Military Review

Composite instead of aluminum. Experimental armored vehicle ACAVP

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Composite instead of aluminum. Experimental armored vehicle ACAVP
Diagram of the ACAVP prototype. Thinkdefence.co.uk graphics


An armored combat vehicle must provide the required level of protection, but at the same time be as light as possible. In the past, this problem was solved with aluminum armor, and then more daring ideas appeared. In the British pilot project ACAVP, an armored hull with a sufficient level of protection was made of a composite material based on fiberglass and epoxy resin.

Bold offer


The main advantages of aluminum armor over steel are associated with its lower density. Due to this, the aluminum part with the same mass can be thicker and provide protection at least as good as steel. In addition, the thicker aluminum part is stiffer, which simplifies the design of the armored hull. All these features of different materials have been repeatedly demonstrated in different projects.

In the early nineties, the newly created Defense Research Agency under the British Ministry of Defense, the Defense Research Agency (later renamed the Defense Evaluation and Research Agency), came up with a proposal to study the prospects for armor based on composite materials. In theory, different types of composites are lighter than aluminum, but are capable of providing the same level of ballistic protection.


Assembling the body from two parts. Photo Thinkdefence.co.uk

In 1991, DRA launched the ACAVP project (Advanced Composite Armored Vehicle Platform - "Advanced platform with composite armor"). Several scientific organizations were involved in the research, and the enterprises of GKN, Westland Aerospace, Vickers Defenses Systems and Short Brothers were to participate in the production of experimental equipment.

Subsequently, the composition of the program participants changed. So, in the mid-nineties the company "Short" left it, which did not have the necessary production capacity. Instead, Vosper Thorneycroft joined the work. In 2001, DRA / DERA was disbanded, and QinetiQ became the main participant of the program.

Armor theory


At the first stage of the project, in 1991-93, the task was to find the optimal composite that could replace aluminum armor. It was planned to study existing and promising materials and find the most technically successful - and economically advantageous. When determining the required characteristics of composite armor, they were repelled by the protection of the serial aluminum Warrior BMP.


Finished case with metal inserts. Photo Thinkdefence.co.uk

The general architecture of the new armor was determined quickly enough. It was proposed to perform it on a matrix of epoxy resin filled with sheet material. This required testing and comparing different resins and materials. At this stage, cost became an important factor. Thus, standard grades of fiberglass with limited strength characteristics cost only 3 pounds per kilogram. Stronger aramid fiber (Kevlar) cost 20 pounds per kg. A wide variety of epoxy resins were available, and the cost varied widely.

The final composition of the armor for the ACAVP prototype was determined in 1993. It was proposed to be glued from glass cloth from Hexcel Composites using Araldite LY556 resin from Ciba. They also needed molds and other tooling for production - Short Brothers were responsible for them.

The parts were to be manufactured using vacuum forming technology. Sheets of fiberglass were placed in a special heat-resistant bag, and this assembly was placed in a mold. A vacuum was created inside the bag, after which the resin was fed inside. After the sheets were impregnated with resin, the future composite part was placed in a sintering oven.


The principle of manufacturing parts. Graphics Assets.markallengroup.com

In the course of research, blocks of composite armor of different composition and differing dimensions were manufactured. The final product of this stage was the aft door for the Warrior BMP. This product was tested in 1993. Composite door with the same resistance to bullets was 25% lighter. This showed that it was possible to manufacture a whole composite body with the desired characteristics.

Prototype


In 1993, development began on the ACAVP prototype with a composite body. This project was developed by the Vickers company on the basis of the Warrior BMP. For the first time in stories of the company, the project was created entirely in digital form. During the design, ready-made components and assemblies were actively used; the power plant, chassis and some other units were borrowed with minimal changes. The design was completed only in October 1996, and after that preparations for construction began.

The composite body for the ACAVP was similar in appearance to the Warrior armor, but had simpler contours that made it easier to manufacture and remove parts from forms. The body was divided into two parts. The lower "bath" was approx. 6,5 m and weighed 3 tons. Bushings and other elements for fastening the power plant, chassis, etc. were embedded in the composite. The upper box of the hull had a mass of 5,5 tons. It received an inclined frontal part and a long roof with a turret ring and hatches. The thickness of the composite armor in the most critical areas reached 60 mm


Experienced ACAVP on the track. Photo Thinkdefence.co.uk

The level of protection of such a hull corresponded to the armor of a serial BMP. It also provided for the possibility of installing hinged booking units - steel, aluminum or composite. This made it possible to enhance protection, using the freed up carrying capacity.

In the rear of the hull, a power unit was installed from an infantry fighting vehicle based on a Perkins V-8 Condor diesel engine with a capacity of 550 hp. The composite could withstand temperatures up to 130 ° C, which made it possible not to worry about the destruction of the engine compartment. A six-roller undercarriage with a torsion bar suspension and a rear drive wheel was used.

The experienced ACAVP was equipped with a Warrior turret. The crew was reduced to two people - the driver and the commander. They were located in the hull and fighting compartment and fell into place through their own hatches. There was no troop compartment.

Depending on the equipment and other factors, the total mass of the ACAVP was in the range of 18-25 tons. The driving performance remained at the level of the existing BMP. With the same level of protection, the composite body was 25% lighter than the aluminum one, and the mass savings reached 1,5-2 tons. When using other armor components, the weight difference could be increased to 30%. However, the new case was not cheap, and the high price could offset other advantages.


Overcoming the obstacle. Photo Thinkdefence.co.uk

Composite at the landfill


Preparations for the construction of an ACAVP prototype armored vehicle began at the end of 1996. At this stage, it became clear that Short Brothers was not able to manufacture two large-sized hull elements due to the lack of furnaces of the required dimensions. The order for the production of armor was transferred to Vosper Thorneycroft.

By the end of 1997, the prototype was completed and taken out for testing. The tests confirmed the high strength and rigidity of the hull, which allows the armored vehicle to move over rough terrain without the risk of deformations, damage, etc. A full-fledged car was not tested by shelling, but individual composite panels made using the same technology passed this test.

Tests of the ACAVP prototype were completed in 2000-2001. with positive results. In practice, all the calculations of the developers were confirmed, and the designers have at their disposal a set of promising technologies suitable for use in new projects. The future of these developments depended only on the plans and wishes of the military department.


Composite armored vehicle as a museum piece. Photo Bovington Tank Museum

The army's interest in the new development was limited. The military highly appreciated the promising development and its advantages. However, they did not have a desire to launch new technologies and use them in a real project. A few years later, the development of a promising family of Ajax armored vehicles began, but in this program they again decided to use aluminum and steel armor. Whether the idea of ​​composite armor will ever return is unknown.

The fate of the prototype


After the completion of the tests, the only experienced ACAVP armored vehicle was transferred to the tank museum in Bovington. She was placed in one of the exhibition halls, along with other interesting developments of British industry. The prototype is still in good condition, and it is regularly taken to the tankport to participate in local “tank festivals ".

Since 2001, the subject of composite armor has been limitedly developed by QinetiQ. Its specialists regularly visit Bovington and inspect the ACAVP machine. Such studies provide insight into how the composite body behaves as it ages. The collected data is used in new research and can be used in promising projects. Of course, if the British army shows interest in new materials.
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  1. Aerodrome
    Aerodrome 17 December 2020 05: 44
    -2
    do it right away from the multi-layer DuPont Kevlar ... if you have enough money.
    1. RealPilot
      RealPilot 17 December 2020 23: 50
      +1
      Well, the composite can be multi-layer. And yet relatively inexpensive and lightweight. In theory, at least.

      Nobody forbids making the case aluminum or steel, but very thinner, and already on top to apply layers of fiberglass / carbon fiber / kevlar, for taste and budget - you can alternate wink
      This approach will reduce molding time and cost, but also make it difficult to "bake" the cake. Which can still be resolved (or avoided, not all composites need this).

      Plus, you can put another layer of metal on top or bottom, for example, a relatively thin sheet of armor steel or titanium. Add ceramics between the layers ... Or, as in T-72, fiberglass in the forehead of the tower between the steel sheets.

      Well, inside the armored hull, there is a classic Kevlar lining for catching fragments and reducing the impact of armor.

      Much can be done! The composite hull, for example, improves air tightness, which is good for buoyancy ...

      Nevertheless, we come to an important question.
      It is necessary to determine the desired degree of protection of the designed machine from the types and calibers of weapons, that is, the protection class.
      And, accordingly, assess the purpose of the vehicle and its place on the battlefield, tactics of use.

      Understand which projections we protect more and which less. Frontal or back, for example. There are always more problems with the onboard side, it's not for nothing that there are no tanks now that uncompromisingly keep the same battered RPG-7 in the side, without any attachments ...
      No one has yet been able to book a "round", it is either overweight, or very expensive, and sometimes all at the same time ... Well, the mobility is appropriate, the wear of the chassis components and the frantic fuel consumption

      Therefore, booking is always a compromise.
  2. Vladimir61
    Vladimir61 17 December 2020 06: 07
    +3
    What we have today is not a panacea for the near future. It all depends on the development of technologies for composite materials and their cost reduction. It is quite possible that after some time the corps of light armored vehicles will start printing on 3-D printers. 30 years ago, we still dreamed of a home computer and a plasma display, although the first developments appeared in the 60s.
  3. Graz
    Graz 17 December 2020 06: 20
    +7
    And what about maintainability in case of damage to the case, I feel it will go straight to the landfill.
    Again, what is the price, how does the case resist weather conditions during prolonged exposure to heat, cold, and in general, what is its durability? questions of course remain
    and the British are better off exposing this car in the open air, then there will be fewer questions about the environmental resistance of the body material for several years
  4. Thrifty
    Thrifty 17 December 2020 07: 15
    0
    The only negative, in my opinion, is the narrow tracks. And so, the machine is not bad for waging war in the second echelon of attacking troops, and no closer. ..
  5. The leader of the Redskins
    The leader of the Redskins 17 December 2020 07: 24
    +2
    It's funny. I have not heard of these experiments. Respect to the author.
  6. Lontus
    Lontus 17 December 2020 09: 59
    +4
    Structural armor cannot be made of light metals or composites based on combustible organic matter. ...
    They are only good for reports of parquet generals in peacetime.
    Their niche is a maximum of hinged armored modules.
    And also inner padding for catching armor fragments (for non-combustible composites).
  7. Mountain shooter
    Mountain shooter 17 December 2020 11: 17
    -1
    And what will a bottle of combustible mixture do with such a pepelat? Somehow the material is not quite "military" ...
    And the direction of work is interesting. Ceramic armor is used, right? Only she is very dear.
  8. vladcub
    vladcub 17 December 2020 12: 01
    +2
    "However, they did not have a desire to give way to new technologies." As a rule, the military are very conservative and live by the principle: "the best is the enemy of the good."
    Of course, the idea is attractive: weight reduction, less metal consumption, but there are many questions, and answers ... It was not tested for bullet resistance, it is not known how it will behave when exposed to a blast wave.
    Until the entire complex of army tests has been carried out, this is an original, but dubious toy
  9. CastroRuiz
    CastroRuiz 17 December 2020 15: 13
    +2
    Vazhno shto est opit i razrabotka, ez est zadel.
    Budet nuzhno, ne s nulia nachinat.
  10. zenion
    zenion 17 December 2020 16: 47
    +2
    Honest October! The USA decided to make a floating tank based on a magnesium alloy. The tank was made, it was light and in some places it even swam on the lake without drowning. Then they dragged him to the landfill. And we decided to check how he holds the shot. The large-caliber machine gun was prepared for testing, in it, after a certain interval, there were tracer bullets. He withstood the first few bullets, and then when a tracer hit him, the tank instantly caught fire and only the barrel, the engine and some steel products remained on the field, and gray powder remained from the tank. And they saw that it was bad. They saw that such a tank could burn up in a moment in any water.
    1. Quadro
      Quadro 19 December 2020 18: 55
      0
      Horns and legs will remain if the aluminum pelvis is set on fire, there are pictures from Iraq of how their delirium melted into a puddle after setting fire and only trash was left.
  11. av58
    av58 17 December 2020 17: 13
    0
    It is possible that "advanced" ceramic armor will suddenly become completely helpless against the most primitive ammunition, as happened with the F-117 in Yugoslavia, which met with the old Soviet air defense system.
  12. Grigory_45
    Grigory_45 17 December 2020 17: 18
    0
    The desire to reduce weight is understandable ... But the main question is: what is the maintainability of the composite body? Steel and aluminum can be welded, but what about molded fiberglass? Seal with superglue?))
    The same questions about installing additional equipment - you can't weld the bonds inside.
    Well, the question of durability. Metal is an elastic thing, and then from time to time it loses its properties, cracks and breaks. Fiberglass plastics are noticeably less fond of any bends and deformations.
  13. vitinka
    vitinka 17 December 2020 19: 06
    0
    The main advantages of aluminum armor over steel are associated with its lower density. Due to this, an aluminum part with the same mass can be thicker and provide protection at least as good as steel.

    I'm probably stupid, obesite plz, why then don't they make MBT out of aluminum? Translit.
    1. cat Rusich
      cat Rusich 17 December 2020 20: 23
      +1
      Quote: vitinka

      I'm probably stupid, obesite plz, why then don't they make MBT out of aluminum? Translit.

      Armor MBT - combined - multi-layer. There is not a lot of iron, armor steel - there are many layers of different materials (the exact composition is a military secret). When converted to "iron" - frontal armor T-90 = 800-830mm homogeneous armor (approximate data).
      Quote: vitinka
      The main advantages of aluminum armor over steel are associated with its lower density. Due to this, an aluminum part with the same mass can be thicker and provide protection at least as good as steel.
      Translit.
      Here you can take the "conditional" 800mm of homogeneous armor (steel) and convert it into "aluminum armor" (I don't know the formula ...) - for example, multiply the thickness of 800mm by 1,5 times ... = 1200mm
      Too "thick" MBT turns out ...
    2. Quadro
      Quadro 19 December 2020 18: 58
      0
      When set on fire, your aluminum mbt will simply melt like raving with m113 in Iraq
  14. Elturisto
    Elturisto 21 January 2021 16: 15
    0
    Composites are extremely susceptible to shock loads, so making an armored hull from composites will only be ...