Preserving Britain's flying history

Citation

(1998), "Preserving Britain's flying history", Aircraft Engineering and Aerospace Technology, Vol. 70 No. 1. https://doi.org/10.1108/aeat.1998.12770aaf.002

Preserving Britain's flying history

Preserving Britain's flying history

With each year that goes by, our wet British climate causes corrosion which destroys a little more of the aircraft in the Imperial War Museum's collection at Duxford, in Cambridgeshire. Each time a piece of corroded metal or perished rubber has to be replaced, the historical integrity of that aircraft is reduced.

Duxford and Munters devised an aggressive campaign to combat this effect by working together to create a drier environment. Moisture is the enemy, but now Munters desiccant dehumidifiers installed in one of the hangars are keeping relative humidity at a controlled level, ensuring that condensation and therefore corrosion is eliminated which means the need to replace corroded parts will be a very rare occurrence in the future.

Nearly half a million people a year visit Duxford, which was at one time a Battle of Britain fighter station and later, during the Second World War, a US Army Air Force base. Today it houses, amongst other military equipment, 140 historic aircraft. There are Spitfires and Mustangs, which still fly regularly, and the fabric-covered Bristol fighter. Concorde is here, along with the U-2 spy plane that flew on the edge of space.

They are all susceptible to the ravages of time, which is why two MXT9000 dehumidifiers have been installed in Hangar 4, to preserve the Museum's collection of restored aircraft for the next millennium.

Duxford's conservation manager, Chris Chippington, explained: "Corrosion of metal is our biggest problem, but non-metallics such as rubber seals also degrade, so we now keep the aircraft in a controlled environment. The alternative would be a programme of constant inspection and replacement of damaged parts, but over time that would mean the loss of the collection's historical integrity."

The two Munters dehumidifiers, each capable of drying 9,000m³ of air per hour, extract moisture from the air by passing it through a slowly revolving wheel which has been coated with a desiccant material. As part of the process, one segment of wheel is periodically heated to drive off the accumulated moisture. At Duxford, the Munters desiccant dehumidifiers also incorporate a heat recovery system which has been installed to enable some of that heat to be used to regenerate the wheel, in line with the museum's energy conservation policy.

Additional efficiencies are gained by the use of humidity sensors that constantly monitor the relative humidity and modulate the reactivation energy to offer more or less drying, as and when it is needed. In this way, no power is wasted and the relative humidity is kept at 50 per cent or less which is below the level at which metals start to corrode and most other materials start to degrade.

The engineers at Duxford are no strangers to Munters dehumidifiers. Smaller units are already installed in some of the aircraft that are kept out of doors, to prevent moisture building up in the interiors. All of which is helping to preserve a piece of British heritage which Chris Chippington describes, succinctly, as: "Unique, priceless, irreplaceable!"

Details from Christine Modla, Munters Ltd, Blackstone Road, Huntingdon, Cambridgeshire PE18 6EF. Tel: 01480 432243. Fax: 01480 413147.