S-25-O/OFM and S-25L have very different burn and speed. Intentional or S-25L speed cap bug?

[Skuva]

The S-25L seems to have a burn profile that makes no sense to me. It's peak velocity gets capped at around mach 1.3 for about 3 seconds of burn, regardless of lauch parameters (high or low, slow or fast, level or steep diving).

Compared to its dumb brothers the S-25-O and OFM, which can easily go mach 2 in a shorter burn.

Sketching their speeds would look like this

Yes, it gets a very flat line, it accelerates gradually and upon reaching that point the velocity gets completely fixed.

Isn't it suposed to just be the same rocket (booster) but with a laser sensor? So burn profile should be the same. There are a few info out there claiming the S-25L reach mach 2, which could just be a copy paste misunderstanding and there is actually some differences the soviets engineered for some reason.

I remember when I started with DCS many years ago, I read on some ancient thread people discussing how the S-25L could be better than the Kh-25ML in very short ranges because it had a shorter time to target due to its faster burn and initial acceleration.

S-25.trk

Edited March 18, 2023 by Skuva

[Skuva]

Adding to it. I've also spotted this same weird hard coded speed limit behaviour on many SAM's, like SA-2, Patriot, but most absurdly on Hawk (which gets locked at mach 1.75 for most of its flight at 1000m). But this limit is not present for SA-10, maybe the coded value is higher than its Q limit.

In the case of the S-25L it's quite easy to see the problem firing it in a very steep dive. You see the missile gaining speed, then when it reach the speed limit it starts to slow down, while still burning in a dive, because the speed limit seems to be coded as a function of altitude.

From my understanding this behaviour could not come from just dynamic pressure, as the transition into max Q would be smooth and not a sudden flat line after a point, even worse if you consider twr should increase as fuel burn.

Edited March 25, 2023 by Skuva