Pintle exotic metal alloys. For World War II aircraft with sideways-retracting main gear units, carefully set-up "pintle angles" for such axes of rotation during retraction and extension allowed the maingear struts to be raked forward while fully extended for touchdown and better ground handling, while permitting retraction into rearwards-angled landing gear wells in their wings to usually clear the forward wing spar for stowing while in flight. Pintle A pintle is a pin or bolt, usually inserted into a gudgeon, which is used as part of a pivot or hinge. Other applications include pintle and lunette ring for towing, and pintle
Closed bolt Closed bolt A semi or full-automatic firearm which is said to fire from a closed bolt is one where, when ready to fire, a round is in the chamber and the bolt and working parts are forward. When the trigger is pulled the firing pin or striker fires the round, the action is cycled by the energy of the shot sending the bolt to the rear which extracts and ejects the empty cartridge case, the bolt then goes forward feeding a fresh round from the magazine into the chamber, ready for the next shot. When World War I era machine