; Brown served on her with
802 Squadron until the carrier was torpedoed in the Atlantic in December 1941 On returning to a United Kingdom then at war, he joined the
Royal Navy Volunteer Reserve as a
Fleet Air Arm pilot, where he was posted to
802 Naval Air Squadron, initially serving on the first
escort carrier, , converted and thus named in July 1941. He flew one of the carrier's
Grumman Martlets. During his service on board
Audacity he shot down two
Focke-Wulf Fw 200 Condor maritime patrol aircraft, using head-on attacks to exploit the
blind spot in their defensive armament. The first rescue ship left because of warnings of a nearby
U-boat, and Brown was left in the sea overnight with a dwindling band of survivors, until he was rescued the next day. Of the complement of 480, 407 survived. The loss of life was such that 802 Squadron was disbanded until February 1942. On 10 March 1942, Brown was awarded the
Distinguished Service Cross for his service on
Audacity, in particular "For bravery and skill in action against Enemy aircraft and in the protection of a Convoy against heavy and sustained Enemy attacks". Following the loss of
Audacity, Brown resumed operational flying, being
seconded to
Royal Canadian Air Force (RCAF) squadrons flying escort operations to
USAAF Boeing B-17 Flying Fortress bombers over France. His job was to train them in deck-landing techniques, though the training took place on airfields. As a form of
quid pro quo he joined them on fighter operations. this time to perform experimental flying, including batting in the much more experienced Admiralty Test Pilot
Lieutenant Commander Roy Sydney Baker-Falkner flying the experimental
Fairey Barracuda onto the deck of a carrier in the Clyde. Almost immediately he was transferred to
Southern Italy to evaluate captured
Regia Aeronautica and
Luftwaffe aircraft. This Brown did with almost no tuition, information having to be gleaned from whatever documents were available. On completion of these duties, his commander, being impressed with his performance, sent him back to the RAE with the recommendation that he be employed in the Aerodynamics Flight department at Farnborough. During the first month in the Flight, Brown flew 13 aircraft types, including a captured
Focke-Wulf Fw 190. Brown was posted to the
Royal Aircraft Establishment (RAE) at
Farnborough, where his experience in
deck landings was sought. While there he initially performed testing of the newly navalised
Sea Hurricane and
Seafire. His aptitude for deck landings led to his posting for the testing of carriers' landing arrangements before they were brought into service. The testing involved multiple combinations of landing point and type of aircraft, with the result being that by the close of 1943 he had performed around 1,500 deck landings on 22 different carriers. In six years at RAE, Brown recalled that he hardly ever took a single day's leave. The fighter hit the crash barrier, sheared off its undercarriage and shredded the propeller, but he was unhurt. While at Farnborough as chief naval test pilot, Brown was involved in the deck landing trials of the
de Havilland Sea Mosquito, the heaviest aircraft yet flown from a British carrier. Brown landed one for the first time on on 25 March 1944. This was the first operation on a carrier by a twin-engined aircraft for the UK, 2 years after the US
B-25 Doolittle Raid in April 1942 which involved takeoffs from an aircraft carrier. The fastest speed for deck landing was , while the aircraft's
stall speed was . During this same period the RAE was approached by USAAF General
Jimmy Doolittle with a request for help, as the
8th Air Force had been having trouble when their
Lockheed P-38 Lightning,
Republic P-47 Thunderbolt and
North American P-51 Mustang fighters, providing top cover for the bombers, dived down onto attacking German fighters, some of the diving U.S. fighters encountering speed regions where they became
difficult to control. As a result of Doolittle's request, early in 1944 the P-38H Lightning, a
Packard Merlin-powered P-51B Mustang and P-47C Thunderbolt were dived for
compressibility testing at the RAE by Brown and several other pilots. The results of the tests were that the tactical Mach numbers, i.e., the manoeuvring limits, were Mach 0.68 for the Lightning and Mach 0.71 for the Thunderbolt; the corresponding figure for both the Fw 190 and
Messerschmitt Bf 109 was Mach 0.75, giving them the advantage in a dive. However the tests flown by Brown and his colleagues also gave a Mach number for the Mustang of 0.78, resulting in Doolittle being able to argue with his superiors for the Mustang to be chosen in preference to the P-38 and P-47 for all escort duties from then on, which was available in growing numbers by very early 1944; for
Doolittle's eventual move to
air supremacy missions permitting the fighters to fly up to 75–100 miles ahead of the bomber
combat box formations, instead of requiring them to remain with the bombers at all times.
Brown's first encounters with jet flight Brown had been made aware of the British progress in jet propulsion in May 1941 when he had heard of the
Gloster E.28/39 after diverting in bad weather to
RAF Cranwell during a flight and had subsequently met
Frank Whittle when asked to suggest improvements to the
jet engine to make it more suitable for naval use. This resulted in the
Gloster Meteor being selected as the
Royal Navy's first jet fighter, although, as it turned out, few would be used by them. Brown was also selected as the pilot for the
Miles M.52 supersonic research aircraft programme, and he flew modified aircraft incorporating components intended for the M.52; however, the post-war government cancelled the project in 1945 with the M.52 almost complete. of the type flown by Brown from
Speke to Farnborough in 1945
Helicopters In February 1945, Brown learned that the Aerodynamics Flight had been allocated three
Sikorsky R-4B Hoverfly/Gadfly helicopters. He had never seen one of these machines, so a trip to Farnborough was arranged and Brown had a short flight as a passenger in one. A few days later, Brown and Martindale were sent to
RAF Speke to collect two new R-4Bs. On arrival, they found the American mechanics assembling the machines, and when Brown asked the
master sergeant in charge about himself and Martindale being
taught to fly them, he was handed a "large orange-coloured booklet" with the retort; "Whaddya mean, bud? – Here's your instructor". Brown and Martindale examined the booklet and after several practice attempts at hovering and controlling the craft, followed by a stiff drink, they set off for Farnborough. Brown and Martindale managed the trip safely, if raggedly, in formation, although sometimes as much as a couple of miles apart. On 4 April, Brown added another "first" to his logbook when engaged in trials in relation to the
flexible deck concept with
HMS Pretoria Castle, in which he was supposed to make landing approaches to the escort carrier in a
Bell Airacobra, which had been modified with a tail hook. During one of these passes, Brown declared an emergency and was given permission to make a deck landing; a ruse which had previously been agreed with the carrier's captain,
Caspar John. Although the landing was achieved without difficulty, the long take off run required for the Airacobra meant that even with the ship steaming at full speed, there was little margin of error. This was the first carrier landing and take off for any aircraft with a tricycle undercarriage.
The RAE's "Enemy Flight" With the end of the European war in sight, the RAE prepared itself to acquire German aeronautical technology and aircraft before it was either accidentally destroyed or taken by the Soviets, and, because of his skills in the language, Brown was made the commanding officer of "Operation Enemy Flight". He flew to
northern Germany; among the targets for the RAE was the
Arado Ar 234, a new jet bomber in which the Allies, particularly the Americans, were very much interested. A number of the jets were based at an airfield in
Denmark, the German forces having retreated there. He expected to arrive at a liberated aerodrome, just after it had been taken by the
British Army; however, German resistance to the Allied advance meant that the ground forces had been delayed and the airfield was still an operational Luftwaffe base. Luckily for Brown, the commanding officer of the Luftwaffe airfield at
Grove offered his surrender and Brown took charge of the airfield and its staff of 2,000 men until Allied forces arrived the next day. Subsequently, Brown and Martindale, along with several other members of the Aerodynamics Flight and assisted by a co-operative German pilot, later
ferried twelve Ar 234s across the
North Sea and on to Farnborough. The venture was not without risk, as before their capture, the Germans had destroyed all the engine log books for the aircraft, leaving Brown and his colleagues no idea of the expected engine hours remaining to the machines. Because of the scarcity of the special high-temperature alloys for use in their construction, the
Junkers Jumo 004 engines had a life of only 25 hours – it was thus not known whether the engines were brand new or just about to expire. During this period, Brown was asked by Brigadier
Glyn Hughes, the Medical Officer of the British
Second Army occupying the newly liberated
Bergen-Belsen concentration camp, to help interrogate the former camp commandant and his assistant. Agreeing to do so, he soon interviewed
Josef Kramer and
Irma Grese, and remarked upon the experience by saying that; "Two more loathsome creatures it is hard to imagine" and further describing the latter as "... the worst human being I have ever met." Kramer and Grese were later
tried and hanged for war crimes. ==Post-war career==