Submarines and their Weapons - Aircraft of World War II

Rhine at Remagen between 7 and 17 March, when Ar
234s made repeated and often suicidal attacks supported
by Me 262 bombers of KG 51. A night-fighter
version of the Ar 234 was produced in small numbers,
and operated from March 1945 with some success.
Later Ar 234 variants had a variety of different powerplants,
and a four-engined version using 'siamesed'
nacelles was also produced in prototype. Maximum
speed at medium level of the latter was over 850km/h
(530mph), which was beyond the level-flight capabilities
of any Allied fighter, but still by no means fast
enough for absolute safety. The limiting factor on its
performance was not, however, the engines: it was the
design of the wing. Straight wings have a finite maximum
speed, after which compression causes local
airflow to exceed the speed of sound, resulting in
potentially catastrophic instability. Arado's engineers
discovered this the hard way, but soon designer
Riidinger Kosin came up with an alternative planform:
a crescent wing, starting out with its leading
edge sweeping back from the wing roots, the curve
returning so that the wingtip sections were at rightangles
to the body axis (a form which was later used
in the British Handley-Page 'Victor' bomber). Wind
tunnel tests showed this to be much more effective,
but the war ended before a prototype could be constructed.
And even while the Ar 234 was in development,
engineers elsewhere were looking at much
more advanced concepts.
Left: The Arado Ar 234 - this is the production-B variant -
with its long, slim fuselage and wings, was the only real
alternative to the Me 262, but was nowhere near as
successful in operational terms.
ARADO Ar 234B-2
Type: Single-seat tactical light bomber
Length: 12.64m (41.46ft)
Span: 14.44m (46.29ft)
Max take-off weight: 9800kg (21,605lb)
THE JUNKERS Ju 287
JET AIRCRAFT
There is no space here to go into the complex aerodynamics
of wing form in any depth, save to say that as
early as the mid-1930s, it had been accepted - following
the work of the Deutsches Versuchsanstalt für
Luftfahrt (DVL - the German Aviation Development
Establishment) - that straight wings had a finite speed
limit thanks to the rise in drag caused by air compressing
at their leading edge. As we have seen, this
was the main factor in limiting the speed of the Ar
234. An interim solution was to sweep the leading
edge backwards but keep the trailing edge straight,
thus producing a variable-chord wing, and this was
adopted with piston- and jet-engined aircraft alike.
The Me 262 had a wing essentially of this form
(although it did have a small sweep to its trailing edge
outboard of the engines) as did the altogether more
pedestrian Douglas C-47/DC-3 transport. At this
time, no aircraft had flown with a wing that had
steeply swept leading and trailing edges, even though
it was known from wind tunnel testing that such a
wing would benefit not only from decreased compressibility
but also from a reduction in the ratio
between its thickness and its chord (the distance
between the leading and trailing edges).
In June 1943, at about the time when the Arado Ar
234 first flew, a development team at Junkers, under
Dr Hans Wocke, produced a design for an advanced
bomber using a double-swept wing form, but with one
Below: A total of 210 examples of the Arado Ar 234B were
produced; just one remains, on display in the Smithsonian
Institution's National Air and Space Museum in
Washington D.C.
Max speed: 742km/h (461 mph) at 6000m
(19,700ft)
Range: 1630km (1013 miles)
Armament: 2 x 20mm machine guns
(some aircraft); 2000kg (4400lb)
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