hm, so what could be actually in service? any sources available for that?
1 kc130 and some 5 or 6 other, cargo herculeses?

can kc130 also be used for regular cargo runs?

12 times more drag sounds about right, i projected similar figures. but do we have any way of knowing for how long so much drag is applicable? are we walking a turn that will last half a second? or two seconds? the difference in accumulated extra drag through time is considerable.

also, what about smaller corrections during cruise phase? the added drag from those, which is surely smaller, perhaps just two or three times bigger than nominal drag, cant last for long. i would imagine the missile would change its direction by a few degrees in perhaps a tenth of a second. is that about right?

another important question is – what happens when loss of energy isnt an issue? what happens when missile is engaging a target perhaps 20 or so km away? rocket motor just burned out and theres like 5 km to go to the target. missile has plenty of speed and energy left. is all that excess speed bad for the missile in such a situation? or does it make no difference for the manouverability?

i see. that does make sense. but just by looking at the extremes, how can i make a (even a semi correct) function which would give me the sense of how much G (in percentage of maximum G force) can a missile pull at which altitudes?

Does the air density closely correlate that? So, say, if the manufacturer says a missile can do 50 G – and then again we assume that’s the highest possible g force, does that mean it can do those 50gs ONLY at low altitudes, where air is densest?

But there’s another predicament. At low altitude drag is bigger, so missile is slower. so less mass of air goes over the control fins per given period of time and less force is used on those control surfaces. So by going higher, the missile is faster and thus more air is used to make up a force. I need to know how those two curves (functions) interact. How much does flying faster compensates the loss of lift/loss of manouverability due to the higher altitude?

I’d really need a graph of missiles envelope, but i cant find those. Can i just assume its similar to a fighters flight envelope graph? Or would that be completely incorrect?

thank you, obligatory. 🙂

So now we come to the agility and/or manouverability.

Say we have a missile with a rocket motor that has just burned out – and it is doing lets say 1200 m/s at that moment, at 12 km. Its target is at 10 km altitude, some 60 km away, but approaching the general direction of the missile at 200 m/s.

For scientific purposes we’ll assume no decoys, jamming, no failure of any systems on both the target and the missile. Everything works as it should. let us also assume missile has really long ranged radar of its own so it doesnt need course corrections. it is fully fire and forget.

1. What happens if the target suddenly starts turning 20 degrees left? Will the incoming missile assume the target will continue going that way and redirect itself sufficinetly so it meets that path when it crosses 60 km?

Or will the missile lead the target a bit, but not too much, as it is quite possible and probable the target will manouver some more in god knows which direction?

How will those manouvers of the missile influence its speed, on top of the speed loss we would see from drag?

2. Let us assume the target just went on that course up until the point where missile was 20 km away from it. then the target started a very hard manouver to get the missile to bleed more energy. Would the missile at such distances try to fully lead the target? What if, at 10 km away, the target tried to change direction? Or even go up, vertical? Would that help?

Let us assume the target is, realistically, with some load, doing 7 G manouvers. Let as assume the missile can do 50 g manouvers.

How much speed would the missile lose in all those manouvers?

Another important question is – how quickly would the missile adapt to the new situation? I don’t want answers like “sufficiently fast so we don’t need to calculate it”, i’d really rather prefer concrete numbers. Are we talking about one second? a tenth of second? A thousandth of a second? a missile does need to process the signal, interpret it, calculate the course adjustment, actuate its fins and stabilize itself on a new course. and perhaps do that several times a second or more.

Those would be scenarios where missile was fired quite far away, with much of its speed already bled.

What would happen if the same missile was fired from a shorther distance, so once its rocket motor burned out, the missile would be just 20 km away from the target, also head on?

Again lets assume the target magically knows the precise moment it would be best to manouver. and does 7 g manouvers, versus missile’s 50 g manouvers. Is it a simple matter of missile staying within targets maonuver envelope? or is there more to it? would barrell rolls, for any reason, help the target?

I know the g force increases exponentially with speed – but would that mean the missile is too fast too manouver the way it should? or if the missile is sufficently slow to follow the manouvers – would that make it so devoid of energy the target could escape?

Would the missile lead the target and start its manouvers from afar, not having to match the G load limits (in percentages of max) of the target? Or would that be too dangerous and the missile would have to follow the tail of the plane more closely at least until its really close? What about the tiny amounts of time needed for course correction by the missile? is that even a factor? Missile does, in the end, react to the target, and not even a magical supercomputer with magical superactuators can react 100% the way it should in zero time.

I would once again like to reiterate that i know this is not a realistic setup, but im not looking for that now – i need a simplified setup with controlled variables to understand some basic concepts first.

So it is true that newer bvr missiles use just a single profile rocket engine? What sort of improvement could we be looking at, in amraams 8 second burn, compared to sparrows 5 second boost phase burn, thrust wise?

Is it safe to assume that the likes of mica, r77, pl-12 and the rest also use single profile rocket motors? Do WVR missiles today use dual or single profile rocket engines?

I still can’t really get my head around the final speed figure. I’d really need an equation for that, not just a thumb rule. How do i calculate a missile’s speed at any given point past the moment the rocket engine dies, along its flight profile? Lets say its a profile where the missile is fired at 12 km altitude and reaches an apogee of 20 km, then starts shallowly diving towards the target. would that flight path even be realistic?

I really want to be sure about the approach speed portion of the whole issue, before we can go onto the another intersting topic – agility/manouverability.

Thanks a lot for your answers. Obligatory, your post was very thorough, it was just the kind of post I was hoping to get for this topic. I would really like to encourage everyone to use real equations as much as possible and try not to simplify everything with rule of thumbs. I gobbled up all the figures and now i have a clearer image of what exactly is going on.

Declassified documents tell us that aim7f has 5 seconds of boost phase and 10 seconds of sustainment phase. Does anyone have data backed by proof for other missiles of same or newer vintage? Do we have any idea about duration of boost and/or sustain phases in newer missiles, in the amraam A class?

Regarding the top speed of a missile – i have to ask if the air itself prevents the missile to reach its top speed, that it would otherwise reach in vacuum? Just like a falling object through air stops accelerating at a certain point, reaching its terminal velocity, shouldnt a missile also stop accelerating due to too much drag? I ask that because the deltav= 10 * spec.impulse*ln(m1-m2) equation is great but nowhere does it mention air density and drag. Which equation would help us get info adjusted for terminal velocity, on top of the mentioned data?

The rule of thumb for the rate a missile decelerates is great, but is there an equation that gives a bit more precise data? (i would imagine it would use derivations ?)

Also, to make things a bit more realistic – all this until now didnt include gravity. I know what roughly happens when we have gravity, but the important question is just how much of it happens? Just to keep flying straight, finless missile will have to compensate for the gravity force vector and trim a little bit, inducing drag. Now, i suppose actual missiles create most of their lift on their own, canceling out the gravity force – but by how much?

And, naturally, most medium and long range missiles now use lofted trajectories. But do we have any data anywhere indicating more precisely what kind of trajectories are used? I once read about aim-54 going to 30 km altitude as a part of its quasiballistic trajectory. Is that also used for various amraams and the like today for max range? At which horizontal point of trajectory is apogee reached? At what altitude is that?

And the ASTRA manufacturer data is great! I would imagine similar set of figures can be used for various other missiles of the same class.

What about the change of CoG that the Distiller mentioned? How much, in percentage, would that influence speed and/or range in short and how much in long ranged shots? Is there an equation for that? I would much rather calculate everything for myself, so i can learn, then just have the answer offered to me.

There are more interesting topics left, of course, but i would rather go step by step and concentrate on these for now, then go on to agility/manouverability.