"It's a Heinkel"
The Luftwaffe's workhorse Heinkel 111 bomber
by Randy Wilson
Copyright © 1996 by the Confederate Air Force and Randy Wilson. All rights reserved.
Today, if one suggested that an aircraft could be designed as both a commercial airliner and a fast bomber, they would be laughed at, and their sanity questioned. That was the specification, however, issued in early 1934 to the designers at both Heinkel and Junkers by the Third Reich's Reichswehr (state armed forces) and Deutsche Lufthansa (DLH), Germany's national airline. At that point in aircraft development, the structural and aerodynamic requirements of a high speed twin-engined bomber and those of a fast, long range 10-passenger airliner were not that different, especially when the DLH airliners were to be flagships for Germany's newly revitalized aircraft industry.
The Junkers response was the Ju 86, which was initially powered by Junkers Moterenbau (Jumo) diesel engines. The Ju 86 saw service with the Luftwaffe in Spain during the Spanish Civil War, in support of the right-wing Nationalist forces of Gen. Franco against the left-wing Republican government. Export versions of the bomber and transport were also used by Sweden, Portugal, Chile, Hungary and South Africa. By the start of the Second World War, however, the Ju 86 was withdrawn from front-line Luftwaffe service, except for a high-altitude reconnaissance variant, the Ju 86P.
Prototypes and Initial Production
The He 111 was developed at Heinkel's Marienehe factory by Siegried and Walter Gunter and initially powered by two BMW VI 6.0 Z 600 horsepower 12-cylinder liquid-cooled engines. The initial prototype, the He 111a, was a bomber version and first flew on February 24, 1935, demonstrating a maximum speed of 217 mph. Two more BMW-engined prototypes followed, the He 111c which was configured as a commercial airliner and mail plane and eventually served with DLH on South American routes, and the He 111b, a second bomber prototype. All three differed in details of their elliptical wings.
Using results gained from the first three aircraft, the He 111 V4 flew in late 1935, fully equipped as a 10-passenger airliner and serving as the production prototype for the He 111C commercial transport series. A new system of Versuchs (experimental) numbers had been introduced throughout the German aircraft industry, using the letter V and a number to designate experimental aircraft. Thus, the He 111 V4 was the fourth prototype or experimental version of the He 111.
A pre-production batch of 10 He 111A-0 bombers was ordered in late 1935 and began tests with the Luftwaffe the next spring. Powered by the same BMW engines as the first prototypes but with an increased gross weight of 18,122 lbs with 2,205 lbs of bombs and three 7.9mm machine guns, these aircraft were obviously underpowered, with a top speed of only 192 mph and cruise of only 168 mph. With the retractable ventral gun position, or "dustbin", lowered to defend against fighter attacks from the rear or below, speed was even further reduced. The Luftwaffe rejected the BMW-powered version but Heinkel was allowed to sell the 10 aircraft to China.
Heinkel had already obtained two early examples of Daimler-Benz's new DB 600 12-cylinder inverted-Vee liquid-cooled engine, and fitted in the He 111 V5, these pre-production engines gave a top speed of 224 mph and a cruise of 211 mph. The result was a Luftwaffe order for the He 111B-1, most of which were powered by the DB 600C of 880 horsepower, with the first aircraft reaching bomber units in the winter of 1936.
Despite emphasis on the bomber versions, Heinkel delivered six He 111C commercial airliners to DLH in mid-1936 and continued the development of a Daimler-Benz powered He 111G series of transports, some of which were exported to Turkey. This model featured a redesigned wing with straighter edges in place of the difficult to built elliptical shape of the original wing. All of DLH's He 111s were impressed by the Luftwaffe after the outbreak of the war in 1939.
With the Condor Legion in Spain
To test its new bomber in combat, Germany sent 30 He 111Bs to its Condor Legion in Spain in February 1937, where they proved a success, being as fast or faster than most opposing fighters. A newly built factory at Oranienburg began delivery of improved He 111B-2s, fitted with 950 horsepower DB 600CG engines, to both Luftwaffe and Condor Legion units in the later half of 1937.
A Problem of Engines
In late 1937, the He 111D series entered production, benefitting from a number of aerodynamic changes and DB 600Ga engines with improved supercharging, which gave it a top speed of 255 mph at 13,120 feet and 230 mph even with the "dustbin" lowered. However, the demand for Daimler-Benz engines in Messerschmitt's Bf 109 and Bf 110 fighters outstripped the supply of these engines, forcing Heinkel to cancel production of the He 111D and begin work on a Junkers Jumo powered E series.
The 1,000 horsepower Jumo 211A engine was similar to the DB 600 in general design, having a slightly greater displacement of 2136 cubic inches vs. the DB 600's 2069 cubic inches. Delivery of Jumo-powered He 111E-1s began in February 1938, and in March arrived in Spain. The success of He 111s in unescorted raids over Spain enforced the Luftwaffe's belief that high-speed bombers could survive without close fighter escort and with only light defensive armament, a belief which was shattered in the air over Britain in 1940.
In late 1937, the straight-tapered wing developed for the He 111G transports was mated with Jumo 211A-3 engines of 1,100 horsepower to produce the He 111F series, 24 He 111F-1s were purchased by the Turkish Air Force and 40 He 111F-4s went to the Luftwaffe. By mid-1938, the supply of DB 600CG engines had improved enough that they powered the 90 He 111J-1s which were originally ordered by the Luftwaffe as torpedo bombers, but ended up differing little from the F-4 model, except for their powerplants.
A New Look
A major change in the appearance of the He 111 came with the introduction of a new aerodynamic nose and crew compartment in the P series, which first flew in late 1938. In addition to the straight-tapered wing, the He 111P replaced the retractable "dustbin" with a permanent ventral gun position, in which the gunner lay prone, and provided for the fitting of either Daimler-Benz or Junkers Jumo engines without major redesign. The first He 111P-1s were delivered in early 1939, with a top speed of 249 mph at 16,400 feet lightly loaded, and a maximum of 202 mph with eight 551 lb bombs stored vertically in its bomb bay. The DB 601A-1 engines featured Bosch direct fuel injection with a maximum rating of 1,100 horsepower, but the bomber's defensive armament remained just three hand-operated 7.9mm machine guns.
The Jumo-powered He 111H-1 entered production a few months after the P series, but on September 1, 1939, the Luftwaffe had more He 111Hs than any other model of the Heinkel bomber, and continued demand for the Daimler-Benz engines for fighter production resulted in the He 111H being the major production series for the rest of the war.
From Phoney War to Battle of Britain
During the invasion of Poland and subsequent operations in Norway and France during the first eight months of the so-called "Phoney War", losses of He 111s to enemy fighters caused its defensive armament to be increased on newer models to a total of five or six machine guns. When the Luftwaffe launched its air assault on Britain on August 13, 1940 (Adler Tag or Eagle Day) He 111Ps and Hs made up a large number of the bomber forces in what came to be known as the Battle of Britain, and they suffered crippling losses at the hands of the RAF's determined Hurricane and Spitfire squadrons.
The He 111H-3 was the major production version throughout 1940, the next standardized version being the He 111H-6 produced from late 1941. Powered by Jumo 211F-1 engines of 1,340 horsepower, the H-6 could carry heavy external loads, including bombs larger than 551 lbs or a pair of torpedoes, beneath the fuselage. The He 111H-6 was both versatile and well liked by its crews, serving on all fronts with the Luftwaffe. By mid-1942, the He 111 was expected to be replaced with two more modern designs, the He 177 and the Ju 288, which would take over the heavy and medium bomber roles respectively. However, delays in development of both designs, and their eventual failure, caused production of the older Heinkel design to continue.
Special Versions and Final Production
A number of special use versions of the He 111H were built, including those designed as aerial guided missile and bomb launchers, but the third standard model to see large production was the He 111H-16. When German positions began to be encircled on the Russian Front in 1942, many older He 111s were used as transports for both men and supplies, and the He 111H-20 was delivered as a transport and glider tug in late 1942.
The most unusual variant of the Heinkel design was the He 111Z Zwilling (Twins), basically two He 111H-6 or H-16 fuselages joined with a new center wing section mounting a fifth Jumo 211F-2 engine. Designed to tow the huge Me 321 cargo glider, a total of twelve were built and continued in service until late 1944. The He 111Z-1 weighed 55,400 lbs fully loaded and had a top speed of 272 mph at that weight. Normal towing speed with an Me 321, however, was only 137 mph.
In the autumn of 1944, nine years of production ended with the He 111H-23, the last of over 7,300 He 111s produced in Germany, the design having remained in service years longer than ever expected, due to the failure of all its planned successors.
Continued Production in Spain
However, 58 He 111s of the former Condor Legion remained in Spain after the end of the civil war, and they were so popular with the Spanish aircrews that Construcciones Aeronauticas S.A. (CASA) obtained a license from Heinkel to produce the He 111H-16 at a plant in Seville, Spain. Three versions were produced for the Spanish Air Force, a medium bomber (C.2111-A), a reconnaissance bomber (C.2111-C) and a dual-control trainer (C.2111-F).
The first CASA aircraft were delivered in 1945, and production of all types totaled about 130, all equipped with German supplied Jumo 211F-2 engines. By the mid-1950s, however, continued production and even maintenance required a new source of engines, and in April 1956, 173 Rolls-Royce Merlin 500-20 engines were ordered from Great Britain. The Merlin powered bombers were designated C.2111-B, the reconnaissance bomber C.2111-D, and a new version, a nine-passenger transport, the C.2111-T8, was produced.
The last Spanish Heinkels were retired in the late 1960s. The Ghost Squadron's He 111 is one of the CASA-built transports modified to resemble a bomber for the epic movie The Battle of Britain and is one of the last of the graceful Heinkels still flying.
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