3.5 Mk 14-0 Head

OVERALL LENGTH

TOTAL WEIGHT

HEAD DIAMETER

HEAD LENGTH

HEAD WEIGHT

MOTOR LENGTH

MOTOR DIAMETER

FUZE

GENERAL:

The 3.5" Rocket Flare was devloped for use from surface ships, particarly Motor Torpedo boats. The illuminant candle produces an average of 800,000 C.P. for approxi-mately 29 seconds. The rocket motor carries the flare out 1800 yards before ignition.

The 3.5" Rocket Flare consists of the following three major components: 3.25" Rocket Motor Mk 12-0, the Mk 14-0, or the Mk 14-1: 3.5" Rocket head Mk 10-0, the Mk 14-0, or the Mk 15-0; and the Rocket body load (flare) Mk 7-0.

ROCKET HEADS:

The head is the carrying unit for the flare and parachute components. All of the heads are interchangeable and differ only in minor details. The Mk 10-0 has a wooden nose piece held in place by three shear pins (see page 22) while the Mk 14-0 and the Mk 15-0 have a sheet metal nose piece press fitted in place. The Mk 15-0 is one inch longer than the other two.

The head consists of a 3.25" seamless steel tube which incorporates a 3.5" diameter closure adapter welded ot the after end. This closure adapter carries a copper dia-phragm plate with a firing pin and serves as a chamber for the Cal. .32 blank cartridge which ignites the fuze. The Mk 134-0 fuze consists of a plastic case containing a length of Ensign Bickford fuse and a 20 gram charge of black powder. The balance of the head is taken up by the Rocket Body Load (Flare) Mk 7 which consists of the cand-le and parachute from the 4 inch illuminating projectile, the composition of the candle having been slightly changed to increase the candlepower with a shorter burning time.

ROCKET MOTORS:

The three motors are similar and interchangeable. The principal distinguisher feature of the Mk 14-1 is the use of welded on launcher lugs replacing the lug bands employed on the earlier models. The motor housing is a 3.25" seamless steel tube container a for-ward closure disc. Igniter Mk 11 Mod 0, tubular ballistite grain Mk 7 Mod 1 (weight: 2.8 lbs.), steel grid, welded nozzle, and pigtail. Four tail fins, 3 inches by 8 inches, are mounted on a sleeve fixed to the after end. A thread projector of the forward end and shipping cover taned on the after end protect the motor in shipment. The Mk 12-0 mo-tor disc not have a shipping cover on the after end.

OPERATION:

When the rocket is fired, gas pressure blows out the forward closure disc and exerts force on the diaphragm plate in the base of the motor adapter. The diaphragm collaps-es and the firing pin is forced into the primer, firing the blank cartridge. The flash from the cartridge ignites the fuse which burns 15 seconds and then ignites the black pow-der ejector charge. The firing of the ejector charge ignites the candle and simultan-eously pushes the load forward out of the head. The parachute opens and the candle burns for approximately 29 seconds.