In 1944 the RLM issued a requirement for an aircraft with a range of 11000
km (6835 miles) and a bomb load of 4000 kg (8818 lbs). This bomber was
to be able to fly from Germany to New York City and back without refueling.
Five of Germany's top aircraft companies had submitted designs, but none
of them met the range requirements for this Amerika Bomber. Their
proposals were redesigned and resubmitted at the second competition, but
nothing had changed. The Hortens were not invited to submit a proposal
because it was thought that they were only interested in fighter aircraft.
After the Hortens learned of these design
failures, they the went about designing the XVIII A Amerika Bomber.
During the Christmas 1944 holidays, Reimar and Walter Horten worked on
the design specifications for their all-wing bomber. They drew up a rough
draft and worked on weight calculations, allowing for fuel, crew, armaments,
landing gear and bomb load. Ten variations were eventually worked out,
each using a different number of existing turbojets. Several of the designs
were to be powered by four or six Heinkel-Hirth He S 011jet engines, and
several of the others were designed around eight BMW 003A or eight Junker
Jumo 004B turbojets.
The version that the Hortens thought would
work best would utilize six Jumo 004B turbojets, which were buried in the
fuselage and exausted over the rear of the aircraft. They were fed by air
intakes located in the wing's leading edge. To save weight they thought
of using a landing gear that could be jettisoned immediately after takeoff
(with the additional help of rocket boosters) and landing on some kind
of skid. The Ho XVIII A was to be built mainly of wood and held together
with a special carbon based glue. As a result, the huge flying wing should
go largely undetected by radar.
The Hortens were told to make a presentation
for their Amerika Bomber design on Febuary 25, 1945 in Berlin. The
meeting was attended by representatives of the five aircraft companies
who originally submitted ideas for the competition. No one challenged their
assertion that their flying wing bomber could get the job done. A few days
later the Hortens were told to report to Reichsmarshall Göring, who
wanted to talk to the brothers personally about their proposed Amerika
Bomber. There they were told that they were to work with the Junkers
company in building the aircraft.
Several days later Reimar and Walter Horten
met with the Junkers engineers, who had also invited some Messerschmitt
engineers. Suddenly it seemed that the Horten's design was to be worked
on by committee. The Junkers and Messerschmitt engineers were unwilling
to go with the design that the Hortens presented several days earlier.
Instead, the committee wanted to place a huge vertical fin and rudder to
the rear of the Ho XVIII A. Reimar Horten was angry, as this would add
many more man-hours, plus it would create drag and thus reduce the range.
The committee also wanted to place the engines beneath the wing, which
would create additional drag and reduce the range even further. After two
days of discussion, they chose a design that had huge vertical fins, with
the cockpit built into the fin's leading edge. Six Jumo 004A jet engines
were slung under the wing, three to a nacelle on each side. The bomb bay
would be located between the two nacelles, and the tricycle landing gear
would also be stored in the same area. The committee would present the
final design to the RML and recommended that it be built in the former
mining tunnels in the Harz Mountains. Reimar was unhappy with the final
design, so he went about redesigning the aircraft, to be known as the Ho
m (131' 4") Length:
Max. Speed: 900 km/h (559 mph)
Artist's conception of the Horten Ho XVIII A
Many thanks to Dr. David Myhra, who graciously
sent me the above material (text and pictures)
from his new book, The Horten Brothers and
Their All-Wing Aircraft, published by Schiffer.