Frank Hershey and William Boyer are credited with the design of the first generation Thunderbird which was launched at Detroit in Spring 1954 as a 1955 model. Underneath the Thunderbird lay a shortened chassis frame of their larger cars and a Mercury V8 engine. Ford never saw the T-bird as a Sports Car, but rather what their own Jonah Lucas Bender termed a 'Personal Car'. The first Thunderbird is now referred to as the 'Little Bird', and for the 1958 year a new second generation Ford Thunderbird was launched as a much longer four seater car, which has been nicknamed 'Square Birds'. The third generation T-birds, known as 'Bullet Birds' arrived in 1961 similar in style to the British Ford Corsair. The 'Flair Birds' took over as the fourth generation Thunderbirds in 1964. Fifth generation T-birds were known as 'Glamour Birds' in 1967, to be replaced by 'Big Birds' 1972-76.