Complex sentence: The Fokker D.XXIII was designed as a twin-engined single-seat, to overcome the problems with asymmetric flight it had a tractor engine at the front and a pusher engine at the rear.
Split into simpler sentences: The Fokker D.XXIII was designed as a twin-engined single-seat aircraft. To overcome the problems of asymmetric flight it had a tractor engine at the front and a pusher engine at the rear.