From an old post
Hey Guys,
This is the gunsight from a B-17. It was located in the Ball/bottom turret. It was made by NCR under license from Sperry. The sight is an Automatic Computing Sight. It has 3 cannon plugs for the power. The settings are Target Dimension in Feet/wingspan, Range in 100 Yards. Elevation 100 Mills (Millibars) Just like you set in an altimeter.
So with this info set say for a FW-190 Dim. 35', altitude 25,000', this would compensate for bullet drop, Range 300yards, also for bullet drop and lead. The rectial/mirror also was self adjusting for lead on a deflection shot.
As a lot of you know my Dad was a Ball turret gunner on the 17s.
Not only did you have to set in the ball for 8 hrs or so no chute and with your knees almost to your chin, while using your feet to control left, right, up, down and your gloved hands, because it is -30 or so in the ball, to operate the 50s and the sight in front of your face.
The later 17s had a computer sight in the waist and tail. The top and ball always had them I think. Our member Fast Ed is going to do some research at the USAFM for me.
Right Ed.
I was not able to show my dad this sight or ask him how it operates before he died.
If you go to this post
http://www.rugerforum.com/phpBB/viewtop ... +europeyou will see some of the pictures my Dad took. He must have had to reach around the sight to take them. Also if you look at the picture of flatgate sighting the waist 50 you will see a small version of this sight. Notice no RING AND PIN SIGHT on the 50.
To me this is amazing technology for 1940 or earlier. How many people had heard or knew what a computer was?????????????
Hope you enjoy and if you have any more info please let me know.
Thanks,
Jim
This is how it would have been mounted in the ball. You would be looking through the lens at the target.
through the lens at the target.
Ya can see the size of it, probably weights 20#
All sides of it with the cover off.