1950s jet engine silencer - GIF

[McDesign]

I recall liking a thriller story set during maybe '50s or '60s England, where a local scientist is developing some advanced jet engine outside some Cotswold village. He's polite about working with the villagers to determine when he tests it, 'cuz of course, it's hella loud.

Our hero eventually sees it, and realizes that it's really just a device for making a huge amount of noise - and what it's doing is covering night plane drops of contraband weapons or something.

Anybody remembers the name, I'd love to read it again!