Issue No 22 THE AVIATION HISTORIAN 111T
HE NIMROD WAS essentially
an extensively modified
military variant of the de
Havilland Comet, the world’s
first jet airliner. Originally
designed by de Havilland’s successor,
Hawker Siddeley, it subsequently had
its development and maintenance
undertaken by that company’s own
successor, British Aerospace (BAe).
Intended to replace the RAF’s
fleet of ageing Avro Shackletons,
the Nimrod was designed to Air
Staff Requirement (ASR) 381, issued
in 1964. Introduced into RAF service in
1969, the Nimrod MR.1 and MR.2 were used
extensively thereafter in the anti-submarine
warfare (ASW) and maritime surveillance (MS)
roles. A lesser-known variant was the Nimrod
R.1, a dedicated signals intelligence-gathering
(SIGINT) and surveillance platform. The R.1s
were often referred to as “Radar Calibration
Aircraft” to hide their true role, and it was not
until the fall of the Berlin Wall and the end of the
Cold War that the real purpose of these aircraft
was officially acknowledged.Into service
The Nimrod R.1 was operated exclusively by No
51 Sqn at RAF Wyton, the unit having reformed
from the renumbered No 192 Sqn on August 21,
1958, and having previously operated adapted
English Electric Canberras and the Comet 2R
until the Nimrod R.1 replaced them in 1974.Three Nimrod R.1s (originally desig-
nated HS.801Rs) were ordered in 1969,
with development costs of an estimated
£2.38m and projected production costs
of £11.5m. The first R.1, XW664, was
delivered as an empty airframe
to Wyton in July 1971 but it took
a further two years to equip the
highly secret aircraft with its highly
specialised electronic equipment.
Externally the R.1 differed
very little from its ASW and MS
counterparts, the only recognisable
difference being the absence of
the latter’s distinctive magnetic anomaly
detector (MAD) boom, used to find submarines.
Internally, however, the R.1 was vastly different
from the MR.1/MR.2, and received a number
of substantial upgrades throughout its service
life. From 1980 the three R.1s — XW664,
XW665 and XW666 — received upgrades to
their surveillance equipment, including the
installation of an ECKO 290 weather-radar
suite to replace the antiquated ASV.21 ASW
radar system and the addition of a Delco AN/
ASN-119 Carousel IVA inertial navigation system
(INS) to replace their long-range navigation
(LORAN) suites. Wingtip-mounted pods, similar
in appearance to the electronic support measures
(ESM) equipment fitted to the MR.2, were also
fitted to the aircraft.
Although official information about the R.1’s
participation remains scarce even today, the
variant was sent to war when XW664 was postedOPPOSITE PAGE, TOP Nimrod R.1 XW666 in the waters of the Moray Firth immediately after its ditching on
May 16, 1995. OPPOSITE PAGE, BOTTOM The same aircraft at No 51 Sqn’s base at RAF Wyton in the 1970s,
photographed in its original grey maritime colour scheme. ABOVE Nimrod R.1 XW665 in the later “hemp” scheme.HE NIMROD WAS essentiallyHavilland Comet, the world’sThree Nimrod R.1s (originally desig-
nated HS.801Rs) were ordered in 1969,
with development costs of an estimated
£2.38m and projected production costs
of £11.5m. The first R.1, XW664, wasVIC FLINTHAM