How Merlin Got Better And Better

Many people remember the Merlin engine for powering iconic planes, such as the Spitfire, Hurricane, Mustang, and Lancaster. However, in all its production life, over 50 different development types of this engine were produced, from the initial engine that was just a thousand horsepower, right at the end of the war, and a stunning plane, the de Havilland Hornet, with a two-speed, two-stage integral supercharged Merlin engine that gives off 2,050 hp each, two of them.

Development

Rolls-Royce developed the engine from 1933 from an engine called the PV12. Initially, about 900 to 990 hp each on the bench, then in full production in the Mk. 1 Spitfire and the Hurricane with over 1,100 hp.

The Merlin engine is small– it’s 27 liters or about 1,650 cubic inches. It’s a very compact engine. With the help of 100 octane fuel developed in the US at the time, this Merlin engine was excellent for development.

Flaws

As fantastic as the Rolls-Royce Merlin is, it does have a few flaws. A negative G maneuver would result in the carburetor flooding and the engine coughing. Definitely not great in the middle of a dogfight. Initially, the coolant was ethanol glycol, which is highly flammable if it’s hit with an incendiary round. Later on, diluted and pressured, it wasn’t so much of an issue.

When the Mustang was developed with the Merlin engine, Rolls-Royce then gave Packard in the US a license to build the Merlin engine, and Packard themselves used the American mass production technique in between 1942 and 1945. Thus, producing a total of over 55,000 Merline engines.

By late 1940 to mid-1943, Merlin engines were powering some of the most iconic planes of WWII. Without the supercharging of a Meteor engine, it was even powering tanks. In the middle of the war, the demand for the engine was huge, now being produced by both sides of the Atlantic, Rolls-Royce in England, and Ford and Packard in the US.

More Improvements

The development of the Merlin continued improving all the way through the war, from a thousand horsepower, a little bit more in the first production, all the way, including 1,350 for a Mk. V Spitfire, 1,650 to 1,700 in Mk IX, and Mk VIII Spitfire, and a P-51, all the way up to 2,050 hp in the de Havilland Hornet, which was built a little too late in action.

It was initially built for taking in Zeroes in the Pacific theater. However, the atomic bombings happened, and the Hornet didn’t get the chance to see service. However, with two 2,050 hp. Merlin, each with a two-speed, two-stage supercharger, a Hornet was just about the fastest production piston engine fighter ever built. By the end of the war, over 150,000 of these beautiful engines had been made, and their contribution to the war effort and the final victory of the Allies cannot be understated.