Better Propellers for “The Few”: Desmond Cooke’s Legacy in the Battle of Britain

65 Squadron became the fourth RAF unit to receive Supermarine Spitfire Mark I fighters in late March 1939. Their Spitfires had three blade two-pitch propellers with lightweight aluminum alloy blades, which were licensed built versions of American Hamilton Standard designs manufactured by de Havilland Aircraft. The “DH” propeller offered two blade angles, or pitch settings, for takeoff and cruise, offering more performance than the wooden, two-blade fixed-pitch propellers that were on the first 77 Spitfires.

After the outbreak of World War II, 65 Squadron and other Spitfire units began to clash with the Luftwaffe, especially during the Dunkirk evacuation in late May and early June 1940. They realized they were operating at a serious disadvantage with their two-pitch propellers. The Bf 109 had a higher operational ceiling, able to fly as high as 30,000 feet, and a clear advantage in acceleration, rate of climb, and power diving due to its VDM constant-speed propeller. Changing from takeoff to cruise as the Spitfire climbed was equivalent to changing from bottom to top gear in a small four speed car, which meant the engine was under strain and underpowered during a crucial and vulnerable moment in the air. If a Bf 109 pilot wanted to dive to escape another fighter, all he had to do was zoom away. A Spitfire pilot had to throttle his engine back in a dive to avoid over-revving his engine if he pursued his quarry. The consensus gathered by de Havilland engineers and test pilots in contact with Fighter Command was that a constant-speed propeller was needed.

Undeterred, Cooke pushed to improve the performance of the Spitfire as 65 Squadron flew from Hornchurch, a central RAF fighter station northeast of London. It was well-known that the addition of a speed-regulating device called a governor to the DH propeller converted it from two-pitch operation to constant-speed. An unknown engineering officer from Hornchurch—possibly Flight Lt. McGrath from 65 Squadron under orders from Cooke—contacted de Havilland directly by telephone on Sunday, June 9. He asked if the company could perform a sample conversion on a Spitfire “without a lot of paperwork and fuss.” De Havilland agreed and immediately went to work gathering the personnel and components needed for the trial. Beginning on June 13, a crew of de Havilland specialists worked 36 hours nonstop to convert a Spitfire for evaluation by Fighter Command.

The converted DH constant-speed fighter Spitfire arrived at Hornchurch on June 15. Squadron Leader Cooke and the pilots of 65 Squadron conducted the flying evaluations with de Havilland test pilot Eric Lane-Burslem. The modified Spitfire could take off in 225 yards, instead of 320 yards; could climb to 20,000 feet in 7 minutes 42 seconds, instead of 11 minutes 8 seconds; could fly as high as 39,000, instead of just 32,000 feet; and had improved maneuverability. The converted Spitfire flown by 65 Squadron generated a performance improvement equal to those demonstrated by 54 Squadron’s Rotol-equipped Spitfires.

Cooke went through official channels to recommend a service-wide conversion program. On June 17, Fighter Command forwarded the results of the Hornchurch comparative tests along with Cooke’s recommendations to the government department responsible for the RAF, the Air Ministry. While waiting on the official response, Cooke had the de Havilland technicians convert his personal Spitfire on Thursday, June 20. The following day, he led his squadron of two-pitch Spitfires on a combat patrol over France against the Luftwaffe.

The Air Ministry instructed de Havilland via telephone to convert all Spitfires, Hurricanes, and Boulton Paul Defiants from two-pitch to constant-speed on Saturday, June 22, the same day France signed its armistice agreement with Nazi Germany. The work was to take precedence over all other existing contracts with the immediate focus placed on Fighter Command’s Spitfires. De Havilland engineers started the conversion program at 12 Spitfire stations on Tuesday, June 25.

The next day, the pilots of 609 Squadron, based at Northolt west of London, were enjoying a lull in operations. Out of nowhere and without prior notice, a team of de Havilland engineers arrived at the fighter station by car. The team finished one Spitfire that evening, and it took to the air. Weary from the Dunkirk campaign where they had lost one-third of their comrades over the course of just three days, 609 Squadron was elated and amazed by the performance of the converted Spitfire. Their general consensus, recorded in the squadron’s operational record book, was that “the Spitfire now ‘is an aeroplane.’”

As the conversion program continued across England, the pilots of 65 Squadron took their improved Spitfires into the air where they learned that fighting the Luftwaffe was still a deadly matter. The six Spitfires of “B” flight, divided into Blue and Green sections, left Hornchurch at just after 8 pm on July 7, 1940, to intercept enemy raiders over the English Channel at 8,000 feet. As they positioned themselves to attack, Green section, consisting of Flying Officer George V. Proudman, Pilot Officer Norman J. Brisbane, and Sgt. Patrick S. Hayes, dove toward their targets, disappeared from view, and were later reported as missing in action and presumed lost over the Channel. Blue section turned to meet half a dozen Bf 109s that dove on them from the rear and engaged in individual combat. Flight Sgt. William H. Franklin claimed two Bf 109s and Flight Lt. Gerald A.W. Saunders one. Blue section survived the attack, engaged their adversaries, and escaped repeated attacks before returning to Hornchurch. The squadron’s intelligence officer noted in his account of Blue section’s encounter that “our pilots report that due to the new DH constant speed airscrews, they were able to out-maneuver enemy aircraft in every instance.”

The following day, Monday, July 8, Cooke led 65 Squadron to intercept Luftwaffe raiders over Dover around 3:30 pm in the afternoon. It was to be his last mission before stepping down from command of the squadron in anticipation of a well-deserved promotion to Wing Commander. They spotted several Bf 109s and “Cookie” ordered his pilots to attack. During the ensuing melee where 65 Squadron pilots claimed two Bf 109s, Cooke led the two aircraft of his section into a large cloud. When they re-emerged into the open, Cooke and his Spitfire were gone, never to be seen or heard from again. Shaken by the loss of their leader, 65 Squadron continued on in their aerial struggle against the Luftwaffe. Unbeknownst to them, Bf 109 pilot Josef Fözö of Jagdgeschwader 51 claimed Cooke as his fifth aerial victory.

Since Cooke disappeared two days before the RAF’s recognized beginning of the Battle of Britain on July 10, he is not counted among the almost 3,000 British and Allied airmen that fought in the battle and were celebrated by Prime Minister Winston Churchill as “The Few.” But he is listed among the over 20,000 RAF personnel lost over the United Kingdom and Europe that have no known graves and are recognized at the Air Forces Memorial at Runnymede in Surrey in southeast England. Cooke’s official combat tally as a fighter pilot was two aircraft destroyed and one shared.

In the grand scheme of World War II, the contributions of engineering- and performance-minded fighter pilots such as Desmond Cooke were not just combat victories. His achievement was ensuring that his fellow Fighter Command pilots had the best equipment available in the hope that Great Britain would prevail in the rapidly unfolding and great struggle ahead. For him, the survival of his nation depended on better propellers.