Viewing page 14 of 101

This transcription has been completed. Contact us with corrections.


dynamic load- See LOAD, DYNAMIC

dynamic pressure- The product 1/2pV^2, where p is the density of the air and V is the relative speed of the air. 

dynamic stability- See STABILITY, DYNAMIC.

dynamometer, hub- A device built into a propeller hub for measuring the engine thrust and/or torque.

earth-inductor compass- See COMPASS, EARTH-INDUCTOR.

edge, leading- See LEADING EDGE.

edge, trailing- See TRAILING EDGE.

efficiency, propeller- See PROPELLER EFFICIENCY.

efficiency, propulsive- See PROPULSIVE EFFICIENCY. 

elastic center- See CENTER, ELASTIC/

elevator- A movable auxiliary airfoil, the function of which is to impress a pitching moment on the aircraft. It is usually hinged to the stabilizer. (See figs. 3, 4, 5, and 6.)

elevator angle- See ANGLE, ELEVATOR.

emergency flotation gear- A device attached to a landplane to provide buoyancy in case of an emergency landing on the water. 

empennage- See TAIL, AIRPLANE.

  axial-type engine- An engine having its cylinders equidistant from and parallel to the main shaft. Power is transmitted to the shaft through a wabble plate, swash plate, or gears. 
  cam engine- A type of engine in which the pistons are reciprocated by means of a cam-and-roller mechanism. 
  compression-ignition engine- A type of engine in which the fuel is sprayed into the cylinder and ignited by the heat of compression of the air charge. 
  double-row radial engine- An engine having two rows of cylinders arranged radially around a common crankshaft. The corresponding front and rear cylinders may or may not be in line. 
  left-hand engine- An engine whose propeller shaft, to an observer facing the propeller from the engine end of the shaft, rotates in a counter-clockwise direction. 
  right-hand engine- An engine whose propeller shaft, to an observer facing the propeller from the engine end of the shaft, rotates in a clockwise direction. 
  supercharged engine- An engine with a compressor for increasing the air or mixture charge taken into the cylinder beyond that inducted normally at the existing atmospheric pressure. 

engine, dry weight of an- The weight of an engine exclusive of fuel, oil, and liquid coolant. 

engine weight per horsepower- The dry weight of an engine divided by the rated horsepower. 

entrance cone- See CONE, ENTRANCE

envelope- (1) The outer covering of an aerostat, usually of fabric. (2) The bag containing the aerostatic gas of a free balloon, kite balloon, or non-rigid airship. (See fig. 3.)

equivalent monoplane- A monoplane wing equivalent as to its lift and drag properties to any combination of two or more wings. 

exhaust-collector ring- A circular duct into which the exhaust gases from the cylinders of a radial engine are discharged. 

exit cone- See CONE, EXIT. 

experiment (or test) chamber- The central portion of a wind tunnel, where aircraft models or other objects are tested. 

  ballon fabric- The finished material, usually rubberized, of which balloon or airship envelopes are made.
  gas-cell fabric- The fabric used in making gas cells for rigid airships. 
  goldbeaters-skin fabric- A fabric consisting of a layer of light, fine, strong cloth, usually cotton, to which one or more layers of goldbeaters skin have been cemented. 

factor, dynamic- See DYNAMIC FACTOR. 

factor, load- See LOAD FACTOR. 

factor of safety (stress analysis)- The ratio of the ultimate load to any applied load. This term usually refers to the probably minimum factor of safety, which is the ratio of the ultimate load to the probably maximum applied load. 

fairing- An auxiliary member or structure whose primary function is to reduce the drag of the part to which it is fitted. 

feather- In rotary wing systems, to periodically increase and decrease the incidence of a blade or wing by oscillating the blade or wing about its span axis. 

fin- A fixed or adjustable airfoil, attached to an aircraft approximately parallel to the plane of symmetry, to afford directional stability; for example, tail fin, skid fin, etc. (See figs. 3, 4, and 5.)

fin carrier- A frame to which the inboard edge of the fin of a nonrigid or semirigid airship is attached, so as to prevent the edge of the fin from sinking into the envelope. 

fineness ratio- The ratio of the length to the maximum diameter of a streamline body, as an airship hull. 

fishtail- A colloquial term describing the motion made when the tail of an airplane is swung from side to side to reduce speed in approaching the ground for a landing. 

fitting- A generic term for any small part used in the structure of an airplane or airship. If without qualification, a metal part is usually understood. It may refer to other parts, such as fabric fittings. 

Please note that the language and terminology used in this collection reflects the context and culture of the time of its creation, and may include culturally sensitive information. As an historical document, its contents may be at odds with contemporary views and terminology. The information within this collection does not reflect the views of the Smithsonian Institution, but is available in its original form to facilitate research. For questions or comments regarding sensitive content, access, and use related to this collection, please contact