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Hello, I was playing a mission yesterday evening after the new 1307.12 update dropped and noticed that SAMs I was firing from one of my ships were having a really hard time hitting a relatively close, non-maneuvering target. Upon closer inspection I saw that they were not really lofting (SM-2MR Block IIIA's) to the target and thus still lower in the atmosphere upon motor burnout, leading them to having very low terminal speeds. I'm not sure if it is a part of the tweak to the drag coefficients of the boost-coast missiles as noted in the 1307.12 changelog, but I built a test scenario and discovered that they aren't doing much lofting at all.

I also noticed that ship-launched SA-N-20s were not actually tracking towards their targets at all, instead acting as a simple unguided rocket that doesn't get even remotely close to the target. I attached my test scenario to this post for everyone to try! There is more info on what I discovered in the blue-side briefing.

Hello and welcome!

The second issue is a recently-spawned bug related to TVM/SAGG guidance. Thankfully it has already been fixed and the fix will be included on the next public update (hopefully this new week).

The first example is quite interesting. I _think_ it is actually WAD but I'd like to take a deeper look for possible micro-tweaks in the boost trajectory shaping. Stay tuned.

Excellent, thank you for reviewing it! And yes, I think it's really just down to small adjustments on the missile's trajectory. The missile's tendency to fly straight and level while gliding towards the target below the target's altitude really kills a lot of its energy, especially when the terminal phase occurs and it has to climb again to reach its target. It just seems really...suboptimal.

It's not the biggest deal in the world for a target flying straight and level, but it really hampers their performance against a maneuverable fighter jet or an incoming supersonic missile. The SM-6s in the test scenario still kick ass, but even they don't loft nearly as high as they used to pre-update (only reaching around 65,000 feet for the target 70 nmi away), and maintain their performance because they remain under powered flight for so long.

I did want to say that y'all have put a ton of really high-quality work into the sim, and I find it thoroughly enjoyable to play. I've been playing since before tiny released, and CMO has come a *long* way since then. Keep up the great work!

Okay, so here is what is happening.

If you look at the distant target engagement, the missile trajectory has enough horizontal space available to get the missile on a parabolic arc slightly above the target and then dive onto it:


When engaging the close-in target, the short horizontal range was less sufficient for this. Additionally there was in the code a "cap" present which limited the ceiling of the pseudo-ballistic trajectory, essentially preventing the missile from reaching the (more favorable in terms of drag) higher altitude. You can observe this here:


(When engaging an air-breathing target with a boost-coast weapon, the choice of mid-course altitude is a delicate tightrope between "too high and I may not be able to get down on terminal dive in time, especially if he maneuvers; and the increased look-down angle may also complicate terminal guidance" and "too low and he'll use the increased atmospheric drag to outrun me, or I may even stall before I get there".)

I was able to correct this issue in two ways:

* Added a slight upward bias to the loft trajectory arc during the boost phase. While the "pure" pseudo-ballistic trajectory is broadly the most energy-efficient one, it overlooks the detrimental effect of increased drag at lower altitude. "Nudging" the trajectory upwards has the effect of getting the missile up to more favorable (drag-wise) environment faster, allowing for a more efficient ballistic curve post-burnout. (This BTW is also why in real-world artillery shots the maximum-range elevation angle is 47-49 degrees rather than the theoretical 45)

* Removed the "cap" on the trajectory arc. This will generally result in a slightly higher apogee, and thus reduced speed bleed due to drag in the mid-course phase.

As a way of comparison, with the original trajectory the missile typically arrived at the target with a ~900-950 knot speed, and the resulting PH was 50-55%. With the improved trajectory the missile arrives at 1200-1250 knots and the PH increases to 72-76%.

These tweaks will be included on the next update release.

Thanks very much for the clear, concise example provided and giving us the benefit of the doubt.