CTA 40mm – Technical Issues

Someone remind me how long as this system been in development?

http://www.janes.com/article/29547/british-army-warrior-faces-up-to-sliding-programme-delays

http://www.flickr.com/photos/73614187@N03/8192576231

And a blast from the pre FRES past

http://www.flickr.com/photos/73614187@N03/7005788794

http://www.flickr.com/photos/73614187@N03/7151877229/

 

 

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wf
wf
November 6, 2013 10:40 pm

Buy Bushmaster or Bofors. They won’t fit in the Warrior turret? Who cares? What is the point of trying to upgrade a platform that’s already 25 years old? Buy more ASCOD

mr.fred
mr.fred
November 6, 2013 10:48 pm

On one hand, I kind of want to gloat, having predicted troubles with the gun.
On the other hand, it is a problem for the Army.
Not one that could be solved by buying more Ascod-derived SV either since they have the same cannon.

A Mk44 firing Super40 would be the gun for me, were I the one to choose.

Chris
Chris
November 6, 2013 11:01 pm

I’m sure I saw on a CTA presentation that they’d run a 10000 round trial or something like, and the gun & feed did OK? Or was that just wishful daydreaming?

Nope – just looked on the archive shelves and found the presentation by a Mr Duckworth of CTAI given in April 2005; 10000 round Reliability Test Programme and a 30000 cycle test applied to all safety critical components. That was 8 years ago. Makes you wonder what these ‘issues’ are, and whether they all are on CTA’s watch…

As for CTA or Mk44, if the gun works there are some advantages in fitting the CTA gun, especially in terms of space claim behind the mantlet – the CTA is very compact.

wf
wf
November 6, 2013 11:14 pm

@mr.fred: I understood the only way of getting a 40mm gun into Warrior was CTA, since the turret ring is so small. Hence my comment

mr.fred
mr.fred
November 6, 2013 11:20 pm

Back when the competition was run openly but before the CT40 was mandated, there were offerings from General Dynamics, OTO Melara and Lockheed Martin all fitted with the Mk44.

There was something more recently about the gun having qualified one of three round types. Can’t find it with a cursory search

as
as
November 6, 2013 11:26 pm

I wish they would pick a calibre and gun type and stick with it.

Mauser BK-27 27×145 mm
F35 General Dynamics GAU-12/U Equalizer 25×137 mm
CTA International 40CTAS 40x? mm ct
30mm DS30M Mark 2 Automated Small Calibre Gun Alliant Techsystems Mk44 Bushmaster II 30×173 mm
Phalanx CIWS M61 Vulcan 20×102mm
Hughes M230 Chain Gun 30×113 mm
Goalkeeper CIWS General Electric GAU-8/A Avenger 30×173 mm
Oerlikon kaa 20 mm cannon 20×128mm

8 types of gun, 7 calibres. There may be ones I have not thought of in service.
As usual, its all waste and extra complications.

Unfortunately the only one that can be bought in all the for all the rolls and platforms is the Mauser BK-27 27×145 mm. Unfortunate because it is perhaps to small a round?

I think the best gun hear for an armoured vehicle if you were designing it from scratch probably is the Alliant Techsystems Mk44 Bushmaster II 30×173 mm. It cousin the 40mm Bushmaster IV Automatic Cannon would be an even better choice as Fires all Bofors 40mm L70 NATO standard ammunition.

There are lots of options though, we can get away with lots of different types of gun. We just need a common calibre.

as
as
November 7, 2013 1:16 am

I can not find a list of the turret ring diameters for armoured vehicles.
Are there NATO standards sizing?

Obsvr
Obsvr
November 7, 2013 7:59 am

The gun is developed, the issue is probably the magazine and round transfer system. I believe at least part of this is to be a sealed unit, requiring very high reliability. I’d guess the reliability growth program is taking longer than expected.

I love it when the self-styled experts tell us what the right answer should have been (one of an array of antiques). CTA has key advantages over all of them, starting with less space needed to store the same number of rounds in an AFV. Anything that makes more space for the same AFV volume gets my vote.

Monty
November 7, 2013 8:47 am

I hate to say I told you so…

Just wait and watch this one go from bad to worse. Another classic procurement cock-up.

Mk 44 firing Super 40 all the way! That’s what we should have chosen. Even a straightforward Mk 242 firing 30 mm would have been a good choice, given the upgraded ammunition that’s currently under development.

” What’s the point of trying to upgrade a platform that’s already 25 years old?”

Exactly. This flawed choice is all about a turret ring that’s too small. How ridiculous to hamstring our entire future armoured vehicle cannon strategy because a legacy vehicles isn’t equipped as we would like. Don’t upgrade the bloody Warriors. It’s going to cost at least £1 billion anyway. Leave them as they are. Fit the Mk 44 to FRES SV Scout and then build an IFV version of ASCOD 2 (its original role) with same gun and use this to replace Warrior from 2025.

Defence Photography
Defence Photography
November 7, 2013 9:15 am

The problem is with the FEED system NOT THE GUN. The feed system is made by the Germans (I think with some US company too) and was selected by Lockheed Martin. It was thought to be, at the time, innovative and high risk.

When things like this happen it is customary for Prime Contractors to infer blame on the Government mandated item.

Red Trousers
Red Trousers
November 7, 2013 9:36 am

there wasn’t actually anything wrong with the Rarden’s rate of fire, from the user’s perspective. It was fiddly as fuck***, which might have mandated an automated system, but if you knew what you were doing, you could pump out rounds every couple of seconds until the ammo tray was empty. For recce and AI, that was more than good enough.

I first came across CTA as a concept in 1994, while at the Gunnery School in Lulworth. That’s 19 years ago, and for what is an overgrown machine gun, 19 years is a long time to come into service.

CTA was a solution in search of a requirement, and it doesn’t appear to be a requirement that the Army actually has. But, Franco / British politics and some slick salesmanship mandated it.

*** Winding a handle 32 times clockwise (not 31, not 33. It was quite particular) until a green arrow points to 3’oclock on a dial, then counter-winding 6 times is not really what you want to be doing in battle.

Chris
Chris
November 7, 2013 10:07 am

RT – I played on the Scimitar turret trainer at Alvis – I thought the Rarden a slick device – until you forgot and fired the last of the clip of 3 rounds before the next clip was loaded. (I didn’t bother to count handle twiddles). Firing triples was almost as easy as a belted ammo or autofed gun would have been. The only issue I saw with the system was that the first round of the triple naturally had to be the same nature as the last two shot, which may not be the desired round against the new target. Generally I thought the Rarden a decent bit of kit. But I can’t speak from the User perspective, obviously.

As an engineer I like the CTAI gun. I can’t speak for its rounds’ comparative tactical effect when put against other 30, 35, 40 or 50mm ordnance, and I accept its unusual ammunition is not NATO standard and currently made by one company. There are disadvantages. But having looked at installation of CTA and its ammunition feed system, it is far better packaged than the more conventional guns (those that load rounds through the side of the breech like overgrown machine-guns or those that load axially from the rear). Many years back two of us Alvis engineers went to a trade show where Rheinmetall had their 35/50mm auto cannon on display. The breech block must have been the size of a typical MBT gun’s – 500mm deep, 400mm wide and a metre long if memory is correct. Absolutely vast. Add to that the swept volume of the ammunition feed chutes and you could see the forward metre length of turret interior was only going to hold the gun. It made for a very big turret – we assessed we couldn’t get a turret armed with this gun on the Stormer chassis; bear in mind a Stormer with 105mm gun had been an early proposal for US AGS programme. (Related to this: http://www.army-guide.com/eng/product4403.html)

Red Trousers
Red Trousers
November 7, 2013 10:21 am

Chris,

the Rarden was a beautiful little gun, if you knew what you were doing. The fiddly bits were only on change of drills or if you didn’t load on round 2 of a 3 round clip. It was a 30mm sniping rifle.

I taught my gunners to load for themselves with their left hands from the ready rounds tray, which freed me up to not be on the wagon at all but instead peering around the side of a tree 10 yards away on the end of 5 or so curlywurly cables attached to my headset. The MoD should have put more effort into long range Bluetooth or Zigbee and then I could have been 100 yards away.

Swimming Trunks
Swimming Trunks
November 7, 2013 1:23 pm

Hmmm… IFV… 40mm cannon… Where I have I heard that before?

http://en.wikipedia.org/wiki/Combat_Vehicle_90

@ as – “There are lots of options though, we can get away with lots of different types of gun. We just need a common calibre.” – That sounds like TD’s ruthless commonality(TM).

@ Chris – Always liked the Stormer… TD found a old concept of equipping it with the ARES(?) 75mm gun. Do you have any info on that?

@ RT – “It was a 30mm sniping rifle” – any chance you think of mounting it on another vehicle when the CVR(T) is retired?

x
x
November 7, 2013 2:56 pm

Put on YouTube nearly 4 years ago showing HE and other natures on target fired from a gun mounted in a vehicle both produced in a country known for outstanding design.

@ Obsvr

I see with you it is all about girth not length…………

http://www.quarry.nildram.co.uk/CTAammo.jpg

The gun is developed, the issue is probably the magazine and round transfer system. I believe at least part of this is to be a sealed unit, requiring very high reliability. I’d guess the reliability growth program is taking longer than expected.

I read this as,

The car is developed, the issue is probably with the wheels. I believe at least part of this to be a sealed unit requiring high reliability; no shit Sherlock. I’d guess it would be like pointing out the bleeding obvious that it ain’t working and that is why it taking a longer time which is like really obvious obviously. But don’t worry the car is alright, it just can’t go anywhere.

I think your argument about space saving in turrets is you speaking as a self-styled expert on production design expressing his opinion and not fact. Others in the same trade as you may have different opinions. As a layperson, not a self-styled expert, I think better the turret fits around a gun and crew that function than worry about fitting a gun into a given turret. Seeing as these things come as a package space shouldn’t be a problem. I think everybody here knows about fitting bodies into vehicles. Remember you speak as a member of an organisation that is supposedly expert in army vehicles yet couldn’t purchase one after pissing a billion up the wall. As a layperson, not a self-styled expert, who pays taxes perhaps you will allow me and my fellow laypersons, who also pay taxes and who mostly themselves are not self-styled experts a bit of latitude when we question yet another programming stumbling along. Turnip.

Chris
Chris
November 7, 2013 3:48 pm

x – I’m no Customer wallah; I do spend time in CADspace trying to fit things together though. The CTA gun is very compact inside the turret compared to the normal guns & cannons, with a max radius of swept volume behind the mantlet axis of 360mm or so. Perhaps 40% of a more traditional belt fed gun breech block. Also the ammunition feed is on the mantlet axis so has in effect no swept volume at all, where belt or chute feed systems demand much volume to cover the full sweep of gun elevation.

While your statement is entirely correct – the turret can be designed around the chosen gun (and is, obviously), but there are consequences. A long breech block might force the mantlet axis to be further forward just to make room for the Gunner & Commander, but this would lead to a larger turret ring to allow the breech block adequate clearance at full gun elevation, which makes the turret footprint larger on the hull.The longer turret overhang at the front increases the area of armour required in the turret structure that in turn makes the turret much heavier for the same protection level. And a bigger target. the bigger turret needs stronger servo drives which use more electricity (or hydraulic power), impacting the power unit of the vehicle. The bigger turret also means the vehicle as a whole is heavier and requires more power and fuel to reach the same performance. The longer turret overhang means the driver hatch must be located further forward to avoid turret & driver’s head occupying the same space – it only happens once but its messy – so the driver must sit further forward which makes the hull longer, thus heavier with consequent effect on power requirements and fuel economy. With the increased length of vehicle, the width would need to be increased – there is a fairly narrow tolerance on the ratio between track length on ground and lateral spacing of track centres if the vehicle is to have usable manoeuvrability. With the extra mass of the turret the extra width would help lateral stability anyway.

So, just because the gun sweeps more volume behind the elevation axis in the turret, the turret has grown bigger and heavier, the hull has grown longer wider and heavier, the powerpack must be more powerful, it needs more fuel, the transmission may need to be replaced with a more robust unit – it affects the whole vehicle design.

I don’t profess to be an expert. But I do spend my days designing this sort of stuff. In my opinion, the choice of gun and its physical shape has a very big impact on turreted armoured vehicle design, going far beyond the local shape of the front of the turret. The CTAI design (despite all evidence apparent in GD’s Scout-SV) allows a much more compact vehicle to be created.

In terms of the Warrior upgrade, I don’t have the data but I’d guess there is little volume demand difference inside the turret between the Rarden mantlet assembly and the CTA equivalent. Although the CTA has a chunky ammo feed unit next to the mantlet pivot which gives the turret a lopsided hamster-cheek. Warrior was fitted with the Delco 25mm turret for some export orders, but I imagine trying to fit a modern conventional-loading 35mm gun or larger into a turret for Warrior was never going to be slick. I would have liked to see the original LM Warrior FLIP turret design with the Mk44, but didn’t have need to know. It would have been interesting to see how the size of the breech block affected the ring, height of turret, personnel space and elevation limits.

Apologies for the lengthy tome; I hope it helps understanding of some of the other comments here.

x
x
November 7, 2013 4:46 pm

@ Chris

I know. My point simply was for Obs to infer we civilians are numpties because we are unhappy that yet another project has slipped and to offer poor reasoning like turret space in a turret designed to fit the gun that is yet to enter service is a bit too much for a Thursday afternoon. I am well aware inches and units of inches make a lot of difference when it comes to ergonomics. And as an armoured vehicle is in some ways like a very simple small ship I know that everything impacts on everything else thank you. Would we really have come off worse with a Bofors 40mm or just buying a 35mm gun? Um not really.

As for turret space there are lots of fresh air options……..

http://image.trucktrend.com/f/roadtests/ultimate/163_1404_1944_buick_m18_hellcat_tank_destroyer_first_drive/58790905+w799+h499+cr1+ar0/1944-Buick-M18-Hellcat-Tank-Destroyer-top-view.jpg

http://farm9.staticflickr.com/8438/8015106111_905dd2dd62_z.jpg

:)

Defence Photography
Defence Photography
November 7, 2013 4:57 pm
Reply to  x

If ANYONE is in any doubt why CT40 is the way to go, just jump into a CV90 with a 35mm gun – it’s an ergonomic disaster – ITDU had a look at it and rejected it in the first few minutes as the Commander could barely see the Gunner due to gun intrusion and the survivability of the turret crew was also bad due to the gun intrusion, especially if they were 95th percentiles with body armour. And a reminder from my earlier comment today, the Janes article highlights the feed mechanism (chosen by Lockheed) as the main technical issue NOT the mandated gun. Could it be that LM are shifting blame onto DE&S? Surely not.

Chris
Chris
November 7, 2013 5:20 pm

ST – ref ARES on Stormer – I wasn’t in the company at the time; it had died five years before I got there. I think the boardroom had some shiny aluminium models of related vehicles, but not the ARES version. The web offers this:
http://s76.photobucket.com/user/abegubler/media/sagiter01.jpg.html

That’s it. No other information in the public domain. Certainly none in my archives. For what its worth, I’d say the concept was somewhat overgunned, as in its firepower would appear to be considerably greater than its protection level, not a strategy for survivability really. But if that’s what the customer wants…

Bob
Bob
November 7, 2013 5:40 pm

X is wrong (again), Chris and DP are right. Just take a look inside any turret to see the effects of a big fat breach and belt feed system on ergonomics and then on the size of the platform as well.

CTA is the way to go- lets just hope they get the feed system working.

x
x
November 7, 2013 6:10 pm

Bob said CTA is the way to go- lets just hope they get the feed system working.

Now it won’t be much flipping use without it will it? Especially if OPFOR, cramped or not, in his vehicle is getting rounds down range out of a proven design that his government bought off the shelf, in greater numbers, with a greater ammunition allowance because its is cheaper and more widely available………

You can bob off now Bob……..

Bob
Bob
November 7, 2013 6:21 pm

x,

Feed system issues will be solved one way or another. Ammunition allowance? A function of how many you can fit in the vehicle, which is helped by having less gun in the turret- so another argument for the CTA.

mr.fred
mr.fred
November 7, 2013 6:44 pm

Interestingly the earlier picture shows a 45mm CTA round rather than the current 40mm (the writing on the side is a bit of a giveaway)

The Janes article, so much as I can read of it, clearly states that the issue is with the gun and the feed.
“Technical issues” with the cannon and ammunition feed have impacted on the signing of the WCSP preliminary design review

The CTA concept, as far as I can see, is inefficient. The unique nature of the gun and ammunition is a poor use of defence money and AFAICT the whole thing only exists as a sop to the French and because some cavalry officer wants to play little tanks.

Looking at published stats, the Mk44 firing Super40 has 70% the HE performance and 80-90% the AP performance of the CT40. At the same time the CT40 weighs 100% more and the CT40 ammunition takes up 100% more space. Even in the 30mm version (and the difference between the two is a barrel and a feeder mechanism.) the performance is not so much inferior with the same increased ammunition depth and massively available ammunition.

Defence Photography,
Who do you work for? MoD? BAE?

Bob
Bob
November 7, 2013 6:46 pm

TD,

Now that is a good point. Could a better feed system have been chosen? possibly. We will find out if/when this one is made to pass the required tests,

I have to concur with some of the remarks earlier though; the same people here squealing about buying something off-the-shelf would also be the same people whining in 10-15 years time that the UK had procured an antique if it had gone for a Bushmaster derivative.

x
x
November 7, 2013 7:00 pm

@ TD

The extra space saved (in a turret designed to take the gun) is for the carriage and use of a Mk1 Knocking Stick for gentle adjustments.

@ Bob

If the CTA round was as narrow as the conventional 40mm round, half its length, and half the price and was being issued by the US or simple financially strong government I would agree, but it isn’t. It is a fat round that width drives storage and mechanical handling considerations as much as length. It will be expensive in a system which is needed for weight of fire as much as accuracy. If your level of technological appreciation amounts to newer is better then really you shouldn’t bother.

Bob
Bob
November 7, 2013 7:29 pm

Fundamental lack of knowledge there x (again).

The CTA system deals with some pretty important issues regarding internal turret volume which impact the entire weight and size of the vehicle. Not to mention the simpler operation of the gun.

But hey, I know that you are very careful never to let facts get in the way of your ranting.

BV Buster
BV Buster
November 7, 2013 7:33 pm

I have to agree about the CV90 35. I worked with the Danish in afghan so managed to have a play with one, a very tight fit (considering the size of our Viking cousins) and worst of all I didn’t spot a single BV. Also, from what the crew was saying it didn’t mix well with IEDs.

I’m in two minds about the CTA, the gun itself is a clever bit of engineering and solves a lot of problems regarding turret intrusion but from what i hear the feed mech is a nightmare, every “X” amount of rounds fired/fed (X not being a particular high number) the feed mech requires stripping and servicing.

I think RARDEN is adequate for warrior/scimitar, the biggest problem is the FCS, lack of stabilization really does limit what you can do tactically.

Does anyone know what other cannons were trailed for the Scout/Warrior?, I remember seeing a list once, it would be interesting to see how high the calibers went, i’m thinking along the lines of 75mm HV etc.

Observer
Observer
November 7, 2013 7:44 pm

http://giaoduc.net.vn/Uploaded/quyhoi/2013_04_24/singapore_2.jpg

That’s the Bushmaster II’s feed mechanism. Doesn’t look that big and bulky to me.

mr.fred
mr.fred
November 7, 2013 7:50 pm

Mk44 was offered for Warrior before the MoD decided that it must be CT40. I am unaware of any other gun being considered for SV.

Rarden could be stabilised and fire controlled without too much of an issue. IMHO that would have been the cheapest and easiest solution from the current situation. Not sure that manually feeding a stabilised gun would be too healthy, but they manage it with tank guns.

The lack of stabilisation is the fault of the installation, not the gun.

as
as
November 7, 2013 8:12 pm

There are lots of factors to figure in when picking witch would be the best option.

Yes ergonomics is a good one so space and ammo capacity can be maximised.

On cost though you want a common calibre that will give you a cheap cannon and shell so you can have more of them.

Reliability really is by far the most important of all.
You can slag of RARDEN but at least it was reliable.

I just hope the CTA does not go the way off the ADEN25. Cost a fortune, fail and then disappear. it does show a lot of potential. If they can get it to work and fulfil its role. we are going to have to try and adapt it for a lot of different rolls. Try and sell a load to make them common enough to make the ammo cheap.
Export or die comes to mind. With that in mind at least it is French and they will sell to any one so export is a likely good option.

Obsvr@ there are a lot of self-styled experts on here. That is part of the fun, a lively discussion with knowledgeable people. Every one has a specialty in which they are particle well informed or they know a little about a lot of different stuff.

Chris
Chris
November 7, 2013 8:14 pm

Obs – good picture. The unit isn’t huge, but the mantlet pivot will be some 200mm in front of this mechanism, so that the feed slot (top right if I read the image correctly) stays inside the turret volume and doesn’t disappear behind the mantlet’s side guards. So from mantlet (elevation) pivot to rear of the pictured mechanism is (approx) 800mm? All that metalwork swings an arc maybe 10 degrees up (inside the turret) and 50 degrees down – add to this the flexible feed chute from ammo bin to feed slot also flexing around as the gun elevation changes. Compare now with the picture right at the top of this page; the pivot for the CTA is halfway along the equivalent of your pictured mechanism, and overhangs by something like 360mm. Less than half the length of swinging metalwork when the gun changes elevation. And the feed mechanism remains static, not adding to the lost volume in the turret. At least (if my understanding is correct) the Bushmaster kicks spent cartridges out of the turret so there isn’t a collection of smelly brassware rolling around the hull floor.

Anyway. Which one of the fellows in the photo is observer, then?

MrFred – while working at Alvis we looked at turreted low profile Stormers; at the time with in-house turrets. SIG Sauer suggested a very nice autostab electric drive system they had – I can’t recall which gun was in the turret design at that time – it might well have been the Rarden. This vehicle (after much development) became Stormer 30, fitted with one of Oto Melara’s Hitfist turrets. But hey, the company might just have worked out the autostab Rarden turret before mothballing the design.

BV Buster
BV Buster
November 7, 2013 8:20 pm

@mr.fred

I must have seen some old stuff from the FRES program then. Loading a stabilized gun isn’t a problem, if you’re struggling to throw one up the spout because the gun is going up and down too fast then you’re probably going to be bouncing around in the turret pretty badly, easily remedied by a swift jab the the back of your drivers head.

Why was Warriors 30mm not stabilized in the first place? the technology was available.

Ref the Mk44 feed mech. The pic just shows the gun body, there is a load of paraphernalia that needs to be attached to get it to work.

Red Trousers
Red Trousers
November 7, 2013 8:20 pm

There’s a bit of a massive CONOPS issue here, whatever the techno-dweebs say.

Nobody actually wants a 40mm CTA. It’s a useless piece of shit, with “useless” being defined as “nobody wants it; it has no use for them”.

Recce? No. Armoured Infantry? No. Anyone else? No.

Recce don’t want to fire guns at all, and if pressed, would want to brass off of high volumes of frightening pyrotechnic shit “in the general direction” while they make good a getaway. There are perfectly good smoke grenade dischargers for that, anything on top easily answered by a 40mm AGL with 10 rounds loaded. (I paraphrase some beautiful staff work garnered over a couple of years of FRES SV requirements generation, but I hope you’ll get the idea).

AI’s main concern is adequate depression to allow the Warrior Chain Gun and main armament to fire like belt-fed wombats into OPFOR’s trench from about 4 yards away, while the boys sneak around the side with fixed bayonets. Frankly, it doesn’t matter what the main armament is, so long as it is LOUD!

No one else gets a vote, except the slimy shit of a Royal Signals officer (a full Colonel, no less) in 2000-1 who signed off this mutual defence cooperation with the Frogs wankery despite having an argument with both DRAC and DInf in 2000 who said they didn’t want it. Frankly, as a R SIGNALS officer, he didn’t have a valid opinion. What was he going to do with CTA? Tune a fucking antenna? Retired now, and running a caravan park in Tenby.

BV Buster
BV Buster
November 7, 2013 8:39 pm

@ RT

40mm does seem to be a bit of a compromise, I am surprised we didn’t choose a larger caliber for the recce vehicle, a few well placed rounds, pop smoke and foxtrot oscar.

What does the 40mm offer over the 30mm in relation to what targets can be engaged? you still can’t engage MBTs so you are limited to BMP/BTR types which 30mm can easily manage.

Red Trousers
Red Trousers
November 7, 2013 8:48 pm

BV Buster,

nothing at all. Some techno dweeb is going to jump up and say 40mm can penetrate a quarter of an inch more RHA at some distance, but it’s all effing obllocks. For a start, it’ll be three weeks more on basic training, and a week more once a year on specialist retraining once at Regimental Duty, and for seconds it doesn’t fit with even standard CONOPS. Recce and AI don’t try to win the firefight. Recce don’t want a firefight at all, AI only want a knife-fight at extremely close range. Neither of them have the task of picking off wagons at 1200-2000 metres. You leave that to MBT or artillery.

For an “around the corner” meeting engagement, you blat off with an AGL and smoke while engaging high reverse.

as
as
November 7, 2013 9:10 pm

New kit always has a bad name at the start no mater how cool. Its just a matter of working out the kinks.
Though some will always be a lemon. you just do not now until it is in full service and even the combat is the ultimate test. Some equipment has failed that test and survived in service. You can never predict. Even among identical equipment made in the same factory on the same machine by the same guy the can be a lemon. made to the greatest accuracy. The world is a strange place. From pens to cruise missiles there will always be failures.
the best example of that are fuses in shells. 200 years of development and the still have a failure rate of something like 20%. You can only do so much with a design.

BV Buster
BV Buster
November 7, 2013 9:16 pm

@RT

What i don’t get is, we don’t have a doctrine on how to use Scout and its bleeding edge 40mil, now someone please correct me if i’m talking out my hoop but are we not supposed to come up with doctrine which needs a capability and we then buy a piece of kit to fulfill that said need? not the other way round.

as
as
November 7, 2013 9:19 pm

Red Trousers, BV Buster

So want you want is a giant auto shotgun. short range, noisy, only useful against soft targets.

and with recce in mind 60mm mortar to launch flares, illumination and smoke ect.

x
x
November 7, 2013 9:20 pm

@ BV

That was all covered on a well known British defence website the name of which escapes me. :)

mr.fred
mr.fred
November 7, 2013 9:51 pm

Chris, BV Buster,
The Mk44 handily has some data available online:
http://www.atk.com/wp-content/uploads/2012/09/AS-Mk44.pdf
It’s 655mm from the front of the feed system to the rear of the breech mechanism (It does look like those Singaporean lads have the bulk of it there, maybe half as much again to add to the bulk, but lengthwise it’s there) and the 30mm and Super40 round are about 300mm long, so it’s going to be 320-340mm from the rear of the feed slot to the breech. Now you could pivot in front of the feeder, or you could pivot around the feed slot like the AIFV does with the M242 (which is pretty much the same gun but in 25mm calibre) which would shift the pivot back at least 150mm and nearly eliminate swept volume of the feed chutes.

If it really bothered you then the RWS style might be the way to go. Put the pivot behind the gun and the feed in fresh air in front of the crew space.

So the intrusion is less than twice, tops, and potentially less than half as much again without going too radical.

Looking at the ammo in the CT40 brochure, I see ten parts for the cartridge case alone, not counting the primer. That doesn’t look simpler.

BV Buster,
Pitching in a vehicle with a stabilised gun can seem quite benign but if you’ve got a couple of hundred kilos of gun going up and down then a nibble from the turret monster is going to cost you fingers/hands.

RT,
One option with a rapid-firing auto cannon with air bursting ammunition is that the fragments can bust up optics. I think the 35mm AHEAD round (similar mass and velocity to the Super40 HE) fired at 200 rpm is equivalent to 30,000 shots a minute from a 5.56mm rifle at point blank range.

BV Buster
BV Buster
November 7, 2013 9:59 pm

@as

Why not combine the two, 76mm low pressure gun that can fire canister and smoke on a lightweight armored tracked vehicle. So it would be a Tracked Reconnaissance vehicle used for Combat, then we could give it a cool name , possibly some sort of insect, lets go for Scorpion

as
as
November 7, 2013 10:32 pm

What about going howl hog and getting a 105mm gun like the Cockerill.

The Cockerill CT-CV 105HP turret integrates the Cockerill 105mm high-pressure gun with an advanced autoloader to deliver high lethality at very light weight. Able to fire the long-range Falarick 105 Gun-Launched Anti-Tank Guided Missile (GLATGM).
http://www.cmigroupe.com/en/p/cockerill-ct-cv-105hp

This is for the new built vehicles not warrior.

Sound like the one gun to do it all. Possible a bit off an exaggeration. It would mean you would need less variants with recco, anti-tank and fire support all buy one vehicle.

Observer
Observer
November 8, 2013 12:46 am

Chris, neither. I’m not dumb enough to help the tankers clean their equipment when I have my own maintenance to do. :)

I think there is a conflict of values currently in play between the advocates and detractors of the CTA. The advocates play up the “best of the best” value of the CTA, while the detractors tend to take more of the “sufficient unto the day” stand that points out that older weapons did the job well enough with less potential problems (development risk, logistics etc).

And that unit is the whole thing save for the barrel and the feed. You replace the unit in the mounting, then lock in the barrel.

http://www.flickr.com/photos/61892799@N08/7292282432/

That is a 2 man turret, so you can see that as a whole, medium calibre weapon systems don’t take up a huge amount of space. In fact, that is actually 2 weapon systems, the small tube above the main gun is a co-ax that is sitting on top of the 30mm and shares the same aiming systems.

Chris
Chris
November 8, 2013 9:08 am

Obs – I wouldn’t dream of saying any option is right or wrong, just that there are good aspects and bad that may not be obvious. I like Rarden; I think a manual feed small calibre gun is probably undesirable these days but that’s a customer/User decision – it is reliable and compact and quite effective. Its out of production though so pointless to consider as a weapon of choice these days, whether adequate or not. So we need to look at modern options.

Much as I respect RT’s opinions of the gun, CTA40 is probably the nearest thing we have available to Rarden from a space under armour perspective. Its APFSDS performance is not spectacular, I understand, despite a heavier projectile the limited charge volume in the round means its slower than some other similar calibre rounds (if I understand the data right). But the general purpose rounds (both point detonation and airburst) are apparently very effective – the bigger volume of projectile packs more charge and makes a big bang; this at the expense of range as the round has a blunt nose to make more space within. I dare say in the future a pointy-nose round may be offered with greater range but less bang. The heavy blunt-nose round also will slow muzzle velocity for the charge available. For RT’s need of a big bang to scare off unexpected hostile visitors, I would have thought the GP rounds were just the thing, but I’m no expert here.

As I said earlier, from an installation point of view the CTA is slick. Minimal intrusion inside the turret. Not that other guns can’t be engineered to fit, just that this one is very neat. I accept that the Bushmaster feed mechanism as illustrated by your link is not that big or heavy, but installed the beast grows much bigger. Here is a US Navy illustration of the feed arrangement for a ship defence Bushmaster installation: http://www.navweaps.com/Weapons/WNUS_30mm_BushmasterII_EFV_cutaway_pic.jpg showing the bulk and complexity of the feed chute required to lift rounds to the feed slot – all that flexibility to accommodate the swing of the feed mechanism as the gun elevates. And here is a brochure from a feed chute manufacturer, Nobles, on the left of which on the front sheet there is an illustration of a turret with chute fed gun installed – a reasonable illustration of the comparative volumes of gun mechanism and the ammunition chutes: http://www.noblesworldwide.com/data/uploaded/files/Data_Sheets/Nobles_sellsheet_EWS.pdf – the eagle-eyed will notice the gun itself is invisible but its volume can still be recognized by the arrangement of the bits that are illustrated. I’m guessing from the turret size this was for a 25mm gun.

From the engineer perspective, I get more nervous of the reliability of the ammunition feed system than the gun itself. Page 6 of the presentation TD put in his post above shows on the right what was designed as a feed system for a CTA40 installation. Just how much more complicated could they have made it? Complicated means lots of bits that all need to interact for successful operation; lots of different bits that all have to work means reliability issue. Keep it simple if reliability is important. Complicated feed systems reduce the space-claim advantage of CTA over belt/chute fed Bushmasters, I agree, but there are simpler ways to do things. Page 17 of this presentation: http://www.dtic.mil/ndia/2009gunmissile/7961leslie.pdf shows three different ammunition feed options, most complicated on the left, simplest on the right. The one on the right could be re-engineered to a vertical arrangement or a shorter taller one as required (by my understanding of its internal arrangement). Interesting to note from other comments here it is the complicated sophisticated LM/Rheinmetall turret ammo feed system that is causing problems for the Warrior upgrade (as in the equivalent of the mechanism on page 6 of this presentation) and not the gun.

Anyway. I have an open mind on this; if CTA proves to be a lemon and other gun options win out, then we’ll all fit the other guns.If they are all much alike from a performance & running cost perspective then CTA has some installation advantage, which should translate into better turret ergonomics for the User.

Obsvr
Obsvr
November 8, 2013 9:24 am

My understanding of the contract is that it is the contractor’s responsibility to fit the gun into a turret of their design, their reponsibility includes tha ammo supply sub-system (being a chartered engineer (even if it is IT) I’m allowed to use technical terms like that although I know most to the army serving and retired hasdn’t got beyond the oxymoronic ‘system of systems’).

I’ve also upset senior bods in R Sigs when I wrote that Ptarmigan and Wavell (unlamented) had an incestuous relationship, they got quite upset but as usual I was right even if they weren’t quite buggering each other (the systems, I don’t know about the bods).

Pete Arundel
Pete Arundel
November 8, 2013 10:20 am

Chris, with regard to the APFSDS performance, CTA should be at least as good as 40mm Bofors L/70. According to Tony Williams article on Light AFV guns it has a muzzle energy “around 500,000j”. The Bofors is given as 468,000j.

Anyone who has ever seen the ammunition system for the Bofors in CV90 will be hard pressed to come up with an argument in favour of it over the CTA.

Except that it’s in service and works, of course . . . :-)

mr.fred
mr.fred
November 8, 2013 11:51 am

Is there something more in the full article? The bit I can read mentions issues with the cannon as well as the feed.
Looking at the feed arrangement of the Mk44 in the EFV and the CT40 arrangements, there doesn’t seem to be that much difference in space taken up, but the Mk46 system is packing 200-240 rounds while the CT40 carries a maximum of 70.

Ultimately I don’t see the advantage in the full cased telescopic round over a conventional case with a partially telescoped projectile. We can see from the make up of the round that the last fifth or more is a solid block of metal or plastic, so one could bottleneck there, have what is essentially a conventional round and get the same or better performance with less cost

Chris
Chris
November 8, 2013 12:44 pm

MrFred – others here have pointed the finger at the feed system – I assume they have knowledge beyond the public press releases. I could read “problems with the cannon and ammunition feed” as problems feeding ammunition into the gun mechanism though, and depending who it was that wrote the press release there might be a case of some corporate spin to hide some of the embarrassment. Not that modern companies would ever do such a thing, of course – that wouldn’t be ethical!

As for the advantage of the cylindrical round, it is necessary in the case of this gun because the front of the round going into the rotating breech block pushes against the nose of the spent cartridge to eject it (I’m pretty sure the breech block rotates 180 degrees each round). Assuming that’s the case, a sound bearing surface must remain after the projectile has gone or the spent case won’t clear the rotating breech completely and the gun will have the mother of all jams…

x
x
November 8, 2013 1:10 pm
mr.fred
mr.fred
November 8, 2013 2:18 pm

Chris,
Yes, the cylindrical ammunition is necessary because of the weapon mechanism. I would advocate a conventional ammunition coupled with a conventional mechanism because it is such a well developed system.

x,
Not entirely sure what you are showing there?
Is it conventional ammunition telescoped back into the case?
No point doing that with a straight-sided case and doing it with an existing case is just going to reduce your propellant volume.

Bob
Bob
November 10, 2013 1:41 pm

With all the talk of going with a 30mm design, is it really suitable long term?

Didn’t the Dutch end up going with the 35mm because they thought 30mm wouldn’t be able to penetrate BMP3 or any future developments of it?

mr.fred
mr.fred
November 10, 2013 3:19 pm

The Mk44 has an upgrade path to 40mm already, which puts it into the same class as the 35mm in terms of energy. The 35mm has a potential upgrade to 50mm though, but it’s a bigger gun.

The Germans deemed the 30mm sufficient, as do the US (armament for the GCV) and quite a few others.
The cannon in most cases isn’t going to be plinking enemy tin cans, it’s going to be acting like a big machine gun.

If you want to take out an enemy AFV you use an ATGW or a decent size cannon.

mr.fred
mr.fred
November 11, 2013 11:17 pm

The linked article seems to be defunct or otherwise removed.

Curious…