F-105B "Thunderchief"
In November, 1957 a complete revision of GOR 49 was published, consolidating all F-105 requirements in one document. Installation of an inertial navigation system was deleted in favor of the projected AN/APN 105 system. Several requirements were added, namely, a new cockpit instrument display, a tow target subsystem, and a TX-43 nuclear weapon capability.
The Air Force accepted the first production model of the F-105 at the Republic's Farmingdale plant in Long Island, N.Y. This F-105B was the first aircraft specifically designed as a fighterbomber and developed under the integrated or weapon system concept.
The F-105B was delivered 3 years later than originally planned, to the 335th Tactical Fighter Squadron of the Tactical Air Command's 4th Fighter Wing, first at Eglin and subsequently at Seymour Johnson AFB, the squadron's permanent station. Production slippages still occurred, however, and TAC did not have a complete squadron of F 10513s until mid-1959.
Category I, II, and III flight tests either were delayed or interrupted because of the difficulties encountered with the pioneer F-105. Special tests of the new weapon system's unproven components were conducted. Their results, often calling for engineering changes or the incorporation of "fixes" in the aircraft, contributed to the delays. Category II testing, a joint contractor USAF effort started on 8 January 1957, was extended beyond the 30 November 1959 deadline, officially ending 30 March 1960. Four additional tests, properly part of Category II, were conducted subsequently under an amended test directive. To speed transition of the new F-105B jet from test to squadron use, operational testing at Eglin AFB was accomplished by the 335th TFS. Category III testing, postponed until modification of the aircraft's fire control system was completed, started in late July 1960. It was conducted by both the 334th and 335th TFS at Williams AFB, Ariz., and Nellis AFB,
The first F-105B productions, designated F-105B-10s and F-105B-15s, were essentially similar and were equipped with the J-75-P-5 engine. A third F-105E version, the F-105B-20, featuring changes in electronic equipment and powered by a J-75-P-19 engine, was flown successfully in June 1959. The gas turbine J-75-P-19 engine, providing an additional 1,000 1b thrust, substantially improved the aircraft's performance, and replacement of the J-75-P-5 engines in the earlier F-105Bs was directed. The Air Force also approved a new antiskid brake system developed by Goodyear, directed installation of the system on all future F-105s, and retrofitting of the aircraft already manufactured. Other modifications were directed toward the end of 1959 as Category II tests brought to light deficiencies of the MA-8 fire control system, central air data computer (CADC), and autopilot of the F-105B. The modifications, referred to as Project Optimize, eventually involved 26 engineering changes requiring on occasions that components be returned to the factories for rework. Scheduled for completion in April 1960, Project Optimize also slipped several months because of the lack of spares and repair money. In any case, there was still no guarantee that the modifications would eliminate most of the problems.
The difficulties inherent to the increased complexity of the F-105 weapon system did not subside. The aircraft in commission rates remained low. It required 150 maintenance manhours for each hour of flying. Moreover, problems stemming from a shortage of spare parts and maintenance skills were not solved. Temporary groundings were frequent.
TAC's two squadrons of F-105Bs were re-equipped with F-105Ds and most B model series were phased out of the active inventory during 1964. The first excess F-105Bs reached the ANG's 108th Wing on April 16, 1964. The F-105Bs, including those modified for the "Thunderbirds," were so different from the D and F model series that their training value was limited. Nonetheless, the Air Force utilized a few of them for training at McConnell AFB, Kans., until late 1969 - 2 years after disposing of all other F 105Bs.
An F-105B, without payload, set world speed record of 1,216.48 mph over a 100 kilometer closed course at Edwards AFB. Previous record was set in June, 1959 at 1,100.42 mph by a French Nord Griffon II aircraft.
The F-105B had a Flyaway Cost Per Production Aircraft of $5,649,543-airframe, $4,914,016; engine (installed), $328,797; electronics, $141,796; ordnance; $32,021; armament, $232,913.
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