| TEXT FROM ABOVEGUNNERS sit in 4 positions about a cluster of 5 projectors (A) which throw pictures of attacking planes on a spherical screen (B). Composite of 5 images covers 150° horizontally, 75° vertically. Both free (C) and turret (D) guns are used; ball turrets (E) will be adapted later. The instuctor (F) has a score board in front of him that counts the number of hits by each gun. Registers (G) operate the scoare boards, and send signal to student's earphones whe he hits. |
TEXT FROM ABOVE
HEART OF WALLER TRAINER
is hit-recording mechanism. As gun swings in
azimuth and zenith, cables move
quadrants (right) which move 3 scanner
bars (above) across register film. Film
has set of light slits for 75° vertical
angle, one for each half of horizontal
throw. Their location is set by plotting
distance to attacking plane against time
it takes bullet to reach it. Film is thrown
on a screen, a frame at a time, and
position of the plane noted. It then is
advanced to show position at end of
time lapse. (Movie film goes through a
projector at 24 frames per second.) This
new spot is where gun should be aimed
so bullet gets to the second position at
same instant plane does. It is marked
by a light beam whose location on the
screen is transmitted to the 3 masks in
a projector loaded with register film,
which are moved in the some manner
as the scanner bars. These masks pass
slits of light to the film in order to
expose on it position of the light beam
on screen. When gun in Trainer is on
correct "point of aim," the scanner bars
are moved by the gun's cables into a
scoring position, permitting light to pass
through slits in them and through the
transparent marks in the film. The light
strikes a photoelectric cell, which closes
a relay, sending signals to both gunner
and hit indicator on the control board.
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