Main parachute: 11 feet.
Pilot parachute: 6 feet.

Upper H.E. charge: RDX/Wax, 95/5.
Lower H.E. charge: RDX/Wax, 95/5.

Upper H.E. charge: 2 pounds 6 ounces.
Lower H.E. charge: 1 pound 10 ounces.

DESCRIPTION. This projectile is of the "aerial-wire-barrage" type and is used to project a steel cable into the air by means of a rocket. (See fig. 213.) One end of the cable is fixed to the ground and the other to a large support parachute and a smaller drag para-chute. When the cable has paid out, the parachutes are pulled from their housing. The projectile is fin-stabilized and consists, from nose to tail, of the rocket motor, parachute housing, and upper and lower cable housing.

Rocket Motor. The rocket motor consists of a motor body, which is secured into the pa-rachute housing, and an ogival nosepiece containing a TNT destruction charge. The mo-tor body is a cylinder closed at the forward end and open at the rear. There is no base plate, but the propellant gases are allowed to escape through four venturi drillings in the forward end of the parachute housing. The propellant is a single, cylindrical, multiperfo-rated stick and is ignited by means of an electrical base igniter, a train along the central drilling, and an ignition charge in a grid at the forward end. Leads to the electrical igniter pass through one of the venturi drillings. A delay fuze in the forward end of the motor body ignites the destruction charge in the nose-piece.

Parachute Housing. The parachute housing, which is a cylinder closed at the forward end, serves not only to house the large main support parachute and the smaller drag parachute, but also as a base plug for the rocket motor. The forward end has four ven-turi drilled obliquely in the sides of the body.

At the forward end of the parachute housing is a TNT destruction charge enclosed in as-bestos. Although this has a primer, there is no means of initiation; it is assumed, there-fore, that this charge is set off by sympathetic detonation from the charge in the nose of the projectile. Below this destruction charge is the main parachute wrapped in asbes-tos and below it the small drag parachute.

Cable Housing. The cable housing is constructed in two separate halves. The upper half is attached to the base of the parachute housing and accompanies the projectile on its flight. The lower portion of the housing has a flanged base, which fits into the mounting and remains on the ground. The finned tail unit is spot welded to the upper half and fits over the lower portion. This maintains the projectile in position until it is fired. A slot is provided in two of the fins through which a wire is passed, holding the lower section in position; this wire should be removed before firing.

A continuous of approximately 950 yards of 1/8-inch steel cable is coiled in equal lengths inside each portion of the cable housing. The end of the cable in the upper portion is at-tached to the parachute, and the other end passes through a hole in the bottom of the lower portion and terminates in an eye-bolt secured to the launching frame.

OPERATION. The actual barrage consists of the support parachute, drag parachute, and cable. The projectile is evidently launched from some kind of frame (no specimen of this had yet been recovered), to which the lower portion of the cable housing is fixed. When the propellant charge is ignited, the projectile climbs until, theoretically, the whole of the cable has paid out. The drag parachute and the main support parachute are then with-drawn from the parachute housing and the main unit continues on its course leaving the cable suspended in the air.

When the propellant burns out, the destruction charge in the nose piece, actuated by the delay fuze, destroys the rocket motor and parachute housing. It is presumed that the charge in the forward end of the parachute housing is at this point set off by sym-pathetic detonation to assist in this destruction.

Figure 213 – 15.2-cm Antiaircraft Rocket