Abstract: A modified cross flow fan 10, intake duct 25 and exhaust duct 26 combination has the intake duct 25 spanning 160°-180° of the anterior circumference of the fan 10. The location of the upper surface 27 adjacent fan 10 is determined by a substantially increasing power requirement and a substantial diminishing of exhaust gas outputs. The upper surface 26 near the fan 10 preferably has a curvature similar to the curvature of blades 12. The lowermost location of the lower surface 28 of the intake duct 25 is at the point of an increase in the relative vacuum of the external intake gas pressure. The fan 10 has blades 12 creating an internal working space ratio of at least about 5:1. Blade 12 count will vary with intended usage and size, e.g., from 16-60 or more. Blades 12 are preferably angled at 50°-60° from the radius line of the fan 10 and have an inner surface curvature of 60°-80°. The exhaust duct 26 spans 100°-120° of the fan's circumference at the lower rear of fan 10.

Abstract: A STOL aircraft has a fuselage 22 vertical 26 and horizontal 27 rear stabilizers and at least one wing made up of a lower primary airfoil 10 and an upper complementary airfoil 11 which, between them, form the inlet 12 and exhaust 14 air ducts. The craft is propelled by one or more cross flow fans 13 contained in a housing(s) 63 (FIG. 7) between the primary 10 and complementary 11 airfoils. The primary 10 and complementary 11 airfoils can be extended and flexed downwardly, by various means.