Description
The motors are used by rotary-wing and other low-speed aircraft; they may also be used with high performance aircraft.
The MK66 motors utilize a longer motor tube (than the MK40) of a different aluminum alloy, and a new nozzle and fin assembly. The fins are of a spring loaded, wrap-around design and are attached around the circumference of the single nozzle. The propellant grain is longer and of a different formation than the standard grain; however, the stabilizing rod and igniter are essentially the same as used on the MK40 motor. The MK66 motors have a substantially higher thrust, 1300 lb, and a longer range. The MK66 Mod 0 was developed by the Navy but never fielded.
The MK66 Mod 1 motor is a nozzle modification of the Mod 0 to increase the spin rate from 4 - 5.5 rps to 9 - 10 rps (at launch) for increased accuracy and provide interface with existing and improved launchers. A detent groove has been added forward of the wrap-around fins.
The MK66 Mod 2 motor is the same as the Mod 1 motor except that it contains a Hazards of Electromagnetic Radiation to Ordnance (HERO) filter which allows it to be handled and stored in electromagnetic radiation environments.
The MK66 Mod 3 motor is physically and functionally the same as the Mod 1 motor except that it has a radio frequency (RF) filter in the firing circuit. The filter is physically located on the igniter can. It also has a metallic brass shield over the fin and nozzle assembly to shunt any arc formed during loading/unloading rockets into or from the launcher. The RF filter resists inadvertent firing by stray RF currents.
The MK66 Mod 4 motor is an improvement on the MK66 Mod 2 motor and is tri-service compatible. Changes include a new E3 filtering system located under the contact band, a new initiator, a new igniter, and a new stabilizing rod and attachment assembly. The new ignition mechanism reduces variations in ignition delay time. The bare MK66 Mod 4 motor is considered Hazards of Electromagnetic Radiation to Ordnance (HERO) safe without special precautions. The MK66 Mod 4 motor is also considered safe in Electrostatic Discharge (ESD) environments.
Functioning
No information about functioning.
Hazardous Components
No information about hazardous components.
See Also
Nothing else to see.
Source(s)
TM 43-0001-30, Rockets (chg 14, 2001)
