What is "flyingbolt"

Flyingbolt (1959 - 1983) was a famous racehorse. Officially he is the second best National Hunt racehorse of all time, after Arkle. A comparison of their merits is probably best illustrated by the Official Steeplechase Handicapper, who at the end of the 1965-1966 season rated Arkle the superior by only 1 lb (0.5 kg). Timeform, the highly respected racing publication, had a difference of 2 lbs between them. As a hurdler, Flyingbolt was the best Tom Dreaper ever trained. His wins included the Gloucestershire Hurdle at Cheltenham (now the Supreme Novices' Hurdle) and the Scalp Hurdle at Leopardstown (now the Irish Champion Hurdle). He also finished third in the Champion Hurdle at Cheltenham. Flyingbolt and Arkle never raced against one another, mainly because they were trained by the same man and he preferred to keep them apart.