The shock of the landing gear

With a staff of seven, an investment of over £1 million, and financial assistance from the DTI, Wiltshire based Aviation Enterprises has designed an innovative light aircraft which it believes is ideal for high-speed, long-distance commuting.

The Magnum aircraft has a 100hp engine and an empty weight of around 350kg; giving it a cruising speed of 160kn and a range of 1000n mile.

The key to this performance, says chief designer Angus Fleming, is advanced aerodynamics, and one of the features of which he is proudest is the design of the retractable undercarriage to reduce drag.

After examining the use of high-performance materials in suspension components for a variety of vehicles, Aviation chose to manufacture the undercarriage shock absorbers from Dynathane. This microcellular polyurethane was developed by materials expert Hyperlast specifically for noise, shock and vibration control.

The two companies worked together customising the properties of Dynathane, and developing a shock absorber which would meet the stringent requirements of the Civil Aviation Authority.

The result was a stack of 10 elastomer discs (2.5in diameter and 2in long) separated by thin metal plates. When compressed to carry the static load of the aircraft (25kN), a deflection of just 4in was achieved, proving the damping characteristics of this interesting system.

Angus Fleming believes that not only is Aviation the only manufacturer using this type of elastomer as the complete shock absorber, but also that this is the first ever glass/carbon fibre epoxy composite retracting undercarriage to be manufactured.

With flight testing, certification, and hopefully, commercialisation just around the corner, Aviation is now using its newly acquired knowledge to offer a consultancy service in the use of this material for shock absorbers.