What is a decent English explanation for "Drallmuntion"
Erik
German - English??
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ChrisMAg2
- Member
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- Joined: 04 Aug 2003, 09:26
- Location: Hannover, Germany or Manila, Philippines
Ian Hogg calls that spin stabilized ammunition:
Keeping a projectile pointing towards its target by spinning it at a high rate. The effect is due to the same principle as which keeps a spinning gyroscope aligned and causes it to resist a change of direction. Once the shell is fired it literally becomes a gyroscope, and any tendency to change direction away from the ordinated trajectory is resisted. The amount of spin which a projectile requires in order to be stable in flight can be calculated, the most significant factor being the length. A projectile in excess of about six calibers in length (eg, for a 15 cm shell, six calibres in length would be 90 cm) is not easily spin stabilized, and projectiles longer than this are usually fin-stabilized. It is for this reason, as much as any other, that the first thing to be designed for a weapon system is the projectile; once this is settled the gun to can be designed to throw it.
Spin causes the shell to drift; ie to move sideways through the air in the direction of the twist of the rifleing., This is due to the effect of the rapidely-moving surface of the spinning projectile upon the surrounding air; to simplify, the air on one side of the projectile becomes rarifiedand on the other side becomes increased, so that the pressure pushes the shell towards the thinner air. Drift can be compensated for in design of the weaponsight, but has to be adjustable in weapons which use propelling charges, since the different charges develop different velocities and thus different rates of spin
Regards
Keeping a projectile pointing towards its target by spinning it at a high rate. The effect is due to the same principle as which keeps a spinning gyroscope aligned and causes it to resist a change of direction. Once the shell is fired it literally becomes a gyroscope, and any tendency to change direction away from the ordinated trajectory is resisted. The amount of spin which a projectile requires in order to be stable in flight can be calculated, the most significant factor being the length. A projectile in excess of about six calibers in length (eg, for a 15 cm shell, six calibres in length would be 90 cm) is not easily spin stabilized, and projectiles longer than this are usually fin-stabilized. It is for this reason, as much as any other, that the first thing to be designed for a weapon system is the projectile; once this is settled the gun to can be designed to throw it.
Spin causes the shell to drift; ie to move sideways through the air in the direction of the twist of the rifleing., This is due to the effect of the rapidely-moving surface of the spinning projectile upon the surrounding air; to simplify, the air on one side of the projectile becomes rarifiedand on the other side becomes increased, so that the pressure pushes the shell towards the thinner air. Drift can be compensated for in design of the weaponsight, but has to be adjustable in weapons which use propelling charges, since the different charges develop different velocities and thus different rates of spin
Regards
