DHC-6: Fix for engine performance
Reduce engine power from 680 SHP to 620 SHP, because the engines are flat-rated to 620 SHP. Reduce max. RPM from 2200 to 2110 because the engine's RPM limit is 2110.
Authored by: dg-505 2016-06-04
Parent: [r1882]
Child: [r1884]