Vapor lock......................................................................2-2 Vapor vent system........................................................2-17 Variable-geometry duct ...............................................3-19 Voltage drop in aircraft wire and cable........................4-47 Voltage drop (IR drop).................................................4-47 Volumetric efficiency ..................................................1-36 V-type engine cylinders ...............................................1-16 Water injection system.................................................2-41 Water injection systems for reciprocating engines ......2-34 Weight............................................................................1-2 Wire groups and bundles .............................................4-51 Wire size ......................................................................4-45 Work ............................................................................1-28 W  I-6