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voltage constant from a no-load condition to the maximum load the generator can produce. See
overcompounded generator and undercompounded generator.
flat file (metal-cutting hand tool). A common type of file used to smooth the edges or surface of a piece
of metal or hard plastic. A flat file is tapered toward the tip in width and slightly tapered in thickness. It has
two sets of teeth arranged diagonally across the surface in opposite directions (double cut), on both sides
and a single row of teeth along both edges.
flat grain wood. Wood that has been sawed in such a way that the annual rings form an angle of less than
45° to the face of the piece.
flathead pin. A high-strength steel pin with a flat head on one end and a hole for a cotter pin on the other
end. A flathead pin, called a clevis pin, is used to connect a clevis to an eyebolt or control horn.
flathead rivet. An AN442 rivet used on the inside of an aircraft structure where it is not exposed to the
airflow. Flathead rivets are often used because they are easy to install with automatic riveting machines.
flat lacquer (finishing material). A type of lacquer that dries with a flat, or nonglossy, surface. Flat
lacquer is used for painting instrument panels and any part of an aircraft that must not reflect light.
flat pattern layout. The pattern for a sheet metal part that has the material used for each flat surface, and
for all of the bends marked out with bend-tangent lines drawn between the flats and bend allowances.
Printed from Summit Aviation's Computerized Aviation Reference Library, 2/7/2007
Page 253
flat-rated engine. A turboprop engine whose allowable output power is less than the engine is physically
capable of producing. Below a specific density altitude, the engine is limited by the amount of torque the
airframe can tolerate. Above this altitude, the engine is limited by the exhaust gas temperature.
flat spin (aircraft maneuver). An aircraft maneuver in which the aircraft is autorotating (being pulled
around by aerodynamic forces) as it descends, with one wing flying, and the other actually stalled. In a
normal spin, the aircraft is pitched steeply nose down, but since it is descending, it has a very high angle of
attack. Recovery is made by moving the control wheel forward (the elevators down). This decreases the
angle of attack and allows the stalled wing to begin flying again, and the airplane stops spinning.
In a flat spin, the angle of attack cannot be lowered enough, even with full-down elevators to bring
the wing out of its stalled condition. Flat spins are caused by the center of gravity of the aircraft being too
far aft, allowing centrifugal force to flatten the spin. Very few aircraft can recover from an unintentional
flat spin.
flat washer. A disk of metal with a hole in its center. A flat washer, also called a plain washer, is used
under the head of a bolt to provide a bearing surface. It can also be used under a nut to make a surface for
the nut to turn against so that it will not dig into the material contacted by the nut.
flaw. An imperfection in a material, often concealed, that impairs soundness.
fleet weight (aircraft operation). The average weight of aircraft of the same model that have the same
equipment installed. Operations under 14 CFR Part 121 and 135 may use fleet weight, rather than having to
weigh each individual aircraft.
Fleming’s rule for direction of magnetic flux. Place the fingers of the right hand around a
current-carrying conductor in such a way that the thumb points in the direction of conventional current flow
(from positive to negative). The fingers encircle the wire in the same direction as the lines of flux.
Fleming’s rule for electric generators. This is the rule for determining the direction of current flow in a
wire caused by the wire passing through a magnetic field.
Hold the right hand with the thumb, first finger, and second finger extended so that they are at
right angles to each other. When the first finger points in the direction of the lines of magnetic flux (from
the north pole to the south pole), and the thumb points in the direction the wire is moving through the field,
the second finger points in the direction of conventional current flow (from positive to negative).
Fleming’s rule for electric motors. The rule for determining the direction of movement of a
current-carrying conductor in a magnetic field.
Hold the left hand with the thumb, first finger, and second finger extended so that they are at right
angles to each other. When the first finger points in the direction of the lines of magnetic flux (from the
north pole to the south pole), and the second finger points in the direction of conventional current flow
(from positive to negative), the thumb points in the direction the conductor will move.
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航空术语词典Dictionary of Aeronautical Terms 中(40)
