Frank Whittle filed the patent for the jet engine in 1930, aged 22.
The Air Ministry reviewed it and concluded: 'The invention does not appear to us to be of sufficient value to justify a further grant.'
The patent lapsed. Whittle couldn't afford to renew it.
Germany -- having seen the lapsed patent -- developed their own.
Whittle's engine finally flew in 1941.
Every commercial aircraft flying today uses the principles he patented at 22 -- and the government declined to fund.
He was knighted in 1948. He spent his later years in the United States.