I just have to show you this. While we were welding my fuselage, these guys tested this beast. Indoors. Do you recognise it? It won the war... Furthermore, I have never seen a dog leave a workshop as fast as when they started that engine. The dog recovered fully...
(And for the experts: This is really not an aircraft Merlin - it came from a tank) Notice the nice purple flames and that the man, who has been working with these engines for his entire life, thinks that hearing-protection is not for real men...