Fortress Mk III
The RAF used the B-17G (Fortress Mk. III) for RCM duties with squadrons
of 100 Group during 1944/45. This Mk. III with black-painted undersides has the
prominent fairing under the forward fuselage for British H2S radar. A
Consolidated Liberator is visible to the right.
With its forward fuselage (cheek) windows overpainted and a prominent
`flame-damper’ visible beneath its outboard engine, Fortress Mk. III HB796 has
the tall Type 313 transmission mast amidships, and smaller spine aerial for the
Airborne Cigar jammer. It later served with 214 Squadron.
The tail `stinger’ of a 100 Group Fortress Mk. III; the TV-like aerials
on each side were for Airborne Grocer equipment, aimed to jam German airborne
interception radars. The smaller lower antenna was a Monica IIIE tail warning
radar transmission aerial, its receivers being two diminutive blades on each
side of the fin.
Many RAF 100 Group Fortress Mk. IIIs carried a large radome for British
H2S radar equipment beneath the forward fuselage, where the B-17G’s chin turret
was usually installed. Conversion work was carried out by Scottish Aviation Ltd
In February 1944 the USAAF started to divert an eventual
total of 98 B-17G bombers to the RAF, in whose service the type received the
designation Fortress Mk III. Some of the aircraft were operated by Coastal
Command for the long-range maritime and weather reconnaissance roles, but
others were operated by two squadrons of Bomber Command’s No. 100 Group for a
variety of electronic warfare tasks after specialised jamming and deception
equipment had been installed.
The B-17G was supplied in comparatively small numbers to the
RAF, and played a largely unpublicised but nonetheless important and
Long before the dramatic exploits of the USAAF’s B-17G fleet
had taken place, the first B-17s flown in combat were the early C models
(Fortress Mk. I) of the RAF’s 90 Squadron, Bomber Command, during July 1941.
Some historians state the lack of success achieved in these early operations as
the reason why the B-17 never served in large numbers with the RAF. Whatever
the reason, as recounted earlier in this book, the RAF received just a
comparatively small total of B-17s of various versions. Twenty Fortress Mk. Is
were followed by the Mk. IIA (B-17E equivalent) and the Mk. II (B-17F), both of
which served with squadrons of Coastal Command where their exceptional
endurance proved important on long-range antisubmarine patrols. One of the
principal operators was 220 Squadron, which had flown Fortresses since
receiving ex-90 Squadron Fortress Mk. Is during late 1941 and early 1942.
The B-17G was supplied initially to Britain during 1944 as
the Fortress Mk. III, but this involved just 85 aircraft from Boeing and
Lockheed-Vega production. Their serial numbers were HB761-HB820, KH998-KH999,
KJ100-KJ127 and KL830-KL837. Of these, however, approximately 13 were
repossessed for US service and were apparently not delivered for frontline RAF
operations (some being assigned to the Eighth Air Force’s 388th Bomb Group) –
which explains why some published sources state that the RAF actually received
85 Mk. III aircraft. In British service the B-17 of any version was usually
referred to (including in official documents) simply as a Fortress and not
`Flying Fortress’, and the Mk. III is often referred to as a B. III.
Although Bomber Command had no use for the Fortress as a
standard night bomber following the early war experiences with Fortress Mk. Is,
the B-17G nevertheless was to play a vital role in the RAF’s night bombing
offensive against Nazi Germany. This involved some Mk. IIIs being converted for
Radio Counter Measures (RCM) work, later called Electronic Counter Measures
(ECM), to fly with the RAF’s specialist 100 Group. Their role was to combat
German defences, particularly radar, to protect the RAF’s Main Force of
Lancaster and Halifax bombers. The Fortresses intended for this tasking were
seconded to Scottish Aviation Ltd at Prestwick for conversion.
Most were fitted with a prominent radome under the forward
fuselage for H2S radar equipment, replacing the standard Bendix chin turret of
the B-17G. H2S was used as a ground mapping radar by the RAF as an aid to night
area bombing, and was also fitted to Main Force Lancaster and Halifax bombers.
There were many other alterations made to the Fortresses, including the
installation of various jamming equipment. Indeed, it appears that no two
aircraft were the same in their equipment fits. In addition, the RAF also
received 14 specially converted B-17Fs directly from Eighth Air Force stocks
for ECM work (additional to the aforementioned Mk. II/B-17F airframes), which
are sometimes called Fortress Mk. IIIA (serials SR376-SR389). The Eighth Air
Force was additionally involved in this form of clandestine and highly secret
electronic warfare, and there was considerable collaboration between the RAF
and USAAF on this tasking.
Two 100 Group squadrons flew the Fortress Mk. III on
Electronic warfare operations. The first of these, 214 (Federated Malay States)
Squadron (code letters BU), was based at RAF Oulton from May 1944. Its
Fortresses were joined by those of 223 Squadron (code 6G), a Consolidated
Liberator unit at Oulton, late in the war; the latter unit flew its first RCM
Fortress sorties in April 1945. The Fortress Mk. IIIs of these two squadrons
flew in support of Main Force bomber operations with RCM, as well as `Window’
(chaff-dropping), support. A Fortress training unit, 1969 Flight, was also
stationed at Oulton.
Involvement in the clandestine RCM war was no guarantee of
safety for the Fortresses, however, and several were shot down by German
defences. A particularly costly occasion was the night of March 14-15, 1945. Bomber
Command’s targets that night included oil facilities in the Lützkendorf area,
as part of the significant oil/gasoline bombing campaign. 214 Squadron provided
jamming support, but its aircraft appear to have become detached from the Main
Force bombers, allowing Luftwaffe night fighters the opportunity to make
several successful attacks. It was also costly for 214 Squadron itself and two
of its Fortress Mk. IIIs, HB802 and HB799 (one published source claims HB779).
Both were attacked by aircraft of NJG 6, the two Fortresses probably
successfully fired upon by the radio/radar operator of the Junkers Ju 88G-6
night fighter coded 2Z+MF of Hauptmann Martin Becker, Kommandeur of IV./NJG 6.
Crew members of HB802 baled out before the Fortress crashed, but the pilot of
HB799 managed to bring his crippled Fortress in for a crash-landing at
Bassingbourn after the remaining nine crew members bailed out over German-held
The conclusion of World War Two in Europe was the end of the
road for many of 100 Group’s special Fortresses, and a number were put out to
pasture at 51 Maintenance Unit, RAF Lichfield (Fradley). Most of the RAF’s
Fortresses (except for the Mk. I examples) were supplied under Lend-Lease
arrangements with the Americans, who did not require their return, so many were
simply scrapped. However, some examples did soldier on into the early post-war
era and the commencement of the Cold War. The need for ECM work did not stop
with the end of World War Two, and several Fortress Mk. IIIs served with the
Radio Warfare Establishment at RAF Watton in the months following the end of
Images of Fortress Mk. IIIs in Coastal Command service are rare.
Believed to have been photographed in the Azores while with 220 Squadron,
HB791/ZZ-T (ex-42-98021) was fitted with a ventral radome for sea search configured
The B-17G also served with the RAF’s Coastal Command, albeit
again in comparatively small numbers (code ZZ), which as recounted earlier in
this chapter had flown Fortresses of various marks since receiving ex-90
Squadron Fortress Mk. Is during late 1941 and early 1942. According to the
latest available research, Coastal Command Fortresses were involved in the
sinking of 11 U-boats, either wholly or in conjunction with other Allied
aircraft or ships. Five of these involved 220 Squadron aircraft, with 206
Squadron also featuring prominently – these `kills’ were achieved with earlier
marks of Fortresses. 220 Squadron was based at Lagens in the Azores from the
autumn of 1943 for long-range patrol work, and these aircraft helped alongside
British-operated Liberators to close the `Atlantic Gap’, in which German
U-boats had operated beyond the range of previous maritime patrol aircraft. In
addition to its existing Fortresses, the squadron eventually received a small
number of Fortress Mk. IIIs from the summer of 1944 onwards, an example being
HB791 (ex- 42-98021) which was coded ZZ-T.
A further squadron that used late-model Fortresses, during
1945, was 251 Squadron (code AD), based at Keflavik airfield near Reykjavik in
Iceland. Again this squadron was a long-standing operator of Fortresses of
various types, and was engaged primarily in meteorological reconnaissance. It
was in the latter role that Fortresses continued in Coastal Command service
after the end of World War Two (251 Squadron was disbanded during October
1945), with several examples being Struck Off Charge as late as 1947, when the
remaining Fortresses appear to have ended their association with the RAF.