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the camera about three mutually perpendicular axes - roll, pitch and 
yaw - as a function of time. Each graph is based on 127 flashes of the 
| lights, i.e., 126 time intervals each of 1/300 second. "Fast" indicates 
a run made at the speed normally used for photographic work. "Slow" 
indicates a situation representative of slow flight such as would be 
used to reduce image motion due to forward motion of the aircraft. 
| Figures 3 to 5 apply to a Falcon aircraft with two rear-mounted 
| fan-jet engines carrying two Wild RC-10 cameras in a front and.a rear 
position. 
Figure 3 is for '"fast" operation. The gross slope of the "roll" 
curve can probably be disregarded as a test artifact due to the air- 
craft not having entirely settled down after manoeuvres to get on 
course over the target lights. 
Figure 4 is for "slow" operation and the same "front" camera. (0 
Lower vibration at lower speed is quite apparent for this jet aircraft. 
Such an effect has not been found significant in slower, piston-engined 
aircraft. 
————G 
Figure 5, the "slow" operation again but the 'rear" camera shows 
much worse vibration, most noticeably a low frequency roll. 
Figures 6 to 10 apply to a DC-3 (Dakota) aircraft with two camera 
positions, a port front position used for Wild cameras RC-8 and RC-10, 
and a standard aft position used for Zeiss RMKA 15/23 cameras. Figures 
6 to 8 indicate some significant differences between different camera- 
mount systems. Figures 9 and 10 indicate the possibility of very 
different vibrations occurring under nominally identical conditions. 
Table 1 summarizes results of vibration measurements from eight 
different aircraft and a variety of cameras, mounts, and operating 
conditions. 
The first two lines present data reported in 1951? for an F 52 (9 
camera, recomputed to apply to a 15 cm focal length and 23 x 23 cm 
format. The "foam rubber" mount was of the typical Canadian air force 
design of that time, the gimbal mount was a purely experimental mount? 
with the centre of gravity of the camera accurately at the intersection 
of the three axes of a gimbal system. 
Conversions from angular velocities to image velocities have been 
made on the basis of certain consistent approximations discussed else- 
8 
where. 
Slowest Permissible Shutter Speeds are those required to keep 
image motion down to 15 um, assuming the angular vibration reported is 
the only motion. In practice a higher speed would be needed to allow 
for the addition of some image motion due to forward motion of the 
aircraft.