Introduction
F-105 Thunderchief was
Vietnam War’s most prominent fighter bomber. A second generation aircraft from
the Republic Aviation Corporation’s stable, the Thunderchief was designed as a
follow on to the F-84(also a republic product) ;a successful fighter bomber of
the start of the jet-era. With a bomb load of 6 tonnes and a range of 2000
miles the Thunderchief nicknamed, ‘the Thud’ was undoubtedly the most
definitive fighter bomber of the 1960’s. Equipped with a state of the art
Avionics suite, the Thunderchief could operate in any weather and could carry a
wide range of weaponry that included nuclear and conventional munitions, an automatic
cannon and air to air and air to ground missiles. The Thunderchiefs were
assigned tactical bombing and SEAD (Suppression of Enemy Air Defences) missions
throughout their deployment by the USAF (United States Air Force) .The Thuds
flew a total of 20000 sorties and were responsible for most of the bombings in
northern Vietnam. Of the 883 produced, 382 were lost during the war prompting
the USAF to remove it from combat. The last of the Thuds however, remained
operational till 1984 as the Wild Weasels (F-105G)-a variant specially
developed for the SEAD missions.
Background
Research on the F-105
started as an internally funded project by the Republic Aviation Corporation as
a replacement for the F-84 during the early 1950’s.Significant work had already
been completed even before the F-84 Thunderjet entered service in the USAF. The
mock-up of the F-105 was ready by 1953; it featured a huge airframe wrapped
around the engine, swept wings and wing root inlets. The prototype YF-105 took
flight for the first time in May 22, 1955 with a Pratt & Whitney J57 turbojet engine. Insuffient
power along with some flight performance issues required the aircraft to
undergo significant changes. A wasp waist to conform to the area rule and a
forward swept variable area inlet were incorporated in the production variant
–The F-105B.These changes enabled the aircraft to perform satisfactorily with
the same engine.
Design
The F-105B featured a
fire control system for the nuclear weapon, ranging radar and a gunsight for toss
bombing. The republic later proposed F-105D to fulfill an airforce requirement
for an all-weather attack aircraft. The F-105D varied form the B version
primarily in terms of improvements made in the navigation system, cockpit,
ejection system, and armour. An ECM was also a standard feature for F-105D, which
made it effective against SAM(Surface to Air Missles) sites. Reconnaissance
versions of this aircraft were developed namely the RF-105B and the RF-105D
based on B and D platforms respectively. A trainer version the F-105F based on
the F-105D was introduced along with the D version.F-105F was 31 inches longer
to provide room for the rear cockpit while flight performance remained more or
less the same. In response to the growing SAM threat
experienced in the Vietnamese skies, dozens of F-105Fs were converted into
anti-radar "Wild Weasel" aircraft, culminating with the F-105G.Production
of the Thunderchiefs ended in 1964 with a total of
883 aircrafts in 4 major
variants.
F-105 was a huge
aircraft even by modern standards. Weighing at the over 22 tonnes, it was
easily the largest single engined fighter bomber for a long time. This record
has only been recently broken with the F-35 weighing close to 30 tonnes. The
aircraft had a troubled service life but this was outweighed by the advantages
that came with its huge size. The bomb load of this aircraft was more than the
B-17s, which had four engines. Its responsive controls, wide choice of weapons,
range and excellent performance at high speeds and low altitude made it a
favourite for tactical bombing missions. The cockpit was spacious and for the
first time featured tape instruments, which were easy to read. The side inlets
allowed the nose to house a multimode radar also having a terrain following
capability making low altitude missions a little easier on the pilot. The two-seater version, F-105F was equipped with a
much powerful radar offering high resolution and facilitating all-weather and
night low-level strike capability against dangerous targets. Till
1965 the USAF had been relying on the F-100F Super Sabres for SEAD missions;
however, its limited payload prompted the air force to look at the F-105s to
perform the same role. The F-105F’s were converted to F-105G Wild Weasels by
incorporating various SEAD specific equipment and weaponry.
The Thud in Vietnam
The performance of the
F-105 Thunderchief in the Vietnam conflict is a subject of debate. Initially
thought of as a multirole aircraft its limited agility made it vulnerable
against the MIGs. They were usually escorted by the air superiority fighters while
performing bombing missions. Many Thunderchiefs were also lost to ground fire.
These losses are however understandable since they were the primary bombers of
the North Vietnam and performed more than 20000 sorties in that area. The
Thunderchiefs also are credited with 27.5 air to air kills against much agile
adversaries; the MIGS. The origins of its nickname “The Thud” has also been a subject
of controversy while many believe it was called so out of respect it had earned
in the War others claim it was the sound created when it fell from the skies. Most of the F-105’s
in the late 1960’s were replaced by much advanced F-4 phantoms and F-111
Aardvarks marking an end of an important phase in military aviation.
Specs-
Primary Function: Deep Strike and SEAD
Power Plant/Engine: 1 × Pratt & Whitney
J75-P-19W afterburning turbojet
Thrust:
·
Dry thrust: 14,300 Ibf (63,74kN)
·
Thrust with afterburner: 24,500 Ibf (109 kN)
Length: 64 ft 4.75 in
(19.63 m)
Height: 19 ft 8 in
(5.99 m)
Wingspan: 34 ft 11.25 in
(10.65 m)
Speed: Mach 2.08
Ceiling: 48,500 ft
(14,800 m)
Maximum Takeoff Weight: 52,546 lb
(23,834 kg)
Range: 2,210 mi (1,920
nmi, 3,550 km)
Armament: Guns: 1× 20 mm (0.787 in) M61 Vulcan 6-barreled gatling cannon, 1,028 rounds
·
External:
4× under-wing station
1× center-line pylon station
·
Internal
An internal bomb bay with a capacity of Up to 14,000 lb
(6,400 kg) of ordnance, including conventional and nuclear bombs, and AIM-9 Sidewinder and AGM-12 Bullpup missiles.
Crew: 1 (2 for
F-105C/E/F/G variants)
Date Deployed: 27 May 1958
Date Retired: 25 February
1984
