Submarines and their Weapons - Aircraft of World War II

AIR-TO-AIR WEAPONS
aim on a target which was taking evasive action from
a fast-flying aircraft whose flight characteristics
caused it to snake at high speed. The answer, of
course, was to provide a guidance system to control
the missile in flight.
AIR-TO-AIR MISSILES
From as early as 1939, the Henschel company - a
newcomer to aviation, but with a very solid background
in heavy engineering - had maintained a team
whose task was to study the remote control of
unmanned aircraft. In January 1940, Herbert Wagner
arrived to head the team, with a brief from the RLM
to concentrate on air-to-surf ace missiles (ASMs). He
was successful, as we shall discover, and in 1943 the
company proposed a version of the Hs 293 ASM he
developed as an air-to-air missile (AAM). Like most
of the ASMs, the Hs 293H was a blast weapon, to be
guided into a bomber formation and exploded there,
instead of being aimed at an individual aircraft, and
had a 295kg (6501b) warhead. One version of it was
to have had a television camera in its nose, the picture
it transmitted to the controller allowing him a clear
view at ranges of up to about 4km (2.5 miles), but the
apparatus proved very unreliable, and the idea, also
tried out on the ASM itself, was shelved. Control was
line-of-sight from the launch aircraft, the operator
using a joystick to initiate radio signals which in turn
actuated control surfaces on the missile itself.
This system was to be used in all the German guided
missiles, and will be explained more fully below,
in the context of the surface-to-air missiles for which
it was originally developed. The missile had both
command and proximity fuzes as well as a barometric
fuze to ensure that it would self-destruct before it
hit the ground. It was powered by a specially designed
Schmidding rocket which used M-Stoff (methanol)
and A-Stoff (oxygen), the latter being, unusually, in
gaseous form, to produce 610kg (13401b) of static
thrust for 11 seconds. The Hs 293 was too big and
clumsy for the anti-aircraft role, and it comes as no
surprise to discover that after some initial enthusiasm,
the RLM went cold on the idea. By then, however,
Henschel had begun work on the 'Schmetterling' surface-to-air
missile (SAM; see Chapter Eight), and had
proposed a version for use in the AAM role.
THE HENSCHEL Hs117H
The Hs 117H, as the variant was known, was very little
different from the basic 'Schmetterling', save that
it required no external booster rockets, but it had a
significantly larger warhead, containing 100kg
(2201b) of explosive. It employed the same guidance
system as the Hs 293H. The intended range of the Hs
I17H was 6-10km (3.7-6.2 miles), at up to 5000m
(16,500ft) above the 'parent' aircraft, which was a
considerable improvement over the earlier missile. It
was still in development at the war's end, having survived
the axe which descended on so many development
projects in January 1945, it is suggested, simply
because it had so much in common with the ASM
from which it was descended.
Henschel also developed a missile specifically
intended for use in the air-to-air role, the Hs 298, considerably
smaller than either of the others and with
reduced range. Like them, it had swept-back wings
and a tailplane with short fins at its extremities, and
control was by means of solenoid-operated 'Wagner
bars' responding to radio signals. The motor was a
solid-fuel two-stage Schmidding 109-543 which gave
150kg (3301b) of thrust for five-and-a-half seconds
followed by 50kg (HOlb) of thrust for 20 seconds.
The first experimental Hs 298 was fired in May 1944,
and altogether some 300 were produced and expended
in trials. With a warhead containing either 25kg
(551b) or 48kg (1061b) of explosive, detonated on
command or by a proximity fuze, it had a range of up
to 2500m (2735 yards), travelled at either 940km/h
(585mph) or 680km/h (425mph), and was designed to
be deployed aboard piston-engined aircraft such as
Do 217s, Fw 190s and Ju 88s. Development ceased in
favour of the Ruhrstahl X-4 in January 1945.
THE RUHRSTAHL X-4
Ruhrstahl AG was, as its name suggests, a steelmaker.
In 1940 it was ordered to collaborate with Dr Max
Kramer of the DVL to develop a series of bombs and
missiles using the spoiler control method the latter
had demonstrated two years earlier. This collaboration
was to result in three very interesting missiles:
the so-called 'Fritz-X' guided glider bomb; the X-7
'Rottkappchen' ('Red Riding Hood') anti-tank missile;
and the X-4 air-to-air missile. Development of
the X-4 began in 1943 in parallel with Henschel's Hs
298. These two missiles had very similar specifications,
though it appears that the X-4 was designed
from the start to operate with jet aircraft, and thus
flew at higher speeds. The primary difference
between the X-4 and other missiles was that it was
equipped not with wings and a tailplane, but with two
sets of four fins, one set swept back at an acute angle,
with parallel chord width roughly halfway back from