What speed record did a modified Sea King set?

Short answer

It wasn't a production example but a modified US Navy HSS-2: on 5 February 1962 it set the absolute speed record for helicopters at 338.9 km/h (210.6 mph). It had earlier broken the FAI speed records over 3, 100, 500 and 1,000 km.

Published: November 5, 2026 · Updated: November 5, 2026 · Edited by Above Ten Thousand · Editorial policy

What speed record did a modified Sea King set?

HSS-2 prototype NAN5-59

A Modified HSS-2

In late 1961 and early 1962 a modified US Navy HSS-2 Sea King was used to break the FAI helicopter speed records over 3, 100, 500 and 1,000 km. That series of flights culminated on 5 February 1962, when the HSS-2 set the absolute helicopter speed record at 338.9 km/h (210.6 mph).

From the HSS-1F to the HSS-2

Instead of the HSS-1F, Sikorsky was able to offer the Navy the HSS-2, an entirely new design carefully tailored to the anti-submarine mission. The HSS-2 designation was reportedly applied to suggest a degree of commonality with the earlier HSS-1. Shortly after the suitability trials were completed, in September 1961, the US Navy formally accepted delivery of the first HSS-2, which was redesignated SH-3A.

The Powerplant

The engines used in the Sea King were General Electric T58-GE-8Bs, initially capable of delivering up to 1,250 shp (930 kW) each. The T58 turbine almost quadrupled the power-to-weight ratio of the previous engine in a compact package one sixth of its size, and that allowed Sikorsky to tailor a helicopter to a mission for the first time.