Not sure a CIWS system that can hit a mach 2 missile that doesn't dodge would necessarily handle the same $$$ spent on a N cheaper drones. How many minutes of firing do modern CIWS systems typically have?
Loitering at max engagement range and dodging might well end up using ammo at a rate that the CIWS can not sustain.
Also I suspect any CIWS can get a kill on just about any part of a missile, where drones often have very small kill zones (often battery or gas, payload, motor(s), and control) that might well be just a few % of the size of the drone.
I googled the phalanx, looks like it typically has a drum of ammo that lasts for about 3 seconds. Is that 3 drones worth? 10? 100?
https://www.youtube.com/watch?v=bdwjcayPuag
Edit: Look they even made a smaller system! https://youtu.be/Drm3kdDYBI4
I guarantee you that just grazing a drone with a 20mm round will still kill it, even if you don't "hit" anything critical. :P
Sure the 20mm round represents an amazing amount of kinetic energy, but the drone doesn't offer any resistance, and I wouldn't expect the round to even notice. Sure the disturbance in the air might throw the drone for a few loops, but any decent software will recover.
Sure hitting more substantial targets the target itself becomes of the shrapnel that causes an ever increasing zone of damage. Not clear to me that a piece of paper or thin fabric would exhibit the same behavior.
1. I think you're conflating "cheap agile drone" with "foam or balsa+durakote fixed wing aircraft".
2. Probable engagement aspect for a drone is not "straight up", as would be necessary for your scenario.
3. A little itty bitty hole in a wing does a whole lot more than you'd think.
4. Expecting a high velocity cannon round to just punch a clean hole in the wing is a little much.
Foam's a bit more robust, but a small pebble at a few miles per hour has wrecked my whole durakote day before.
And yes, there's degenerate cases, like you could have a whole sheet of dollar tree foam board maybe take a hit or two.
Explosive (self-destructing) and incendiary
https://www.gd-ots.com/munitions/medium-caliber-ammunition/2...
Modern antiship missiles have complex programs. Some are capable of flying in formation with each other, with one missile flying high for visibility and communicating with the other missiles in the formation that are flying very low. If/when the missile on top is destroyed, another missile in the formation can be automatically selected to take its place.
That ciws will likely exhaust its magazine before it can take out all the drones unless I’m missing something.
https://youtu.be/1DXpPmpmcak?t=365 (watch this entire video for air defense against saturation attacks)
Lasers, electronic countermeasures, tangly stuff, etc, are much more attractive than systems that fire thousands of cannon rounds per minute or that launch explosive missiles.
Whereas naval Phalanx systems fire tungsten armor-piercing rounds, the C-RAM uses the 20–mm HEIT-SD (High-Explosive Incendiary Tracer, Self-Destruct) ammunition, originally developed for the M163 Vulcan Air Defense System.[26][34] These rounds explode on impact with the target, or on tracer burnout, thereby greatly reducing the risk of collateral damage from rounds that fail to hit their target.
Not that the risk is zero, but at least it's "greatly reduced".
A CIWS is not a reasonable way to stop drone attacks on civilian targets.
The thing is exactly that those drones are so slow, and low.
Phalanx performance against sea skimming missiles is know to be poor.
And that on dielectric, flat sea surface.
Even military drones weighting few tons can fly autonomously under 100m.
Ironically, it's now depressions in the terrain which will provide more air defence since they will force terrain following drones, and cruise missiles to move at oblique angles.
Basically the problem is the same as with low, and slow cruise missiles, except worse.