Has anyone explored the use of Beehive/Flechette anti personel tank rounds on drones?

[On the way]

Rounds like the 105mm M546 APERS, I would think would be effective against drones. They are employing small arms and heavy machine guns on trucks to combat drones, especially the quad copter types and they seem to be quite effective. I mean we are talking Russian 12.7mm heavy machine guns able to shoot down most of the lower flying drones. I would imagine these rounds, if brought back into production would work great too. We are talking 8000 8grain flechettes with a spread pattern that would be quite wide at say 3000m and beyond. They can be fused up 100 seconds. The dispersal cone at 300m is 110m wide. I know its intended for close range use, but if the fused could be designed for a longer detonation, out to 2000m-3000m, it should take out drones at that range. Maybe use the optics on the tank to seek out drones?

http://uxoinfo.com/blogcfc/client/includes/uxopages/Mulvaney_Details.cfm?Ord_Id=P183

 

[Ssnake]

1

I don't think these are in production anymore, anywhere. But I may be mistaken.

 

2

Existing stockpiles are probably past their nominal shelf life already.

 

3

I was under the impression that the loader was to set the detonation range manually. This strikes me as somewhat time-consuming and potentially inaccurate enough that the resulting spread pattern would either be too wide to be effective, or too narrow to hit if you don't get the range and flight vector right.

8,000 flechettes sounds like a lot. "110m width", to go with your number, means a 55m radius for a near-circular area where the front of flechettes travels. With a uniform distribution (which it probably isn't) the target area is 9,503 m², which gives a density of just .84 flechettes per square meter.

If the drone doesn't have a cross section of at least 2.4 square meters to ensure, statistically, two hits, a single round is not sufficient. Or, seen differently, the ranging error by the time that round and drone meet must not exceed 35m for a density of two flechettes per square meter of the target area. This may appear possible if the drone hovers or moves perpendicular to the line of sight. If it's closing fast or moves at an oblique angle, the window to score a hit will narrow considerably.

This could be mitigated with a fire-control system update that

a. uses a constantly pulsing laser to develop an estimate for the flight vector in 3D space, and

b. constantly updates the expected range in the ballistic computer, which

c. programs the detonation flight time electronically

Such a system exists - for 30mm and 35mm caliber, with near-inert KETF rounds.

 

4

The biggest challenges however are, for a conventional 105mm tank cannon system, to actually spot the drone due to the elevation limit (+20...+22°), and the narrow field of view which makes tracking the drone rather hard.

[DB]

You're firmly into the notional "micromissile" territory at this point, and you'd be better off using a more conventional PFF warhead. I say micromissile, because if you want the payload of a beehive-like round, then the calibres you mention aren't near that. So, you'd then be looking at an RWS box mount with maybe 4 rounds and the ability to engage out to a couple of kms, with a guidance capability, proper fuze and proper warhead. Might cost less than the 10-20 cannon rounds you'd have to use instead. Optical guidance F&F, I'd suggest.

[bojan]

IMO Anti-drone options on MBT should be strictly defensive - IOW short range jammers (vs commercial ones)/APS (vs missile firing ones). It is not for the tank to fight drones, just like they do not fight long range artillery directly.

Edited May 9, 2023 by bojan

[JWB]

I wonder how effective this is against drones:

https://techlinkcenter.org/news/heres-the-armys-now-patented-emp-rifle-attachment-for-taking-out-small-drones#!

[Tim Sielbeck]

19 hours ago, On the way said:

Rounds like the 105mm M546 APERS

That's the 105mm artillery round.  Tanks used M494 APERS-T(also range is input, not time).

14 hours ago, Ssnake said:

I was under the impression that the loader was to set the detonation range manually. This strikes me as somewhat time-consuming and potentially inaccurate enough that the resulting spread pattern would either be too wide to be effective, or too narrow to hit if you don't get the range and flight vector right.

It depends.  Is the command "Beehive," or "Beehive Time."  Loading the M494 APERS-T without changing the range, Beehive, makes it like a cannister round going off at the end of the barrel.  Beehive Time requires setting the range by rotating the fuse in the proper direction which would greatly extend the range at which it bursts.  It goes without saying that proper ranging and accurate shooting were required to make it effective.

[On the way]

14 hours ago, Ssnake said:

1

I don't think these are in production anymore, anywhere. But I may be mistaken.

 

2

Existing stockpiles are probably past their nominal shelf life already.

 

3

I was under the impression that the loader was to set the detonation range manually. This strikes me as somewhat time-consuming and potentially inaccurate enough that the resulting spread pattern would either be too wide to be effective, or too narrow to hit if you don't get the range and flight vector right.

8,000 flechettes sounds like a lot. "110m width", to go with your number, means a 55m radius for a near-circular area where the front of flechettes travels. With a uniform distribution (which it probably isn't) the target area is 9,503 m², which gives a density of just .84 flechettes per square meter.

If the drone doesn't have a cross section of at least 2.4 square meters to ensure, statistically, two hits, a single round is not sufficient. Or, seen differently, the ranging error by the time that round and drone meet must not exceed 35m for a density of two flechettes per square meter of the target area. This may appear possible if the drone hovers or moves perpendicular to the line of sight. If it's closing fast or moves at an oblique angle, the window to score a hit will narrow considerably.

This could be mitigated with a fire-control system update that

a. uses a constantly pulsing laser to develop an estimate for the flight vector in 3D space, and

b. constantly updates the expected range in the ballistic computer, which

c. programs the detonation flight time electronically

Such a system exists - for 30mm and 35mm caliber, with near-inert KETF rounds.

 

4

The biggest challenges however are, for a conventional 105mm tank cannon system, to actually spot the drone due to the elevation limit (+20...+22°), and the narrow field of view which makes tracking the drone rather hard.

Good points you raise. And I would even say if its possible to add proximity fuse to such a round to detonate near drones, would create a better kill probability. That would remove the need to manually set the fuse and save time. As for the FCS, yes, it would need a software update if that is even possible to engage aerial targets. But if such a system already exists for 30mm and 35mm caliber, can it not be translated to a 105mm or 120mm caliber? Anyway, its just a theoretical exercise in defeating drones, and perhaps a method not considered before.

[On the way]

13 minutes ago, Tim Sielbeck said:

That's the 105mm artillery round.  Tanks used M494 APERS-T(also range is input, not time).

It depends.  Is the command "Beehive," or "Beehive Time."  Loading the M494 APERS-T without changing the range, Beehive, makes it like a cannister round going off at the end of the barrel.  Beehive Time requires setting the range by rotating the fuse in the proper direction which would greatly extend the range at which it bursts.  It goes without saying that proper ranging and accurate shooting were required to make it effective.

Yes. Could a proximity fuse work in this case, instead of manually setting the range?

[On the way]

7 hours ago, bojan said:

IMO Anti-drone options on MBT should be strictly defensive - IOW short range jammers (vs commercial ones)/APS (vs missile firing ones). It is not for the tank to fight drones, just like they do not fight long range artillery directly.

Yes, definitely defensive. The tank can't travel as fast and be as mobile as say a truck mounted with 2 X 12.7mm heavy machine guns. The Ukrainians are driving these trucks around rapidly to where drones have been reported and shooting them down. The tank can't be that mobile. For defensive purposes, the drones are coming for the tank anyway, whether the tank likes it or not. The ability of the tank to fire beehive at the drone, whether it is traveling with anti drone teams, or not, just adds to the their protection.

[Tim Sielbeck]

I suppose so.

[Tim Sielbeck]

Forgot this:

[Ssnake]

1 hour ago, On the way said:

But if such a system already exists for 30mm and 35mm caliber, can it not be translated to a 105mm or 120mm caliber?

You don't really get that much of a range advantage compared to 35mm, and you lose cadence. I think it's better to fire five 35mm rounds with high accuracy at 3,500m range than just one round with mediocre accuracy, even if you could open fire at a range of 5,000m+.

Programmable airburst munitions exist for the Gepard (with the added benefit of radar guidance; 35mm AHEAD), CV90/35 (35mm KETF), and Puma IFV (30mm KETF).

[KV7]

I think there is a case for 'micromissiles' but preferably cheap ones using command guidance, so the expensive electronics can remain on board and not be expended. If you can get it to a couple metres, a proximity fuse should be enough to destroy most drones. 

I suspect the cost of effective radars or combined EO suites also to fall, which can make such a solution more effective, and even more so if the missile FCS also can support an APS by tracking incoming threats. 

 

[DB]

My favoured guidance system would be optical, thermal IR against a sky background is easy, and the only reason it isn't cheap is because of the small number of systems purchased offset against the massive overburden of Mil Spec qualification activities. The command system of a guided missile is not close to being as complex as a mobile phone, and the latter offers everything you need for the former.

Shock loading and EMC qualification are about the only hard things.

[KV7]

I suspect the thermal imager will still be expensive, especially if you want an ability to track targets in a wide variety of conditions. 

Also command guidance lets you adjust the FCS to target all sorts of different targets. 

An EO based FCS could work though. 

[DB]

See Enforcer, mentioned in another topic. Its price point and size are a massive overmatch for most drones, though. 

The thermal imager might be relatively the most expensive component, but you can buy fully-functional FLIR kit for a small fraction of what the standard military procurement system would charge, and it would offer less. Just the paperwork is far more expensive in manpower than any of the hardware costs.

When it's considered acceptable for a standard Windows Laptop transferred into a hard case to cost an order of magnitude more than a standard laptop, you should understand that it's not the components that make the cost.

Take a look at GriD's current military offerings. You have to send them a request for information to get a hint of how much.

[DKTanker]

The 120mm HEAT M830A1 has a proximity fuse.  Not sure if it is still in production.  Not even sure a drone would have a great enough return signature to initiate the proximity fuse.

[Ssnake]

On 5/9/2023 at 10:13 AM, Ssnake said:

The biggest challenges however are, for a conventional ... tank cannon system, to actually spot the drone due to the elevation limit (+20...+22°), and the narrow field of view which makes tracking the drone rather hard.

Whether the proximity fuze is reliable is certainly an interesting question, but I still think that the (in)ability to detect and track the drone is the main factor. When the drone is far away you won't see it by accident, and you can't hear it. When it's close enough to hear it, it's too late, and somewhere in between these two point in time the angular velocity of the drone becomes so big while the FoV of the crew's sensors remains so small that intercepts become very unlikely.

Some radar (or other sky surveillance) detector to sweep the sky, alert the crew, and to override the turret is necessary if you want tanks to be able to defend against LMs at range. I suspect that it won't be done, and we'll rely on short-range intercepts by APSs instead, and we might enable IFVs in a secondary anti-drone role due to their autocannons (if those can be equipped with KETF or similar).

[bojan]

40mm Bofors prox fuse works vs mid-sized civilian drones, I forgot which one exactly, and it is used locally for life fire AD training as a cheap expandable target.

 

[Ssnake]

Sure, but then we're talking about intercept ranges at under 3km rather than well above that. Whether you fire eye-wateringly expensive 40mm 4P or godawfully expensive 35mm KETF/AHEAD doesn't matter at these ranges.

[DB]

Set a target price and give a guaranteed order in the 100s of thousands and they will be provided.

Continue with peacetime penny-pinching and when the time comes you'll have spent 80% of the money and got 10% of what you need.

 

[Ssnake]

Seems like 35mm AHEAD, functionally identical to KETF except pellet count and mass, is being ordered in the 100k ranges lately.

It's just that Rheinmetall had to relocate the whole factory away from Switzerland for this, which doesn't help with the costing.

[bojan]

8 hours ago, Ssnake said:

...Whether you fire eye-wateringly expensive 40mm 4P...

That is a part of problem, instead of 3 or 4 types of reasonably cheap ammo someone decided to go with single expensive one because "it can do everything". Well, yes, it can, but it will also cost per round as 3 or 4 rounds of "inferior one", and in the end you are going to fire more or less same amounts of either...

 

Edited June 30, 2023 by bojan

[Ssnake]

1 hour ago, bojan said:

That is a part of problem, instead of 3 or 4 types of reasonably cheap ammo someone decided to go with single expensive one because "it can do everything". Well, yes, it can, but it will also cost per round as 3 or 4 rounds of "inferior one", and in the end you are going to fire more or less same amounts of either...

Look, I'm with you. KETF is in a way brilliant in its versatility (and better than 3P IMO), and it's not necessarily the fault of these rounds or their engineers and manufacturers that western armies willingly trapped themselves in the low numbers death spiral. Hopefully, we'll work ourselves out of it.

That being said, the whole point of this thread is whether it's practical to use rounds from tank guns against drones. I remain of the position that it is not, even if the proximity sensor of an M830A1 is sensitive enough because in all likelihood you'll never get the proximity part in proximity fuze right. The (current) MBT limitations in sensors and fire control system simply prevent sufficiently accurate targeting.

I think Gepard currently shows the value of 35mm AHEAD. If we don't want to bring back high cadence medium caliber AAA for lack of manpower in our armies, we need to enable the force to perform close range general air defense. I remain skeptical about the practicality of tank gun rounds in that role even if we get the sensor and fire control part right; you just don't get area coverage to make up for the inevitable minor targeting errors.

[bojan]

No disagreement about (non)utility of tank guns in those cases.