Story of Heinkel He111. Part 2. German Dzib -Compiler-

Basic design

Picture 1

The design of the He 111 A-L initially had a conventional stepped cockpit, with a separate pair of windscreen-like panels just for the pilot and co-pilot. The introduction of the P variant meant that the He 111P and following production variants were fitted with a fully glazed "bullet" or "fishbowl"-like, laterally asymmetric nose, with the port side having the greater curvature for the pilot, off setting the bombardier to starboard. The resulting "steeples cockpit", which was a feature on the majority of German bomber designs during the war years in varying shapes and formats, no longer had the separate windscreen panels for the pilot, who now had to view their exterior flight environment through the same bullet-like glazing that was used by the bombardier and navigator. Within the cockpit the pilot was on the left and the navigator/bomb aimer on the right. The navigator went forward to the prone bomb-aiming position, or could tilt his chair to one side so that he could move into the rear of the aircraft. There was no cockpit floor below the pilot's feet - the rudder pedals being on arms - giving very good visibility below. (14)

Picture 2. 1,2 : The Norway-restored He 111P-2's nose, showing the nearly-straight right side of the P and H-series' laterally-asymmetric "stepless cockpit".

The fuselage contained two major bulkheads. The cockpit was at the front of the first bulkhead. The nose was fitted with a rotating machine gun mount which was offset to allow the pilot a better field of forward vision. The cockpit was fully glazed, with the exception of the lower right section, which acted as a platform for the bombardier-gunner to be positioned. The commonly-used Lotfernrohr series bombsight penetrated through the cockpit floor into a protective housing on the external side of the cockpit area. (14)  Between the forward and rear bulkhead was the bomb bay, which was constructed with a double-frame to strengthen it for carrying the bomb load. The space between the bomb bay and rear bulkhead was used up by Funkgerät radio equipment and contained the dorsal and flexible casemate ventral gunner positions. The rear bulkhead itself contained a hatch which led to the rest of the fuselage which was held together by a series of stringers. The wing was a two spar design. The fuselage was formed of stringers to which the fuselage skin was riveted. Internally the frames were fixed only to the stringers which made for simpler construction but at the loss of some rigidity (14)

The wings' leading edges were swept back to a point inline with the engine nacelles, while the trailing edges were angled forward slightly. The wing contained two 700 L (190 US gal) fuel tanks between the inner wing main spars, while at the head of the main spar the oil coolers were fitted. Between the outer spars, a second pair of reserve fuel tanks were located carrying an individual capacity of 910 L (240 US gal) of fuel. (14) The outer trailing edges were formed by the ailerons and flaps, which were met by smooth wing tips which curved forward into the leading edge. The outer leading edge sections were installed in the shape of a curved "strip nosed" rib, which was positioned ahead of the main spar. Most of the interior ribs were not solid, with the exception of the ribs located between the rear main spar and the flaps and ailerons. This was of solid construction, though even they had lightening holes. (14)

From the nose gunner's view

The control systems also had some innovations. The control column was centrally placed and the pilot sat on the port side of the cockpit. The column had an extension arm fitted and had the ability to be swung over to the starboard side in case the pilot was incapacitated. The control instruments were located above the pilot's head in the ceiling which allowed viewing and did not block the pilot's vision. (15) The fuel instruments were electrified. The He 111 used the inner fuel tanks closest to the wing root. The outer tanks acted as reserve tanks. The pilot was alerted to the fuel level when the tank had 100 L (26 US gal) left. A manual pump was available in case of electrical or power failure, but the delivery rate of just 4½ L (1.2 US gal) per minute demanded that the pilot fly at the lowest possible speed and just below 3,048 m (10,000 ft). Fortunately, the He 111 handled well at low speeds. (16)

Single (loose) and twinned (MG 81Z in case) MG 81 machine guns.

The defensive machine gun positions were located in the glass nose, the flexible ventral, dorsal and lateral positions in the fuselage, and all offered a significant field of fire. (16) The design of the nose allowed the machine gun position to be moved 10° upwards from the horizontal and 15° downwards. (16) The gun could traverse some 30° laterally. Both the dorsal and ventral machine guns could move up and downwards by 65°. The dorsal position could move the 13 mm (.51 in) MG 131 machine gun 40° laterally, but the ventral Bola-mount 7.92 mm (.312 in) twinned-up MG 81Z machine guns could bemoved 45° laterally. Each MG 81 single machine gun mounted in the side of the fuselage in "waist" positions, could move laterally by 40°, and could move upwards from the horizontal by 30° and downwards by 40°. (16)

Two views from He 111 Nose and MG 131

  

Early civilian variants

 

The first prototype, He 111 V1 (W.Nr. 713, D-ADAP), first flew from Rostock-Marienehe on 24 February 1935. (17) It was followed by the civilian-equipped V2 and V4 in May 1935. The V2 (W.Nr. 715, D-ALIX) used the bomb bay as a four-seat "smoking compartment", with another six seats behind it in the rear fuselage. V2 entered service with Deutsche Luft Hansa in 1936, along with six other newly built versions known as the He 111C (18) The He 111 V4 was unveiled to the foreign press on 10 January 1936 (18) Nazi propaganda inflated the performance of the He 111C, announcing its maximum speed as 400 km/h (249 mph), in reality its performance standing at 360 km/h (224 mph). (19) The He 111 C-0 was a commercial version and took the form of the V4 prototype design. The first machine, designated D-AHAO "Dresden". It was powered by the BMW VI engine and could manage a range (depending on the fuel capacity) of 1,000 km (621 mi) to 2,200 km (1,367 mi) (19) and a maximum speed of 310 km/h (193 mph). (20) The wing span on the C series was 22.6 m (74 ft 1¾in). (20) The fuselage dimensions stood at 17.1 m (56 ft 1¾in) in the He 111 V1, but changed in the C to 17.5 m (57 ft 5 in). The Jumo 205 diesel-type powerplant engine replaced the BMW VI. Nevertheless, the maximum speed remained in the 220–240 km/h (137–149 mph) bracket. This was increased slightly when the BMW 132 engines were introduced. (20)A general problem existed in powerplants. The He 111 was equipped with BMW VI glycol-cooled engines. The German aviation industry lacked powerplants that could produce more than 600 hp. (9) Engines of suitable quality were kept for military use, frustrating German airline Luft Hansa and forcing it to rely on the BMW VI or 132s. (20)

Prototype He 111 V 16 D-ASAR

The He 111G was an upgraded variant and had a number of differences to its predecessors. To simplify production the leading edge of the wing was straightened, like the bomber version. Quite a few different engine types were used, among them the BMW 132, BMW VI, DB 600 and DB601A. Some C variants had been upgraded with the new wing modifications. A new BMW 132H engine was also used in a so-called Einheitstriebwerk (unitary powerplant). These radial engines were used in the Junkers Ju 90 and the Focke-Wulf Fw 200. The wing units and engines were packed together as complete operating systems, allowing for a quick change of engine. (21) The He 111G was the most powerful as well as the fastest commercial version. (21) The G-0 was given the BMW VI 6.0 ZU. Later variants had their powerplants vary. The G-3 for example was equipped with the BMW 132. The G-4 was powered by DB600G inverted-vee 950 hp (710 kW) engines and the G-5 was given the DB601B with a top speed of 410 km/h (255 mph). By early 1937, eight G variants were in Lufthansa service. The maximum number of He 111s in Lufthansa service was 12. The He 111operated all over Europe and flew flights as far away as South Africa. Commercial development ended with the He 111G. (21)