Externet Posted July 1, 2019 Share Posted July 1, 2019 The rifling grooves impart the torque that makes the spin for better trajectory of a bullet. Would the same be convenient to have for a projectile in outer space; -no air, no gravity- ? What if the projectile is spherical ? Link to comment Share on other sites More sharing options...
iNow Posted July 1, 2019 Share Posted July 1, 2019 What would the grooves grab onto in the almost vacuum of space? Link to comment Share on other sites More sharing options...
MigL Posted July 1, 2019 Share Posted July 1, 2019 The spin imparts directional stability. Same reason a spinning top stays upright and doesn't fall over. It has nothing to do with air, and would give a space-going rocket more problems than it would alleviate. Link to comment Share on other sites More sharing options...
swansont Posted July 1, 2019 Share Posted July 1, 2019 8 hours ago, Externet said: The rifling grooves impart the torque that makes the spin for better trajectory of a bullet. Would the same be convenient to have for a projectile in outer space; -no air, no gravity- ? What if the projectile is spherical ? If there's no air to cause the path to deviate, what would be the gain? Link to comment Share on other sites More sharing options...
Externet Posted July 1, 2019 Author Share Posted July 1, 2019 Thanks, gentlemen. I sense the effects of two actions in your comments. The rifling in the barrel producing the initial torque, and the tiny grooves 'imprinted' on the bullet surface that interact with air during flight. Do both take part in the gyroscopic effect ? Are the markings on the bullet helical or straight ? Link to comment Share on other sites More sharing options...
swansont Posted July 1, 2019 Share Posted July 1, 2019 6 minutes ago, Externet said: Thanks, gentlemen. I sense the effects of two actions in your comments. The rifling in the barrel producing the initial torque, and the tiny grooves 'imprinted' on the bullet surface that interact with air during flight. Do both take part in the gyroscopic effect ? Are the markings on the bullet helical or straight ? I don't think the grooves are a major player in this during flight. It's the angular momentum. The bullet grooves are angled, because the rifling is helical Link to comment Share on other sites More sharing options...
MigL Posted July 1, 2019 Share Posted July 1, 2019 (edited) The 'rifling' imparts the spin to the bullet in the barrel. That's where the bullet gains all its momentum ( linear and angular ). The spinning bullet's angular momentum resists changes to momentum along other axis. This gyroscopic effect will keep it from tumbling end over end ( the other axis ), due to destabilizing forces, and keep its nose pointing forward. These destabilizing forces are more prevalent in air, but even in space, rockets are subject to external forces, or imbalances in the thrust line caused by CG shifts ( a spinning unbalanced rocket will experience precession of its thrust line instead of larger and larger deviation ). Edited July 1, 2019 by MigL Link to comment Share on other sites More sharing options...
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