Dezamet supports F-35 [ANALYSIS]

27 października 2017, 13:35
F-35 during firing the cannon. Photo:
USAF F-35As during an exercise in UK. Dezamet has created a fuze for F-35 25 mm gun APEX projectile. Photo: Tech. Sgt. Matthew Plew/USAF.
An Overview of 25 mm APEX projectile. Illustration: Nammo.
APEX round as it hit the target. Photo: Nammo.
APEX round as it hit the target. Photo: Nammo.
Photo: Nammo.
F-35A during an exercise in the United Kingdom. Master Sgt. Eric Burks/USAF.
A 25 mm APEX projectile. Photo: Nammo.


Lockheed Martin F-35 Lightning II is often perceived as the most advanced aircraft in the world and practical implementation of the concept of a fifth generation multirole fighter aircraft – although for many people, including experts, it is a highly controversial thesis. One of technical solutions within the scope of its armament is a work of Polish engineers from Zakłady Metalowe Dezamet SA in the Subcarpathian region.

Owing to this solution Polska Grupa Zbrojeniowa, to which ZM Dezamet belongs, may achieve a major success comprising a direct export of the Polish technical concept and a product of the Polish defence industry to one of the most technologically advanced global military concerns.

Polska Grupa Zbrojeniowa that we are part of, for the first time in the history will be a supplier of a sensitive component which decides about combat effectiveness of the most advanced military product in the world, that is F-35 aircraft of this day. It is an amazing success of Polish technical concept, because everything has been invented, designed, tested and manufactured in our factory.

Grzegorz Niedzielski, President of the Company Dezamet SA

It refers to a fuze intended for the latest generation projectile for cannon of F-35 aircraft. A Norwegian company Nammo has undertaken to develop the concept of the projectile, and in the form of R&D program ordered development of the fuze to Dezamet. ZM Dezamet SA cooperates with this company very closely also in several other fields. It is related to implementation, in the form of a three-party contract, with participation of USA and Norway, of an offset procedure connected with purchase by Poland of F-16 aircraft. In other words, Americans performed their offset obligations towards Poland through Nammo, with which they had their own settlements.

F-35 APEX działko
F-35 during firing the cannon. Photo:

The genesis of the project underpins the project assumptions of an American new generation multirole Joint Strike Fighter that is not only to ultimately replace F-16 and A-10 battle planes in the air forces, but also AV-8 powered-lift aircrafts and multirole F/A-18 in the naval aviation of both USA, as well as Great Britain. In October 2001 the LM project marked as XF-35 was announced a winner of the contest to design JSF. The design supplied to production has become a living reality in 2006 in the form of a first serial unit of F-35A – the first from three planned versions of the aircraft that was to include, depending on the variant, also such features as STOVL (short take-off vertical landing).

Based on the conceptual analyses, structural assumptions and planned use of this aircraft in combat it resulted that even 70-80 percent of its combat missions will be performed in “air to ground” operations, namely during attacks on ground targets. The limit of the structure’s weight, as well as spatial restrictions imposed by the drive system posed limitations for design engineers responsible for F-35 armament.

Hence the idea of equipping the basic version of F-35A with only one fixed cannon. It was decided to use a new cannon cal. 25 mm of the GAU-22/A Gatling system, comprising a slightly simplified, four-barrelled lighter version of a five-barrelled cannon GAU-12U with GE design, manufactured by General Dynamics Armament and Technical Products. The place and installation method limited the number of ammunition possible to be taken up to 180 pieces. B and C versions provided for a cannon carried in a special external tanks, which enabled to increase the capacity up to approx. 220 pieces.

An Overview of 25 mm APEX projectile. Illustration: Nammo.

The limit of the number of taken ammunition, in combination with high rate of fire of 3300 shoots/min., limiting the length of the firing bursts, as well as there was no possibility of bilateral supply of the cannon with various munitions, intended for combating targets of distinctly different characteristics caused that very high requirements were set for the munitions themselves. It was considered fundamentally important to be able to effectively hit both “soft” targets, such as aircrafts in direct combat in the air, as well as “hard” targets, such as armoured vehicles, technical infrastructure components, fortifications, also those covered by reinforced concrete slabs using the same type of ammunition. All this – using munitions with a projectile of a diameter of 25 mm. This meant a necessity of combining the properties of HEI class ammunition (high explosive incendiary) and API class ammunition (armour piercing incendiary) in one projectile. Until present MP/SAPHEI ammunition (multi-purpose/ semi-armour piercing high explosive incendiary) has been a substitute for combination of such two types of projectiles.

Thus the ammunition for F-35 was expected to be effective both with regards to airborne, as well as armoured targets. It was to allow for combating aircraft, helicopters and BWP class vehicles and armoured transporters using a single projectile, not to mention other typical military vehicles, self-propelled artillery, command positions, radiolocation stations etc.

From the engineering point of view the task was impossible in theory. The main problem was to achieve such ammunition characteristics, so that the same projectile in case of hitting a non-armoured target would be able to “understand” what target thickness it is piercing and depending on that it would have to initiate explosion in such a structural target segment, so as to cause the greatest damage (most of the known fuzes operate based on activated delay principle, short or long, or point detonating), and in case of hitting an armoured target, while piercing a thick armour plate, so that nothing would disrupt the operation of a penetrating core.

In case of targets such as aircrafts, helicopters or non-armoured vehicles the main goal was to achieve the effect of the so-called constant delay in fuze activation and at the same time projectile detonation, regardless of what resistance the hit obstacle causes for the projectile. That is – whether it is a “soft” duralumin aircraft skin of small thickness, or a thin steel plate of a non-armoured vehicle. It was expected for this group of targets that projectile detonation and destructive action of fragments and igniting charge would always take place at the same distance behind the pierced obstacle, optimum from the point of view of effective destruction of a target. In case of armoured targets a role in the process of destruction has already been adopted by a penetrating core. Installation of penetrating core above a fuze caused that its impact on the target was direct, undisturbed by other projectile elements, such as fuze in the structures known until present. In such a situation fuze localisation inside a projectile, between a core and the basic explosive material seemed obvious.

Apart from the tactical and technical parameters specified by the customer, it was necessary to comply with all the strict safety requirements, including inter alia the fact that a fuze should have double safety devices, no stored energy for arming and other technical properties (which could not be omitted) in accordance with the requirements of American standards MIL-STD 1316, 810 and 2105, and NATO standards AOP 21, as well as STANAG 4187.

APEX round as it hit the target. Photo: Nammo.

Nammo began case studies related to the project of such ammunition, specified as APEX (Armor Piercing with Explosive) in 2004, in order to proceed with conceptual design phase in 2006, and with the stage of first tests at the end of 2007. In this part of works the Polish company from the Subcarpathian region appeared. Within this period, as is now evaluated by its management – the company was in a very difficult situation: its present civil production did not survive the transformation period, and there were no orders for military production.

Then Nammo launched an international, open competition for development of the so-called middle fuze for new ammunition with APEX projectile. It was a first concept of this kind in the world. Until then head or bottom fuzes were constructed, installed in the front part of the projectile.

Five companies from around the world entered the competition, which could present their concepts of a fuze, unique from the point of view of requirements. Two companies moved to the second stage of competition. One of them comprised ZM Dezamet, presenting two fuze versions for evaluation. In relation to their projects Nammo imposed a condition of simplifying the design, because the level of safety devices exceeded the specified requirements and made the two concepts much too complicated.

After such settlement of the competition Nammo signed a contract for specific work with DEZAMET – for development and implementation of this fuze into production. The fact that Norwegians invested the money for financing all stages of works led to certain effects: all intellectual property rights in the solutions that should arise in the course of development and expansion of fuze design were established in favour of Nammo.

A plant being in a very difficult situation had much more to gain than to lose.

Now, it is assumed that Dezamet will deliver a significant batch of fuzes for the ammunition for F-35 fighter aircraft, which will be provided to various air forces, using the F-35. The APEX ammunition has already passed the required qualification tests in Europe as well as in the United States.

The requirements set in the competition of Nammo for a fuze for APEX were very high. Norwegians expected development of a mechanical fuze, without any electronic components (which is easy to understand if we consider the requirement of stable fuze parameters in extremely low temperatures, present in stratospheric flight ceilings of F-35).

The fuze would have to cause projectile detonation with the so-called constant delay, after hitting a non-armoured target, irrespective of the thickness of the skin that it encounters.

It had to fit in the central part of a technically sublime projectile 25 mm, between a penetrating core made of tungsten carbide and explosive. Thus, the fuze had had to be significantly miniaturised. At the same time, it had to be resistant for various stress factors that take place during the flight as well as during shooting of the Gatling system gun. The muzzle velocity of the APEX 25 x 137 mm PGU-47/U projectile, for the GAU-22/A gun is about 970 m/s

Forces with complicated and variable vectors affected various elements of the small fuze, the design of which had to be included in a 25 mm projectile body. In such conditions the fuze mechanism had not only to remain capable of initiating detonation, but earlier – release and arm the fuze.

This only partly reflects the scale of the problems to be faced by a constructor. In relation to the speed of processes connected with movement in the space, fractions of a microsecond had to be taken into consideration, during which specific sequences of mechanism’s operations had to be performed. The constructor of a fuze had to face a series of difficult tasks.

It was all related not only to the operating principle itself, but also use of sufficiently light and necessary materials, available in terms of reasonable economic common sense, guaranteeing strength in the conditions of extreme overloads, and at the same time – possible to be used in terms of technology and economy, in a mass production system, making allowance for automation of certain processes related to installation.

- Assuming that we compare the most sophisticated mechanical Swiss watch to Mercedes, then our fuze had to become Maybach. There was no other solution, but to face it – inż. Grzegorz Jączek (engineer), constructor of the fuze.

Construction works began at the beginning of 2007. The constructor adopted an assumption so as not to imitate the known solutions and not to impose someone else’s thinking and approach to the subject. The fuze was to be unique.

While discovering new design solutions of component parts of a fuze the only thing that had to be complied with was fundamentals of fuze designs and norms regarding fuzes. In the course of building a fuze construction many new special laboratory and tests stands were created, enabling to test the specific elements and solutions, as well as much special technological devices for productions of parts and components.

During the years, in the course of which basic works were commenced at ZM Dezamet, construction of an ultrafast photographic camera or a device allowing for testing part of fuze during spin motion of a fuze amounting was a major challenge that had to be dealt with despite limited funds at the disposal of the company.

For instance, a truck’s engine turbocharger was successfully used for stationary tests, from which a centrifuge for testing modules responsible for fuze release and arming was made. Explosive train of a fuze were also tested in such a manner in case of testing self-destruction function.

Another challenge was to increase the frequency of field tests performed in Norway. After each field test – regardless of its results – we had to return to Nowa Dęba, analyse the results, their reasons, draw conclusions, make changes in the design and perform new modules or components for shipment, which in practice took from 4 to 6 months. Inż. Grzegorz Jączek (engineer) together with Paweł Chlebowski, who was then responsible for contact with customer and who participated in research studies in Norway, built a team that shortly and to a large extent increased the frequency of field tests in Nammo. Theoretical analysis of the results from previous years allowed for specification potential weaknesses of the design and possible threats and problems. Production department was ordered to perform components with changes for anticipated fuze configurations, making allowance for all possible events during the consecutive tests. Fuzes prepared in such a manner were sent to Norway, after prior reservation of direction at the field for the entire week. After tests and possible failures the team from Dezamet being present in Nammo, on the same day, after analysis of results, replaced malfunctioning parts or components and on the following day it was possible to resume the tests. This system was implemented to the satisfaction of Norwegians from 2012 and the works accelerated.

In such a manner reaching 5-6 series of tests per week was possible, without the necessity of coming back to Nowa Dęba. Two years ago a group of Norway students came to Dezamet, who wrote their work on the methods of tests that Norwegians learned from their colleagues in the company from Nowa Dęba.

On its way to the destination Nammo resigned from the part of originally imposed, strict requirements if they turned out to be unreasonable (such as. e.g. the requirements of self-destruction of a projectile that missed its target). In the course of conducted research works as many as 17 design solutions of a fuze were created, before the last one turned out to be the perfect one. With evolving construction the latest versions were different from the previous ones to a lesser and lesser degree.

It was necessary to consider the relationship between production tolerances and required clearances between the cooperating parts, making allowance for e.g. thermal shrinkage of miniature elements, control of friction forces between the components etc. During works – in our own plant – thousands of small parts were manufactured with incredible precision.

ZM Dezamet, making preparations for serial production of a new fuze, has already been building a supply chain of component suppliers. It also considers factories from Germany or Switzerland, dealing with the production of precise elements.

However, it turns out that not all of the companies interested in cooperation comply with the requirements established by the Polish party. At present ZM Dezamet has an advanced machine park for production of fuzes. And the park decides about the final result.

USAF F-35As during an exercise in UK. Dezamet has created a fuze for F-35 25 mm gun APEX projectile. Photo: Tech. Sgt. Matthew Plew/USAF.

As far as Dezamet is concerned – which is not an issue for discussion – a priority in serial production projects for fuze is its reliability. Tests in Dezamet and Nammo confirmed that it achieved 100 percent for the basic modules of a fuze, composed of 56 components.

All the design solutions that are used in the fuze were developed in Dezamet, apart from a stab detonator that is generally available on the market, for which there was no point in constructing from scratch and several commercial elements such as balls or screws.

Nammo began a series of qualification tests related to ground shooting in the second half of 2013, air shooting – in 2015. The design practically has all the necessary certificates and attestations, also the American ones. A formal issue is their transfer to a form of commercial contracts related to serial production. As it was mentioned, it is planned that Dezamet will manufacture a significant number of fuzes, to be used by different F-35 users in their serial aircraft, deployed by their air forces.

It means not only secure, stable income for us, but at least several dozen places of permanent, stable and long-period work in this part of Subcarpathian region. Mainly – in the region of Nowa Dęba and Tarnobrzeg, where finding work is still a serious problem for many people

Grzegorz Niedzielski, President of the Company Dezamet SA

Nammo officially confirms that a fuze with such a design will be implemented to APEX projectile of ammunition 27 x 145 mm, hence intended inter alia for Mauser BK-27 cannon, constituting arming of Eurofighter and JAS-39 Gripen combat aircrafts. First field tests of this ammunition have already been carried out. Adaptation of the fuze to a slightly increased calibre did not cause any serious problems. Besides, we cannot rule out using this fuze technology to other ammunition types, such as 30 mm airburst for combat vehicles, or other. However, it is too early to make any concrete statements on this issue.

Serial production of F-35 accelerates, armed forces of USA themselves (three branches of military forces) would like to acquire in total over 2400 of such machines. Added to this are surely export users. Apart from USA, the group of declared purchasers and future users of F-35 already includes such countries as Great Britain, Japan, Italy, Holland, Norway, Israel, Singapore, Australia, South Korea, Canada, Turkey and Denmark.

However, if we also take into consideration already used Eurofighter aircrafts (Great Britain, Germany, Italy, Spain) and Gripen aircraft (their users, apart from Sweden already include Czech Republic, Hungary, RPA, Brazil, Thailand, acquisition in other countries has already been taking place) with a BK-27 cannon that can use APEX 27 mm ammunition, we can talk about as many as ca. 30 countries, which ammunition with a fuze manufactured by ZM Dezamet can reach.

It is assumed that armament, to which this fuze will be used, will be operated for 30-40 years, which specifies the scale of demand for ammunition, thus fuzes as well.
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