THE SOUND OF MERCURY
WORDS: Jack McBride
PHOTOS: George Romain
One of the first things you’ll notice when setting eyes upon the Blenheim is her two Bristol Mercury XX engines. Starting with the port-side, the propeller will turn through half a rotation before catching and throbbing into a guttering ‘chug’, as the nine radial cylinders fire and eventually settle at idle. Not so dissimilar to other radial engines, there is a consistent tone, with a slight underlying ‘purr’ as hot air is expelled from the engine. The leading copper exhaust rings on both her radial powerplants catch the eye with a shimmer, contrasting against her painted black underbelly and standard 1939-40 camouflage. The Blenheim was originally designed as a small airliner by Frank Barnwell, Chief Designer of the Bristol Aircraft Company, in the early 1930’s. The aircraft was quickly redesigned for use in the Royal Air Force as a light bomber, swiftly becoming the backbone of the RAF at the start of the Second World War with 1089 in service, more than any other type. Now, the only airworthy Bristol Blenheim left in the world is the Aircraft Restoration Company’s example, making her and her two Mercury engines equally both rare and historic.
The Aircraft Restoration Company began the resurrection of their Blenheim in 2005, using the badly damaged airframe of a Blenheim Mk.IV. After some consideration, it was decided that the new Blenheim would be restored to an early Mk.1 variant, with no other examples of this early type in existence in any condition around the world. This decision would not only require the restoration of the damaged airframe, engines and wings, but would also require an entirely new nose section to be fitted, a task that would add years to the restoration project timeline. The Mk.1 nose that would be used originated from a Blenheim issued to 23 Squadron RAF in September 1939, serving as a night fighter before being written off shortly after the Battle of Britain. Post-war, the nose section was purchased by a Bristol Aeroplane Company employee, Ralph Nelson, who combined the aircraft part with the chassis of an Austin Seven to construct a personal electric car. After a decade of use in 1957, Ralph’s design suffered an electrical fire that damaged it beyond repair. He eventually decided to donate the car to one of the previous restoration projects at Duxford in 1992, where it was on public display until finally being returned to its true purpose as an aircraft cockpit.
Following 25,000 hours of volunteer work, ARCo engineers including John Romain, Colin Swann and Blenheim expert John ‘Smudge’ Smith finally saw the Mk.1 return to the skies again for the first time in November 2014. Tracing the nose section back to the original wartime aircraft, the Blenheim now represents her original markings of a Mk.1F of 23 Squadron, with the serial number and code L6739 YP-Q. Back in the air, the Aircraft Restoration Company’s Blenheim has re-established herself as one of the most unique aircraft flying in the world today. It didn’t take long for the Blenheim to become an airshow favourite. Showcasing extraordinary British engineering, the aircraft plays an important role of continuing the legacy of the RAF crews that flew the Blenheim.
Keeping the aircraft and its two rare engines airworthy takes the utmost level of care and skill. Before the Blenheim can take to the sky, several hours of maintenance are required to ensure that each engine is prepared for use. The day before a flight, ARCo engineers will perform a set routine that includes the removal of parts, draining and replenishing of oil, and finally running both Mercury XX engines. If everything is functioning properly, the following day will see ARCo engineers pulling the propeller through by hand to distribute oil to each of the nine cylinders of the engine as the pilot works through the standard start-up procedure. Each step is keenly observed for malfunctions that could impact the aircraft systems. With the first engine up and running, the routine is repeated for the second.
Now in her fourth display season, the Blenheim has firmly lodged herself as the flagship aircraft of the Aircraft Restoration Company’s flying collection. Not only playing a huge part in commemorative air displays across the UK where she is often accompanied in the air by Spitfires, Gladiators and Hurricanes, the Blenheim is also featured in Christopher Nolan’s war-time thriller, Dunkirk alongside another from the ARCo fleet, the Hispano Buchon. The demand for the Blenheim to make appearances both off and on screen shows no sign of declining.
Usually in the hands of John Romain, the aircraft performs a poetic routine of underside and topside flyby’s, along with wingovers that produce an elegant chain of sweeping manoeuvres. Conservation is at the front of the pilot’s mind throughout the performance as he keeps a watchful eye over the gauges monitoring the Mercury engines. Even when the aircraft has inevitably returned back at the airfield, landed and has taxied to its parking spot, the engines are left to cool back at their 700rpm idle for approximately two minutes as oil is preserved and pumped back to the tanks. The engine’s growl softens, and the background purr is more prominent for a few final moments before the props slow to a stop. In the silence that follows, only the ticks and hiss of cooling Mercury engines is heard.