To enable full functionality of the K14 gun sight there are several things that need to be done. First change the <nasal> section of your *set.xml file so that it looks like the following. <nasal> <!-- your other nasal files --> <!-- the following three lines must be exactly like this --> <K14> <file>Aircraft/Instruments-3d/computing-gun-sights/Nasal/lead-computer.nas</file> </K14> </nasal> Animation: For dark conditions when cabin/cockpit illumination is used all of the K14 sight is illuminated in response to <property>/controls/lighting/cabin-norm</property> If you are using a different property for your cabin/cockpit lights you will need to map your lighting property to /controls/lighting/cabin-norm. Aircraft Specific Properties: See README.lead-computer Below is an example from the P-51D using the K14A sight which needs some additional settings to control power and lighting for the sight. <controls> <armament> <gunsight> <!-- gunsight computer parameters --> <!-- start/stop the sight computer the computer will be reinitialized if the power is cycled --> <computer-on type="int">0</computer-on> <!-- offset of guns below sight line in feet --> <z-offsetFeet type="float">3.125</z-offsetFeet> <!-- average lateral offset of guns in feet relative to sight line --> <y-offsetFeet type="float">0.0</y-offsetFeet> <!-- elevation of guns relative to alpha in degrees --> <gunElevationDegrees type="float">1.0</gunElevationDegrees> <ballisticCoefficienct type="float">0.00136354</ballisticCoefficienct> <!-- 0.50 BMG --> <muzzleVelocity type="float">2900.0</muzzleVelocity> <!-- feet per second 0.50 BMG --> <!-- convergence distance in feet --> <gunHarminizationRangeFeet type="float">900.0</gunHarminizationRangeFeet> <timeStep type="float">0.2</timeStep> <!-- cycle rate of gun sight computer in seconds --> <!-- sight computer damping factor must be between 0.3 and 1.0 --> <dampingFactor type="float">1.0</dampingFactor> <gunsight-computer-initialized type="int">0</gunsight-computer-initialized> <maxAzimuth type="int">170</maxAzimuth> <!-- maximum sight deflection in mils --> <maxElevation type="int">170</maxElevation> <!-- K14 parameters --> <power-on type="int">0</power-on> <intensity type="float">1.0</intensity> <mask-off type="int">1</mask-off> <reticleSelectorPos type="int">0</reticleSelectorPos> <rocketLadder type="int">1</rocketLadder> <!-- set to 0 for K14 and 1 for other K14 models --> <!-- The next three are to setup the reticle to the correct starting values --> <span type="int">30</span> <mils type="float">0.0</mils> <range type="float">1000.0</range> <!-- in feet --> <fixedReticleOn type="int">0</fixedReticleOn> <zCenterLine type="float">0.7375</zCenterLine> <!-- sight line distance from model z axis in meters --> <K14C type="int">0</K14C> <!-- set to 1 for K14C --> <sunScreenDown type="int">1</sunScreenDown> </gunsight> ... </controls>