Active Radar Homing Missiles I: First Launch Opportunity & Ranges

In the last few years, I put together at least a dozen articles and videos discussing DCS missile performance, peculiarities, effects of range, altitude, manual loft, and more.
To complement the recent analysis of the JF-17, I wanted to take a better look at the SD-10, and while I was there, I expanded the study to include other ARH missiles.
This series’ approach is different from the past. It is more visual and has fewer numbers. If you are looking for cold data instead, check previous articles.

That being said, these are the Active Radar Homing missiles discussed and in order of introduction:

• AIM-54A: 1974
• AIM-54C: 1986
• AIM-120B: 1994
• R-77: 1994
• AIM-120C-5: 2000
• SD-10: 2005

ARH Missiles: FLO

The First Launch Opportunity, FLO, represents the start of the enemy’s Weapon Engagement Zone (WEZ). Simply put, a missile’s WEZ represents the combination of many parameters and suggests if such a weapon can hit our fighter jet. The WEZ is dynamic: its variables include altitude, closure rate (V_C), aspect angle, loft angle, and many more.

The simplest scenario to eyeball the FLO and the missiles’ general characteristics is a “dead-ahead” situation: zero Target Aspect and Antenna Train Angle, TA and ATA, respectively, or 180 Aspect Angle, AA. The scenario can be complicated further if the target starts a cranking manoeuvre.
I used these two situations in the first part of the study to get an overall idea of the performance of Active Radar Homing missiles against altitude and geometry.

Parameters

As mentioned, the first scenario is simple: 0 TA, 0 ATA. In other words, the two aeroplanes are flying toward each other’s faces. The second scenario begins in a similar fashion, but shortly after the “FOX-3”, the targets start a turn to a 60° crank.

Test	Altitude	VFGT	VTGT
Test I	10,000	M.9	M.8
Test II	25,000	M1	M.8
Test III	35,000	M1.2	M.9

V_C changes as a function of the altitude, and the used values are coherent throughout the study.
The fourth and last test attempts to demonstrate how missile performance changes depending on many parameters. In particular, these are human-executed launches with manual loft. Note that the combination of variables is not optimal for a very long range. These are just examples to prove a point.

The idea behind manual loft is quite simple: introduce an upwards trajectory or increase the momentum by pitching upwards whilst launching the missile. Since air provides less drag at high altitudes, the missile retains more speed whilst cruising and may also accelerate during the terminal phase.

Since the range at which the targets are engaged varies drastically, a direct comparison between the missiles is out of place. The next part will show the results of the same scenarios but at a fixed range, enabling data comparison.

Data are presented in the following table:

• “FOX Range” represents the separation when the missile is launched.
• “Impact Speed” is self-explanatory.
• “Flight Time” describes how long the missile was in the air, from launch to impact or to the moment of minimum separation in case the missile missed.
• “Peak” and “Δ altitude” represent the highest point the missile reached in its flight towards the target, both as absolute and relative values.
• “Missile Flown Distance” is extracted by calculating the distance the missile covers from launch to impact.
• “Linear Average Speed” is the average speed if the trajectory were a flat line.
• “TacView Average Speed” is the average speed of the missile determined by TacView. Note that if the missile did not hit the target, TacView’s average considers the period when the missile fell like a brick.
• “Δ Speed” is the difference between the two speeds. High Δ indicates trajectories that differ the most from the simple linear one. A negative Δ can indicate several possibilities: for instance, the missile has dipped below its original launching altitude, or the trajectory has negatively impacted the missile. A positive delta, instead, may indicate that the missile is faster than it appears, usually due to loft trajectory. In the example shown, the 25,000ft-related data indicate that the SD-10 has struggled to reach its target, thus losing quite a lot of speed post loft. Vice versa, at 35,000ft, the missile had plenty of energy and benefitted greatly from the additional altitude and speed. A corroborating factor is the total time: the 35,000ft launch arrived 10 seconds earlier than at 25,000 ft! We can, therefore, conclude that either the launch range at 35k is too conservative or the range at 25k may be a bit stretched. Or, well, both.
• “Manual pitch angle” represents how much the fighter pointed upwards when launching. Previous studies have highlighted how beneficial manual loft is and the shortcomings it can cause. Note that this angle is not the best-case or most efficient loft angle for each specific missile.
• “Minimum Distance” indicates how close the missile managed to get to the target. This value is populated when the missile misses its target.

SD-10 (PL12)

The newest addition to the ARH missiles rooster in DCS, the SD-10, also known as PL-12, is considered by reliable sources somewhere between the performance of the AIM-120B and the AIM-120C-5.
Two points are worth raising: consistency and good performance. The SD-10 managed to splash their target at reasonable ranges in any scenario. Interestingly, the FLO at 25,000 or 35,000 feet is fundamentally unchanged. Observe, in fact, how the flight time decreased at high altitudes and the impact speed increased by a solid 40%.
On paper, the only issue of the SD-10 is the countermeasures resistance but given how absurd notching is in DCS, I wonder how much of a problem this is. Consider, for example, the old AIM-54A Mk60 and how it was the best version of the Phoenix due to its kinematics performance, even at the cost of less luck in the chaff RNG.
The SD-10 is a fairly big missile, slightly bigger and heavier than the AIM-120 AMRAAM. Checking the “Crank” scenario, we see that the manoeuvre of the target is not that big of a deal for the SD-10. I have found the 35,000 ft scenario rather absurd. Data suggest that the missile cruised at high speed for quite a long period, resulting in a higher average speed. Impressive!
So, what is the secret of the SD-10? Well, it is immediately apparent when we observe the speed versus time chart generated by TacView. The SD-10 sports a dual-thrust rocket motor, similar to the last versions of the AIM-7 Sparrow. This peculiarity allows it to maintain thrust for a prolonged period, something extremely handy in basically any combat situation.
Looking at the AI launching the SD-10, it is immediately visible how they do not loft missiles.
I ran a quick test using the exact parameters of the 35,000ft setup with a pitch angle of 15°, and the results are listed in the bottom row of the table.
As expected and mentioned many times on this channel and website, manually lofting missiles significantly boosts their kinematics performance, with the caveat that it can increase the odds of thrashing them. The most evident aspects of manually lofting the SD-10 are the increased terminal speed, the peak altitude more than doubled whilst the very high average speed is maintained throughout the flight. De facto, this has made the SD-10 more dangerous at a range over 10 nm greater.
In DCS, the limit of the SD-10 is its launching platform, the JF-17. More on this later.

AIM-120B and C-5

The AMRAAM, acronym of Advanced Medium-Range Air-to-Air Missile, has taken the place of the veteran AIM-7 Sparrow as the main missile of US forces and many allies. In DCS, it comes in two variants, the B and the C-5. The differences between the two include the body, guidance, rocket motor, CMs and ECMs resistance and more. Ergo, a solid upgrade across the board. In DCS, these differences result in the C having better luck in the chaff RNG game, better kinematics and better guidance. Moreover, the AIM-120 has often been used by ED devs as a guinea pig for logic and guidance improvements.
Looking at the numbers, the C consistently arrives slightly faster than the B and performs slightly better against manoeuvring targets. In both cases, the First Launch Opportunity scales with range, whereas the SD-10 saw constant range at 25 and 35 thousand feet.

Both the AIM-120 B and C greatly benefit from manual lofting. The “B,” however, has reduced battery life and cannot fully benefit from the improved kinematics.
The C-5 instead almost doubles its effective range, becoming a threat even at distances normally prerogative of long-range missiles such as the Phoenix.

R-77

Known in NATO shores as the AA-12 Adder, the R-77 had a complicated and curious development. Looking at it, the first thing that catches the eye is the grid fins, something uncommon in air-to-air missiles.
Time-wise, the closest competitors of the R-77 are the AIM-120B and partially the AIM-54C, although the era of the Phoenix and the Tomcat was already ending.
The numbers show a solid missile with good average speed but incapable of reaching as far as the AMRAAM does. The primary culprit is the missile trajectory. Contrary to any other missile in this discussion, the R-77 does not loft, at least on its own. As we know, everything can be lofted on DCS, even in cases where the missile would be thrashed in real life.
The R-77 appears to be suffering the most against manoeuvering targets. The initial, powerful energy burst the rocket motor provides is not backed up by lofting, and speed is bled quickly chasing agile contacts. Therefore, to make the best out of the R-77, the pilot must thoroughly understand the geometry and the parameters of the engagement.
Manual lofting considerably helps the R-77, providing a certain amount of altitude to be reinvested into energy. However, as the numbers show, a manual loft can provide a greater range but may not be sufficient, especially when the target manoeuvres.

AIM-54C Mk47 & Mk60

The Phoenix is the most complex missile to master in DCS. Not many players understand that, or are willing to put some effort into learning.
A project of the ‘60s, it was introduced with the Tomcat in 1974 and, if the F-111B project had not fail, it would have been fielded probably even earlier.
This big, heavy and comically expensive missile was intended for all sorts of targets. Its primary function and doctrinal use in the US Navy was against bombers and threats to naval assets at long range, with the AIM-7 and AIM-9 employed against threats at closer ranges. The Iranian experience differed, with the Phoenix employed against all sorts of targets and with good results, no matter the lack of maintenance and spare parts.
In the middle of the 80s, the doctrine shifted, and with the introduction of the digital AIM-54C, the Phoenix became vastly better against CM and ECM, with brand new guidance, missile seeker, logic and much more. However, the price was a minor loss in kinematic characteristics, as the missile got heavier but the rocket motor stayed the same. In other words, this is the opposite of what happened to the AIM-120 AMRAAM.
I have dedicated many videos and articles to the Phoenix already, so do check those to understand the differences between the Mk47 and the Mk60 rocket motors. Each has pros and cons and, ultimately, the crew should pick the one that fits better mission and timeline. In reality, apparently, the two rocket motors were an attempt to diversify the supply.

The numbers will blow your mind if you are unfamiliar with the Phoenix. The other missiles discussed reach 25, perhaps 30, nautical miles, but the AIM-54 is easily employed at 70!
Data reveals many other secrets of the Phoenix, fundamental to understanding how this missile works and achieves its goals.
Simply put, post-launch, the missile climbs to the high heavens, reaching altitude even 4 or 5 times higher than other missiles. This allows this lumbering missile to reinvest the altitude into energy and cruise until it dives onto the target. The numbers confirm the love for the high, thin air: given the drag caused by the size of the missile, it benefits from high-altitude employment. The drag and the time it spends in the air also cause it to dislike manoeuvering targets, especially at long-range and medium altitudes.
Although often considered a slow missile, the Phoenix is actually surprisingly fast, almost on par with the others. However, the trajectory of the AIM-54 causes it to take the long way to the target rather than a more direct one.
Its greatest strength is the ability to engage targets completely unaware. In an era where the AIM-7E was barely effective outside visual range, a telephone pole capable of reaching a target at 70 nm most of the time completely undetected was really, really scary. It is a shame that DCS does not allow us to replicate these conditions, putting gameplay over realism.

Fighter’s performance

The fighter’s parameters at the missile launch play an important role in the overall outcome. For instance, a better-performing missile may be hindered by poor launch geometry, slow speed, and altitude. I put together a quick test to get a general idea of the impact of the fighter’s speed on the missile performance.
The three F-15s carry one AIM-120C-5 each, each flying at different speeds. Intuitively, the faster the launching platform, the better the overall result.

Quick observations: although the AI does not increase the separation at launch, a human can take advantage of the better kinematics to extend the missile’s effective range. From a certain point of view, the maximum range of a missile becomes subject to two factors: the fighter’s radar performance and the battery life.
Although a direct comparison between missiles is not the primary purpose of this chapter of the study, we can certainly say that the SD-10 has very good characteristics, on par with or slightly superior to the AIM-120C-5. However, the KLJ-7’s performance appears to be worse than the F-15C, the Strike Eagle, and the F/A-18 Hornet. Ergo, they can employ earlier. The Fighting Falcon’s radar instead is closer to the KLJ-7 in terms of performance, but the F-16 can leverage its immense thrust, as long as the fuel lasts, that is, and “push” the AMRAAM faster and farther.
The following chart shows the performance of clean aeroplanes in terms of Thrust-to-Weight, acceleration and speed at ground level.

At 30,000ft, the top speed after a defined amount of time is the F-14A’s Mach 1.86. The Fighting Falcon touches Mach 1.79, and the JF-17 Mach 1.58. It is when the payload is introduced that the situation drastically changes. With a fairly standard loadout, the Tomcat hits Mach 1.46, the Falcon Mach 1.52, but the JF-17 languishes at Mach 0.97 in level flight. A competent pilot can help the Thunder cross through the transonic region, but the point stands: the energy the F-16 can “gift” to the AMRAAM is superior in almost all conditions.
As mentioned, a detailed study regarding TWR, speed and performance is still WIP.

Conclusions

The numbers discussed in this study should have given a general idea of how far and dangerous a missile can be in various scenarios. More importantly, since the launching conditions are the same, we can obtain a sort of “baseline impression” of them. We now better understand, for example, which missile can be a threat at what range, how effective simple geometry changes can be against it, and a general idea of how each missile behaves at different altitudes.
The next step, covered in the following part, enters into the details of the missiles by comparing the results of launches at a fixed range.