[WAD] AAMs burn up fuel far too fast.

[HalfLifeExpert]

UPDATE: I now realize this is my own fault
I forgot about the new feature in the beta (Energy-based flight model for boost-coast missiles.)

Just a couple notes on this. A) The DB entries don't reflect this change (still show original fuel burn times), and B) thanks to Faceplate below:

When 'Engaged Offensive', AI fighters will generally accelerate to afterburner. This really belongs as a requested feature, but a more accurate inheritance and reaction to launch conditions - mostly speed and altitude - would go along very nicely with the fancy, new kinematic missile modelling, which is fantastic. Really, in entails just a completion of the giant leap in missile modelling for this new era. Hopefully it should not be too hard to tell the AI to accelerate before missile launch. In most situations, I think they manage this already by accident.

I made a thread about this a while ago, and there wasn't much response, so I felt I needed to bring this back up.

I noticed this both before and since Build 1265.1

Air-To-Air Missiles burn through their rocket fuel almost instantaneously, as in under 3 seconds. Rendering them gliding and losing airspeed at an alarming rate.

I just ran a test with the Quick Battle "A2A BVR Duel, 1975" with 4x Phantoms going up against 4x MiG-23s.

Before engaging, i looked at the DB entries for both the Sparrows and Sidewinders.

The Sparrow entry states the rocket booster should have 31 seconds of fuel, while the Sidewinder should have 23 seconds worth of fuel.

Immediately upon firing the first Sparrow missiles, their fuel is gone in under 3 seconds.

This needs to be addressed ASAP, as it renders air combat close to impossible.

[Gizzmoe]

Immediately upon firing the first Sparrow missiles, their fuel is gone in under 3 seconds.

Yes, and according to the informations I have found on the Internet that's about right for this and some other AAM. The fuel burn rate seems to be generally fine for missiles, the speed loss rate and how the AI handles it is what's can be debated though imo.

[c3k]

Doing a bit of digging, I've found AIM-9A through AIM-9J to have published rocket burn times of 2.2 to 2.3 seconds.

I have not found anything definitive beyond that. Current AIM-9X-2 ((alternatively AIM-9XII) and the "stealthy" AIM-9XII+) aren't listed. The AIM-9X-3 (in development (may have been cancelled then resurrected?)) has rocket engine improvements being listed.

There are improvements from AIM-9J motor to the AIM-9M motor, but I can't find burn/thrust info.

[bsq]

Fuel burn is likely correct, the actual launch of the missiles may not be modelled correctly (most fighters that can will quickly push to over Mach 1 to use their (more abundant) fuel to get the missile through the sound barrier and then launch.

Think there are several issues at play here:

Missiles dont have a lot of fuel.
They should reach Vmax at burn out.
The lower they are the faster the velocity bleed off, thats why big platforms evade low, its also why SAMs have great big boosters to propel the missile through the dense air into the thinner stuff...

Fairly sure the atmosphere is modelled with a fair degree of accuracy.
Not sure if the tactic (push supersonic, launch, slow down) is modelled or just factored into the fuel. If its neither then that may be an issue.

[CV60]

Doing a bit of digging, I've found AIM-9A through AIM-9J to have published rocket burn times of 2.2 to 2.3 seconds.

I have not found anything definitive beyond that. Current AIM-9X-2 ((alternatively AIM-9XII) and the "stealthy" AIM-9XII+) aren't listed. The AIM-9X-3 (in development (may have been cancelled then resurrected?)) has rocket engine improvements being listed.

There are improvements from AIM-9J motor to the AIM-9M motor, but I can't find burn/thrust info.

FWIW, I shoot high power rockets as a hobby. A solid fuel rocket will burn its fuel pretty quickly. While you can change the burn time of a "grain" of propellant by how you shape it and where in the grain you being ignition, the burn time will be pretty quick in all cases. An extremely long burning hobby engine, the F-10-8 burns for 8 seconds. I believe this is the longest burning solid fuel grain in the hobby. For a 75mm grain, such as an M1350-W, the burn time is around 3.8 seconds. See https://www.thrustcurve.org/simfiles/5f ... 000000875/. Based on this, I suspect that any solid fuel Air to Air missile has a pretty short (less than 8 seconds) burn time.

[Gizzmoe]

most fighters that can will quickly push to over Mach 1 to use their (more abundant) fuel to get the missile through the sound barrier and then launch.

I was always curious how much that tactic matters in Command and how much it would help the missile range, but never actually tested it, until now Here is a save, the left F-15 flies at AB, the right one at 350 kts, both fire a Sparrow from the same distance. The left Sparrow is about 1200m ahead after a few seconds thanks to the higher launch speed.

[Swant]

most fighters that can will quickly push to over Mach 1 to use their (more abundant) fuel to get the missile through the sound barrier and then launch.

I was always curious how much that tactic matters in Command and how much it would help the missile range, but never actually tested it, until now Here is a save, the left F-15 flies at AB, the right one at 350 kts, both fire a Sparrow from the same distance. The left Sparrow is about 1200m ahead after a few seconds thanks to the higher launch speed.

That is about 1.5% in extra range witch is negligible. There should be a much bigger difference, especially if one is supersonic. The problem is that both missile reaches the same max speed

[Gizzmoe]

That is about 1.5% in extra range witch is negligible. There should be a much bigger difference, especially if one is supersonic.

It's more than 1.5% when you take into account that a Sparrow has an effective range of only around 15nm, but yes, it is kinda negligible. How much higher should the difference be?

[Swant]

Don't know but the difference in max speed of the two Sparrows should probably be at least be difference in speed between the launching aircraft, probably more since the faster Sparrow doesn't have to break the sound barrier. Then the extra drag will of course play a role so it is hard to say

[Gizzmoe]

Don't know but the difference in max speed of the two Sparrows should probably be at least be difference in speed between the launching aircraft, probably more since the faster Sparrow doesn't have to break the sound barrier.

Yes, that makes sense. I don't want it be that realistic though for gameplay reasons, there need to be some hard limits, the AI would never be able to counter a player using that tactic, that player would basically cheat. The AI has a hard time already, it doesn't need more problems

[Swant]

Yes that is a good point

[Faceplate]

When 'Engaged Offensive', AI fighters will generally accelerate to afterburner. This really belongs as a requested feature, but a more accurate inheritance and reaction to launch conditions - mostly speed and altitude - would go along very nicely with the fancy, new kinematic missile modelling, which is fantastic. Really, in entails just a completion of the giant leap in missile modelling for this new era. Hopefully it should not be too hard to tell the AI to accelerate before missile launch. In most situations, I think they manage this already by accident.

[HalfLifeExpert]

Ah, I now see where this came from. So it's mainly my fault for failing to remember something from the original Tiny update notes:

MAJOR NEW FEATURE: Energy-based flight model for boost-coast missiles.
Boost-coast missiles (ie. most tactical missiles that are not powered continously) now use a much more realistic flight model that distinctly models the initial boost-sustain and post-burnout regimes, and takes into account the effects of gravity (shedding speed while climbing and regaining it when diving) and aerodynamic drag. The drag changes with altitude, built-in drag coefficient and whether the weapon is maneuvering (pitching/turning) or not.
This change makes it possible to apply real-life "exhaust the threat" tactics and further constrains edge-of-envelope shots.
On missiles that use this model, the "fuel bar" indicator now represents only the remaining boost-sustain fuel, NOT to the total remaining energy. After burnout, the fuel bar is removed and the weapon will coast until it reaches its stall speed.

So this is more realistic behavior for missiles. However, the Database entries don't necessarily reflect this, as the fuel stats still state the original burn times.

And I agree with Faceplate above:

When 'Engaged Offensive', AI fighters will generally accelerate to afterburner. This really belongs as a requested feature, but a more accurate inheritance and reaction to launch conditions - mostly speed and altitude - would go along very nicely with the fancy, new kinematic missile modelling, which is fantastic. Really, in entails just a completion of the giant leap in missile modelling for this new era. Hopefully it should not be too hard to tell the AI to accelerate before missile launch. In most situations, I think they manage this already by accident.

As it's pretty jarring to see fighters in combat seem to outrun their own missiles. Really calls for a change in tactics.

[thewood1]

Will capable fighters always accelerate to AB when launching? Would they sometimes not want to decrease closing time? Just wondering how universal this is.

[Gizzmoe]

Just wondering how universal this is.

You know the answer already It is not universal, it all depends on the situation.

[thewood1]

Well...I don't. Thats why I asked. Thats why I qualified it with "capable". But thanks for reading my mind wrongly.

[Gizzmoe]

Well...I don't. Thats why I asked. Thats why I qualified it with "capable".

"Capable" or not has nothing to do with it. What I just meant to say is that sometimes you can deal with a certain tactical situation successfully in different ways , there's no particular Right or Wrong per se, just "guidelines". That's nothing new, you know that.

[thewood1]

Capable can be unit-specific or situation-specific. I'm looking for what situations would differentiate using a high-speed launch vs a non high-speed launch. Is it that hard to list them. The last few posters seemed to feel pretty adamant its common to the point of being assumed. I am just asking when isn't warranted? Is it that hard?

[Gizzmoe]

I'm looking for what situations would differentiate using a high-speed launch vs a non high-speed launch.

Imho, in CMO Beta, the more range an AAW has, the less important the launch speed. When I do for example long-range suppression shots with AMRAAMs then there is no bonus for launching them at high-speed. If we only have short-range AAW then it can be useful to launch them high-speed to hopefully give them a relevant enough advantage.

I am just asking when isn't warranted? Is it that hard?

No, it isn't, and I am sorry for reacting that way, that was stupid.

[Dimitris]

That is about 1.5% in extra range witch is negligible. There should be a much bigger difference, especially if one is supersonic. The problem is that both missile reaches the same max speed

That is a good point, actual burnout speed achieved by the missile will depend on the at-launch kinematic conditions (most open-source AAM stats assume a M1.5 launch at high altitude). Filed as a future refinement to the model.