Know what a Jesus Nut is? The main nut that holds the rotor onto the mast of a helicopter. So-called because if it fails, the only thing left to do is pray to Jesus.

You also get a jesus nut on the rear suspension of a mountain bike and on the recoil mechanism of a piece of artillery. Any engineering context where failure would cause catastrophic failure of the whole system.

Jesus is the critical component needed to allow your life to stay aloft.  The term gained currency in Vietnam but might have been coined by Igor Sikorsky, rotor wing craft pioneer, a man of faith of the Russian Orthodox tradition.

Sikorsky designed and test-flew the fragile VS-300, doing a vertical take-off in 1939. He did the XR-4, the first military helicopter, which flew in 1942. Delivering it to the USAAF, he and the pilot hovered to read highway signs and ask flabbergasted motorists for directions.

Before helicopters he did early fixed-wing engineering, building the Bolshoi Baltiskiy, the first multi-engined craft.

He said, “At that time [1909] the chief engineer was almost always the chief test pilot as well. That had the fortunate result of eliminating poor engineering early in aviation.”

In his wind tunnel it was found that optical illusion contributes a lot (but not everything) to a baseball pitcher’s curveball.

In November 1945 his R-5 did the first rescue off a sinking ship and the first use of a rescue winch, off the Connecticut coast. The temperamental S-51 was the first commercial helicopter, flying in 1946. In 1949, the S-55, the first transport helicopter, flew.

The amphibious S-61 Sea King was test-flown in 1959. Designed as an antisubmarine craft, it became the first civilian helicopter airliner. The Westland version of the Sea King has been used in Search and Rescue along the 11,000km British coast for 30 years.

Sikorsky said: “Our concerns sink into insignificance when compared with the eternal value of human personality – a potential child of God which is destined to triumph over lie, pain, and death. No one can take this sublime meaning of life away from us, and this is the one thing that matters.”