So what's the real performance of AIM-120C

[GGTharos]

Dodgy indeed, I'll say :)

There's a declass R-27 kinematic diagram laying around somewhere and the range is er ... 35km at high-high profile :)

[cool_t]

How useful is it to be talking about supersonic launch speeds for these things anyway? Who fights like that? At launch, you want to minimize your fighter's own closing speed, so to maximize F-pole or A-pole.

 

 

Thats where it gets interesting.

 

I actualy like to use the term "Post hole" one thing to remember that the higher the speed the more distance you cover. So inturn the missile that eather comes off your air-craft or a bandits aircraft as well, is covering more distance in less time.

 

A superb tacticionist will utilze/maximise all know varables in "High speed" BVR engagements. One of the most important componantas to a Kill in BVR is "Speed". Im not going to go into details about off-set vectoring push/pull/drag/kill meathods but just remember speed is potential energy and at high alt/speed you have a multitude of options, compared to low and slow "WORM-BURNERS"

 

P.S. Just a reminder anyone who works with "Classified" blue-prints/information about Aerospace/Military knows who knows there stuff. ;)

[SwingKid]

But you will probably get more drag at mach 1 than at mach 1.3 :) (wave drag / shock-induced boundary-layer separation )

 

I don't think this is true. Do you have a source for it?

 

I'm not an aerodynamicist, but my understanding is that Mach 1 is an inefficient cruising speed, not a "bump" in the way you describe. That is - for a little extra energy, you could be cruising at Mach 1.3 instead of just Mach 1, thus making supersonic flight more cost-effective than transonic flight. But it's still extra energy, not less energy. If it was less draggy at Mach 1.3 than at Mach 1, then aircraft would quickly accelerate past the sound barrier on their own, even while the pilot was reducing the throttle. This doesn't happen, AFAIK. You still need to increase throttle all the way through transonic speed.

 

Of course, missiles don't cruise at transonic speed at all, but rather just accelerate through it to supersonic speeds, where they encounter the levels of drag that affect their range much more.

[HubMan]

...

I actualy like to use the term "Post hole" one thing to remember that the higher the speed the more distance you cover. So inturn the missile that eather comes off your air-craft or a bandits aircraft as well, is covering more distance in less time.

...

 

Hi cool_t, :)

 

Your assumption is right if you consider you are flying straight toward the threat, but not completely right otherwise.

If you can crank enough and if you have a good radar gimball limit, you will make a missile shot a you run a longer way and make more corrections than if you were flying at lower speed.

 

High speed crank is another tactic used by the F-22 or Eurofighter to "exhaust" weapons (eventually) launched at them :)

 

Cheers :)

 

 

Hub.

[HubMan]

But you will probably get more drag at mach 1 than at mach 1.3 (wave drag / shock-induced boundary-layer separation

 

I don't think this is true. Do you have a source for it?

 

I'm not an aerodynamicist, but my understanding is that Mach 1 is an inefficient cruising speed, not a "bump" in the way you describe. That is - for a little extra energy, you could be cruising at Mach 1.3 instead of just Mach 1, thus making supersonic flight more cost-effective than transonic flight. But it's still extra energy, not less energy. If it was less draggy at Mach 1.3 than at Mach 1, then aircraft would quickly accelerate past the sound barrier on their own, even while the pilot was reducing the throttle. This doesn't happen, AFAIK. You still need to increase throttle all the way through transonic speed.

 

Of course, missiles don't cruise at transonic speed at all, but rather just accelerate through it to supersonic speeds, where they encounter the levels of drag that affect their range much more.

 

 

 

Hi Swingkid, :)

 

You can get some very good information on the wave drag principle here : http://history.nasa.gov/SP-367/chapt5.htm#f86

 

If you look at the text above Figure 86, you can read :

...

Throughout the transonic range, the drag coefficient of the airplane is greater than in the supersonic range because of the erratic shock formation and general flow instabilities. Once a supersonic flow has been established, however, the flow stabilizes and the drag coefficient is reduced. Figure 86 shows the variation of an airplane wing drag coefficient with Mach number.

...

And the Figure 86 itself is pretty clear :

 

 

Actually, if you google : "transonic+drag" the 4 first links will agree :

http://aerodyn.org/Drag/speed-drag.html

http://www.aerospaceweb.org/question/aerodynamics/q0104.shtml

http://history.nasa.gov/SP-367/chapt5.htm

http://www.adl.gatech.edu/classes/hispd/hispd04/Transonic_Drag_Rise.html

 

To anwser your post : there is a mach / transonic "bump", and recent fighters like the Rafale equiped with a "light" loadout will have to use the afterburner to go mach 1.2, but should be able to stay supersonic with military power only :)

 

To my opinion, there is no reason it should be different for missiles :)

 

Cheers :)

 

 

Hub.

 

 

PS : I wish I could help you to modelize the transonic regime for minizap, but it's beyond my competence :unsure: I'm sorry :)

PPS : would be nice though, to have supersonic missile shot vs subsonic ones correctly modelized in Lockon 1.13. Flying high would get a better incentive bonus :)

PPPS : I know... Sweet dreams :D

[SwingKid]

And the Figure 86 itself is pretty clear :

 

To anwser your post : there is a mach / transonic "bump", and recent fighters like the Rafale equiped with a "light" loadout will have to use the afterburner to go mach 1.2, but should be able to stay supersonic with military power only :)

 

What is shown in the Figure 86 is exactly what I described in post #150: the drag coefficient has a bump. Not the total drag, as suggested in post #152.

 

To calculate drag, you must multiply the drag coefficient by v^2.

Above Mach 1, v^2 should be rising faster than the drag coefficient is falling. Therefore, total drag always keeps rising.

 

and recent fighters like the Rafale equiped with a "light" loadout will have to use the afterburner to go mach 1.2, but should be able to stay supersonic with military power only

 

This sounds fishy. I can accelerate from Mach 0.6 to Mach 0.8 with afterburner too, and then stay at Mach 0.8 with military power only. That doesn't prove a drag bump at Mach 0.7.

[nscode]

Taking that subsonic drag coefficient in fig-86 is 0.02 (like an F-4) and if I didn't mess something up :D, this is what drag should look like:

[SwingKid]

Taking that subsonic drag coefficient in fig-86 is 0.02 (like an F-4) and if I didn't mess something up :D, this is what drag should look like:

 

Does that include the wave drag component, or just the "wing drag"?

[HubMan]

What is shown in the Figure 86 is exactly what I described in post #150: the drag coefficient has a bump. Not the total drag, as suggested in post #152.

 

To calculate drag, you must multiply the drag coefficient by v^2.

Above Mach 1, v^2 should be rising faster than the drag coefficient is falling. Therefore, total drag always keeps rising.

No :) "Squared function" does not always outperform constant / linear functions : it's only true for large enough values (f(x) = x^2 is smaller than g(x) = x for x = 0.5) ;)

Actually, total drag will -decrease- after the transonic area is cleared but it will increase again after a while, because, as you said, the v^2 will finally overcome the drop in the drag coefficient value as the mach is going up.

 

I agree on the fact that the gain will not be as spectacular as on the Figure 86, as the "squared" speed will limitate the drop, but nevertheless, the total drag should be lower at Mach 1.4 than at Mach 1 :)

 

And what is beautifull is that you don't need the drag to be extremely lower at higher speed, just being the -same- than at slower speed is enough (mach 1.4 vs mach 0.9) : the weapon would be traveling faster but at the cost of the same thrust / energy :)

 

This sounds fishy. I can accelerate from Mach 0.6 to Mach 0.8 with afterburner too, and then stay at Mach 0.8 with military power only. That doesn't prove a drag bump at Mach 0.7.

Swingkid, if you want to go over a bump, you need more power, thus if dry thrust is not enough, you need to crank the A/B. In some cases, military power would be enough to do the work, but if you are right on the limit, you will need the extra power of the A/B to get you over the mach and then you will be able to stay there without A/B :)

 

Anyway,you coud perhaps have a look at papers like those ones : http://www.ssdl.gatech.edu/Papers/Masters/APAS_Transonic_Drag_Miller.pdf

page 5 you will find :

It is common knowledge that an aircraft or spacecraft encounters a drag rise as is approaches

the sound barrier, which then tapers off again once the vehicle has gone supersonic.

 

Or again here : http://history.nasa.gov/SP-367/chapt5.htm#f86 just before our old friend Figure 86, you will clearly read :

Once past the transonic regime, the drag coefficient and the drag decreases, and less thrust is required to fly supersonically. However, as it proceeds toward higher supersonic speeds, the drag increases (even though the drag coefficient may show a decrease).

 

I'm sorry, but as I told you, firing a missile over the mach is common practice and gives you a nice range bonus :) If the Raptor and the Eurofighter are -designed- to fight at very high speed (and high altitude) it's for a very good reason : you want to fire your missile at at least mach 1.4...

Incidently, the design of the russian MiG-29 is not absolutely foreign to this principle : if you have a very high T/W ratio and look down shoot down capability (even not a perfect one), you can take off, climb, go supersonic, fire your missiles and then go home, while staying out of reach of enemy fighters forced to fly -lower- because of the density of long / middle range SAMs or at least not figthing with an altitude / speed disavandtage on a GAI mission :)

 

Cheers :)

 

 

Hub.

[HubMan]

Taking that subsonic drag coefficient in fig-86 is 0.02 (like an F-4) and if I didn't mess something up :D, this is what drag should look like:

Should look like something like that. Ideally, drag should decrease after Mach 1.2, but the idea is there :

- there is a (small) transonic "bump" that peaks at mach 1.

- the drag tends to decrease after the transonic regime.

- it would have been very nice to have mach 1.2 instead of mach 1.5 on the schema, but I won't complain :D

 

Hub.

 

 

PS : thanks for taking the time to plot the schema :thumbup:

[nscode]

Does that include the wave drag component, or just the "wing drag"?

 

It includes whatever fig-86 includes :) It does say "wing drag coeff." but as I understand it, the divergence (that increase in CD when approaching transonic) is a result of wave drag. But I'm not very clear on that.

[SwingKid]

Hmm.

 

It seems to be a difference between aircraft and missiles - probably related to the aircraft having a more complex shape to push through Mach 1. In the chart that you show (for aircraft?), the Cd seems to increase by around 4 times at Mach 1. For missiles, the Cd is flatter, seeming to increase only about 1.5 times (see attached). Perhaps v^2 dominates the equation for missiles, while Cd dominates for aircraft.

 

So, I still believe that for practical purposes, launching a missile at high speed rather than slow speed will give an F-pole disadvantage, that must be compensated by the fighter slowing down or maneuvering after the launch. So IMHO, accelerating above Mach 1 might be good for intercepting defenseless bombers and spy planes that happen in real life (in which case F-pole doesn't matter), but not for the fighter duels we like to have in our sims (in which case F-pole is often more important than maximum range).

[HubMan]

Hmm.

 

It seems to be a difference between aircraft and missiles - probably related to the aircraft having a more complex shape to push through Mach 1. In the chart that you show (for aircraft?), the Cd seems to increase by around 4 times at Mach 1. For missiles, the Cd is flatter, seeming to increase only about 1.5 times (see attached). Perhaps v^2 dominates the equation for missiles, while Cd dominates for aircraft.

 

So, I still believe that for practical purposes, launching a missile at high speed rather than slow speed will give an F-pole disadvantage, that must be compensated by the fighter slowing down or maneuvering after the launch. So IMHO, accelerating above Mach 1 might be good for intercepting defenseless bombers and spy planes that happen in real life (in which case F-pole doesn't matter), but not for the fighter duels we like to have in our sims (in which case F-pole is often more important than maximum range).

Ok :)

 

Thanks for pointing out the differences between the AIM-9 and a generic aircraft, that may explain a lot of things :)

I need some time to properly think about it and I'll try to come with a decent answer :D

About flying at supersonic speed to engage fighters, I always heard that it's a standard tactic, at least for long shots and even more since the aircrafts of the last generation like the Raptor or the Eurofighter can accelerate fast enough, and sustain high Gs while at the supersonic / transonic speeds :)

I'm french and it hurts a little bit my nationale pride to point you to a link like this one : http://www.eurofighter.com/et_sr_as_bv.asp

 

But it may give some ideas of how modern BVR is fought :) (just don't pay too much attention to the marketing / propaganda that can be found on the site... :D)

 

Cheers :)

 

 

Hub.

[HubMan]

Hi Swingkid :)

 

I finally found the time to answer you :

 

Hmm.

 

It seems to be a difference between aircraft and missiles - probably related to the aircraft having a more complex shape to push through Mach 1. In the chart that you show (for aircraft?), the Cd seems to increase by around 4 times at Mach 1. For missiles, the Cd is flatter, seeming to increase only about 1.5 times (see attached). Perhaps v^2 dominates the equation for missiles, while Cd dominates for aircraft.

It's hard to use you chart to estimate precisely the total drag coefficient, but 1.5 is probably a good estimate :)

Anyway, your chart being about zero lift drag only, the drag induced by -lift- is not displayed. I know that the drag induced by lift tends to be negligible at high supersonic speed, but for a missile fired at subsonic speed, I think that this is not the case.

 

Besides, missiles fired at "slow speed" (under the mach) will tend to start with a nice angle of attack, that means some extra drag to fight at the beginning of the boost phase.

Finally the transonic regime being the mess it is, it is higly possible that missiles may suffer buffeting or other effects that would alter their trajectory and require the missile to correct it's course once supersonic, especially if it entered the transonic region with some AoA.

 

Firing a missile over the mach would avoid that kind of problems :)

 

 

So, I still believe that for practical purposes, launching a missile at high speed rather than slow speed will give an F-pole disadvantage, that must be compensated by the fighter slowing down or maneuvering after the launch. So IMHO, accelerating above Mach 1 might be good for intercepting defenseless bombers and spy planes that happen in real life (in which case F-pole doesn't matter), but not for the fighter duels we like to have in our sims (in which case F-pole is often more important than maximum range).

No, sorry :D If you get a 25% range advantage, if you are cranking, you are winning : the extra range and the fact that you can pump / notch as soon as your missile is active should do the magic :D (you are using Fox 3, it's the A-Pole and the E-Pole that matter... ;) ) Just do the maths... :D

 

 

Cheers :)

 

 

Hub.

[SwingKid]

if you are cranking, you are winning

 

You can be "cranking," or you can be supersonic. Pick one, please.

[GGTharos]

You can be both. Supersonic aircraft -can- turn, and do.

[SwingKid]

At 20,000 feet, an F-15 flying Mach 0.9 can pull about 6.1 Gs and turns 12 deg per second. At Mach 1.2, that drops to 4.8 Gs and 7 degrees per second. What's you're definition of "cranking?"

 

A loftless miniZAP AIM-120 fired at 20,000 feet and Mach 0.9 travels 20.7 km in 34.4 s. The same missile fired at Mach 1.2 travels 22.5 km in 35.5 s. Note: a 33% launch speed advantage (including advantage of not having to overcome the "Mach barrier") translates into less than 9% range advantage, due to the 2nd-power drag penalty felt by the missile at the higher speed.

 

Now consider F-pole. Immediately after launch, the Mach 1.2 fighter begins a 60-degree turn to the side, which takes him 8.6 seconds. In this time he simultaneously closes 2.7 km towards the target. After this, he keeps the target 60 degrees off his nose, closing an additional 5.1 km in the remaining 26.9 s of his missile's flight. His F-pole is thus (22.5 - 2.7 - 5.1) = 14.7 km.

 

The Mach 0.9 fighter after launch turns 60 degrees in 5 seconds, in which time he closes 1.2 km. Keeping the target at 60 degrees, he then closes an additional 4.2 km in the remaining 29.4 s. His F-pole is thus (20.7 - 1.2 - 4.2) = 15.3 km.

 

Now, you can say that the Mach 1.2 fighter will decelerate after launch to improve his F-pole, but then, the Mach 0.9 fighter can do the same. The shooter's deceleration is basically a function of his starting speed, with the slower fighter having a closure advantage. For all the Rmax advantage enjoyed the supersonic shooter, he is still facing a fundamental F-pole disadvantage that he is going to have to solve one way or another. The problem is that the drag on the missile worsens with the square of the speed, but the closure increases linearly with the speed - and this is true *no matter what angle you're flying*. So, if you have to choose between a supersonic shot for longer-range, or a subsonic shot with shorter range - all things being equal, your F-pole is probably better with the latter.

[nscode]

A loftless miniZAP AIM-120 fired at 20,000 feet and Mach 0.9 travels 20.7 km in 34.4 s. The same missile fired at Mach 1.2 travels 22.5 km in 35.5 s. Note: a 33% launch speed advantage (including advantage of not having to overcome the "Mach barrier") translates into less than 9% range advantage, due to the 2nd-power drag penalty felt by the missile at the higher speed.

 

I really doubt the mach effects are ZAPulated.. i mean simulated :D

[HubMan]

At 20,000 feet, an F-15 flying Mach 0.9 can pull about 6.1 Gs and turns 12 deg per second. At Mach 1.2, that drops to 4.8 Gs and 7 degrees per second. What's you're definition of "cranking?"

The standard one : put the contact at radar gimbal limits. Going to 60° will take five more seconds at mach 1.2 than at mach 0.9, that's more than acceptable in a BVR engagement, provided firing supersonically is worth it :D

 

A loftless miniZAP AIM-120 fired at 20,000 feet and Mach 0.9 travels 20.7 km in 34.4 s. The same missile fired at Mach 1.2 travels 22.5 km in 35.5 s. Note: a 33% launch speed advantage (including advantage of not having to overcome the "Mach barrier") translates into less than 9% range advantage, due to the 2nd-power drag penalty felt by the missile at the higher speed.

:no_sad: Sorry, your scenario is not relevant to illustrate the mechanism of supersonic BVR :

- your AIM-120 will probably be active at the time you fire it or a couple of seconds after : there is -no- need to support it, instead, the decent tactic will be either to go to the notch or push (anyway, at ~20km ie ~10nm there is a fair chance that you should be commited to the merge and in pure pursuit)

- you should be faster than mach 1.2. I have the feeling that minizap does not modelize the transonic regime : it's an outstanding piece of software, but as I said : if simulating the subsonic and supersonic is quite feasible, simulating the transonic is extremely complicated... As a result, you get a mere 9% when you need something like 20/30% that you can get in real life, provided you fly high and fast enough (mach 1.4...)

- supersonic BVR is interesting for long range shots : you are talking about 20km, but it should be at least -20nm-. The idea is to fire missiles before your opponent and use your speed to crank / notch / pump to make it's missiles enveloppe shrink.

- 20km would have been a decent range for a Fox 1 engagement against targets at low altitude, forcing them to defend (beam) and then pushing and going to the CAC, but if it's a Fox 3 fight, you simply do not want to get within this distance, because its a "two widows" scenario : both sides fire missiles that are immediatly active, well within the enveloppe, best way to get everybody killed ;)

 

Now consider F-pole. Immediately after launch, the Mach 1.2 fighter begins a 60-degree turn to the side, which takes him 8.6 seconds. In this time he simultaneously closes 2.7 km towards the target. After this, he keeps the target 60 degrees off his nose, closing an additional 5.1 km in the remaining 26.9 s of his missile's flight. His F-pole is thus (22.5 - 2.7 - 5.1) = 14.7 km.

 

The Mach 0.9 fighter after launch turns 60 degrees in 5 seconds, in which time he closes 1.2 km. Keeping the target at 60 degrees, he then closes an additional 4.2 km in the remaining 29.4 s. His F-pole is thus (20.7 - 1.2 - 4.2) = 15.3 km.

What you are demonstrating, is that, despite not having the extra range that a supersonically launched amraam should have, the F-Poles are almost identical ;) Anyway, as I said, F-Pole is not as relevant than A-Pole compared to E-Pole : if the A-Pole is larger enough than the E-Pole, you are winning :D

 

Now, you can say that the Mach 1.2 fighter will decelerate after launch to improve his F-pole, but then, the Mach 0.9 fighter can do the same. The shooter's deceleration is basically a function of his starting speed, with the slower fighter having a closure advantage. For all the Rmax advantage enjoyed the supersonic shooter, he is still facing a fundamental F-pole disadvantage that he is going to have to solve one way or another. The problem is that the drag on the missile worsens with the square of the speed, but the closure increases linearly with the speed - and this is true *no matter what angle you're flying*. So, if you have to choose between a supersonic shot for longer-range, or a subsonic shot with shorter range - all things being equal, your F-pole is probably better with the latter.

If you get something like 10 or 15km of extra range due to missile launch over the mach, you will realize that this extra range you will get is enough to crank a lot, considered that in addition you do not need to crank all the way but only until you achieve A-Pole, you should have the upper hand :)

And in addition to that, if your aircraft can sustain a large amout of supersonic / transonic Gs like the F-15, you can manoeuver at supersonic speed, exhausting the missiles that may have been launched at you, because you are running fast and far from the target :)

Finally, if you have Fox 3 and are fighting in a multi target environment, you better like to use your radar in TWS mode firing multiple missiles from far away, because the closer you will be to the targets, the more difficult it will be for your radar to keep them all in the scanning volume it can handle...

 

The problem with Lockon, is almost -all- the mechanism that could make that kind of real life Fox 3 BVR technic works were not correctly modelized, mostly for the sake or gameplay and partly because it would have been too complicated / time consuming to do it :)

 

Cheers :)

 

 

Hub.

 

PS : I have the feeling you analyse too much a modern BVR fight as if it would be a Fox 1 environment only and that you really do not want to admit that flying fast and firing at high speed may be a big advantage in BVR :) I found an old post from Rhen here : http://forums.eagle.ru/showpost.php?p=391265&postcount=36 you may find it interesting ;)

[SwingKid]

I found an old post from Rhen here : http://forums.eagle.ru/showpost.php?p=391265&postcount=36 you may find it interesting ;)

 

Rhen has been right (and I've been wrong) in the past, and I'd be happy to learn from him again, but I haven't yet seen him claim:

- that the AIM-120 has a "cruising speed of Mach 4"

- that transonic drag affects the missile more than supersonic drag,

- that "high and fast" is the tactic of choice in a duel between equally-capable opponents, or

- that a higher launching speed improves F-pole or A-pole

 

I'd be happy to eat my words over anything he actually says.

 

If, however, the best we can interpret his statements is to infer that F-15 pilots "enter the notch" (thereby dropping radar contact) after a supersonic high-altitude launch - well, in that case I'm a little more skeptical, and find miniZAP very useful to fill voids in our knowledge.

 

You asked for the maths...

[SwingKid]

I really doubt the mach effects are ZAPulated.. i mean simulated :D

 

I included all four supersonic drag effects (form, skin, wave and one other I don't remember) that I could find in the literature, to the best of my ability at the time.

 

Since then, it has been shown with two sources that miniZAP generally underestimates the drag.

[GGTharos]

You're calculating effects for a rigid body though (non-moving surfaces) even when running straight, right?

[SwingKid]

You're calculating effects for a rigid body though (non-moving surfaces) even when running straight, right?

 

Only if you set "Gravity Factor" to 0.0 G.

With default 1 G gravity, the missile must generate 1 G lift to run straight, and miniZAP calculates some induced drag based on wing area and AOA.

[HubMan]

Rhen has been right (and I've been wrong) in the past, and I'd be happy to learn from him again, but I haven't yet seen him claim:

- that the AIM-120 has a "cruising speed of Mach 4"

- that transonic drag affects the missile more than supersonic drag,

- that "high and fast" is the tactic of choice in a duel between equally-capable opponents, or

- that a higher launching speed improves F-pole or A-pole

 

I'd be happy to eat my words over anything he actually says.

Swingkid, :) Rhen said:

 

The real question for a pilot is the effective range of the weapon in question. Range is effectively increased by 40% (or more) when accelerating from M0.9 to M1.3 before release of the Slammer. This allows the missile enough energy at terminal maneuver to make a successful kill. We train to be high (where the Eagle likes it), and fast at release.

 

That and the optimum autopilot flight path in the Slammer guidance system allows ranges to increase significantly without changing weight, motor, or missile design characteristics. Only software (autopilot flight path) and release point are necessary to increase it's range. That's why the -120D looks the same but has a significantly increased range.

It's pretty clear : "range is effectively increased by 40% (or more) when accelerating from M0.9 to M1.3 before release of the Slammer". What do we have between mach 0.9 and mach 1.3 ? Transonic drag rise and transonic issues !!!

And if an increase of speed of roughly 40% causes an increase of range of 40% (or more), when your computation showed that an increase of 33% in speed causes only an increase in range of only 9%, either Rhen or the way minizap simulates the transonic regime is wrong :D

 

It's not a matter of "eating your words" or pride : you did an astounding job with minizap and you did it on your free time. But as you said, you are not an aerodynamist, and taking in account the transonic part of the flight is incredibly difficult, especially with so few elements available on the behavior of the AIM-120 :)

What I wanted to do is point out some parameters that you probably did not take in account, because they are discarded in most of the accessible models as they are just to complicated to modelize :)

 

If, however, the best we can interpret his statements is to infer that F-15 pilots "enter the notch" (thereby dropping radar contact) after a supersonic high-altitude launch - well, in that case I'm a little more skeptical, and find miniZAP very useful to fill voids in our knowledge.

Minizap is a great tool, I mean it :) But you cannot dissociate it from the tactical use of the weapons : if you fire a Fox 1, you must do it at quite close range as it will raise a big spike alarm on any decent SPO and your opponent will be able to defend itself. And you may be able to notch during the inertial part of the flight of your missile if it has a datalink like the AIM-7P, but you will have to have your nose pointed at your opponent for the end game.

 

Fox 3 are of a different kind : you can :

- fire them, eventually support them and then break of the fight (Brevity code tactic "Skate" ("Informative call/directive to execute launch and leave tactics.")

- fire them, eventually support them and then go to the notch (Brevity code tactic "Banzai" "Informative call or directive to execute launch and decide tactics."). By the way going to the notch is not always synonymous of breaking the radar lock, especially at high altitude : you do it also because it will make the enemy missiles run a long way and manoeuver almost constantly while improving a little bit the efficiency of your chaffs.

- fire them and go to the merge, but it's probably not the safest way to fight :)

 

 

You asked for the maths...

I'm sorry, I should have defined the postulates myself :

- at least 30% or range increase for a missile fired between M 0.9 and M 1.4

- the AMRAAM has to be fired at ~45km

- it will go active at 15km, at which time you notch or pump :)

 

Anyway, if we are talking about contemporary BVR, cranking and such is almost not relevant anymore as missiles are supported by wingmen flying out of the opponent missile range or AWACS with the Link 16. It improves even more the tactical advantage of firing a missile at high speed :)

 

 

Cheers :)

 

 

Hub.

 

 

PS : if you crank at really high speed and support your missile all the way, you will perhaps get a smaller F-Pole, as you will end up being closer to the opponent, but the missiles launched at you will have to run a longer trajectory as well and alter their course all the way. But to do so, you will need an antenna with a large gimball limit like the one of the Eurofighter (+70°) :D

[SwingKid]

It's pretty clear : "range is effectively increased by 40% (or more) when accelerating from M0.9 to M1.3 before release of the Slammer". What do we have between mach 0.9 and mach 1.3 ? Transonic drag rise and transonic issues

 

He also said the range continues to increase beyond the transonic regime, e.g. by 50% instead of 40% if you launch at M1.5 instead of M1.3. So, independent of transonics, faster still equals more range. What role does transonic drag really play, then? Even the way Rhen describes it, you're still getting 40% extra range ("or more") for 44% extra speed - i.e. by going faster, you get less out than what you put in.

 

How much flight time does the missile spend in the transonic regime after subsonic launch anyway? miniZAP says 1 second. If a missile's range could be increased by 40% by carrying 1 more second of propellant burn, why don't they carry 1 more second of propellant burn? I think something quite different is the explanation here.