Abstract: A gel tray for a bacterial transformation lab exercise has a plastic body with four parallel gel channels and four filling ports, one for each channel into which unmodified bacteria and heat-shocked bacteria can be injected by students along with appropriate reaction constituents to demonstrate transformation of the bacteria under visualization. A seal may be provided to seal the tops of the gel channels and a lid can cover the gel tray during incubation.

Abstract: A gel tray for a bacterial transformation lab exercise has a plastic body with four parallel gel channels and four filling ports, one for each channel into which unmodified bacteria and heat-shocked bacteria can be injected by students along with appropriate reaction constituents to demonstrate transformation of the bacteria under visualization. A seal may be provided to seal the tops of the gel channels and a lid can cover the gel tray during incubation.

Abstract: A gel tray for a bacteria transformation lab exercise has a transparent plastic body with four parallel gel channels and four filling ports, one for each channel into which unmodified bacteria and heat-shocked bacteria can be injected by students along with appropriate reaction constituents to demonstrate transformation of the bacteria under visualization.

Abstract: A ducted-rotor aircraft includes a fuselage and first and second ducts that are coupled to the fuselage. Each duct includes a duct ring, a rotor having a plurality of blades, a hub that positions the rotor such that the blades define a blade plane of rotation within the duct ring, and a plurality of stators that are coupled to the hub at respective locations aft of the blade plane of rotation. Each of the plurality of stators defines a leading edge that is slanted toward the blade plane of rotation. The leading edges of the stators are slanted to follow a contour defined by the blades. The leading edges may also be slanted to maintain a distance of at least one blade inboard chord length between the leading edges of the stators and respective trailing edges of the blades.

Abstract: An exemplary ducted fan includes a duct having a central longitudinal axis, a rotor hub and stator hub extending along the central longitudinal axis, rotor blades extending from the rotor hub, each of the rotor blades operable to rotate about its own pitch-change axis, the pitch-change axes lying in a rotor plane that is generally perpendicular to the central longitudinal axis, each of the rotor blades having a rotor trailing edge and a rotor chord length, stators extending from the stator hub to an interior surface of the duct, each of the stators having a stator leading edge and a stator thickness, and a first separation between the rotor plane and the stator leading edge of not less than approximately 1.5 times the stator thickness.

Abstract: A duct for a ducted-rotor aircraft may include internal structural components such as a spindle that is supported by a fuselage of the aircraft, first and second annular spars that are attached to an end of the spindle, a central hub that supports a motor of the aircraft, a plurality of stators that extend from the central hub to the second spar, and a plurality of ribs that are attached to the first spar and the second spar at respective opposed ends. The spindle may include an attachment interface to which the first and second spars are attached. The attachment interface may be disposed at the second end of the spindle. The attachment interface may define first and second arc-shaped planar surfaces to which the first and second spars, respectively, are attached.

Abstract: A duct for a ducted-rotor aircraft may include an internal structure and an aerodynamic exterior skin that is adhesively bonded to the internal structure. The skin may include a leading-edge portion disposed at an inlet of the duct and an inner portion disposed along an interior of the duct. The inner portion of the skin may be bonded to the internal structure with a first bondline of adhesive and the leading-edge portion of the skin may be bonded to the inner portion of the skin with a second bondline of adhesive. One or both of the first and second bondlines of adhesive may be of non-uniform thickness to take up tolerance stackups between the inner portion of the skin, the leading-edge portion of the skin, and the internal structure.

Abstract: A ducted-rotor aircraft includes a fuselage, first and second ducts, and a spindle that is coupled to the fuselage. Each duct includes a rotor having a plurality of blades. The first and second ducts are coupled to opposed ends of the spindle. The spindle is rotatably coupled to the fuselage with first and second bearings. The first bearing is configured to react to radial loads and the second bearing is configured to react to both radial and axial loads. The spindle includes a shaft, first and second fittings secured to opposed ends of the shaft, and first and second attachment interfaces that are attachable to the first and second ducts. The attachment interfaces may be integral with the fittings. Alternatively, the fittings may be configured to be secured to the attachment interfaces with fasteners.

Abstract: A duct for a ducted-rotor aircraft includes a hub, a duct ring, and a plurality of stators that extend outward from the hub. The duct ring defines a trailing edge. The duct includes one or more fittings, such as a system of fittings. Each fitting has a body that defines a first attachment interface that is configured to couple to structure of the duct ring and a second attachment interface that is configured to couple to one of the plurality of stators. The first and second attachment interfaces are spaced from each other such that when the fittings are coupled to the duct ring and the plurality of stators, all or substantially all of each of the plurality of stators are located aft of the trailing edge of the duct ring.

Abstract: A duct for a ducted-rotor aircraft includes a hub, a duct ring, and a plurality of stators that extend outward from the hub. The hub may be configured to support a motor. The duct ring defines a trailing edge. The duct ring is coupled to each of the plurality of stators such that all or substantially all of each of the plurality of stators is located aft of the trailing edge of the duct ring.

Abstract: A ducted-rotor aircraft may include a fuselage and first and second ducts that are coupled to the fuselage at respective first and second locations. The first location may be on a first side of a fuselage of the aircraft and spaced from a nominal yaw axis of the aircraft. The second location may be on an opposed second side of the fuselage and spaced from the nominal yaw axis. Each duct may include a rotor that is disposed in an opening that extends through the duct. Each rotor may include a plurality of blades. Each duct may further include a control vane that is mounted aft of the plurality of blades and that is pivotable about a vane axis that is oriented toward the nominal yaw axis.

Abstract: An exemplary ducted fan includes a duct having a central longitudinal axis, a rotor hub and stator hub extending along the central longitudinal axis, rotor blades extending from the rotor hub, each of the rotor blades operable to rotate about its own pitch-change axis, the pitch-change axes lying in a rotor plane that is generally perpendicular to the central longitudinal axis, each of the rotor blades having a rotor trailing edge and a rotor chord length, stators extending from the stator hub to an interior surface of the duct, each of the stators having a stator leading edge and a stator thickness, and a first separation between the rotor plane and the stator leading edge of not less than approximately 1.5 times the stator thickness.

Abstract: A gel tray for a bacterial transformation lab exercise has a plastic body with four parallel gel channels and four filling ports, one for each channel into which unmodified bacteria and heat-shocked bacteria can be injected by students along with appropriate reaction constituents to demonstrate transformation of the bacteria under visualization. A seal may be provided to seal the tops of the gel channels and a lid can cover the gel tray during incubation.

Abstract: A gel tray for a bacteria transformation lab exercise has a transparent plastic body with four parallel gel channels and four filling ports, one for each channel into which unmodified bacteria and heat-shocked bacteria can be injected by students along with appropriate reaction constituents to demonstrate transformation of the bacteria under visualization.

Abstract: A hub assembly for a ducted-rotor aircraft includes a plurality of stator supports, a first integral fitting that attaches to first ends of the stator supports, and a second integral fitting that attaches to second ends of the stator supports. The first fitting includes a plurality of motor attachment portions configured to locate and support a motor of the ducted-rotor aircraft, a plurality of fairing mounts configured to support attachment of an aerodynamic fairing to the hub assembly, and a plurality of stator locators configured to locate respective ones of the plurality of stator supports for attachment to the hub assembly. The first fitting has a body portion with an annular wall that supports the motor attachment portions, the fairing mounts, and the stator locators. The first fitting may be fabricated as a monolith that includes the body portion, motor attachment portions, fairing mounts, and stator locators.

Abstract: A ducted-rotor aircraft includes a fuselage, one or more ducts, and a spindle that rotatably couples the one or more ducts to the fuselage. Each duct includes a hub that is configured to support a rotor, a plurality of stators that are coupled to the hub, a duct ring that is coupled to the plurality of stators, and a fitting that is coupled to a first stator of the plurality of stators. The fitting has a tubular collar that defines a first aperture that extends through the fitting. The collar is configured to receive a portion of the spindle. The first stator includes a rib that is spaced inward from the fitting and that defines a second aperture that is aligned with the first aperture and that is configured to receive an end of the spindle.

Abstract: A ducted-rotor aircraft includes a fuselage, one or more ducts, and a spindle that rotatably couples the one or more ducts to the fuselage. Each duct includes a hub that is configured to support a rotor, a plurality of stators that are coupled to the hub, a duct ring that is coupled to the plurality of stators, and a fitting that is coupled to a first stator of the plurality of stators. The fitting has a tubular collar that defines a first aperture that extends through the fitting. The collar is configured to receive a portion of the spindle. The first stator includes a rib that is spaced inward from the fitting and that defines a second aperture that is aligned with the first aperture and that is configured to receive an end of the spindle.

Abstract: A duct for a ducted-rotor aircraft includes a hub, a duct ring, and a plurality of stators that extend outward from the hub. The hub may be configured to support a motor. The duct ring defines a trailing edge. The duct ring is coupled to each of the plurality of stators such that all or substantially all of each of the plurality of stators is located aft of the trailing edge of the duct ring.

Abstract: A ducted-rotor aircraft may include a fuselage and first and second ducts that are coupled to the fuselage at respective first and second locations. The first location may be on a first side of a fuselage of the aircraft and spaced from a nominal yaw axis of the aircraft. The second location may be on an opposed second side of the fuselage and spaced from the nominal yaw axis. Each duct may include a rotor that is disposed in an opening that extends through the duct. Each rotor may include a plurality of blades. Each duct may further include a control vane that is mounted aft of the plurality of blades and that is pivotable about a vane axis that is oriented toward the nominal yaw axis.

Abstract: A ducted-rotor aircraft includes a fuselage and first and second ducts that are coupled to the fuselage. Each duct includes a duct ring, a rotor having a plurality of blades, a hub that positions the rotor such that the blades define a blade plane of rotation within the duct ring, and a plurality of stators that are coupled to the hub at respective locations aft of the blade plane of rotation. Each of the plurality of stators defines a leading edge that is slanted toward the blade plane of rotation. The leading edges of the stators are slanted to follow a contour defined by the blades. The leading edges may also be slanted to maintain a distance of at least one blade inboard chord length between the leading edges of the stators and respective trailing edges of the blades.