The 2.75-inch motor was originally developed as a replacement for the MK66 rocket motor, part of the Hydra 70 tactical missile system. Because of the composite case, the Thiokol rocket motor provides increased insensitive munitions capability and flexibility to meet more than just the mission requirements of the Hydra 70 system.

The composite case is capable of withstanding internal pressures up to 10,000 psi, which translates directly into increased velocities or range depending on the mission. Safety factors for the case are four or five times greater than current safety levels, which is unheard of in the propulsion business.

Once the basic composite case and motor are qualified on the Apache, the velocity, range and other mission profiles can be increased to meet a variety of small diameter rocket motor requirements. The composite case has been tested and has excelled in a wide range of tactical environments.

Six Thiokol 2.75-inch rocket motors with composite cases flew from the Avenger ground vehicle in an Army demonstration program in January. The target trucks were one kilometer away and the warheads were the Hydra M-255 flechettes. These tests successfully proved the compatibility between the Hydra warhead and the Thiokol motor, and the ability to fulfill a ground-launch mission to intercept truck columns. Thiokol's 2.75-inch motor will beflight tested from the Army Apache helicopter this year and fully qualified in 1999.