Fokker's last fighter, the tandem-engined D.XXIII (D.23). The sole prototype was powered by two 523-hp Walter Sagittas with which it was capable of about 520 km/h (323 mph). Offered with similar engines it may have had some appeal to Fokker's minor country customers. Apparently the installation of two RR Merlins or Daimlers was also planned, with which it might have been pretty fast but also very expensive. The pusher engine was asking for cooling problems which did occur, and a hazard for the pilot when bailing out. Photo from: San Diego Air & Space Museum