first Cullum Detuner Mark IV c. 1944

Cullum Mark V Detuner

Detuner is a generic term for a jet engine test cell exhaust system.

A silencer for the “supercharger” is how the detuner was developed. The supercharger was the code name for the jet engine being pioneered by Sir Frank Whittle and his team at power jets at Lutterworth in Leicestershire. In 1942, the prototype ‘detuner’ was produced and early in 1943, installed in a jet test bed at the de Havilland Engine Company in Hatfield; this ‘Jet Engine Test Cell Exhaust Silencer’ was possibly the first in the world to be used during the testing of jet engines. This silencer became known throughout the world as the Cullum Detuner.

This type of Detuner was a straight through silencer, a simple acoustic tube. A later version consisted of four acoustic sections with a plain entry section inside the test cell - flanged and bolted together, mounted on wheels, installed on rails to permit fore and aft movement. Each acoustic section consisted of an inner and outer casing, the outer casing was plain mild steel plate and the inner casing was perforated mild steel plate. The cavity between inner lining and outer casing was tightly packed with an acoustic absorbent material known as rock (mineral) wool.

Modified versions of the prototype detuner were installed on the Rolls-Royce jet engine test beds at Clitheroe in Lancashire, Barnoldswick in Yorkshire and Derby, Derbyshire where the jet engine continued being developed.

Detuners at Rolls-Royce, Derby

Inevitably the development of the Cullum Detuner was inextricably associated to the development of the jet engine. As the power of the engines increased, the Detuner had to be developed to cope with larger and more powerful engines.

BOAC Boeing 707 at London Airport circa 1960

Eurofighter Typhoon Hush House Facility with an air cooled exhaust Detuner

Since the pioneering days Cullum Detuners Limited has been a leading supplier of noise control equipment to the aerospace industry from manufacturing and installing their first commercially ordered Detuner for the de Havilland Engine Company in 1943, to completing the largest Advanced Test Cell facility in the world for Rolls-Royce, Derby.

Rolls-Royce Test Facility, Derby

References

• Dousing the Decibels’ Flight Magazine- 5th September 1952

• Jest Test Bed Silencing’ The Aeroplane - 12th December 1952. Printed by Temple Press London

• Silencing the Swift’ Flight Magazine - 8th October 1954

• Silencing Pens for Jet Aircraft’ The Engineer, Volume 198 October 8th 1954

• Keeping the big Jets quiet’ BOAC News - 10th June 1960

• Noise Testing at London Airport’ The Times - Thursday 16th June 1960

• The Control of Noise’ Dr B Wheeler Robinson, New Scientist 29th June 1961

• How do you Silence a hi-tech jet engine capable of 160,00 pounds of thrust?’ Article by Oliver Astley Derby Evening Telegraph Tuesday July 8th 2008