Re: gunsight reflectors/glass/combiners
I have a K-14b sight which uses a clear plexiglass reflector. There is no detectable distortion through the angled plexiglass.
This unit, btw, is actually two gunsights in one head unit. The center of each of two projectors are the same distance apart as our eyes. The right eye sees the ranging diamond and pipper. The left eye sees a small center cross and a 70 mil circle (where the circle can be blocked with a lever on the left side of the sight head). Both projectors can be operated independantly or together.
Each image is focused at infinity but neither appears as a 3D image since both are not combined. There is a very interesting effect that happens, however. When one eye is closed, the other sees an image on the left or right side. When both eyes are open, both images appear to move to the center of the reflector without changing the aiming point. In fact, its not even possible to photograph both images together since the camera is essentially acting like one eye. Also the size of the image does not change with distance of your eyes from the sight head. Moving closer to the sight has the exact opposite effect that we see in AH (where moving your head closer zooms the image)- the image appears to get smaller in relation to the gunsight and reflector unit. Moving away
makes the image appear to grow in relation to the gunsight head and reflector unit. The size of the image over target, however, does not change with head movement. ( Ex - Imagine being parked several hundred yards from a building in your car. Moving your head closer to the steering wheel makes the wheel appear bigger in relation to the building but does not change the size of the building.)
There is no ground attack reticle image in the K-14b and this is/was the standard installation in the P-51D. It features the standard fixed circle/cross and the moving diamond/pipper. The diamond image used for computing lead is ingenious in its function and design. You set the the target's wingspan (in feet)on the up front span lever. The rotating throttle handle is turned (like a motorcycle grip), causing the diamonds to expand or converge around the center pipper. This allows the pilot to fit the targeted airplane within the diamonds to determine range. Using a gyroscope mounted mirror, a mechanical computer in the sight head computes the range and corrects for ballistics and G-load to move the diamond sight around the field of view. The pilots maneuvers the airplane so that the sight appears to sit on the target for more than two seconds (basicly a steady state gunnery solution) then fires for a high percentage shot. If you want to see how it works, fire up the brand AW sim and enable the computing sight. Heh, one of the few things the sim actually modeled correctly.
MiG
