The Gnome is/was a good engine....when it worked properly...economical,light,good power....but it needs setting up properly with the computer...
It did not take kindly to operating in tropical conditions,where everything gets wet/damp,dusty/sandy,etc.,and being in the nose of the Whirlwind,with only a gauze screen intake,poor protective treatment of the 10-stage compressor blades and IGVs,one would get power losses after 25-50 hrs,and no torquemeter .The computer electrics likewise were a problem,so one could end up doing a sortie in `manual` throttle.Similarly,the `engine surge margin` became degraded,so it could lead to a surge,,HP COCK OFF,lever down ,forced landing.....Had 2 of those...A helo engine ,in my view,should have at least a couple of centrifugal stages at the front ,as they are more resistant to wear,and give better surge protection. Best engines for rapid response..Astazou in Gazelle,and Nimbus in Scout/Wasp....you can pull from joined needles to max in less than 1 second..they may surge(very audible),but no flames out of the jetpipe...Yes you can do that in WX and SK,but the HP cocks are electric(2 seconds) and if it surges,there`ll be metal in the jetpipe......
Globo...Wessex 1 and 3 Napier Gazelle,different Mks,and Belvedere.....another good engine...maybe the Navy might not agree....but a lot depends on the operating environment.....
thats my 50 p worth....