An ultra-lightweight solar-powered aircraft developed by a Midland-based UK defence firm has smashed the world record for the longest duration unmanned flight.

The Zephyr High Altitude Long Endurance (HALE) unmanned aerial vehicle flew for 54 hours, technology company QinetiQ said.

The official Federation Aeronautique Internationale world record for unmanned flight stands at 30 hours 24 minutes, set by a Global Hawk in March 2001.

The Zephyr is said to have beaten the record during trials at the US Military's White Sands Missile Range in New Mexico.

QinetiQ, based in Malvern, Worcestershire, said because there was no FAI official present at White Sands, the time might not stand as an official world record.

But the FAI was made aware of a later flight, lasting more than 33 hours, and an application is being made for the time to be listed in the record books.

A QinetiQ spokesman said the FAI, which maintains aviation world records, was not informed over the first flight because it was not specifically a world record attempt, but part of a development programme.

"The team were focusing on the technical challenges," he said.

Zephyr, launched by hand, is described as an "ultra-lightweight carbon-fibre aircraft" with a wingspan measuring up to 18 metres (59ft) and weighing 30kg (66lb).

During the daytime it flies on solar power and by night it is driven by rechargeable lithium-sulphur batteries that are recharged during the day using solar power.

QinetiQ said the trials, funded through the Ministry of Defence (MOD) research programme, validated recent modifications to improve the efficiency of Zephyr's power system.

The tests saw the same aircraft flown twice - first for 54 hours to a maximum altitude of 58,355ft, and then for 33 hours 43 minutes to a maximum altitude of 52,247ft.

Paul Davey, Zephyr business development director at QinetiQ, said: "The possibilities suggested by unmanned flight are truly exciting and with these trials Zephyr has secured its place in the history of UAV development.

"Both flights were achieved in the face of thunderstorms and debilitating heat in the hostile environment of the New Mexico high desert in the summertime. They have proved that an autonomous UAV can be operated for the duration required to support persistent military operations."

Potential uses for Zephyr include earth observation and communications relay, supporting defence, security and civil needs.

QinetiQ said Zephyr has shown "consistent progress" during a series of flight trials.

In December 2005 two aircraft achieved a maximum duration of six hours and an altitude above 26,000 feet.

* QinetiQ is not the first Midland company to use its skills at innovating to smash a world record.

In August last year the JCB Dieselmax hit 350 mph on the salt flats in Bonneville, Utah, USA, breaking the land speed record for diesel-powered cars.

The vehicle was powered by an engine that was based on a version used in the Staffordshire group's diggers.

The project was funded by the privately-owned company, which is based at Rocester near Uttoxeter. However, the car was designed and built under the supervision of John Piper at Visioneering Ltd in Coventry.

The driver of the JCB Dieselmax was certainly qualified to reach such speeds. Andy Green was an RAF fast jet pilot and the absolute land speed record holder.

He drove the Thrust SSC when it became the first vehicle to break the sound barrier on land, recording an average of 763.035 mph in 1997 at Black Rock Desert, USA.

The world water speed record was set by Australian Ken Warby, in 1978, on Blowering Dam, New South Wales, Australia. The Spirit of Australia reached speeds of 317.596 mph.

Despite the 50 per cent fatality rate, the water speed record is still coveted by boat enthusiasts and racers. Currently there are three major projects aiming for the record - The British Quicksilver and The American Challenge project.

Plus, spurred into action by the new challengers, Ken Warby has also built a new boat.