Whistling spinning grenade

A grenade comprising:

• a body defining a body axis and defining a chamber;
• the chamber containing a teargas generation component and an ignition component;
• the body defining a plurality of exhaust apertures, each exhaust aperture communicating externally from the chamber;
• the chamber being open to the atmosphere within gas communication via the exhaust apertures wherein relative pressure differentials are relieved by gas flow through the exhaust apertures;
• each exhaust aperture having a thrust direction in which exhaust gas pressure in the chamber is relieved by venting through the exhaust aperture;
• each thrust direction having a tangential direction component with respect to the body axis, such that the body is impelled to spin about the axis in response to expulsion of gases from the chamber via the exhaust apertures;
• each exhaust aperture having a whistle geometry wherein a tonal sound having a pitch is generated upon expulsion of gas via the exhaust apertures while the body is rotating;
• and
• wherein each exhaust aperture defines a passage including a sharp lip at an intermediate location along the passage to generate a flow discontinuity as gas is exhausted through the aperture.