The next couple of videos aim to complete the overview of the Phoenix, starting with the second favourite geometry by any RIO or WSO, right after Collision Course: ergo, zero-cut, aka 180 DTG or HCA.
Zero-Cut
Zero-cut’s properties should be known already, I covered them 5 or 6 years ago.
If you are new to this, here is a brief refresh. The two aeroplanes fly following parallel and reciprocal courses. Besides being easy to recognise on the TID in Aircraft Stabilised mode, in a zero-cut situation TA equals ATA, and the angles tend to double as the range is halved.
On top of that, the lateral separation remains constant as the range decreases.
45,000ft
As discussed in Part II of this series, 45,000ft or 13.7km is the ideal environment for the updated AIM-54. Even at 80nm, the missile reaches an altitude on par with the old version, and takes full advantage of the corrected drag and improved rocket motors. The charts displayed show both the performance of the old AIM-54 in this scenario, but also the data of the new Phoenix in the 0TA/ATA test. This should help to quantify how much energy is lost due to the different geometry. As we can see, the difference is totally minimal.
The same trend applies to every other set, so let’s jump down 3km and check 35,000ft.
35,000ft
At 35,000ft or 10.6km, the Phoenix performs well at any range. The altitude is still considerable and helps to propel the missile to extreme ranges. In fact, the new AIM-54 performs almost identically at any range. However, we can notice a minimal but appreciable discrepancy between the curves against targets flying zero-cut and 0TA/ATA when it comes to the old missile.
This chart seems to hint that the new Phoenix performs better than the old version when dealing with a non-manoeuvring target and “imperfect”, so to speak, geometry.
25,000ft
At 7.6km or 25,000ft, what we noticed in the previous sets does not change. The following charts show the results for the 40nm test.
Besides that, there is really not much to talk about.
15,000ft
Down another step, the properties of the atmosphere start to have an effect. At 60nm, the discrepancy between the old missile sets is evident. The 10° offset causes the old Phoenix to struggle, arriving later and slower. What about the new Phoenix? Well, it does not care, regardless of which series is considered: levelled employment or manually lofted.
At 40nm we see almost a mirror of the 25,000ft scenario, so let’s jump to the 20nm range, which we have not considered yet. Here the angles are important: 30° and, with the drift rapidly creeping up, the scenario forces the Phoenix to spend more energy in the turn. The old AIM-54 did not even connect in this scenario, whereas the new missile arrived at M1.3 and M1.58 depending on the employment type. Not bad!
5,000ft
Last set, 1.5km or 5,000ft. At 30nm and beyond, the Phoenix struggles: its big arse does not like physical exercise, and runs out of breath almost immediately. Not even manual loft helps, but I find very curious that the offset has very little effect on the results. There is a reason for that, and it will be discussed in the conclusions.
The 20nm set is probably the most interesting: this is a real cardio workout for our beloved chunky missile. In fact, out of the three employment methods, only one connected: new Phoenix plus manual loft.
Conclusions
This brief discussion has shown how the AIM-54 Phoenix is barely affected by engagement geometry. The differences between 0TA/ATA and Zero-cut are minimal, and slightly smaller than the same tests run with the old version of the AIM-54.
This outcome is reassuring: the Phoenix can handle geometry imperfections, for lack of better terms, without too many issues. The guidance technique is responsible for that: the proportional guidance, in fact, executes fundamentally only one correction towards the target, then the missile continues until timeout.
Leave comments and feedback in the Discussion Forum thread.
You must be logged in to post a comment.