This is *my* house... Actually, they're both "lobbed." The only difference is the angle at which the interior ballistics becomes exterior ballistics: a rifle shot, because of its higher velocity and shorter distance to target than a mortar round, requires less elevation for the round to "fall" on target.
Using sound as the indicator of position is inadvisable, since there is a huge difference between the natures of subsonic and supersonic signatures, and also since physical structures and their variables can make the perceived reception of these signatures very different from reality. Now if you combined that sound indicator with another mask, such as a rapid sample heat signature, and possibly a range-corrected sound signature combine with an active infrared transmitter/receptor (smoke readily absorbs infrared radiation), then that would probably work quite well. By the way, there is another interesting phenomenon that happens with all spin-stabilized weapons (whether imparted by rifling in the rifle barrel or artillery barrel, or by a rifling ring on the artillery shell): 1) Because of small imbalances inherent in the round fired, there is a sudden violent struggle between the natural centerline of balance and the centerline artificially imposed by the confines of the barrel. 2) This struggle manifests itself as a sudden and rather pronounced earthward dip in the nose of the round. 3) Gravity immediately exerts its force on the round, causing it to fall. 4) As it falls, "the fluid known formerly known as air" (as I like to call it when discussing ballistics) becomes more compressed on the underside of the round than on the top of the round. 5) Fluids adhere to the surfaces that travel through them, and the "layer" of fluid next to that fluid adheres somewhat less, as does the "layer" of fluid next further away. To see this in action, put a single ice cube in the center of a glass of still iced tea, then turn the glass and keep turning it at a relatively high consistent speed for about twenty seconds. 6) Since the uncompressed fluid on the top of the round sticks to the surface of the round as it spins, when it approaches the underside of the round where the fluid is gradually more and more compressed, it itself becomes more compressed as it tries to wedge its way between the surface of the round and the compressed air on the bottom. 7) This act of compression occurs slightly above and bottom and to the side, so it generates a force that pushes the round to the opposite side and upward, against the force of gravity. 8) The result of all this balancing act and opposing forces is a continuous "porpoising" motion along the entire trajectory that degrades in a "sawtooth" fashion (porpoising rapidly and pronounced, then very little for a while, then porpoising less rapidly and less pronounced, then very little for a while, then a bit more porpoising, etc). The faster the spin, the more pronounced the motion. Since mortar rounds don't spin, and since they mainly present their noses rather than their profiles toward the force of gravity and the resulting compressed air, they don't exhibit this behavior. Cool, huh? Respectfully, Adam Phillip Churvis President Productivity Enhancement ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Adobe® ColdFusion® 8 software 8 is the most important and dramatic release to date Get the Free Trial http://ad.doubleclick.net/clk;192386516;25150098;k Archive: http://www.houseoffusion.com/groups/CF-Community/message.cfm/messageid:259806 Subscription: http://www.houseoffusion.com/groups/CF-Community/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=89.70.5
