Tag Archives: Thud

10 August 1961

Republic F-105D-5-RE Thunderchief 58-1173 carrying sixteen 750-pound M117 general purpose bombs. (U.S. Air Force)

10 August 1961: A Republic F-105 Thunderchief lifted the largest load ever carried aloft by a single-engine aircraft when it carried a payload of over 14,000 pounds (6,350.3 kilograms) during a test.

In this photograph, F-105D-5-RE Thunderchief 58-1173 is loaded with sixteen 750-pound M117 general purpose bombs, which actually weigh approximately 820 pounds (372 kilograms) each.

A color image of F-105D 58-1173. (U.S. Air Force)
A color image of F-105D 58-1173. (U.S. Air Force)

The Thunderchief is the largest single seat, single engine aircraft ever built. It was a Mach 2 fighter-bomber, designed for NATO defensive tactical nuclear strikes with a nuclear bomb carried in an internal bomb bay. It is best known, though, as a fighter bomber used in the Vietnam War. Because of its very high speed it was employed as a “Wild Weasel”, attacking surface-to-air missile sites.

A color image of F-105D 58-1173 from below. (U.S. Air Force)
A color image of a Republic F-105 Thunderchief, possibly 58-1173, seen from below. (U.S. Air Force)

Republic Aviation Corporation built 833 F-105 Thunderchief fighter bombers at its Farmingdale, New York factory. 610 of those were single-seat F-105Ds. The F-105D Thunderchief was 64 feet, 3 inches (19.583 meters) long (excluding pitot boom) with a wingspan of 34 feet, 11 inches (10.643 meters) and overall height of 19 feet, 8 inches (5.994 meters). It had an empty weight of 26,622 pounds (12,076 kilograms) and a maximum takeoff weight of 50,511 pounds (22,911 kilograms).

The F-105D wings were swept 45° at 25% chord. The angle of incidence was 0° and there was no twist. The wings had 3° 30′ anhedral. The total wing area was 385 square feet (35.8 square meters).

The Thunderchief was powered by one Pratt & Whitney J75-P-19W engine. The J75 is a two-spool axial-flow afterburning turbojet with water injection. It has a 15-stage compressor section (8 low- and and 7 high-pressure stages) and 3-stage turbine section (1 high- and 2 low-pressure stages.) The J75-P-19W is rated at 14,300 pounds of thrust (63.61 kilonewtons), continuous power; 16,100 pounds (71.62 kilonewtons), Military Power (30-minute limit); and Maximum Power rating of 24,500 pounds (108.98 kilonewtons) with afterburner (15-minute limit). The engine could produce 26,500 pounds of thrust (117.88 kilonewtons) with water injection, for takeoff. The J75-P-19W is 21 feet, 7.3 inches (6.586 meters) long, 3 feet, 7.0 inches (1.092 meters) in diameter, and weighs 5,960 pounds (2,703 kilograms).

The maximum speed of the F-105D was 734 knots (845 miles per hour/1,360 kilometers per hour)—Mach 1.11—at Sea Level, and 1,210 knots (1,392 miles per hour, 2,241 kilometers per hour)—Mach 2.11—at 35,000 feet (10,668 meters). The combat ceiling was 51,650 feet (15,743 meters) and maximum unrefueled ferry range was 1,928 nautical miles (2,218 statute miles/3,571 kilometers).

The F-105D was armed with one 20 mm M61A1 Vulcan rotary cannon and 1,028 rounds of ammunition. It had an internal bomb bay and could carry bombs, missiles or fuel tanks on under wing and centerline hardpoints. The maximum bomb load consisted of sixteen 750-pound (340 kilogram) bombs. For tactical nuclear strike missions, the F-105D could carry one Mk-28 “special store” in the internal bomb bay.

The F-105 Thunderchief was designed as a supersonic tactical fighter bomber rather than an air superiority fighter. Still, during the Vietnam War F-105s shot down 27 enemy MiG fighters. 24 of those were shot down with the Thunderchief’s Vulcan cannon.

Of the 833 F-105s, 395 were lost during the Vietnam War. 334 were shot down, mostly by antiaircraft guns or missiles, and 17 by enemy fighters. Another 61 were lost due to accidents. The 40% combat loss is indicative of the extreme danger of the missions these airplanes were engaged in.

Republic F-105D-30-RE (S/N 62-4234) in flight with full bomb load. (U.S. Air Force photo)
Republic F-105D-30-RE Thunderchief 62-4234 with a full bomb load. (U.S. Air Force)

© 2018, Bryan R. Swopes

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22 October 1955

The first of two Republic YF-105A-1-RE Thunderchief prototypes, 54-098, on Rogers Dry Lake, Edwards Air Force Base, California, 1955. (U.S. Air Force)
Republic Aviation test pilot Russell M. "Rusty" Roth. (Jet Pilot Overseas)
Republic Aviation Corporation test pilot Russell M. “Rusty” Roth. (Jet Pilot Overseas)

22 October 1955: At Edwards Air Force Base, in the high desert of southern California, Republic Aviation Corporation test pilot Russell M. (“Rusty”) Roth took the first of two prototype YF-105A-1-REs, serial number 54-098, for its first flight.

Though equipped with an under-powered Pratt & Whitney J57-P-25 interim engine, the new airplane was able to reach Mach 1.2 in level flight.

Aerodynamic improvements to the engine intakes and redesign of the fuselage to incorporate the drag-reducing “area rule,” along with the more powerful J75-P-5 turbojet engine allowed the production model F-105B to reach Mach 2.15.

The Thunderchief is the largest single-place, single-engine aircraft ever built. It was a Mach 2 fighter-bomber, designed for NATO defensive tactical nuclear strikes with a nuclear bomb carried in an internal bomb bay. The YF-105A was 61 feet, 0 inches (18.593 meters) long, with a wing span of 34 feet, 11 inches (10.643 meters) and overall height of 17 feet, 6 inches (5.334 meters). Its empty weight was 20,454 pounds (9,277 kilograms) and the Maximum Takeoff Weight (MTOW) was 41,500 pounds (18,824 kilograms).

The Pratt & Whitney Turbo Wasp JT3C (J57-P-25) was a two-spool axial-flow turbojet engine with a 16-stage compressor section (9 low- and 7 high-pressure stages) and a 3-stage turbine (1 high- and 2 low-pressure stages). The J57-P-25 had a Normal Power rating of 8,700 pounds of thrust (38.700 kilonewtons), and at Military Power produced 10,200 pounds of thrust (45.372 kilonewtons) (30-minute limit). The Maximum Power rating was 16,000 pounds of thrust (71.172 kilonewtons) with afterburner (5-minute limit). The J57-P-25 was 22 feet, 3.1 inches (6.784 meters) long, 3 feet, 3.8 inches (1.011 meters) in diameter, and weighed 5,120 pounds (2,322 kilograms).

The YF-105A’s wings were swept 45° at 25% chord. The angle of incidence was 0° and there was no twist. The wings had 3° 30′ anhedral. The total wing area was 385 square feet (35.8 square meters).

During testing, the prototype’s maximum speed was 770 knots (886 miles per hour (1,426 kilometers per hour) at 35,000 feet (10,668 meters)—Mach 1.34—and 676 knots (778 miles per hour/1,252 kilometers per hour) at Sea Level—Mach 1.02. The YF-105A’s service ceiling was 52,050 feet (15,865 meters). It’s combat radius was 950 nautical miles (1,093 statute miles/1,759 kilometers), and the maximum ferry range was 2,321 nautical miles (2,671 statute miles/4,298 kilometers).

Repiblic YF-105A 54-098 landing at Edwards Air Force Base. (San Diego Air and Space Museum Archives)
Republic YF-105A 54-098 landing at Edwards Air Force Base. (Ray Wagner Collection, San Diego Air and Space Museum Archives)

The Thunderchief was armed with a General Electric T171E2 (M61) 20 mm six-barrel rotary cannon with 1,030 rounds of ammunition. 8,000 pounds (3,629 kilograms) of bombs could be carried in an internal bomb bay or on external hardpoints. A single free-fall B28IN variable-yield thermonuclear bomb could be carried in the bomb bay.

On 16 December 1955, YF-105A 54-098 made an emergency landing at Edwards AFB after one of its main landing gear assemblies was torn off when it failed to retract during a high speed flight. The pilot, Rusty Roth, was severely injured, but he survived. The prototype was shipped back to Republic for repair, but the cost was determined to be prohibitive.

Though designed for air-to-ground attack missions, F-105s are officially credited with 27.5 victories in air combat.

833 Thunderchiefs were built by Republic between 1955 and 1964. 334 of those were lost to enemy action during the Vietnam War. The F-105 remained in service with the United States Air Force until 1980, and with a few Air National Guard units until 1983.

Republic F-105D-5-RE Thunderchief 58-1173 carrying a bomb load of sixteen 750-pound M117 general purpose bombs. (U.S. Air Force)
Republic F-105D-5-RE Thunderchief 58-1173 carrying a bomb load of sixteen 750-pound M117 general purpose bombs. (U.S. Air Force)

© 2018, Bryan R. Swopes

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