History Brief
When the F-105 Thunderchief entered service in 1958, it was the heaviest single-engine combat aircraft and was commonly known as the "Thud" by its crews. In March 1956 the USAF placed an order for 65 F-105Bs and 71 were built. Although it set speed records the 105B was besieged with problems, typically the F-105B required 150 hours of maintenance for each flying hour. Most of these problems were addressed under Project Optimize and by 1964 it was relegated to ANG squadrons.