The secret fuel that made the Spitfire supreme

In the year that sees the 70th anniversary of the outbreak of the Second World War, a previously untold story has emerged of how, through a "miracle" chemical breakthrough, Spitfire and Hurricane fighters gained the edge over German fighters to win the Battle of Britain.

An American scientist and author has claimed that the famed pair of war-winning aeroplanes gained superior altitude, manoeuvrability and rate of climb by a revolutionary high-octane fuel supplied to Britain by the USA just in time for the battle.

Books, documentaries, and movies have chronicled the brilliant contribution of UK designers and engineers behind the legendary fighter planes that won the Battle of Britain, preventing invasion of the British Isles.

The courage and sacrifice of RAF pilots who flew the aeroplanes is rightly celebrated and their bravery has become an inspirational chapter of the British national story. 

What has not been known until now, however, is the story of the revolutionary aviation fuel supplied to the RAF by an American company, using a process invented by a Frenchman, without which Spitfires and Hurricanes might not have achieved crucial dominance over the Luftwaffe.

The Royal Society of Chemistry read the claims about Eugene Houdry, and his process at the Sun Oil Company, in a paper written originally for the journal Invention and Technology  by American science writer Tim Palucka.

The introduction to the paper by Palucka says of Houdry: "His miraculous catalyst turned nearly worthless sludge into precious high-octane gasoline and helped the Allies to win World War II."

He continued: "That process would make a crucial difference in mid-1940 when the Royal Air Force started filling its Spitfires and Hurricanes with the 100-octane gasoline imported from the United States instead of the 87-octane gasoline it had formerly used." 

The RSC is inviting experts and the public to challenge the new claim and if it remains intact then the society will send the report to aviation and military historians to mark the newly-discovered contribution of chemists to victory in one of the key battles. 

Eugene Houdry, born in France, developed, after settling in the USA, one of the earliest catalysts to convert useless crude oil into high octane fuel. He revealed the "cracking" process at a Chicago chemicals conference in 1938

The 100-octane fuel that resulted from the Houdry Process increased the Spitfire's speed by 25 mph at sea level  by 34 mph at 10,000 feet. 

This extra speed gave the British fighters in the summer of 1940 the edge over the Luftwaffe above the English Channel and in the skies of London and south-east England.

With the balance tipped towards the British, the German invasion was abandoned and Hitler turned eastwards, allowing the UK armed forces time to regroup and to revive.

"Luftwaffe pilots couldn't believe they were facing the same planes they had fought successfully over France a few months before. The planes were the same but the fuel wasn't," said Palucka.

Tim Palucka says that in the 1943 book The Amazing Petroleum Industry, V A Kalichevsky of the Socony-Vacuum Oil Company explained what high-octane gasoline meant to Britain. Kalichevsky wrote:

"It is an established fact that a difference of only 13 points in octane number made possible the defeat of the Luftwaffe by the RAF in the fall of 1940. This difference, slight as its seems, is sufficient to give a plane the vital edge in altitude, rate of climb and manoeuvrability that spells the difference between defeat and victory.