Launch Cues Inaccurate

[elitewill1200]

Hello all! I noticed a weird bug with launch cues on the Strike Eagle. The BLUF is that the Rpi cue seems to actually be the Rmnvr range, and Rmnvr cue doesn't seem to denote anything at all. In fact there are situations that the Rmnvr cue will be beyond the Rpi cue (which doesn't make sense conceptually). For those that don't know, the Rpi cue is a maximum launch range with current steering that assures a high likelihood of success. It also assumes no maneuvers from the target, ie. that it maintains its current velocity with no acceleration. While the Rmnvr cue represents maximum range against a target executing at launch a constant speed, level 4-G turn towards the tail at missile launch. These definitions are straight out of the F-15E manual from RAZBAM.

In order to test these cues I designed two scenarios that roughly approximate a situation in which I discovered the bug, but in a sterile environment. Scenario A is a Hot Aspect intercept at about 45 miles on a F4E, co altitude, both planes starting at mach 1.0 and 36000 feet. The F4E has 4 Aim 7s, 2 bags, 2 Aim9s. It is designed to show a situation where the target is roughly the same energy as the F15E. Scenario B is a Hot Aspect intercept at about 45 miles on a F4E, both planes starting at mach 1.0. The F15E starts at 36000 feet and the F4E starts at 13000feet (however the AI usually climbs). The F4E has the same armament. It is designed to show a situation where the target is much lower on energy than the F15E.

The first attachment is of the AA Radar page with an example for Scenario A. As you can see, the Rmnvr cue and Ropt cue are roughly co-located, and Rpi is much below both even though the steering dot is centered within the ASE circle. As per the manual "With the Steering Dot centered in the ASE, Rpi is the same as Ropt." so this is the first clean kill error shown. Moving along, I tested 6 shots in scenario A, 3 of which an Aim120 was launched at Rmnvr and 3 of which an Aim120 was launched at Rpi. Before the launch, the F4E was put into STT, throttle to full AB. Post launch the throttle was retarded to full gate (if I remembered, it shouldn't really matter). All 6 times the F4E reacted when the missile went Pitbull by doing a diving 3-4 turn roughly cold. Conceptually, this SHOULD defeat missiles launched at Rpi, while missiles launched at Rmnvr should have a decent chance at intercepting. This was not the case however as you can see from the attached track files, each shot at Rpi hit while each shot at  Rmnvr missed, which is inverse of the expected behavior.

Moving on to scenario B. As you can see from the attached AA Radar screenshot, Rmnvr is now in a position between Rpi and Rtr as it should  be. I tested 6 shots in scenario B, 3 of which an Aim120 was launched at Ropt with the steering cue centered and 3 of which an Aim120 was launched at Rpi in straight in level flight. Before the launch, the F4E was put into STT, throttle to full AB. Post launch the throttle was retarded to full gate (if I remembered, again it shouldn't really matter). Conceptually, the shots at Ropt with steering cue centered and Rpi straight and level flight SHOULD both be defeated with any amount of maneuvering, and roughly demonstrate the same amount of performance (recall with the steering cue centered Ropt and Rpi are the same). Once again this was not the case. All 3 shots at Ropt with steering cue centered were trashed, while all 3 shots at Rpi straight and level flight intercepted despite the F4E maneuvering. 

All of this is what drives my belief that Rpi cue is actually using the calculated range for Rmnvr, while Rmnvr cue is flat bugged. I hope that all  of this makes sense and if anyone has any questions please ask below.

 

P.S. For trackfile naming conventions, the first number is the altitude of the bandit at the  start of the scenario (36 for Scenario A and 13 for Scenario B), and the text is what cue the Aim120 was launched at (Ropt, Rpi, or Rmnvr). Some of these hits/misses were EXTREMELY close, so do not be surprised if mixed results happen when you play back the track files. Rest assured I was not lying when I described the performance as simulated.

13Ropt1.trk 13Ropt2.trk 13Ropt3.trk 13Rpi1.trk 13Rpi2.trk 13Rpi3.trk 36Rmnvr1.trk 36Rmnvr2.trk 36Rmnvr3.trk 36Rpi1.trk 36Rpi2.trk 36Rpi3.trk

[Sarge55]

Nice bug report elite. 

[tdk]

It's a nice report, and I found the same thing in other modules such as Viper. You shoot at Rpi but it has a ridiculously high chance to hit successfully even though the bandit full gate maneuvered cold. AFAIK the Rpi assumes a non-maneuvering target, so I guess it's actually an AIM-120 bug or something.