My grandmother helped make Merlin engines, she worked on the phosphor bronze exhaust valve guides...... she died in 1986 RIP

I remember seeing an aged Afro American airman who had come to UK to an airshow because he wanted to thank the RR engineers. He said that a number of times his P51 was well shot up but the RR engine never let him down.

I live in the countryside near Dover. For some reason these WW2 warbirds fly over us almost every day in the summer. A couple of years ago, a pair of Spitfires flying in close formation flew over unusually low, perhaps less than 1000 feet. I can understand how our grandparents felt so reassured by the sound of the Merlin. Hats off to all the restorers and fabricators who keep all these wonderful old aircraft and their engines flying.

No matter how many times I hear a Merlin, whether singly in the Spit, doubled in the Mozzy or four up in a Lanc, it/they always give me goosebumps. Never, ever get tired of hearing a Merlin.

Congrats on your 20 years service! How amazing to be surrounded by those dream machines...

A lovely presentation, balanced and calmy spoken, with the obvious respect for the engineering excellence. The sound of the Merlin has a strange allure. Once while in the magnificent gardens of an English manor house with families having picnics, the perfect sound of a Merlin came from the sky. About 100 men and teenagers poured out of the gardens and orchard's, all looking up trying to get sight. A single shout of 'Spitfire, there'. Arms pointed and silence came of everyone until the 'bird' had passed. As the gathering started to return a few Women appeared muttering together 'what is wrong with these men over a plane'. No sense of the poetry within that glorious music.

"Its contribution cannot be understated." Truer words never spoken. I was born in April 1940 in the south of England, I remember the noise of flights of fighters and bombers going overhead on their way to enemy targets when I was three years old. Recommended reading is a book by Sir Stanley Hooker "Not Much of an Engineer", it was his work on superchargers etc that enabled the massive horsepower gains.

There is no sound in the world like that of a Merlin engine. I always get goose bumps when I hear one! The contribution of the Merlin to the Allied war effort is immeasurable. Thank you, Rolls Royce, we are, and remain, very grateful.

Fascinating video! As a kid in Ohio in the early 1970s, I was fortunate to hear the beautiful sound of the Merlin. A friend's dad owned a P-51D Mustang, and flew in our area with a club of Mustang owners. It was awesome to see and hear them maneuvering overhead. I learned of the Merlin's legendary status back then, but all I ever knew about the engine itself was that it was supercharged.

The carburettors in the Merlin were later replaced by Stromberg pressure carburettors, which meant that the pilots could safely pull negative-G manoeuvres.

My Grampa was an RAF mechanic with PR squadrons at Benson and then with 2nd TAF, and he always spoke about the Merlin with something very close to love. Heaven only knows how much time he must have spent working on them and their successor, the Griffon. It was a Griffon engined Spit that gave him his finest hour - he was one of the ground crew on Flying Officer Frank Fray's machine that took the photos after the Dams Raid.

Wonderful segment, well done! And I must agree: here in the U.S. at the annual airshow in Oshkosh Wisconsin, there is always a large number of WWII aircraft in attendance, and the sound of a Merlin is- as you say- distinct, unforgettable, and one you never tire of hearing.

Congratulations on your long service at Duxford, I am lucky enough to have witnessed a Merlin powered hydroplane running on methanol do a full speed run about 75 metres from the edge of lake burley griffin in Canberra in the act. The regatta it took part in had a special dispensation as power boats were not normally allowed on the lake. The Sound was UNBELIEVABLE.

My, so far, only visit to IWM Duxford was made all the better by hearing Merlin engined Spitfires and Mustangs flying over while I was enjoying the exhibits. The sound reverberating around the hangars as they flew over brought the place to life. It was fantastic.

The lovely sound of a Merlin engine is instantly recognizable, I am so lucky to have a Spitfire and a P51 located at the local airport, i hear them, and see them several times a year when they are out flying, often passing just over my house. There is even a Fiesler Storch at the airport, that engine makes quite a racket for its size and displasement.

There is no sound on Earth quite like the Merlin engine when it's angry! It /growls/ at you, and you can feel it in your chest if the air show performer flies low enough. What an amazing piece of engineering! Good on you, Rolls Royce! ^_^

A very good video told with humility. In my view, British heroism and defiance of the Axis will stand as long as history of the free world is told. The brilliant Merlin engine is a thrilling part of the story. Cheers from the US.

As far as I know Sea Hornet TT193, originally sent to Canada in 1948 for Trials, was sold off in 1950 to a private operator to save the cost of bringing it back to the UK. A few years later it was dismantled. It was bought by a New Zealand company in 2017 and is currently undergoing restoration, hopefully to flying status.

That was Brilliant. And you are right - there is NOTHING like the sound of a Merlin. And again you are right - all the best aircraft used it! You mention the Griffon and that its rotation was opposite to the Merlin. The reason was the Griffon was initially developed for naval aircraft, and the rotational torque of the engine would make the fuselage turn to starboard, "into" the deck of the ship and not off the deck during landing and takeoff. Genius!

The Packard-built Merlin’s were in many ways, better than the RR model. As the RRs were hand-built, the tolerances were all over the map. Packard’s mass-production techniques built the tolerances much closer and more consistent.

Thirty or so years ago, I saw a Merlin stripped down completely and being entirely rebuilt; even stripped down to parts, she is an beautifully built; impressive.

Another outstanding video from IWM Duxford. I’ve been to all the big Aero museums in the US and a plane geek my whole life. These IWM videos are stunningly good! Finally getting to see the UK in April/May and this is on my Must Do list. Great job, gentlemen.

as an A&P mechanic I loved the sound of a merlin from childhood till now I only have worked on 1....

Fascinating video. When my son was a wee boy I took him to Leuchars airshow using back roads to avoid congestion, I could see the BBMF Lancaster, a Hurricane and a Spitfire approaching from the West to go out over the bay and approach to land. I got my son out of the car and got the engine off, just in time to see and hear 6 Merlins go over the top of us. Incredible sound.

Congratulations on your 20 years of service. I’m not a particularly patriotic man at 61. But with the country in such decline and it’s international reputation so tarnished, this upload by IWM on the Merlin, makes me feel proud of British ingenuity and what we were once capable of. Thank you.

Sir Stanley Hooker played a vital role in the Merlin’s development . He was responsible for developing the super charger . Baron Hives called Hooker “ not much of an engineer ! “ 😂

Unfortunately, no mention of the contribution made by Sir Stanley Hooker and his team to supercharger development which enabled all of that extra power to be wrung out of that engine. His Autobiography ‘Not Much of an Engineer’ is a brilliant read, covering not only his work on the Merlin but also the RB211 and the Concorde pwerplants

Thanks great presentation, I still have my dads RR issued Merlin Operators handbook and blue prints. Much cherished, he started military life in the Royal Flying Corp, when WW2 came around he was working for RR as an engineer and specifically on the Merlin. He got to meet many of the famous names in British air industry and told me many stories.

I live not too far from Biggin Hill, and they do tourist flights in Spitfires. You can't mistake the sound of that thing. And then, one day I was driving back from the supermarket, and a frickin Lancaster went right over the top of me (it was the BBMF at the Farnborough air show). My grandfather was a flight engineer on the Lancaster, and rests in Abbeville. I didn't know whether to feel scared or proud. I picked the latter.

I heard one at full chat flying over lake wanaka in NZ, he then pulled up and cleared the alps, absolutely magnificent. I have not heard a sound like that since.

Thank you. You mean (right at the end) that the contribution of the engine cannot be "overstated", not "understated".

Brilliant film, thank you. I live in East Sussex near the south coast of England and in the last few years the explosion of Spitfire experience days has meant what was a once or twice a year experience, hearing a Merlin, has turned to something to enjoy daily through the flying season. Despite the regularity, it's enough to bring me out of the house, garage or workshop and watch every time. It truly is a privilege to witness. For me there is no more evocative sound on the planet.

Nearly a century later the sound of a Merlin still weaves its magic over any lucky to hear lt.

During my training as a motor mechanic in the 60s, we had a certain instructor Mr Gibson who was a fitter on Merlins during WW2 - a really lovely man who managed to purloin a Merlin from the RAF for the workshop, which us lads regularly tore apart for sheer fun 😁

I agree, I love the sound of Merlins. We use to have a Spit' flyfing regularly in the summer at Filton and it really is the most distinctive and almost heavenly purr on any aeroplane.

This year to celebrate the late Queen Elizabeth's platinum jubilee a Spitfire and a Hurricane did several fly-bys by the Humber bridge in Hull, hairs on the back of the neck went up and a lump in throat, (and maybe I got something in my eye) what a mgnificent sight and sound!

The sound of the Merlin engine is so distinctive! Congratulations on 20 years at IWM, keep up the good work.

During the summer through to early autumn in this part of the world we can hear Merlins almost every day. Such a treat.

in the day, 70's 80's they used the Merlins on the hydroplane racing, i'd hit tri cities or lake washington in seattle to watch.. welp one seafair sunday I was stuck working at Sambos on 15th and what 61st is it in ballard, just a kid then.... I sat out back on this fine Sunday on my break and I could hear the Hydros racing all the way from lake washington, made me miss it even more but of course I drew the black card, my turn.. and they were pretty loud not just a faint rumble, you could tell when one had a miss for sure, 5-6 on the lake at once, why it was dubbed "thunder on the lake" .. them some good times for sure

Loved my trip to Duxford in September! One of the highlights of my UK visit. Thanks guys for such a great museum!

As a child of the 1950s, I associate the Merlin and its beautiful sound with hydroplane racing here in the U.S.

A great presentation. Very easy to watch similar to Battleship New Jersy with Ryan. You both have a love for the old machines that hopefully will get passed down to the next generation. Saw a Merlin engine out in a shop in Phoenix some years ago getting cyrotreated. The machinists said it machined like virgin material. Says a lot for the original quality control of the metalurgy department.

The sound of a Merlin is possibly the greatest sound... In the world.

Visited the IWM in the late 70s, impressed to this day by it. Wish I could go again.

I'm very fortunate to live not far from Oshkosh, Wisconsin where the EAA has its annual Airventure. The Merlin Powered aircraft have such a distinct sound one cannot help but look.

It gives me goose bumps every time I hear the Merlin over the White Cliffs.

I totally agree: The sound of the merlin engine is so beautiful and delightful :) I love to hear it at airshows, and sitting inside a spitfire it does such a good job!

Happy Birthday! What an amazing job you have! I'm extremely envious! Thanks for the usual great video and the fantastic information.

The spitfire in all its iterations is unquestionably the most beautiful flying object ever made.

I agree 100 percent, the sound off the Merlin engine is so beautifull... Keep those warbirds flying. Big tumbs up for everyone who keeps history alive!

Graham....we met yesterday in Graveley...your knowledge of the Merlin engine is very very impressive. A fabulous presentation, well done.

That sound is so distinctive and sends a shiver down my spine every time.

De Havilland Hornet, such a pretty plane, it just looks right, so graceful. Genius design.

Regarding the negative-G problem with the carburettors, have you heard of "Miss Shilling's Orifice"? This was an extra diaphragm in the float chamber, with a hole in the middle to prevent engine cut-outs, proposed by Beatrice Shilling, a scientist at the Royal Aircraft Establishment, Farnborough. It was used from 1941 to 42 when RR developed an anti-G version of the SU carbs. RR stayed away from fuel injection because carbs allowed a greater fuel-air density the injectors, giving a power advantage.

A retired aviator with a widely varied background ... ag driver, corporate, charter, ferry, aerobatic, CFI, with IFR etc. . I have the supreme honor that will live with me forever, of having several PIC hours in a Mustang. I was introduced to this airplane by the owner, who during my first flight, actually performed a half-hour air show routine. You never lived until you've ridden through a precision, crisp, eight-point roll in a Mustang, a hundred feet off the deck!! (This airplane had a makeshift "back seat" --- you sat with an auto seat belt across your lap, on the wing spar, behind the pilot!) THIS was a crowning achievement for my aviation career. Those all too few precious hours will never leave me. I flew that Mustang down a strip, twenty feet off the deck, at something over 430 MPH!! Then, pulled straight up at just under six Gs and was through 12,000 ft in seconds!!! That stunning airplane just wanted to go, and go ... staright up!! The Merlin was just superlative. One thing which seems to be rarely mentioned, it was totally, literally DEAFENING!!! A few seconds of no ear protection would render you quite seriously deaf for some time. Few aviators who haven't been there, can start to imagine that sound level .... in the cockpit. SIX straight stacks, on either side of the engine cowling, six feet in front of your face? It truly has to be experienced to understand that level of engine noise, sound energy. It is actually palpable!! It literally pounds your chest. One last comment, that engine LOVED to run at power .... smooth, and always with the sense it was power incarnate. BUT .... like all thoroughbreds .... it did NOT like to be throttled down, in flight! Thing would backfire, shake on the mounts, pop, cough .... spit ... until you brought the power to something a bit above idle. THE most incredible experience of my life!! Every aviator should have the experence ... just once (more if possible, of course!!)... to appreciate this engine. The particular a/c I flew ... was later purchased by an individual I believe, and was sent to an air museum in England, then flew for some time under the registration G-SUZY.

Another great video Graham! Completely agree about Hornet, an absolutely beautiful aircraft! 20 years of doing something you love, lucky you!

I agree it is the best sounding engine ever made. Hearing a Lancaster or a group of spitfires fly over is just thrilling to me. It stirs my heart and gives me goose bumps. No jet does the exact same though it has it's own thrill.

Congratulations on 20 years with the IWM! Excellent presentation.

I think you meant to say at the end “cannot be overstated” - a minor quibble because I knew what you meant.

3.00 "More permanent solutions involved moving the fuel outlet from the bottom of the carburettor to half way up and the use of fuel injection using a Stromberg pressure carburettor (used on Allison engines from 1939) and finally an SU injection carburettor." 3.14 "It had been intended to utilise the evaporative cooling system but was replaced by the more reliable ethylene glycol liquid cooling system developed in the United States." The Spitfire Society Technical page

"Truely great masterpiece of engineering. ❤️✌️

For me, the Merlin is as much a work of art as it was a feat of engineering for its time. A magnificent, haunting sound that actually makes me tear up when I hear one. Hats off to Rolls Royce's designers, engineers and the brave few who operated them...

Whenever i hear a Merlin, i get 'goosebumps'. It was, and still is, the most beautiful sounding piston engine bar none. Absolutely glorious sound.

11:20 absolutely agree. Here in Melbourne we occasionally hear one of the old warbirds (Mustangs) with their Merlin’s roaring along. A great sound .

Certainly a great engine. This, along with the Pratt & Whitney R2800 radial, certainly were huge influences in the Allied war effort. Superb engines.

The capital/industrial might, cooperation, ingenuity and research development of all the allies was a giant awoken.

As usual Graham a polished and professional presentation could listen to you all day ,also congratulations on 20 years at IWM .

Such a perfectly assembled video, thank you for all the information!

Quand j'étais jeune, dans les années 70, j'ai vu passer un spitfire au dessus de ma tête, au cap gris nez en France. Je n'oublierai jamais le son du merlin !

Wet well presented! I as a Canadian am proud to have been a part of Mitchell’s genius in the contribution to the war effort!

I love your videos and Graham is a great story teller and even better in person when I get to visit IWM Duxford

Great video! Thank you! 👍

So many astounding facts that just kept making my jaw drop! What a testimony to the amount of sheer brilliance that went into supplying the Allied effort in World War II! And to the sheer versatility of the internal combustion engine!

Many thanks for the extra footage of the Hornet flying - never seen this footage before. Really shows what an elegant aircraft it was.

I too love the sound of the Merlie. I got goosebumps the first time I heard it.

In some aspects, the Allison was a better engine design, but the Merlin had a more efficient supercharger. The two-stage supercharger gave the Merlin better altitude performance. It wasn't that the Allison engineers didn't appreciate the benefits of multi-stage supercharging, but USAAF doctrine was that altitude performance would be achieved using turbocharging. Unfortunately the turbochargers of the time were very large and required the aircraft to be designed around them. Lockheed succeeded brilliantly in packaging two turbocharged Allisons in the P38. Then when the wartime crush of demand set in, there was not enough production capacity to provide turbochargers to the big bomber programs as well as the fighters. G-model Allisons came late in the war with 2-stage supercharging and intercooling, but it was too late for the V1710's reputation. The P82 Twin Mustang used G-model Allisons. The last Allison was produced in 1948, capping an overall production run of 70000. But yeah, the Merlin has a raspy edge to its sound that the Allison just lacks. Different firing order.

It was, and still is the best sounding engine ever built.. And it's British 😊

I live in Hamilton, Ontario Canada and we have one of the two flying Lancaster bombers in the world. And you can hear those Merlins a mile away. I love hearing that roar and looking outside to see the Lanc flying overhead. A beautiful plane, and an amazing engine.

I’m with you on the sound: every time it makes my eyes moist. We must never forget.

What’s not often acknowledged is the important work done by Ford UK engineers and drawing office making it possible to mass produce Merlín engines by the thousands. Rolls Royce were used to producing engines pre-war in hundreds that could be tuned, hand finished and fettled by their apprentice trained highly skilled engineers. Ford made the tolerances finer and improved quality control so every part was uniform and could be assembled quickly by semi-skilled wartime production line operators.

The song of a Merlin, once heard, never forgotten.

Appreciate the extended commentary concerning the De Havilland Hornet. The Merlin 130/131 engines installed in that airplane made power equivalent to the Rolls Royce Griffon, but without all the bulk and weight of the larger engine, thus contributing a great deal to the excellent performance of the Hornet. To add a bit to the recording of Captain Brown that you played, he also had this to say about the Hornet: _"For sheer exhilarating flying enjoyment, no aircraft has ever made a deeper impression on me than did this outstanding filly from the De Havilland stable."_ - that's saying quite a lot, considering that a very solid argument can be made that Captain Brown is the one pilot with experience in more different types of aircraft than any other pilot in the history of aviation.

There's an excellent argument between the Merlin and the P&W R-2800. I wouldn't make either argument by tearing the other one down, just by building one of them up.

What the Rolls Royce did to the North American A-36 (I think, I could be wrong) is noteworthy. The P-51 Mustang, the RAF was the originator of the Mustang program, was a war winning weapon.

Watched from Jamaica and congratulations on your 20 years of service.

Very well presented here! Enjoyed it. Thanks for posting!

It is my understanding that when Rolls-Royce sent plans for the Merlin to the Packard company, Packard found that Rolls-Royce was essentially hand finishing the engines and that they had to create an entirely new set of blueprints in order to build the engines to the proper tolerances for Mass production.

In Stanley Hookers book, 'Not just an engineer', he talks through some of the Merlin development.

Great video and beautifully presented. Yes, the Merlin was the backbone of a lot of air power. They made a lot of them because they were just so good.

Duxford is brilliant, went there as a kid in the early 80's and I have heard they have made it even better, hope to go back one day

Well, it is related in Stanley Hooker's Autobiography "Not much of an Engineer" on pages 58-59. " ...A number of Ford engineers arrived at Derby, and spent some months examining and familiarizing themselves with the drawings and manufacturing methods. One day their Chief Engineer appeared in Lovesey's office, which I was then sharing and said " You know, we can't make the Merlin to these drawings" I replied loftily " I suppose that is because the drawing tolerances are too difficult for you, and you can't achieve the accuracy". ' On the contrary', he replied, ' the tolerances are far too wide for us. We make motor cars far more accurately than this. Every part on our car engines has to be interchangeable with the same part on any other engine, and hence all parts have to be made with extreme accuracy, far closer than you use. That is the only way we can achieve mass production'. Lovesey joined in, "Well, what do you propose now?" The reply was that Ford would have to redraw all the Merlin drawings to their own standards, and this they did. It took a year or so, but this was an enormous success, because, once the great Ford factory at Manchester started production, Merlins came out like shelling peas at a rate of 400 per week. And very good engines they were too,....."

What is better than the sound of a Merlin in a Spitfire? The sound of 4 in a Lancaster.

Good video. Thanks. The Merlin really was brilliant. (We Yanks love the P-51, but we know what its heart is.) We were at an airshow 20 years ago at Edwards Air Force Base, California. We heard this rumble. One of my friends said, 'a jet', I knew it was more than one P-51. It was four. Absolutely distinctive sound. And because I'm not that old, clearly the movies made an effort to properly match the Merlin engine sound with clips of Spits and Mustangs. That's how I knew. At 4:15 is the Packard plant in Detroit, Michigan -- right off Outer Drive. Last time I was in Detroit that plant and the houses right across the street were still there. But that was over a dozen years ago. Almost every other historically important factory (like Dodge Main, where Sperry gyro compass were mass produced for ships and my grandmother made tank parts) is gone. It wasn't at all uncommon that when anything was handed off to an American car company for mass production they didn't make improvements, make it cheaper and make a lot more of them. Packard with the Rolls Royce Merlin, Chrysler with the Sperry gyro compass, Ford with the B-24. I think it's the 'handing off' that turned this trick. After all the 2000hp Merlins in the Hornet didn't come from Detroit but likely incorporated some of the improvements.

I live next to Blackpool Airport which is regularly used as a base for airshows here and across the NW. It's still great to be in the garden and hear Merlin engine power coming low into land or takeoff. Nowhere near peak revs anymore of course due to their value. late wartime Merlins at full power must have sounded fantastic.

The one thing that made the merlin engine was getting 130 octane fuel from America. It would never have made the horse power figures with out that fuel. The English fuel was only 100 octane. This 130 octane gave the merlin a 300 hp power increase. Great engine was able to reach its full potential.

Merlin always.

Merlin and griffons send chills down my spine with joy , just an awesome sound ❤

Fascinating; thank you very much for sharing this.

A wonderful video. Can you make one about the DeHavilland Hornet please?What was its maximum speed ? Where did it have its armaments installed was it sideways or in the wings?It kind of resembles a bit to the He129,.Have a good one.

The Merlin was improved by the use of additional superchargers and fuel formulations.