The report on this particular type of bomb, known by the Italian name of bomba vento, gives
the following dimensions:
|Total weight|| ||11.5 lbs (approx)|
|Over-all length (without fuze)||15.2 in|
|Over-all length (with fuze)||17.4 in|
|Length of body|| 8.9 in|
|Length of tail|| 9.2 in|
|Maximum diameter of body|| 5.2 in|
|Diameter of tail|| 7.0 in|
The bomb is formed on a thin, sheet-metal cylinder (1) - see figure A - 6.7 inches in
length and with a diameter of 3.1 inches. The lower end is closed by a thin steel
disk (2) which has a central hole 0.9 inch in diameter. The fuze tube (3) is fitted
over this hole and pressed into the disk (2). The four supports (4) for the vanes are
spot-welded to the side of the cylinder. The short tube (5), 1 inch long and threaded
at its outer end to receive the suspension lug (6), is also spot-welded to the cylinder (1). (For
vertical suspension the lug in the fuze is used.) Four additional short tubes of small diameter
are welded over four corresponding holes near the open end of the cylinder. One pair of these
short tubes, which are 0.9 inch apart, lies symetrically between two vanes, and the other
pair directly opposite between the other pair of vanes. They are intended as guides for the
wire*(7) (see figure B). The bomb body (8) consists of hard concrete in which steel
pellets are embedded. Two sets of spiral reinforcing are provided. Three turns of
wire (approximately 16 standard wire gauge) are wound clear of the cylinder (1) near the
open end. The wire passes through holes (9) in its vane-supports (4) and is
welded at its end to the cylinder. Five turns of heavier reinforcing (about 8 standard wire
gauge) are wound as shown at (10). This wire is welded to the cylinder (1) at one end
and to the tube (3) at the other.
The vanes (11) are made of aluminum alloy and are riveted to the supports (14).
The cylinder contains the bomb filling, which may consist of a cardboard tube (12) filled
with a smoke composition (13). The cylinder is closed by a cork plug (14, in figure B) held
in position by the wire (7). The smoke composition is labelled Luce e Fumo Bianco, which
indicates that a flash as well as a white smoke is emitted from the bomb.
An alternative filling which has been found consists of a 1-kilogram incendiary
bomb (15, in figure C) with a black-powder charge (16) placed between it and the fuze
when assembled in the vento bomb. When so employed, the incendiary bomb has the usual
transit plug (21) drilled to take the flash from the charge (16).
An alternative tail has been recovered in which the cork plug (14) is not used to close
the bomb, but instead a wooden plug of the shape shown at (16) figure D performs the
double function of closing the bomb and supporting the vanes. These latter, shown at (17),
are 8.7 by 2.6 in. and made of three-ply wood. They are inserted in slots in the
plug (16) and are strengthened by a metal binding (18) and by four level
strips (19) running the whole length of the vanes. There are four holes (20) passing
through the plug located halfway between each pair of vanes. The plug (16) is attached
to the bomb by four nails inserted through the concrete body. The fuze employed in this bomb
is type S.
From specimens examined it would appear that the concrete bombs, which are fitted with
wooden tails, have no fuzing arrangement. In one case, there was no metal cylinder (1) or
fuze tube (3). A single suspension lug was cast in the bomb at the nose. It is thought
that these may be the Italian practice bomb, Bomba 5E.
It is learned from Italian sources that the vento (wind) bomb is designed to be
used in conjunction with the 500-kilogram gas bomb (Bomba 500 0). The purpose
of the bomb when dropped is to indicate the force and direction of the wind at ground
level. The former is estimated from the angle the smoke makes with the ground, and the
latter from the direction of the smoke trail.
During the day, the "smoke" filling is used, while as an alternative at night, the
incendiary filling would be effective.
*i.e., to provide a passageway through the concrete body of the bomb for the wire.