PNSAC Newsletter Project North Star Association of Canada March 2007 Merlin Musings Second in a series Eagle The Eagle was the first of Rolls-Royce’s long line of Ted Devey successful aircraft engines. It was naturally aspirated (no blower of any kind): a water-cooled V-12 with separate cylinders and 4 carburetors (two at each end). Rolls-Royce also produced a straight six cylin- The Rolls-Royce Company started as a partnership der engine, the Hawk, which was based on an engine between Charles Rolls and Henry Royce to manufac- used in the Silver Ghost car. ture beautifully crafted automobiles of the highest The last engine of World War I was the Fal- quality-the best automobiles in the world! In 1910 con which was conceptually similar to the Eagle-a Charles Rolls had the unhappy distinction of being slightly smaller V-12. The Falcon was used in the the first aviation fatality in England when his Wright Bristol Fighter introduced near the end of the War. aircraft went into a spin, from which he was unable (The CAvM recently took delivery of a fully-restored to recover, during a flying contest at Bournemouth. Bristol Fighter with Falcon engine 13. It is in the stor- It was up to Henry Royce to achieve the goal of mak- age hangar ready for display.) The Falcon was fol- ing products of outstanding quality. He always sur- lowed by the Condor which was the first engine to be rounded himself with the best designers, engineers equipped with four valves per cylinder ( two intake and draftsmen available. and two exhaust of the poppet type). This increased the breathing capability of the engine and valve cool- In 1914, the British Air Ministry requested Rolls- ing was much improved with considerably smaller Royce to manufacture French Renault air-cooled en- valves. gines that were of doubtful quality. Instead, Royce After World War I, Rolls-Royce nearly abandoned offered to build superior engines of his own design. the aircraft engine business due to a large surplus of These Rolls-Royce piston aero engines were named engines on the market. There was little demand for after birds of prey. Although, there were exceptions. military aircraft but there was a booming demand Contents of this volume: CrewChiefReports . 6 PNSACLaunchesMembershipDrive . 7 MerlinMusings .................. 1 Miscellany ..................... 8 Interview–BudGraves. 3 PNSAC Newsletter March 2007 for Rolls-Royce automobiles. There was just enough ing upgrades which further improved engine perfor- work in overhauling Eagle engines and Condor de- mance. velopment to keep the company in aviation. Because "R" engines were used in cars and boats to estab- of the Eagle’s reliability, many of them were installed lish land and water speed records respectively and on Vimy bombers and De Havilland commercial air- is on record as the only engine to power the world’s planes. fastest boat, car and airplane. Such achievements es- In 1923, the United States won the Schneider Tro- tablished Rolls-Royce as the premier builder of high- phy Air Race. The engine used was an improved ver- performance aero engines. sion of the Curtis R3X. This led to the development of The British ran their aircraft engines at higher the 400 HP Curtis D-12 engine, a water-cooled V-12 manifold pressures than other nations, resulting in of 1145 cu. in. displacement. It featured a mono- more power for their front line World War 11 aircraft. block cylinder construction of cast aluminum with This had drawbacks due to the weight penalty re- wet steel cylinder liners. This engine established sulting from stronger internal components to over- a standard for subsequent water-cooled and liquid come higher stresses and loads. Maintenance dif- (water plus ethylene glycol) cooled V-12 engines. ficulties and shorter service periods between over- Within a year, Fairey Aviation produced a Curtis hauls resulted, which Rolls-Royce satisfactorily re- D-12 powered single-engine bomber which outper- solved over time. formed other RAF aircraft with ease.. The RAF, pride wounded over the prospect of planes powered by American-built engines, arranged to have two D-12s Merlin delivered to the Rolls-Royce Works at Derby, where they were reverse engineered. Changes in design, Sir Henry Royce was knighted in 1931. He suc- such as, open-end cylinder liners (an improvement cumbed to failing health and died in 1933. However, over D-12s closed end design) were incorporated to he had laid out the most significant piston engine in create the Kestrel engine with 1296 cu. in. displace- history, the immortal Merlin, which can be described ment. The Rolls-Royce philosophy of a liquid-cooled as a 60 degree liquid cooled V-12 displacing 1639 V-12 with 4 poppet valves per cylinder continued to cu. in. Each bank of 6 cylinders has a single over- the end of the piston engine era. head camshaft actuating 4 valves for each cylinder, Early Kestrels were naturally aspirated (no turbo 2 intake and 2 sodium-cooled exhaust. Single-stage - or supercharging) using two downdraft carbure- single-speed supercharging was initially employed. tors. Later, Kestrels were supercharged, a first for The propeller was driven through a gearbox having Rolls-Royce engines. Early superchargers were in- about a 2 1/2 to 1 reduction ratio. efficient so engineers at the Royal Aircraft Estab- lishment at Farnborough carried out extensive re- Early Merlins were rife with problems. The search and development work on superchargers dur- first one was built in 1933 and it did not fly un- ing WW1. Superchargers of higher efficiency were til 1935. By 1936, Rolls-Royce was under pressure developed and added to Kestrel engines, resulting in from airframe builders to build Merlins, especially increased power and improved fuel economy . with clouds of war appearing on the horizon. The Supercharger development was the basis for British Government was relying on Merlins for fight- Rolls-Royce engine performance enhancement in the ers. Early in the war demand far exceeded the following years. Improved fuels allowed ever- production capabilities of Rolls-Royce and arrange- increasing manifold pressures which spurred on ments were made with the Packard Motor Company even more supercharger development. (In airplane of Detroit to build Merlins. Many of these were engines, the supercharger is a blower that is driven shipped to Britain while others went to Canada for directly from the crankshaft and blower RPM is di- Canadian- built Hurricanes, Mosquitoes and Lan- rectly proportional to the crankshaft RPM.) caster bombers. About 160,000 Merlins were built, The Air Ministry persuaded Rolls-Royce to pro- 60,000 of them by Packard. duce an engine for the 1929 Schneider Trophy Race. The Buzzard engine had many Kestrel design fea- tures with nearly twice its displacement at 2239 cu. Griffon in., and, it formed the basis for developing the "R" engine (not named after birds of prey.) This engine Development of the Griffon started in 1939 initially was installed in the Supermarine S6 racer which won at the request of the Fleet Air Arm as carrier borne the Schneider Trophy in 1929 and again in 1931. The airplanes tended to be larger and heavier than their "R" engine suffered many failures such as, connect- land-based counterparts. The Griffon can be consid- ing rods, crankshafts, valves, etc. In true Rolls -Royce ered a modernized Merlin with a larger displacement manner, these failures led to design and manufactur- and greater power. As the air industry was geared 2 PNSAC Newsletter March 2007 up for Merlin production, priority was given to Mer- the energy sector. lins and Griffons were produced late in the War and The next in the series of Merlin Musings will dis- after. These were the last piston engines designed cuss the Merlin engine from early days to the pro- and built by Rolls-Royce. Today, the company builds duction of the 620 series. The Griffon will be looked turbo shaft and jet engines for airplanes. gas turbines at as a further refinement of the Merlin. and diesels for a variety of marine applications and PNSAC Interview – Bud Graves In view of the limited number of aircraft types in use by the RCAF at that time, the technical training Herbert G. (Bud ) Graves was born on a homestead near was based on the need to provide the pilot with McCreary, Manitoba, on October 18, 1919.He attended a crewman who could service and repair fabric- one- room schools for grades one to seven and then com- covered, open cockpit aircraft on wheels, skis or pleted grade eight and high school at Rosmand School in floats on operations in the far north. Due to the McCreary. Bud applied for entry into the Royal Cana- lack of funds in the depression years, little recruiting dian Air Force (RCAF) in 1937 but was advised that he was possible until the late 1930s. In 1938 some 200 required a second language in order to qualify. Through were enlisted for training as either Aero Engine or self- study of correspondence course material borrowed Airframe Technicians (fitters and riggers). Unfortu- from a classmate, he was able to get a passing grade in nately only 28 of that group remain. French. He was accepted into the RCAF (Permanent Force) in June 1938 and was assigned to No. 2 Technical All promotions were based on seniority; that is Training School at Camp Borden for training as an Aero the date of commissioning, enlistment, or promo- Engine Technician. His assignments between 1939 and tion. So if Smith was commissioned on 1 July 1937 he 1945 included flying training schools at Camp Borden, would always be senior to Jones who was commis- Brantford, Deseronto, Saskatoon and Summerside which sioned on 2 July 1937.