Aviation of Word War II
Fuselage: All-metal semi-monocoque square section with heavily rounded corners. The power set consists of 52 frames and stringers. Sheathing - duralumin sheets, riveted flush. Technologically, the fuselage was divided into five parts. The hatch for the crew to enter the aircraft was located in the lower part of the ventral gondola, there was an additional hole in the bottom of the rear fuselage. The glazed cap of the tail firing turret was opened by tilting to the side.
Single-spar wing with two auxiliary spars, trapezoidal shape with rounded tips. In the center section, motor mounts were attached to the main spar. In the front parts of the center section there are niches for the internal landing gear, and in the consoles - niches for the external landing gear. Behind them were wing-mounted petrol and oil tanks. Oil coolers are installed in the root parts of the consoles.
The wiring of the ailerons and flaps is rigid, the trim tabs are soft, cable.
The plumage is of the usual type, the keel and stabilizer are single-spar, trapezoidal. The stabilizer on early modifications is reversible, starting from A-3 - with a fixed installation angle of +2°. The metal skinned rudders are fitted with trim tabs and Flettner flaps. The steering wheel is tight.
Three-point chassis of the classical scheme. A characteristic feature of the machine was the twin main racks, each of which consisted of two separate "half-racks" with its own wheels and cleaning mechanisms. The inner "half-pillars" were removed towards the fuselage, and the outer ones - towards the ends of the wing. This design is caused by the desire to reduce the load on the wheels and fit rather massive chassis elements into a relatively thin wing, without "inflating" the engine nacelles. The tail wheel also retracted in flight by turning back into the fuselage. The release of racks and chassis shields was carried out using a hydraulic drive. The sashes in the parking position are closed and opened only at the time of release and retraction. Depreciation of the main struts is air-oil, tail - spring.
Powerplant. For He 177A-5, the DB 610 engine (paired with DB 603) was used instead of the DB 606 used on the first versions (paired with DB 601).
For their fire hazard, "Vultures" received the nickname "lighters", and there were good reasons for this. In an effort to improve aerodynamics, Heinkel's designers arranged the engine compartment so tightly that there was no room for fire bulkheads in it, and oil tanks and oil lines had to be installed next to the exhaust pipes, which often glowed red hot in flight. Electrical cables ran there. As a result, at the slightest depressurization, a fire became inevitable. In addition, at high altitudes, the oil sometimes boiled, while the lubrication of the engines was broken, the engines overheated and, at best, they stalled, and at worst, they caught fire.
Each pair of engines rotated a four-blade VISH automatic machine VDM with a diameter of 4.5 m through a reduction gear. In the event of an emergency, any engine could be turned off manually, for which special clutches served. The propulsion systems were cooled with a mixture of water and ethylene glycol, and to increase the survivability, the cooling system of each motor was a completely autonomous unit. For the same purpose, the frontal radiators in the engine nacelles were divided into four closed sections. The passage of air through the radiators was automatically regulated by thermostats and hydraulically controlled shutters. The fire extinguishing systems also operated automatically.
Despite the tests of one aircraft, on which 56 causes of engine fire were identified and eliminated, the problems could not be completely eliminated. Obviously, the finalization of the design could seriously slow down the production of machenes.
Defensive weapons. On the He 177A-5/R2 heavy defensive armament was installed to fight enemy fighters: on the tail turret (position 3) - 20 mm MG 151 gun , 300 rounds of which were in the ammunition box in the rear of the fuselage: on the rear dorsal turret (position B2) - MG 131 machine gun with 750 rounds, which controlled remotely from a blister above the cockpit; in the glazed nose - machine gun MG 81J (position A1) with 2000 rounds: in front of the ventral gondola 300 rounds, and in the back of the gondola - two MG 81 machine guns (position B) with 2000 rounds each.
He-177 aircraft were in service with KG-40 and KG-100, in which these bombers took part in air raids on London in the first weeks of 1944. Six aircraft of the A-6 modification had a pressurized cabin, but the problems with the reliability of the engines were not resolved. For example, in February 1944, out of 14 He-177a-5 aircraft that took off to bomb the British Isles, one could not take off as a result of engine problems, and 8 were forced to return halfway due to overheating or engine fire. Another plane was shot down by the enemy, so they reached England and dropped bombs on the target only four machenes.
In the end, tired of fighting the vagaries of "sparks", the Germans set about developing the "Vulture" with four conventional engines in four nacelles. At the end of 1943 and 1944, several prototypes of the aircraft were built, which received the designation He 177B (or He 277). But in June 1944, due to the rapid deterioration of the economic situation in Germany, the expensive project was closed.
Heinkel and Arado firms produced a total of 565 He-177A-5 aircraft.