Prior art signal cartridges are usually launched from shoulder or hand-fired weapons, and utilize a parachute type canopy to suspend and retard the descent of the cartridge or flare to prolong the pyrotechnic display. Without such a parachute, the light-producing payload would fall rapidly back to the ground, and the light display would be rather shortlived.
Even with the use of a parachute, the pyrotechnic display does not have as great a duration as would be desirable since space, which could otherwise be used for increased payload, is required to accommodate the parachute within the restricted confines of the cartridge or projectile body.
Furthermore, unreliable deployment of the parachute at the prescribed height frequently renders the signal ineffective. Such so-called "duds" are of course costly and time consuming.
Prior art efforts to overcome these disadvantages have centered on improved parachute deployment or larger cartridges for larger payloads. However, generally cartridges in the 30-50 millimeter range are the maximum size used for hand-held weapons.
Accordingly, a primary object of this invention is to eliminate the need for a parachute for suspending the signal display.
Another object of this invention is to provide a self-levitating signal cartridge.
A further object of this invention is to provide a signal cartridge having thrust means for levitating the cartridge.
Still another object of this invention is to provide a self-levitating signal cartridge which may incorporate a larger payload than previously used within the same size cartridge.
Still a further object of this invention is to provide a self-levitating signal cartridge which utilizes a payload which will simultaneously provide a signal and a means for suspending that signal using the same mass of material.
Yet another object of this invention is to provide a signal cartridge which incorporates separate solid masses of material to yield levitation and a light or smoke signal within the same cartridge.
A still further object of this invention is to provide a signal cartridge which utilizes a rocket motor for levitating the cartridge at or near the zenith of its trajectory.
Yet a further object of this invention is to provide a self-levitating signal cartridge having thrust producing means which is balanced over time with respect to the mass of the signal cartridge.
A still further object of this invention is to provide a signal cartridge utilizing a rocket motor for levitating the signal cartridge and including a self-compensating thrust modulator for the rocket motor.
Still another object of this invention is to provide a signal cartridge which utilizes a configured thrust-producing charge for balancing the thrust output with respect to the mass of the projectile over time.