Whatever Happened to the Plastic Tank?


The Advanced Composite Armoured Vehicle Platform (ACAVP) was often called the ‘plastic tank’ although it was neither. The aim was demonstrate how an advanced plastic/glass fibre composite called E-Glass could provide comparable protection with steel and aluminium with a reduced infra red and acoustic signature and significantly improved corrosion resistance, especially against salt water. A separate spall liner, common on steel and aluminium vehicles, could also be eliminated

Development started in 1993 after a 2 year feasibility study and progressed through a number of stages until mobility, safety and survivability tests concluded. Only the hull was composite, all the other components were straight out of the existing vehicle parts bin, running gear, engine and transmission from an Alvis Warrior and turret from a Fox for example.

The trials did reveal a few failures in some of the automotive components but reportedly, the hull exceeded all expectations.

Weighing in at 24 tonnes the monocoque hulled demonstrator was configured for the recce role with a 2 man crew pod at the front, mission module in the middle with turret and powerpack at the rear. It had frontal protection against 30mm AP and 14.5mm elsewhere.

GKN, Westland Aerospace DRA (DERA), Army Base Repair Organisation (ABRO), the University of Plymouth, Shorts Brothers, Vickers, Alvis, Hexcel Composites, Ciba, Kidde-Graviner, Perkin and Vosper Thorneycroft were all involved at some stage.

Whilst it should be remembered that Russia trialed a fibre glass PT76 and the USA the Advanced Technology Demonstrator (ATD) – Composite Armored Vehicle (CAV) the Advanced Composite Armoured Vehicle Platform (ACAVP) was more ambitious in its use of a composite materials for the monocoque hull.

Composite Armoured Vehicle (CAV)
Composite Armoured Vehicle (CAV)

A 2000 Parliamentary Question provided information on the cost

HC Deb 06 June 2000 vol 351 cc172-3W 172W

Mr. Hancock: To ask the Secretary of State for Defence what is the cost to date of the work carried out to develop the Advanced Composite Armoured Vehicle Platform; what was the total budget provision and completion date for development and trials; and if he will make a statement. [124540]

Dr. Moonie: The total cost to the MOD of the Advanced Composite Armoured Vehicle Platform is expected to be £6 million, which is within the total budget provision when the programme started in 1993. The 173W initial automotive trials have been successful and the development and trials process is expected to be complete in October 2000.

The material chosen was one of the cheapest available, at £3 per Kg, E-Glass was considerably cheaper than S2 Glass at £11 per kg or Kevlar aramid fibre at £20 per kg and one of the design innovations was the stud mounted armour panels that would allow sections to be removed for carriage in a c130. The hull alone was 60mm thick and weighed about 6 tonnes with the automotive, mission equipment and appliqué armour panels making up the balance

Composite Armoured Vehicle Platform (ACAVP) 05

Composite Armoured Vehicle Platform (ACAVP) 07

Composite Armoured Vehicle Platform (ACAVP) 06

Composite Armoured Vehicle Platform (ACAVP) 08

QinietiQ Plastic Tank and inflatable fascine
QinetiQ Plastic Tank and inflatable fascine

Composite Armoured Vehicle Platform (ACAVP) 01

It was only a technology demonstration programme that concluded in 2001 but it was definitely at the cutting edge of material and fabrication science and proved that a 20-30% weight reduction was possible. The general conclusion from ACAVP was that although valuable weight savings were possible carbon fibre composites would provide greater potential due to it being much stiffer, thus reducing the need for additional material density

Pull through to the TRACER programme was planned but as we all know, FRES killed TRACER and the rest is history.

It is interesting that since, the use of composites has been limited to add ons are panels in protected vehicles like the Snatch and Foxhound rather than what we might consider ‘fighting vehicles’ where steel and aluminium hulls still reign supreme.

The vehicle is currently at the Tank Museum and regularly gets an outing at shows

It is even in the Guinness Book of World Records



  1. Chris says

    The concept is good; its time will come. It had always struck me that this particular vehicle was large for its role & fit – Warrior sized but no dismount space – but it was a technology demonstrator not a prototype fighting vehicle so not a real problem. I would guess the original plan was to top the thing with a Warrior turret, which would have looked a bit more balanced (and to the casual observer made the vehicle look like a Warrior of no particular interest) – maybe Vickers only offered Fox turret. I certainly saw it with DERA painted on its nose, I might have spotted it at Chertsey marked as DRA but if so that was a fleeting glimpse; how strange that it should have been gifted to QinetiQ rather than remaining in DSTL.

    Point of interest, in the photo labelled Build 2, on the lower sideplate by the second and the fourth suspension mounts it looks like someone sprayed a few bullets at the composite to see how tough it was. As this was soft E-glass not tough S-glass that probably wasn’t how the marks got there, but they don’t appear to have anything to do with vehicle design (too irregular to be damper mounts for example).

  2. Peter Elliott says

    What happened is we basically stopped being interested in the next generation of tracked Fighting Vehicles.

    The sandpit wars revived interest in Protected Vehicles but there seems to be no interest at the moment in Fighting Vehicles. Given how few we now think we need and the ability we have to keep upgrading Warrior and Challenger 2 this is not altogether surprising. We will also have Scout which will end up getting adapted to cover tasks it wasn’t really designed for as Warrrior and Challneger continue to age.

    Scout is supposed to be low risk and off the shelf and is still costing a fortune without making use of either hull composites or diesel electric drive. A bit like Type 45 however this is a product of a disatrously chaotic procurment rather than of considered design choices. In the next programme a concious effort will be made to avoid those mistakes.

    What we will find some time in the mid to late 2020s when we sit down to decide that will replace our remaining tracked Fighting Vehicles is that (a) the skills and the industry from the UK will have gone and (b) simply through passage of time what comes next will look different from what went before. For me the big driver of that change is likely to be logistics rather than fighting capability. Driving down vehicle weight and in-theatre fuel costs will be a big priority, as will logistic commonality with NATO allies.

    Gazing the crystal ball today I would foresee a Spanish built composite hull, with a forward mounted BAe diesel-electric powerpack, offered with a selection of MOTS turrets from Rheinmetall to give the British Army a common tracked hull using standard NATO ammunition. But 10 years is a long time. Things might be very different by the time we actually go shopping for tracks again.

  3. ArmChairCivvy says

    Related to Chris’s comment above, about the size, would the material work for anything else than a boxy shape, with straight lines?

    This is what armada.ch wrote about Panhard Crab, so redoing it with non-reflecting, 20-30% lighger ore might give us a silent,& stealthy, xtra-mobile recce platform, able to do also ounter recce with some having the 25mm autocannon, some with ATGMs and accompanied with Fennek style mobile sensor posts taht only have a .50 cal for self-defense. The dimensiins will make 3 of them cir onto a A400:

    “One of the key elements of mobility is power-to-weight ratio. Currently Panhard is considering two different engines for its Crab, both ensuring a minimum of 35 hp/t for an 8.5 tonne combat weight, which means an output of about 300 hp. Horses can be increased when needed thanks to a 400-Amp starter-alternator that can not only provide an additional shove when needed, but also enable the Crab to silently creep over short distances using the electric energy stored in its batteries (two solar cell panels are installed on the two sides on the rear of the vehicle to assist recharging the batteries in daylight). The Crab’s stealthiness is further increased by the reduced shape of the vehicle, its height being a mere 1.8 metres over the roof. The cabin shape has also been engineered to minimise radar reflection, with angled surfaces contributing to both a lower RCS and a higher protection against ballistic threat.
    Turning back to mobility, the Crab has a permanent 4×4 drive, but while both its axles steer they can do so either in opposition to generate a turning circle of less than 10 metres, or in unison, hence heading in the lateral same direction (albeit at a limited angle), to enable the vehicle to “drift” sideways like a crab! Moreover a rear-looking camera and a two-ratio reverse gearbox enable the Panhard vehicle to quickly back away in yet another configuration where only the rear wheels are allowed to steer”

  4. Chris says

    Peter E – I suspect all interest in advancing UK armour technology stopped in 2004 when BAE took over the entire UK AFV industry in one gulp. Until then there was the non-BAE Alvis-Vickers and the BAE owned VSEL/Royal Ordnance companies, all British and capable of a bit of competition. (Competition in the UK industry had been a bit academic as each organisation concentrated on their own niche in the market – Vickers did MBT, GKN did medium weight AFV/IFV, Alvis did small armour etc.) Once the UK’s only military aircraft builder and military shipbuilder also became the nation’s only AFV builder the monopoly bell must have been clanging frantically in Whitehall. Had BAE retained the hungry small-business attitude to its customer that some of its ancestor companies had, where MOD might have felt well served with good value product, then perhaps there might have been a different MOD reaction to the takeover. But there’s a clear feeling that Main Building’s groupthink on the matter was “Oh no – not the AFV industry too…”

    As for the future, all is not quite lost yet here in the UK. We still have expert manufacturers at component and subsystem level, although they must be struggling a bit, and we still have world-renowned specialist vehicle manufacturers albeit not necessarily in the military domain (see http://www.thinkdefence.co.uk/2015/01/jcb-parade/). There is still expertise on hand. And I remain hopeful that the remnants of Alvis-Vickers might be allowed to buy themselves out of BAE at some point – you never know. Manufacture might not be the issue. R&D into new technology might be a problem though; traditionally performed by Gov’t Scientists and provided to developers under strict controls. Again there are still DSTL scientists so the domain knowledge may have been retained, but there seems little will to make use of it. Hopefully its all still going on behind closed doors.

  5. Martin says

    @ Chris – it’s not just BAE in the UK, Same thing has happened in the US when aerospace companies take over costs seem to get out of hand and the are only prepared to innovate when Government is picking up the tab.

    One would have thought a plastic tank would be the only way acceptable within the rules of physics to meet the MOD’s requirement for FRES.

    It hardly seems like advanced technology either.

  6. wf says

    Cristina apparently not a big fan of whistleblowers…


  7. Chris says

    My understanding of the material is that plastic (fibre-resin composite and/or high density polymers) are good armour in some respects but not good in isolation for all threats. So I would expect plastics to be used with other high technology materials and with simple old fashioned metals in compositions that create the lightest and/or most robust protection for the given situation.

  8. The Other Chris says

    “…only prepared to innovate when Government is picking up the tab.”

    I think Sikhorsky is bucking that trend. They’re pretty much self-funding coaxial compound technology (consider development of S-97 with no AAS funding) with the intention to base all of their future designs on the technology.

  9. […] Thinkdefence.co.uk. The Advanced Composite Armoured Vehicle Platform (ACAVP) was often called the ‘plastic tank’ although it was neither. The aim was demonstrate how an advanced plastic/glass fibre composite called E-Glass could provide comparable protection with steel and aluminium with a reduced infra red and acoustic signature and significantly improved corrosion resistance, especially against salt water. A separate spall liner, common on steel and aluminium vehicles, could also be eliminated […]

  10. ArmChairCivvy says

    Chris, about your latest:

    Would thatbe the big secret about the Scout’s frontal armour-on par with MBTs?

  11. Hohum says

    This blog consistently struggles with the notion of technology readiness levels- just because something has been experimented with it does not mean it is remotely ready for production, or for that matter that some major problem with it has not been found. Also consider that just because the entire concept has not been adopted lessons have not been learned from the project and incorporated into other programmes.

  12. Think Defence says

    Hohum, struggling to see where anyone here was saying it is ready for the big time. Would have thought it pretty obvious from the comments and main body that all composite hulls are not ready for the big time yet but likely will do so in the future.

    The trials proved the science, fabrication and basic performance of using composites in hull construction to reduce weight by negating the need for spall liners etc but as we know with others, composites have issues with cost, being able to spot damage and repairs for example.

  13. Chris says

    ACC – I have no idea. I would expect the vehicle to carry a high-hardness disruptor plate on its nose, but whether there’s composite or metal behind that I don’t know. Courtesy of HMG’s generosity in the 60s & 70s I understand GD has full details of Chobham (AKA Dorchester) as well as the related US Burlington armour so there might be some fancy construction employed.

  14. DavidNiven says

    ‘This blog consistently struggles with the notion of technology readiness levels- just because something has been experimented with it does not mean it is remotely ready for production’

    I was under the understanding that the South Korean AIFV used some sort of glass fibre reinforced composite armour.

  15. Think Defence says

    DN, Foxhound and Snatch use composites but I think this was different because it used them for the hull, not pods or panels or add ons.

    The hull was cast in two parts and joined using stainless steel pins I read, the idea being you could split them for air transport (bonkers I know!)

  16. wf says

    @DavidNiven: good point, I had forgotten. I suppose the key point about this demonstrator is the distinct lack of holes to show that they had progressed to live fire testing. Like ceramics, I suspect the acceptance of composite hulls is directly tied to the users happiness at replacing armour panels or indeed the entire hull in case of damage, in a way they would not be used to with a steel hull :-)

  17. DavidNiven says

    TD, the manufacturers are neither confirming or denying the fact openly but a lot of sources seem to claim it is.

    ‘The K21 leans toward the light end of the IFV spectrum, at 26 tonnes (about 28.67 tons), thanks in part to a chassis that will reportedly be built out of fiberglass. In addition to weight savings, this may avoid some of the mine lethality problems experienced by vehicles that use aluminum’


    We have always loved airportability :-) I wonder if it is down to the number of senior officers who are paras that we always want airportability regardless of the role or size of the vehicle.

  18. Think Defence says

    DN, oh, interesting, thanks for that!

  19. Hohum says

    Don’t get carried away with the K21, the Koreans have been pushing it to multiple potential customers and the consistent theme has been that its short on protection.

  20. DavidNiven says

    I’m not getting carried away with the K21, I was pointing out that the technology must be at production level if a nation is using it to produce a large number of vehicles.

  21. Hohum says

    Hardly, you don’t actually know what they have done or if it is the same technology.

  22. DavidNiven says

    Well they have reportedly reduced the weight of their vehicle by using a composite for the hull, was that not our reasoning for investigating the technology? It does not matter whether it is the same mix of materials or processes to produce the composite, the reported fact remains that they are using a hull made from composite in a mass produced vehicle.

  23. Observer says

    “Composite” is a pretty nebulous term, it just means “a mix of materials”, in this case probably a mix of plastics and ceramics, so calling it “composite” armour is rather open ended. Chobham itself is a “composite” of metals, ceramics and plastics too.

  24. Hohum says

    Observer neat me to it; composite is a very broad term- it is far from clear exactly what it includes but it seems that the K21 is not like the “plastic tank” where the entire hull was made from plastic.

  25. mr.fred says

    True enough, but in common usage the term “composite” usually refers to fibre reinforced plastics.

    The CAV100 (commonly called the Snatch Land Rover) is the only composite AFV deployed by the British Army.

  26. Chris says

    Obs, Hohum – as I noted upthread at 12:03, as far as I understand in the AFV business ‘composite’ is shorthand for fibre & resin materials, as in the finished material (as in flat sheet or the like) is made of two very dissimilar materials intimately bonded and intermixed. True in dictionary terms a steel/aluminium/ceramic layercake could be described as composite – literally ‘put together’ – but it is not a material but a set of materials in separable layers.

    As for the ability to make resin/fibre material hulls without metal armatures within, I believe that’s been possible for some 50 years or more. The materials have increased in ballistic strength, and the processes for manufacture and curing may make a stronger material but also may make complex large 3D shapes difficult to construct, but conceptually there really is no reason why its not done. Indeed there are advantages, particularly on structure edges and corners, in laying up such a composite structure compared to joining sheet metal structures.

    The probable issues are that its really difficult to be sure the resin/fibre structure is fault-free as each is a one-off (what effect a blob of grease dropped unnoticed and buried deep in the structure?), it is a manual process reliant on moulds to get the final shape (no machine cut parts to jig-weld here), it probably takes a good while longer to produce each hull, presumably metal mounting plates would be necessarily bonded in – accurately – where higher strength than the composite can provide is required, and as a hull conventional wisdom says its much more expensive than an equivalent welded metal box.

    In the 1950s and early 60s many lorry cabs were moulded GRP items, allowing much more complex shapes than the earlier fabricated frame & tinplate versions. But pressed steel turned out to be faster to make, quicker to build, easier to modify and (for the user) quicker to repair, and I guess the pressed & welded cab structure was a cheaper component to produce. As a result GRP cabs ceased to be mainstream. Just because something is possible does not necessarily mean it will be done; there are many factors to take into account.

  27. Hohum says

    Nope, composite is used to describe multiple armour types including Chobham. I dont doubt that the Koreans have included a lot of fibreglass but based on what I have seen of the vehicle it is not being used in the same way as the above discussed demonstrator.

  28. monkey says

    They developed the technology to maturity on the FSC family, the USMC EFV and many others on so called ‘light’ wheeled vehicles weighing around 8t+ like the ULCV . All have failed to make production so far but aspects of the armour systems are extensively used where weight is critical, on aircraft , applique on light wheeled vehicles like the humvee or on ships . As for Heavy tracked / wheeled armor of the 20t+ range and up its a no show . To commit to a buy of 1000+ heavy armored vehicles at several million each is more than the military have the balls to place an order for something that should last decades in peacetime activity and at least a year in heavy combat.

  29. as says

    I thought the plastic tank became the SEP/Alligator modular armoured vehicle family that the Swedish were working on. That went from being tracked to being 6×6 or 8×8 and went from having a hybrid drive and transmission to a conventional drive system. So as the Alligator was entered in to the Canadian Armies Tactical Armoured Patrol Vehicle (TAPV) project and the British FRES program. but then everything went silent and I have not heard anything since.

  30. mr.fred says

    In a more technical sense, composite is the correct term for most advanced armours.
    Given the descriptions of the K21 (that aren’t Wikipedia) I would guess that it is a fairly thin aluminium monocoque with structural glass fibre close bonded to the inside and ceramics bonded to the outside. Using the glass fibre spall liner as an integral part of the armour would boost the protection level and if you could make it structural then that would allow you to have thinner metallic sections over much of the vehicle while locally reinforcing where needed.
    The ceramic outer layer will break up most hard AP rounds. Once.

  31. Hohum says


    SEP/Alligator/Thor are dead and have been since the Swedes selected the AMV. There was some suggestion that it would be offered for TAPV but in the end the BAE offer was an RG-35 derivative, it also lost and has now been sold (along with the rest of the BAE South African business) to Denel for peanuts. BAE has also shut down the wheeled vehicle business in Sweden and they are instead offering the AMV in partnership with Patria for Land 400 and the Super AV with IVECO for whatever MPC now is in the US.

  32. mr.fred says

    Just looking at the videos in the article – ACAVP’s ever so light on the front, isn’t it?

    On the subject of armoured vehicle structural technology:

    Put some FRP inside that and you’d have a very solid structure with excellent all-round coverage and no joints to exploit.

  33. S O says

    “K21 is not like the “plastic tank” where the entire hull was made from plastic.”

    Except it wasn’t. Such AFVs don’t have a plastic hull, they have a hull of fiberglass with very little thermoset resin. The higher the glass content, the better the protection. You need enough resin to hold everything together, though.
    IIRC the fiberglass content was (mass share) 80-90% in such experiments.
    Ordinary fiberglass as used in cars usually has only 15-45% glass share and a thermoplastic matrix with low heat tolerance.

  34. PhilEeeeeee says

    Are there outstanding question marks on the environmental survivability?

    UV, thermal, chemical, all big questions on plastic composites.

  35. mr.fred says

    Some questions on environmental stability of FRP remain, but with extensive use in aircraft, automobiles and construction those questions are being answered. As noted, the British army has had a FRP armoured vehicle in service for over two decades which may give some pointers

  36. S O says


    60 mm thick E-glass or S-glass with thermoset (duroplastic) resin can be trusted to withstand UV, thermal and corrosion issues faced by an AFV at least as well as aluminium alloys.
    Cheaper thermoplastic compounds are a different topic.

  37. John Hartley says

    I have vague memories of one of the later Tomorrows World progs, where they featured a plastic safe. Some advanced plastic with little stones in it, that buggered up anyone trying to drill through it. They put the directors passports in it then stuck it on a bonfire. Contents were not harmed. Would something like that be suitable for an armoured vehicle?

  38. Chris says

    JH – I would be surprised if new materials/combinations of materials for armour didn’t pop up over the coming years. There are many interesting materials and structures not yet tried as armour but which ought to be quite useful – see TD’s post on ceramic beads for an example of a new structure for armour.

  39. Secundius says

    Last I heard it got Cancelled for being too Heavy. At 48,000-pounds, NO Western Helicopter could lift-it…

  40. Ksk says

    So, as far as i understand, this is the same knowledge as one of those FRP boats that are being used nowaday?

Comments are closed.