German Fighter Engines in World War 11

The He112 and the Me109 were both low-wing monoplanes of advanced design and nearly equal in performance. However, the RLM tended to restrict individual aircraft manufacturers to one class of aircraft. As Heinke! was already producing the He111 medium bomber, the Messerschmitt plane was accepted. The Me109 was also less sophisticated than the He112, probably less vulnerable, and more suited to mass production.

Heinkel was disappointed about this decision and demonstrated the quality of his fighter by setting up a world speed record of 465mph on 30 March 1939 with the He100 V-8, a modified He112. Messerschmitt, on the other hand, was not content with his former record. He equipped his 109 with an OB601A engine, boosted to a continuous power output of 1,400hp and a short time maximum power of 1,600hp. With this he achieved a new world speed record of 470mph on 26 April 1939.

By this time the Me109D, equipped with a Daimler Benz D8600 engine rated at 1,000hp, had proved its superiority during the Spanish Civil War. During 1938 and 1939 the E model was followed with the DB601A; a liquid-cooled, 12-cylinder inverted inline engine with fuel injection and rated at 1,200hp. It had a three-bladed variable pitch propeller with manual and, later, automatic pitch control.

At the outbreak of war, all German fighter units were flying these two models, the Ds gradually being replaced by the Es. There was no urgent need to replace these aircraft, since the E was considered to be at least equal to the early version of the Spitfire.

But Adolf Galland, at that time OC 26 Fighter Wing stationed in northern France, states in his book The First and the Last that by the summer of 1940, the Spitfire was already a serious adversary; although slightly slower, it was superior in manoeuvrability. The primary RAF fighter aircraft at this time, the Hawker Hurricane, was no match for the Me109.

German aircraft still had a slight advantage with their superior weapons and the fuel injection system which allowed unrestricted negative accelerations. Nevertheless, during a visit of the Commander in Chief German Air Force, Reichsmarschall H. Goering, a few weeks later, Galland and Werner Moelders, OC 51 Fighter Wing, were asked what they would like to have to improve the combat capability of their fighter units. Moelders asked for a Me109 with a more powerful engine. Galland requested Spitfires.

Another German fighter ace, Col Priller, writes in his memoirs: ”The Me109E was superior to the French fighter aircraft, but inferior in climb, manoeuvrability and speed to the British Spitfire of 1941. ”

At the beginning of 1941 the first fighter squadrons were equipped with the Me109F. Its OB601N engine required 100-octane fuel, which was difficult to obtain, and was soon replaced by the DB601E engine, rated at 1,350hp and requiring only lower-octane fuel. Apart from the engine, the Me109F-4 (with the DB601E) differed from the Me109E (with the DB601A) in having rounded wingtips, a larger fuel tank and two automatically controlled coolers beneath the wing roots. A retractable tailwheel! Reduced its drag.

The F-4 was less manoeuvrable than the Spitfire V but was considered to be equal in speed; moreover, for the first time, German pilots were able to outclimb the Spitfire.

In August 1941 another famous fighter aircraft appeared on the scene: the Focke Wulf 190. Professor Kurt Tank, in charge of the Focke Wulf factories, had been directed by the ALM as early as 1938 to develop a new fighter aircraft that would be easier to fly than the Me109 and outperform it and the Spitfire.

In June 1939 the Fw190 made its first flight, powered by a double-row radial BMW139 engine delivering 1 ,500hp. The aircraft underwent a thorough test programme until mid-1941. This included evaluation flights to compare the 190 with the 109 and captured Spitfires.

Serious problems with the cooling system required major modifications to the BMW139 engine, and as a result, the BMW801 was evolved. This was a double-row air-cooled radial engine with 14 cylinders and a supercharger, rated at 1,560hp and in the D-2 version at 1,700hp. Exhaust-pipe boost jets provided approximately 320lb thrust at a maximum performance altitude at 392mph. A command and control unit automatically regulated mixture, ignition, supercharger, fuel injection pump, engine speed and other engine functions.

Until the summer of 1942, the Fw190 and the Me109 F-4 performed well against their main adversary, the Spitfire VB, creating a serious threat to the British air defence. As a countermeasure, a number of Spitfire VC aircraft were equipped with Merlin 61 engines. Comparative flights showed a small advantage for the Fw190 A-3 between 2,000 and 8,000ft. Above 25,000ft the Spitfire was faster; up to this altitude, both aircraft were equal in their climb speeds. At all altitudes, the Spitfire proved its superb manoeuvrability.

The following year saw the introduction of the Merlin 66 and 70, the Merlin 70 replacing the 61 in the high-altitude versions of the Spitfire. With these new engines, the aircraft received the designation Spitfire IX LF (low-altitude fighter) and HF (high-altitude fighter) respectively. Although the Spitfire IX was planned only as an intermediate solution, more than 5,500 were built.

With the appearance of the Griffon-powered Spitfire XII, designed to counter the low-level threat of the Fw190, an urgent uprating of German fighter aircraft became essential. Enemy aircraft were now proving their superiority at all altitudes.

Two new improved BMW801 engines for the Fw190, the E and the F model with a power output of 2,000 to 2,200hp had been ground-tested successfully, but wartime Germany was unable to procure the necessary machinery, tools and metals for their production. These engines might have provided sufficient power for the heavy 190 to match the advantages of the light Spitfires. The MW50 water-alcohol injection system and the GM-1 nitrous oxide system were therefore developed to provide a short-term power boost for combat and emergencies.

The MW50 system increased the power output of the BMW8Q1 to 2,100hp, but created difficulties for the engine and only later could it be used for more than ten minutes at a time. The DB engines of the Me109 were more easily adaptable and used the system right from the beginning without major problems.

With the GM-1 – jokingly called the “Goering Mischung (Goering Mixture)” – nitrous oxide was injected into the fuel system. The system worked satisfactorily, but fuel consumption increased enormously, the components were heavy and the mechanism was very complicated.

By 1943 the war in the air had moved from low and medium level to high altitudes. The main task of German fighter operations in the west and over Germany became air defence against enemy bombers. On daylight raids, these were heavily protected by escort fighters. Thus a hit-and-run tactic had to be applied, with a fast attack on the bombers and a hasty retreat before escort fighters were able to engage.

The need to reach extremely high service ceilings became as important as speed and manoeuvrability. Up to that time Germa11 fighters had been able to reach altitudes slightly higher than the bombers. However, Mosquitoes, Lightning, Spitfires and Mustangs were able to fly their missions practically unmolested at altitudes no German fighter could reach and thus had all the advantages of the initiative.

In 1943 the Me109G was introduced as a high-altitude fighter. With an advanced supercharger, pressurised cockpit and the MW50 system the aircraft’s performance was improved, but it was in no way superior to enemy aircraft.

The last 109 models to see combat, the K, did not arrive until mid-1944. Its engine, the DB605AM, had the powerful supercharger of the 08603 – an engine approximately 25% larger than the 08605- and the MW50 system. Take-off power was 1,800hp and the service ceiling was above 41,000ft.

The last propeller-driven fighter to enter the war, in mid-1944, was the Fw190 0-9, the “Longnose”. It had the liquid-cooled 12-cylinder inline Jumo 213A-1 engine. The performance of this aircraft was excellent and further improvements could have been expected. However, a new age was dawning which revolutionised the entire flying scene. Jet aircraft made their appearance and proved their immense superiority against aircraft with conventional engines.

When writing this article I felt sorry for Professor Heinkel. He was always well ahead of his main competitor Messerschmitt in research, design and development, yet his piston-engined fighter aircraft were never accepted for mass production.

However, as regards engines, I feel that the best design was invariably selected for the most suitable airframe. All the engine manufacturers – Daimler Benz, Junkers, BMW, etc – shared in tne production of excellent engines. And if further uprating of one engine was not possible, there was usually some other powerplant available which had already proved its worth in service.