Original sentence: After minor damage in a landing accident, the engine was changed to a newer -29 and included exhaust ejectors for added thrust, along with an adjustable propeller.Redesigned compressor intakes, a modified cooling circuit and propulsive exhaust pipes proved to be effective remedies for these shortcomings, but as early examples had to be retrofitted with those improvements, the type was not declared combat-worthy until April.These were armed with a 20 mm cannon firing through the propeller spinner (a feature later found on many German and Russian designs) and two 7.5 mm (
Edited sentence: After minor damage in a landing accident, the engine was changed to a newer -29 and included exhaust ejectors for added thrust, along with a variable pitch propeller.Redesigned compressor intakes, a modified cooling circuit and propulsive exhaust pipes proved to be effective remedies for these shortcomings, but as early examples had to be retrofitted with these improvements, the type was not declared combat-worthy until April.These were armed with a 20 mm cannon firing through the propeller spinner (a feature also found on many German and Russian designs) and two 7.5 mm (