Merlin The Legendary Engine and its Aircraft (Aeroplane Aviation Archive №29)

100 Pages·2016·39.88 MB·English

M E R L I N
The legendary engine and its aircraft
The power behind:
Spitfi re
Lancaster
Mustang
Mosquito ISSUE 29 £7.95
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INTRODUCTION 3
Rolls-Royce Merlin
The legendary engine and its aircraft
No other sound in aviation has the power to evoke such an This, then is the fascinating and intriguing story of the world’s most
emotional response as that of the Rolls-Royce Merlin, without famous engine, told through the aircraft that it propelled to glory. The
doubt the world’s greatest and most famous engine. Forever entries are listed under type (single-engine, multi-engine and transports)
synonymous with the iconic Spitfire, the legendary Merlin was also and chronologically from the dates of their first flights.
the beating heart behind such history-makers as the Hurricane,
Lancaster, Mosquito and Mustang, to name but a few. Quite simply, AVIATION ARCHIVE SERIES
without Sir Henry Royce’s masterpiece, the RAF would not have had ‘Rolls-Royce Merlin’ is No 29 in the Aviation Archive series. As ever the
the power to take on the might of the Luftwaffe during World War 2. series features unparalleled photographic coverage, including many
Like the Spitfire, the strength of the Merlin lay in its ability to evolve and exclusive and rare shots that have never been published before. The
adapt, meaning that it was still in production in 1951 with over 168,000 words and photographs are complemented by ‘period’ cutaways from
having been produced to power over 40 aircraft types, from fighters to the talented pens of the ‘Flight’ and ‘Aeroplane’ artists of the era, together
bombers, transports to trainers... and even a helicopter. with aircraft profiles from the archives of Pete West.
Aviation Archive Series
Rolls-Royce Merlin: The legendary engine and its aircraft
• Editor: Allan Burney • Design: Key Studio
• Publisher and Managing Director: Adrian Cox • Executive Chairman: Richard Cox • Commercial Director: Ann Saundry • Group Editor: Nigel Price
• Distribution: Seymour Distribution Ltd [phone] • Printing: Warners (Midlands) PLC, The Maltings, Manor Lane, Bourne, Lincs PE10 9PH.
All rights reserved. The entire content of Aviation Archive is © Key Publishing 2016. Reproduction in whole or in part and in any form whatsoever is strictly prohibited without the prior permission of the Publisher. We are unable to guarantee the
bona fides of any of our advertisers. Readers are strongly recommended to take their own precautions before parting with any information or item of value, including, but not limited to, money, manuscripts, photographs or personal information in
response to any advertisements within this publication. Published by Key Publishing Ltd, PO Box 100, Stamford, Lincs PE19 1XQ. Tel: [phone]. Fax: [phone]. Website: www.keypublishing.com ISBN: 9781910415788
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CONTENTS 5
Rolls-Royce Merlin
The legendary engine and its aircraft
MULTI-ENGINE
50 ARMSTRONG WHITWORTH WHITLEY
The case of an aircraft re-invented by the Merlin
52 HANDLEY PAGE HALIFAX
The first four-engined heavy to be fitted with Rolls-Royce engines
56 DE HAVILLAND MOSQUITO
The lightning fast ‘wooden wonder’, a true multi-role aircraft
61 AVRO LANCASTER
Engine and aircraft in perfect harmony, a combination that helped
change the course of the war
HISTORY 68 AVRO LINCOLN
The last Merlin-powered heavy bomber
6 THE LEGEND OF MERLIN
70 DE HAVILLAND HORNET
The story of the world’s greatest aircraft engine
The Merlin’s ultimate speedster
72 SHORT STURGEON
SINGLE-ENGINE
A rather inglorious end to service life
16 HAWKER HURRICANE
The story begins with Hawker’s classic fighter TRANSPORT
21 SUPERMARINE SPITFIRE
74 AVRO LANCASTRIAN
The legends of the Spitfire and the Merlin are simply inseparable
The Merlin and Lancaster turn civil
28 FAIREY BATTLE
76 AVRO YORK
A case of the wrong aircraft at the wrong time
A reliable transport in war and peace
32 BOULTON PAUL DEFIANT
81 AVRO TUDOR
A flawed concept, reinvented as a night fighter
Britain’s first pressurised airliner was unloved and unwanted
36 FAIREY FULMAR
86 CANADAIR NORTH STAR
The Royal Navy’s first dedicated monoplane fighter was sturdy
AKA the Argonaut, a DC-4 hybrid with Merlins
rather than agile
41 FAIREY BARRACUDA
OTHERS
A purposeful rather than aesthetic torpedo- and dive-bomber
46 NORTH AMERICAN P-51 MUSTANG 90 MINOR TYPES
The Merlin made a good aircraft great Other aircraft that were fitted with Merlin engines
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6 THE LEGEND OF MERLIN
The legend of Merlin
Above: Two pioneers that changed the course of
history, Reginald Mitchell (left) and Henry Royce.
Sadly neither was to live to witness the true
success of their endeavours.
Above right: Where it all began, with the
Rolls-Royce ‘R’ engine that propelled the
Supermarine S6B racing seaplanes.
were already afoot to increase this output to
1,000hp (746kW). With the death of Royce on
22 April 1933, the engineer was not to see his
PV12 begin test runs, let alone the startling
success that it would eventually yield. On the
day that Sir Frederick Henry Royce died, the
final drawing for the PV12 was completed in
the company’s design office.
Six months after Royce’s death, a first test
run of an initial PV12 engine took place on
15 October 1933. At first, however, the new
engine proved troublesome and it was
probably only a degree of luck that saved it
from being abandoned altogether. Among
other failings, the PV12’s reduction gear
required replacement and the monobloc
The path to creating the with a ‘monobloc’ casting for casting was prone to cracking. Nevertheless, in
Merlin – the most prolific each bank of six cylinders. The July 1934 an example completed a successful
Rolls-Royce engine in history – can Kestrel proved to be such a success that test, developing 790hp (589kW) at 2,500rpm.
be traced back to 1931 and the Schneider its production even outstripped that of the In April 1935 the engine was test-flown in a
Trophy that was held at Calshot. The Rolls- World War 1-era Eagle (4,750 compared to Hawker Hart.
Royce ‘R’ engine propelled the Supermarine 4,674 engines built), and it also set a precedent Meanwhile, two British fighter prototypes
S6B racing seaplanes to victory and a for continued refinements throughout its would be designed around the Rolls-Royce
new world air speed record. Despite these career, adding full supercharge, automatic engine: the Hawker Hurricane and
achievements, the Air Ministry was, at the boost control, 87-octane fuel and other Supermarine Spitfire. By spring 1935 the
time, unwilling to fund development of a improvements. Among the many and varied new engine had finally gained Air Ministry
new production engine based on the ‘R’. aircraft powered by the Kestrel were the support and as a result it was named Merlin,
Instead, Rolls-Royce decided to go it alone, Hawker Demon, Fury, Hart and Hind, and the continuing the tradition of naming Rolls-Royce
approving a private venture initiative in Short Singapore flying-boat. aero engines after birds of prey. The first of
December 1932. As conceived by Sir Henry The result of Royce’s new project was the the Merlins proper was the Merlin B, which
Royce, the new aero engine would combine PV12 of early 1933, the designation signifying introduced changes including ramp-type
the reliability of his earlier Kestrel design with that the new engine was a private venture, with detachable heads with twin inlet valves at 45
the power of the ‘R’ engine that had won the the now classic V-12 arrangement. Generally degrees, but which continued to suffer from
Schneider Trophy. conventional, this 27-litre liquid-cooled cracking of the cylinder blocks.
The definitive Kestrel had appeared in 1930 engine featured a single-stage supercharger. It was intended that the 890hp (663kW)
and set the standard of a Rolls-Royce V-12 While initially rated at 750hp (559kW), plans Merlin C should power both the Hurricane
AA29_pp 6-15.indd 6 06/12/2016 09:16
and Supermarine. The ‘C’ fi nally dealt with the by the fact that Rolls-Royce provided funds 50-hour civil test accomplished in December
cracking problem by replacing the monobloc of £7,500 towards construction of the initial 1935. The ‘C’ was succeeded by the Merlin F,
casting with separate cylinder blocks. Despite Spitfi re prototype – half the total required. which was the fi rst of the line to be approved
the limited performance of the ‘C’, the engine In the end, failure of the Merlin C in a 955hp for production, as the Merlin I. In this form,
was suffi cient to demonstrate the potential (712kW) type-test in May 1935 put an end it provided the power for the Hurricane and
of both aircraft, and their importance to the to this variant, although a glimpse of future the Fairey Battle, and production extended to
engine-maker’s fortunes was demonstrated potential had been provided by a successful around 180 examples.
Rolls-Royce aero engine origins
Today, the Rolls-Royce name is fi rmly associated with aircraft engines, the British manufacturer’s
current product line ranging from the Trent 1000 that powers the Boeing 787, to the lightweight Merlin production totals
RR300 used in the Robinson R66 light helicopter.
Derby Crewe Glasgow Ford Packard
Frederick Henry Royce initially established himself as a manufacturer of electrical and
2,377 26,065 23,647 30,428 55,523
mechanical components in 1884. His fi rm produced its fi rst automobile in 1904 and in the same
year Royce met Charles Rolls, an established car dealer. Between them it was decided that Royce
Limited would produce cars that would be sold exclusively by C. S. Rolls & Co, under the Rolls-
Royce brand.
The story of Rolls-Royce aero engines begins with World War 1, the outbreak of which
found the Derby-based company, under chief engineer Royce, as a leading manufacturer of
luxury automobiles. Concerned that banks might begin to refuse wartime credit for such an
expensive consumer product, the company board elected to downsize and prepare to refuse any
government request to switch to aero engine production.
However, this decision was swiftly reversed after the Royal Aircraft Factory convinced the
company to tender to build a batch of Renault aero engines. After the board agreed to the move,
Royce led the company in its new direction, despite deteriorating health that forced him to
move to the south coast. Royce’s ailing health was certainly worsened by the long hours that he
worked, and his stubborn refusal to eat proper meals.
The fi rst aero engines to leave the Rolls-Royce factory were 50 examples of the Renault design,
urgently required to power Royal Aircraft Factory B.E.2 light bombers. After examining the
French design, Royce decided to begin work on his own aero engine, a water-cooled V-12 that
would draw inspiration from the company’s existing car engines and the German six-cylinder
Daimler DF80 aero engine. This would become the Eagle.
Within just four weeks of the outbreak of World War 1, the board agreed to build two
experimental V-engines at a cost of about £1,500 each. With the banks now behind it, the
company rebuilt its workforce and by October 1914 the company was also developing two
smaller derivative engines, the Falcon and the Hawk.
By early 1915 the company had received orders for the Eagle, to power the Handley Page
O/100 bomber. By the end of the war, Rolls-Royce completed around 2,000 Eagle engines. The
The Rolls-Royce Eagle powered the Vickers
Eagle also powered the Vickers Vimy, the aircraft in which John Alcock and Arthur Whitten Brown
Vimy of World War 1 fame. This aircraft was
completed the fi rst non-stop transatlantic fl ight in June 1919 and which would fi rmly cement taking part in an air race to Australia in 1919,
the company’s reputation as a builder of aero engines. and won.
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8 THE LEGEND OF MERLIN
The magic begins MERLIN II
The initial Merlin I version was not the most Cutaway diagram of a Merlin II as fitted to Spitfires
and Hurricanes at the start of World War 2.
auspicious debut for the new engine. Very soon,
it was apparent that the ramp-head potential
was not being achieved. After major changes
were incorporated in the cylinder head design,
the Merlin G emerged, now with an output of
1,030hp (768kW) at 3,000rpm. Compared to
earlier versions, the Merlin G’s flat head was cast
integral with the block, with the four valves in
parallel. The ‘G’ would enter production as the
Merlin II early in 1937. The changes heralded in
the Merlin II required a major redesign of the
nose of the Hurricane, as well as the fighter’s
engine controls, but this was considered a small
price to pay for the promised improvement in
performance. Similar changes also had to be
made to the Battle light bomber.
It was also in 1937 that Rolls-Royce engineer
Ernest Hives, a former chief test driver and now
head of the company’s experimental division,
developed a ‘racing’ version of the Merlin.
Thanks to high-octane fuel, the racing Merlin
could develop 2,160hp (1,611kW) for short
periods, and was capable of running at 1,800hp
(1,342kW) for a full 15 hours. The performance
of this engine suggested that the Merlin would
finally be able to match the larger powerplants
then being developed for Germany’s fighters.
At the outbreak of World War 2 in September
1939, the Merlin II powered all Spitfires and
Hurricanes in Royal Air Force service, while the
Merlin III arrived in time for the Battle of Britain
in 1940. During the battle, the fighters’ Merlin
Right and below: The Rolls-Royce experimental
department at Hucknall, Nottinghamshire,
testing 12-cylinder engines in 1938.
engines were powered, where possible, by
100-octane fuel, bulk quantities of which had
first arrived in the UK in June 1939.
The key to the success of the Merlin design
was its capacity for continued development.
Throughout the war, Rolls-Royce engineers
continued to eke more and more power out of
the engine, including through the introduction
of improved superchargers and the use of
high-octane fuels.
A ‘bomber’ version of the engine appeared
in the form of the Merlin X, which powered the
Armstrong Whitworth Whitley and Handley
Page Halifax. This version featured a two-
stage supercharger and its introduction in
1938 coincided with the arrival at the firm of
Stanley ‘Doc’ Hooker, whose legacy included a
refinement of the supercharger to yield even
greater performance from the Merlin family.
AA29_pp 6-15.indd 8 06/12/2016 09:16
THE LEGEND OF MERLIN 9
When faced by the German Messerschmitt
Bf109 in the Battle of Britain, the RAF’s Merlin-
powered Hurricane and Spitfire initially faced
a major disadvantage against the Luftwaffe
fighter. Since the early Merlins lacked the
direct-injection of the German engines, the
British fighters were unable to sustain sudden
negative-g in combat: the engine would be
starved of fuel and suffer a loss of power. As a
result, the pilot of a Hurricane or Spitfire faced
the possibility of being unable to follow a Bf109
into a dive. Beatrice ‘Tilly’ Shilling at the Royal
Aircraft Establishment was able to provide a
simple solution. ‘Miss Shilling’s orifice’ added a
metal diaphragm with a small, calibrated hole
Right: A Merlin engine, with its distinctive ‘fishtail’
exhaust stubs, is fitted into a Hurricane airframe
at a Hawker factory during final assembly.
• AA29_pp 6-15.indd 9 05/12/2016 11:45
10 THE LEGEND OF MERLIN
inside the carburettor’s float chamber. This war-winning fighter. Ultimately, Packard would
ensured the engine would keep running even produce a total of over 55,000 examples of the
under negative-g conditions. Merlin under the V-1650 designation. At first, it
With Hooker’s work on superchargers had been planned for the American Merlin to
continuing, Rolls-Royce was able to introduce be manufactured by Ford at Dearborn,
the Merlin XX for the Hurricane and the Michigan, but this was switched to the
Merlin 45 for the Spitfire, as well as related Packard Motor Corporation. After a batch
engines to power different families of bombers. of development V-1650s was produced by
Among the latter was the Avro Manchester, Continental, in August 1941 Packard ran a
which was converted to become the Lancaster first example of its Merlin, totally redrawn and
once it had been fitted with complete Merlin adapted for American production. In addition
‘power eggs’ originally developed for the Bristol to US output, the demand for Merlin engines
Beaufighter II. With a readymade powerplant during the war saw additional UK production
available, the Lancaster became the most facilities established at Crewe and Glasgow,
important RAF heavy bomber of the war. and Ford Motors in Manchester also produced
Of the first generation of supercharged engines under sub-contract.
Merlins, Hooker subsequently recalled: ‘The work Despite the arrival of the larger, more
I had done on the supercharger and its air intake powerful Rolls-Royce Griffon engine, the Merlin’s
appeared on production in 1940 in the form of continued success was ensured by the variety
the Merlin 45 for the Spitfire and the Merlin XX of its applications, including the Lancaster
for the Hurricane, Mosquito and Lancaster. The and de Havilland Mosquito. By the end of the
effect was to increase the full-throttle altitude war, versions of the Merlin were producing
of the engine from 16,000ft (4,877m) with the 2,780hp (2,073kW) thanks to the use of fuel
Merlin III to over 19,000ft (5,791m) with the with monomethyl aniline additives. As well as
Merlin 45. For me, the impossible had come a range of fixed-wing aircraft, the adaptable
to pass. I had changed a Rolls-Royce engine Merlin also found use as the powerplant of one
designed by the great Henry Royce himself.’ of the United Kingdom’s first helicopters: the
Midway through 1940 the need for a high- impressive Cierva Air Horse was an evolutionary
altitude addition to the Merlin family had been dead-end, but made it into the air in December
recognised. Such an engine was needed to 1948 on the power of a 1,620hp (1,208kW)
power the Vickers Wellington VI, and the solution Merlin driving three equal rotors; left and right
was initially seen as being a turbocharged rotors at the back and one above the nose. At
version of the Merlin. The work was charged to the time of its appearance it was the largest
Hooker, who instead developed a two-stage helicopter ever built.
supercharger, including an intercooler, with the In an ironic turn of events, one of the final
initial ‘blower’ being derived from that used in applications for the Merlin was the Hispano
the Rolls-Royce Vulture. Aviación HA-1112, a post-war Spanish fighter
‘I argued that, to obtain the necessary power, that was essentially a licence-built version of
all we had to do was raise the full-throttle the Bf109, the wartime foe of the Hurricane and
power of the Merlin from 16,000 to 30,000ft Spitfire. After a batch of aircraft powered by
(4,877 to 9,144m)’, Hooker remembered. ‘To do Hispano-Suiza engines proved to be inadequate
this we needed two superchargers in series at for front-line service, these were re-engined with
the back of the engine, driven by the same Merlin 500-45s ordered from the UK as surplus
gears that existed on the standard Merlin.’ in 1953. The first of these ‘Merlin Messerschmitts’
The supercharged Merlin emerged as entered service in 1956, and a total of 173 were
the Merlin 60 series, which provided twice produced, finally being retired in late 1965.
the power at high altitudes, as Hooker had Quite apart from military applications, the
promised. Once incorporated in the Spitfire, Merlin saw success within the civil aviation
the fighter was now able to boast a 10,000ft industry. Immediately after the end of the war,
(3,048m) improvement in ceiling and a 70mph the Merlin provided the powerplant for the
(113km/h) increase in maximum speed. Avro Lancastrian and York transports and the
By 1942 the RAF’s Spitfire IX was thus Canadian-built DC-4M Argonaut, examples
powered by the Merlin 61, fitted with the two- of which also supported the Berlin Airlift that
speed, two-stage supercharger and developing began in 1948.
1,280hp (954kW). Such was the degree of Production continued until 1951, by which
improvement in terms of performance that time a total of 168,040 Merlin engines had
the Merlin was now adopted for the North been made, including Packard versions in the
American P-51 Mustang, to create another United States. Thomas Newdick
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