by hvengel » Tue Apr 29, 2014 5:10 pm
Good point. There is already some documentation and at this point it is somewhat K-14A specific although it does cover the settings needed for the lead computer. I intended this to help others use the lead computer and the K-14A but I think it probably should be more extensive than it currently is and it needs to be divided into two documents - one that covers the lead computer only and one that adds information for the K-14A. Also something that is typical for developers is that we end up being so familiar with things that stuff we think is obvious is really not obvious to others so our documentation tends to have gaps that can be confusing.
One of the reasons that I offered to work with someone on integrating this into a new aircraft was that this would give me an opportunity to have someone new to the code work through the process so that I could see where the documentation (and perhaps functionality) gaps are (IE. where did they stumble) and fix those. Since it has been a few months it is probably a good idea to review the existing docs and fix any apparent issues before someone else tries to use it.
One other consideration is that this has only been used with a gun sight that has manual ranging so integrating it into something like an F-16 we will need to setup a radar ranging system. The lead computer or the radar system will need to be extended to interface the range info from the radar system to the lead computer. Probably not very difficult (likely less than a dozen lines of Nasal since all that is needed is to have the radar system push the range, in feet, to the designated target to the /controls/armament/gunsight/range property) but once this is in place other aircraft with radar ranging gun sights will be very simple to integrate although the reticle animation will still be a significant issue for some aircraft.
There are currently a total of 12 properties that are used to configure and interface to the lead computer. 8 of these are configuration properties that give the lead computer aircraft and gun sight specific info (gun offset - vertical and horizontal relative to the sight line in feet, elevation angle relative to 0 alpha in degrees, muzzle velocity - feet per second, ballistic coefficient, harmonization range - in feet, maximum azimuth and elevation of the gun sight in mils). 2 are run time input parameters - power on/off and range to target - in feet, 2 are output - elevation and azimuth in mils relative to the sight line. These last two drive the sight animation. I need to expose the time step and the damping factor configuration parameters to have this be fully generalized.
A mil is a 1 foot deflection at 1000 feet. The lead computer is capable of giving steady state (IE. constant G maneuvers) solutions that are accurate to less than 1.1 mils at a 2000 foot range (IE. with in 2.2 feet).