Aviation News – June 2018

of 3,100 miles (4,898km), and engines either

supplied by Argus, Daimler-Benz or Junkers.

Take-off run was to be 3,000ft (914m) and

the aircraft was required to carry normal

bombs up to 250kg, but with the capacity to

load heavier munitions.

Manufacturers Blohm und Voss, Heinkel,

Henschel, Junkers and Messerschmitt had

two months to submit proposals. Heinkel

was successful and design work began in

early 1937 on what would become the He

1 7 7.

A series of interventions followed, either

from the military or politicians, which delayed

a project already wallowing in a series of

technical difficulties.

PROBLEMS

The first prototype was expected to fly in

June 1938, but it was clear there were

faults with the cockpit layout. During the

redesign, senior German political leaders

again questioned the need for a strategic

bomber. Then, the Luftwaffe insisted the

range, altitude and crew size was increased

with the aircraft being capable of dive-

bombing, which meant the fuselage had to

be strengthened.

Vibration was a problem, while the

suitability of the powerplant was also

called into question. Two engines on each

wing were linked to a single airscrew to

achieve the specified distances and height.

However, the Daimler-Benz DB 606 coupled-

engine was still experimental and further

problems emerged. Despite these concerns

and setbacks, the Luftwaffe continued

supporting the design, expecting delivery of

the first aircraft at the end of February 1940.

The paired engines ran hot, not helped by

a revolutionary evaporative cooling system

that was found to be insufficient. Radiators

were fitted, increasing the drag, which

required more power from the engines. It

was a vicious circle.

The aircraft’s weight grew and, as a

result, the top speed dropped to just in

excess of 280mph (451km/h).

Construction and design refinement

continued throughout 1939. Even before the

first prototype flew, a contract for 800 aircraft

for delivery by April 1943 was placed.

At long last, on November 9, 1939, the

first prototype took to the air for a 20-minute

flight with the landing gear locked down.

Immediately, there were concerns about the

undercarriage shock absorbers, brakes, high

rudder forces and poor cockpit conditioning.

In addition, engine oil temperatures

increased beyond safety margins.

The next flight, 11 days later, saw the

wheels retracted (albeit very slowly) but then

an undercarriage door broke loose.

Myriad problems emerged as testing

continued and there were two crashes.

The first operational trial was not until

February 1941. At the same time, the initial

pre-production aircraft began flight testing

with at least two prototypes undergoing

a limited programme with IV Gruppe/

Kampfgeschwader 40 from August 1941

onwards.

Engine failures, major component

shortages, delivery delays and accidents

continued to plague the He 177 and lack

of defensive armament then became an

issue. The bomber, originally designed with

manual guns, was changed to use remote

turrets.

Twelve months elapsed in finding

solutions to the problems, only for

another issue to raise its head in early

1942. As flight testing continued, engine
      fires began to increase – oil caught
      fire after flowing through holes made in
      the crank case when con rods failed.
      Softer aluminium rivets had been used
      in construction rather than the harder
      duralumin rivets. When this was sorted,
      manufacturing faults in the propeller

http://www.aviation-news.co.uk 79

This 2./KG 100 example, 6N+SK, also carries the name Susi.

The eighth prototype, Wk Nr 0008 coded SF+TC, which later flew with IV./KG 40.

78-82_he177DC.mfDC.mfDC.mfDC.mf.indd 79 02/05/2018 12:45