WW2 US Army Aircraft – SPERRY K-13 COMPENSATING GUNSIGHT – B-17 B-24 – NICE!

You are bidding on a VERY NICE used example of a WW2 US Army Air Force Sperry K-13 Compensating Gunsight! This gunsight was used specifically in waist/side gunner positions of various bomber aircraft, such as the B-17 Flying Fortress and B-24 Liberator!

Made by Sperry, the K-13 Compensating Gunsight, is pneumatically-powered, designed to compensate for altitude and airspeed.  Typically mounted on the rear housing of a 50 cal machine gun from a side/waist gun position in the aircraft.  It was a late war innovation that used the aircraft altitude and speed with the direct correlation of where the weapon was pointed to calculate the reticle. The aircraft altitude and speed was programmed on the rear of the sight. The correlation was determined by drive lines that connected the K-13 Sight to the K-7 Mount.  A compensating sight offsets the line of sight only to compensate for the speed of the firing aircraft.   These sights do not take into account target range, but base their calculation on the angle between the gun line and the aircraft axi.  In these sights the full compensation for own speed is only applied when set to the STRAFE position.  In all other situations only a fraction (about 65%) of the full compensation is applied, because in a pursuit curve the attacking aircraft’s speed has a component in the direction of the target’s flight.

Made of aluminum, steel, and glass, and dating around 1944, this is a EXCELLENT used example! Though there are some light scratches and wear from storage, it retains 98% of its original finish with the original bulb!  All the glass is original to this sight, and includes the flip up sun shield so that the pilot could see easier when flying in brighter light. The data plate is 100% intact, and clearly indicates the model and type.  The cross hair is 100% intact and functions well! Would make an EXCELLENT addition to any collection, display, or simply as a conversation piece!