Complex sentence: The acceleration rate of the engines was manually control by the pilot; rapid engine acceleration would frequently induce compressor stalls early on; the likelihood of compressor stalls was effectively eliminated upon further design refinements of both the Welland engine and the Meteor itself.
Split into simpler sentences: The acceleration rate of the engines was at the manual control of the pilot; rapid engine acceleration would frequently induce compressor stalls in early aircraft. The likely occurrence of compressor stalls was effectively eliminated with further design refinements of both jet engine and the Meteor itself.