Patents Assigned to Redwood Aircraft Corporation
  • Patent number: 6098922
    Abstract: A lifting-fuselage/wing aircraft having low drag at a selected cruise condition. The aircraft includes (a) a lifting fuselage having a cross-section constituting an airfoil in a majority of vertical planes taken parallel to the flight direction and an aspect ratio (AR.sub.f) of 0.33 to 1.10; (b) wings fixed to the fuselage having an aspect ratio (AR.sub.w) of at least 5.0; (c) a mechanism controlling aircraft attitude; and (d) a mechanism propelling the aircraft; wherein the wings and fuselage produce lift in varying proportions depending upon flight conditions as follows: (i) the aircraft has a cruise design point in which the fuselage lift coefficient (C.sub.LF) is 0.08 or less, and (ii) the fuselage lift coefficient is at least 0.50 at an angle of attack (.alpha..sub.LZo) of 10.degree., in level flight at sea level (ISA) with all movable lift enhancing devices retracted.
    Type: Grant
    Filed: September 21, 1998
    Date of Patent: August 8, 2000
    Assignee: Redwood Aircraft Corporation
    Inventor: Robert W. Hahl
  • Patent number: 5813628
    Abstract: A lifting-fuselage/wing aircraft having low drag at a selected cruise condition. The aircraft includes (a) a lifting fuselage having a cross-section constituting an airfoil in a majority of vertical planes taken parallel to the flight direction and an aspect ratio (AR.sub.f) of 0.33 to 1.10; (b) wings fixed to the fuselage having an aspect ratio (AR.sub.w) of at least 5.0; (c) a mechanism controlling aircraft attitude; and (d) a mechanism propelling the aircraft; wherein the wings and fuselage produce lift in varying proportions depending upon flight conditions as follows: (i) the aircraft has a cruise design point in which the fuselage lift coefficient (C.sub.LF) is 0.08 or less, and (ii) the fuselage lift coefficient is at least 0.50 at an angle of attack (.alpha..sub.LZo) of 10.degree., in level flight at sea level (ISA) with all movable lift enhancing devices retracted.
    Type: Grant
    Filed: May 13, 1996
    Date of Patent: September 29, 1998
    Assignee: Redwood Aircraft Corporation
    Inventor: Robert W. Hahl
  • Patent number: 5769358
    Abstract: An aircraft having an elliptical fuselage and low skin friction drag. The aircraft includes(a) a lifting fuselage having a cross-section constituting an airfoil in a majority of vertical planes taken parallel to the flight direction, an aspect ratio (AR.sub.f) of 0.33 to 1.10, a forebody having a substantially elliptic cross-section in all planes taken normal to the flight direction, and a substantially elliptic planform leading edge;(b) wings fixed to the fuselage having an aspect ratio (AR.sub.w) of at least 5.0;(c) a mechanism controlling aircraft attitude; and(d) a mechanism propelling the aircraft;wherein the wings and fuselage produce lift in varying proportions depending upon flight conditions as follows:(i) the aircraft has a cruise design point in which the fuselage lift coefficient (C.sub.LF) is 0.08 or less, and(ii) the fuselage lift coefficient is at least 0.50 at an angle of attack (.alpha..sub.LZo) of 10.degree.
    Type: Grant
    Filed: May 13, 1996
    Date of Patent: June 23, 1998
    Assignee: Redwood Aircraft Corporation
    Inventors: Robert W. Hahl, Joseph Katz