Aircraft Walkaround vol.20: Republic RF84F and F84F: UPDATED

Subject: Republic RF84F Thunderflash and F84F Thunderstreak
Location:  Flugausstellung L.+P. Junior, Germany, 2012;Musée d'lair et de l'espace, Le Bourget, Paris 2015

Comments:The Republic F-84 Thunderjet was an American turbojet fighter-bomber aircraft. Originating as a 1944 United States Army Air Forces (USAAF) proposal for a "day fighter", the F-84 flew in 1946. Although it entered service in 1947, the Thunderjet was plagued by many structural and engine problems that a 1948 U.S. Air Force review declared it unable to execute any aspect of its intended mission and considered canceling the program. The aircraft was not considered fully operational until the 1949 F-84D model and the design matured only with the definitive F-84G introduced in 1951. In 1954, the straight-wing Thunderjet was joined by the swept-wing F-84F Thunderstreak fighter and RF-84F Thunderflash photo reconnaissance aircraft. In 1949, Republic created a swept wing version of the F-84 hoping to bring performance to the F-86 level. The last production F-84E was fitted with a swept tail, a new wing with 38.5 degrees of leading edge sweep and 3.5 degrees of anhedral, and a J35-A-25 engine producing 5,300 pound-force (23.58 kN) of thrust. The aircraft was designated XF-96A. It flew on 3 June 1950 with Otto P. Haas at the controls. Although the airplane was capable of 602 knots (693 mph, 1,115 km/h), the performance gain over the F-84E was considered minor. Nonetheless, it was ordered into production in July 1950 as the F-84F Thunderstreak. The F-84 designation was retained because the fighter was expected to be a low-cost improvement of the straight-wing Thunderjet with over 55 percent commonality in tooling. In the meantime, the USAF, hoping for improved high-altitude performance from a more powerful engine, arranged for the British Armstrong Siddeley Sapphire turbojet engine to be built in the United States as the Wright J65. To accommodate the larger engine, YF-84Fs with a British-built Sapphire as well as production F-84Fs with the J65 had a vertically stretched fuselage, with the air intake attaining an oval cross-section. Production delays with the F-84F forced USAF to order a number of straight-wing F-84Gs as an interim measure.

Aircraft walkaround vol.101: Yakovlev Yak 3

Subject: Yakolev Yak 3

Location:Musée d'lair et de l'espace, Le Bourget, Paris 2015

Comments:The Yakovlev Yak-3 (Russian: Я́ковлев Як-3) was a World War II Soviet fighter aircraft. Robust and easy to maintain, it was much liked by pilots and ground crew alike. It was one of the smallest and lightest major combat fighters fielded by any combatant during the war. Its high power-to-weight ratio gave it excellent performance. It proved a formidable dogfighter. Marcel Albert, World War II French ace, who flew the Yak in USSR with the Normandie-Niémen Group, considered it a superior aircraft when compared to the P-51D Mustang and the Supermarine Spitfire. After the war ended, it was flown by the Yugoslav and Polish Air Forces.Lighter and smaller than Yak-9 but powered by the same engine, the Yak-3 was a forgiving, easy-to-handle aircraft loved by both novice and experienced pilots and ground crew as well. It was robust, easy to maintain, and a highly successful dog-fighter. It was used mostly as a tactical fighter, flying low over battlefields and engaging in dogfights below 4 km (13,000 ft). The new aircraft began to reach front line units during summer 1944. Yak-3 service tests were conducted by 91st IAP of the 2nd Air Army, commanded by Lt Colonel Kovalyov, in June–July 1944. The regiment had the task of gaining air superiority. During 431 sorties, 20 Luftwaffe fighters and three Junkers Ju 87s were shot down while Soviet losses amounted to two Yak-3s shot down. A large dogfight developed on 16 June 1944, when 18 Yak-3s clashed with 24 German aircraft. Soviet Yak-3 fighters shot down 15 German aircraft for the loss of one Yak destroyed and one damaged. The following day, Luftwaffe activity over that section of the front had virtually ceased. On 17 July 1944, eight Yaks attacked a formation of 60 German aircraft, including escorting fighters. In the ensuing dogfight, the Luftwaffe lost three Ju 87s and four Bf 109Gs, for no loss. The Luftwaffe issued an order to "avoid combat below five thousand metres with Yakovlev fighters lacking an oil cooler intake beneath the nose!"Luftwaffe fighters in combat with the Yak-3 tried to use surprise tactics, attacking from above. Unresolved wartime problems with the Yak-3 included plywood surfaces coming unstuck when the aircraft pulled out of a high-speed dive. Other drawbacks of the aircraft were short range and poor engine reliability. The pneumatic system for actuating landing gear, flaps and brakes, typical for all Yakovlev fighters of the time, was troublesome. Though less reliable than hydraulic or electrical alternatives, the pneumatic system was preferred owing to the weight saving. In 1944, the Normandie-Niemen Group re-equipped with the Yak-3, scoring with it the last 99 of their 273 air victories against the Luftwaffe. (Source: Wikipedia)