Evening Republican, Volume 23, Number 199, Rensselaer, Jasper County, 18 August 1920 — Shape of Shells. [ARTICLE]

Shape of Shells.

“Modern long-range shells are ci-gar-shaped. They taper both at the front and at the rear. This tapering of the rear end is called ‘boat-tailing.* You have noticed that racing automobiles have torpedo-shaped sterns. A square-tailed shell or automobile is actually held back at high speeds because of the, vacuum created behind It by the velocity of its movement. Tapering the tall leads the air gently and easily Into the hole that the shell or the racing car bores in the atmosphere and thus lessens vacuum’s Impeding grip on the flying object.”—Everybody’s Magazine.