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István KUN SZABÓ, brigadier general1
Further development of unguided rockets as reflected in helicopter procurement project
of the Hungarian Defence Forces
Introduction
One of the most important tasks of the combat helicopters is to provide fire support of
the combat of the field troops. This is accomplished by means of machine guns and cannons
of different calibers, guided missiles and unguided rockets or, eventually, bombs. The
different versions of unguided rockets (hereinafter: UGRs) can be practically the weapons for
any type of helicopters as they do not require a precision sight or launching system, they are
simple to use and of low cost. As drawback one could mention the low level of precision of
hits, therefore, there is a high risk of collateral damage in an urban setting. Therefore, this
kind of weapon cannot be used for a precision strike. The advantage of low cost is lost, as a
minimum of 6 to 8 rockets are needed for destroying a target. UGRs are primarily suitable
for suppressing an area, with a low level of armor protection of the troops and hostile
equipment.
Demands defined in the Hungarian Defence Forces
The different versions of the combat helicopter Mi-24 used by the Hungarian Defence
forces carry to air-to-ground unguided rockets S-5 and S-8 fitted with different warhead
types. The rockets S-5 are carried in 4 launcher pods type UB–32A, holding 32 rockets, while
the S-8 rockets are held in two B8V20 pods, each of them with 20 rockets. This means that
one combat helicopter can carry at any time either a total of 128 S-5 rockets or 40 units of S8. The transport helicopter Mi-17 can carry 6 launcher pods type UB-32A suspended on hard
points to allow the launching of 192 rockets in total.
As Hungary's fleet of military helicopters will substantially come close to the end of
its service life expectancy, and the limited budgetary funding at this point prohibit the
procurement also of specific combat helicopters, when procuring new helicopters, preferably
multi-task versions should be selected. Such a compromise, naturally, does not mean that
there is no need to keep in service helicopters designed and built to be combat helicopters,
however, this is to be achieved with the minimum possible reduction of the capabilities until
the new models enter into service. Of course, when making a decision of such a great
importance, not only professional arguments are to be considered, but also the security policy
conditions of the region concerned – Hungary, in this given case -, the expected fields of use,
moreover, the financial, political and economic possibilities. In addition to the multi-use
capabilities it is also warranted to assess the optimum use and development trends of the
weapon systems, more specifically the advancement of unguided rockets and their
possibilities.
Hungary's NATO membership is based upon the collective defence obligations and
cooperation. In the procurement and commissioning into service of any and all defence
equipment a key consideration should be the feasibility of cooperation with partner countries.
In addition to communication and navigation, the unified logistics network and quality
assurance systems, the armament systems shall also allow the multinational joint operations.
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Commander of MH Vitéz Szurmay Sándor Budapest Garrison Brigade, doctoral student of NKE (National
University of Public Service), Grade 3
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The weapon systems operating with laser target designation and capable of strikes with
surgical precision superbly satisfy the requirements of this system of conditions.
Historical overview
The development of the air to surface UGR S–5 started in the early 1950's. Originally
it was intended to be a directly sighted air to air rocket for the MiG–19 fighter, however, it
was not efficient against air targets. S-8 is its "bigger brother”, basically the same as type S-5,
again a weapon of very simple design. The rocket body of S-5 is of dia. 57 mm, while that of
S-8 is made of steel pipe of 80 mm in diameter. It features a warhead in the front with high
explosive charge and the impact fuze. The rear segment includes the blowpipe with the
stabilizer fins around. The rocket also has a self-destruct timer, so the parts missing the target
or not exploding for any other reason, shall be destroyed automatically after a preset time.
Warheads may have various functions. Typically fragmentation-destruction and cumulative
(shaped) charges were used, however, lighting versions were also produced.2
Fig. 1: Weapon systems of combat helicopter Mi-24 P and the rocket type S-8
(Source: László Hajdú)
Unguided rockets are launched by means of the sight system. Whatever is the level of
advancement of the system, after launching the rockets the flight crew has not power to
modify the rocket's trajectory in view of the target position and the movement of the rocket.
In the beginning the collimating sight type PKV was used for the UGR system, by means of
which the hair-cross of the sight could be set approximately, by taking into account only the
estimated range of the target (the projected launching distance) and the speed of flight.
Before firing the rocket, the crew could also consider the estimated direction and strength of
the wind, so they could also aim with an aim-off distance. In fact, the hitting accuracy was
equivalent to that of a simple on-board barrel type weapon mounted rigidly (machine gun,
cannon), as aiming also followed basically the identical principles. In the versions V and P of
Mi-24 the sighting system ASP-17V was a major improvement over its predecessor. In
automatic mode the system vectored in the signals transmitted by the different sensors of the
helicopter, and projected on the sighting device the hair-cross and the expected place of
impact of the UGR. This could lead to a relatively high precision of hit, even if the trajectory
could not be corrected after launching. It is important to stress that the rocket body remained
unchanged, i.e. no improvement was made in that regard.
Of course, the "eastern" system had its "western" counterpart, and they were
equivalent as far as the basic principles were concerned. They differed in gauge and the
2
Bali Tamás alezredes: A Légierő helye és szerepe a tűztámogatási feladatokban – Repüléstudomány
Közlemények, XXIV. évfolyam, 2012. 1. szám.
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warhead applied. The best known and perhaps most widely applied rocket carried by
helicopters is the 70 mm (2.75 inch) Hydra produced by General Dynamics, further improved
based upon the Mk4/Mk40 rockets developed by the US Navy in the 1940's. The rocket
motor type Mk66 is the basis, which carried more than 10 different warheads from the blastfragmentation type to the smoke generating dummy version.
The 68 mm SNEB rocket - also available in 37 and 100 mm versions - produced by TDA
Armements of France should be highlighted by all means. SNEB was engineered as early as
in World War 2, and with respect to its principles it is identical with the types described
earlier. It was commissioned into service in the states of the French sphere of interest. Of
course, similarly to the Russian system, these UGR's have only a limited accuracy of hit.
Fig. 2.: Versions of the Hydra rocket and the SNEB rocket
(Source: http://en.wikipedia.org/wiki/SNEB downloaded: May 10, 2013)
The development of helicopters and their related target reconnaissance and spotting
systems was not followed by the modernization of the UGR systems quite up to the early
2000's. While the aim was to achieve an as accurate hit as possible for the mitigation of
collateral losses, the guided missile systems were undergoing a continuous development, the
related costs drastically kept on rising.
Clearly, lower cost options had to be identified, also confirmed by the asymmetrical
warfare typical of the past period drove the technically advanced parties to employing
weapon systems with lower cost requirements, while still achieving the objectives desired,
instead of relying upon expensive assets. A further argument in this regards is that conflicts
today are typically not clashes between large troops (divisions, corps). Using an area
suppression weapon, particularly in a built-in urban environment may involve excessive
collateral losses, which could put the user of such weapons in a politically sensitive situation,
as the permanent presence of the media is to be reckoned with in the course of armed
conflicts.
APKWS program of the USA
Pentagon invited proposals in a tender for the APKWS (Advanced Precision-Kill
Weapon System) in 1996. The program was aiming at the development of a low-cost, guided
weapon system of high accuracy capable of destroying soft or unarmored targets, using as
many components of the existing 70 mm Hydra rocket system. The tender was cancelled in
April, 2005, due to the repeatedly poor test results. However, due to the continuing demands
the program was relaunched six months later, in October, 2005, renamed as APKWS II.
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There were three bidders submitting proposals for the modified criteria: Lockheed Martin,
Raytheon and the BAE Systems, and the latter, as a general contractor won the tender.
After announcing the winner, BAE Systems continued the development program of
APKWS II. already together with the original producer of the Hydra rocket, i.e. General
Dynamics and Northrop Grumman. The contract signed in November, 2008. In the course the
tests, after engineering was completed, the rocket was exposed to all effects, which may
occur in battlefields (dust, sand, ice, vibration and drop safety tests). The test results were
disclosed in January, 2010 and the development team already received the first purchase
order for the rockets in July, 2010. 3
Recognizing the application possibilities of the weapon system, the Pentagon
extended the original contract with the capability of use on fixed wing aircraft, in February,
2011. The rocket was tested on board of AV-8B Harrier and A-10 Thunderbolt as well as the
AT-6C light turbo-prop aircraft participating in CAS (Close Air Support) operations. The
testing of the APKWS II system was fully successful, it demonstrated cost-efficient, broadbased application possibilities, also acceptable politically. The next step was the testing of
UAVs, opening up further opportunities.
The battlefield use of the new laser-guided Hydra rockets was started as of March,
2012 by the US Marine Corps (USMC) on board of its UH-1Y Venom and AH-1Z Viper
helicopters. The first sizeable purchase order was received by the manufacturer BAE Systems
at the end of July, 2012. In accordance with the data of January, 2013 not a single case of
faulty launching had been recorded from among the 100 launches with the new rocket system
in the Afghanistan theater.
Application possibilities of the APKWS II system
The warhead of the 70 mm guided, precision kill rocket has an adequate blast capacity
against most military targets, while the unintended collateral damage can be substantially
mitigated. The diverse warheads enable their use against live force (blast-fragmentation),
moreover, light armored vehicles (e.g.: BTR, BMP) as well as buildings. All this is combined
with a relatively low cost when contrasted with other guided missiles (Hellfire, TOW, Spike).
The maximum range of the rocket is 5000 m, again being a match for its bigger brothers. As
far as the accuracy of hit is concerned, it is less than 1 m.
Of course, its destruction power remains short of the capabilities of heavy duty, multistage missiles specifically designed to destroy hardened targets and shelters. Even so, it can
damage a heavy tank to the extent preventing its continuing use in combat operations
(external sensors, reactive armor, active protection system etc.).
The airborne platform can carry more of these rockets, owing to their lower mass and
smaller size, while improving the aircraft's maneuverability, top speed and fuel consumption
features. Having bigger fuel reserves on-board, it can have a greater range of operation.
Owing to the smaller mass the UAV's have also become potential platforms for these rockets.
As the system is semi-active, laser designation must be provided with some external
source, and the sensors of the rocket will track the reflected laser beam all the way into the
target. The laser target designator illuminating the target can be mounted on the helicopter or
any other aircraft, but it could also be a target designator unit used by the ground based Joint
Terminal Attack Controllers (JTAC), therefore, a greater accuracy can be achieved in the
cooperation.
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Defense Industry Daily: APKWS II: Laser-Guided Hydra Rockets in Production At Last
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The weapon system requires not more preparation on the aircraft than the underlying
unguided 70 mm Hydra rocket, and the existing hardpoints can be used for the launching
tubes of similar design, even though these are somewhat longer than the original ones.
As a limit to usability the lock-on before launch feature could be mentioned, i.e. the
sensors of the rocket must capture the laser beam reflected from the target before launch.
Rockets with more powerful features can also lock-on after launch, so the Hydra is less
capable in this regard. A word for its defense, the range of 5 km can also be the limit of visual
identification, therefore, this missing capability is not a major shortcoming.
The APKWS II system of the BAE Systems
BAE Systems, in fact, has engineered only the sensor and control units, as everything
else has been derived from the legacy Hydra rocket. In accordance with the concept of the
winning BAE Systems, the vulnerable control part is mounted between the warhead and the
rocket motor by means of an adapter, instead of on the front of the rocket. Having installed
this unit in the middle, the development engineers tried to protect the delicate sensors and the
control unit from mechanical impacts, heat and flame, corrosion or damage caused by
eventual pressure changes. As a further measure for the protection of the delicate sensor and
control units from transport-caused injuries, they are transported separately from the other
parts of the rocket and final assembly with the other elements of the rocket is performed only
before loading.
The essence of Distributed Aperture Semi-Active Laser Seeker (DASALS)
engineered by BAE Systems is that the optical sensors mounted on the entry edges of the
canard foreplanes of the control unit in the mid-section of the rocket transmit the signals
through optical fibers to the signal processing and control units, which deflect the fins in
proportion to the control signal produced, to keep the rocket inside the laser beam, i.e.
heading towards the target. The angle of vision of the sensors is 40°, which ensures that the
sensor considers only the laser beam reflected from the target. The system is semi-active,
which means that the target is illuminated by laser with some external laser designating
source and the sensors of the rocket detect the beam reflected from the target.
Fig. 3: Configuration of APKWS II, its sensor and control unit
(Forrás: http://www.defensemedianetwork.com Downloaded on: April 04, 2013)
Another problem was also identified in the course of development, which had a major
impact on the accuracy of the hit by the rocket. Due to the vortices produced by the fold-out
fins deployed after launching, the rocket drifted, "rolled", laterally along its trajectory. In
order to achieve the required accuracy of hit, the control unit had to be so designed that this
drift would also be compensated for, however, to a certain extent only. It may happen in
certain cases that the rocket "breaks out of the laser beam", as the vortices induced by the tail
fins are so strong, that they can no longer be compensated by the canard foreplanes.
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Although BAE Systems were named as winner in April, 2006, the other two manufacturers
participating in the tender also continued the further testing of their own weapon systems,
moreover, additional producers have also embarked on the development of their comparable
weapon systems.
Lockheed Martin DAGR's system
The DAGR system (70 mm Direct Attack Guided Rocket) was first demonstrated in
the UK at a specialized defence show in September, 2007. Although Lockheed Martin was
not the winner of the tender, it still carried on with the development started. DAGR was
intended to become a 70 mm semi-active, laser guided rocket, with much lower cost than that
of AGM-114 Hellfire II., however, equivalent to this latter as far sensitivity and accuracy of
hit were concerned. This led to the nickname Hellfire Jr. for the DAGR system, as it can be
used on all platforms which serve the antitank missile Hellfire, manufactured by this
company.
SAL (Semi-Active Laser Kit) is the brains of the system, which can be fitted at the
front of the 70 mm Hydra rocket, directly before the warhead, thus retaining the original
MK66 motor and all the different types of warheads and fuzes. SAL came with the well
established laser sensor of Hellfire II., therefore, the DAGR has the same accuracy of hit as
its bigger brother. Canard foreplanes (four in all) belong to the sensor-control unit, these are
deployed after launch.
The special pod developed for the system and holding 4 DAGR rockets can be quickly
mounted on the launcher M299, i.e. it can be used on any and all platforms, which can carry
and use the Hellfire missiles. Its mission is practically the same as that of the Hellfire
missiles, therefore, only a minimum of additional training is required. However, its cost is
just a fraction of that of the Hellfire.
Fig. 4.: DAGR rockets and Hellfire missiles on the M299 launcher
(Source: http://www.lockheedmartin.com downloaded: November 26, 2012.)
This is also a semi-active system, meaning that laser target designation is required just
like in APKWS II and its role is the same.
TALON of Raytheon Systems
Raytheon proposed its TALON Laser Guided Rocket system in the US APKWS II
tender, a system jointly engineered with the Emirates Advanced Investments (EAI). As far as
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its system goes, it is most comparable to the Lockheed Martin DAGR system. Its laser sensor
and guidance sections are installed at the front of the Hydra rocket, before the war section,
thus retaining the motor and warheads specified in the tender. The laser sensor, engineered by
the Israeli firm and service proven in other weapon systems, is compatible with all the laser
target designation devices currently in use. The seeker-guidance section also includes the 3
canard foreplanes, which deploy after launch.
Fig. 5. Configuration and use of the TALON rocket from an AH-64 helicopter
(Source: http://www.raytheon.com/capabilities/products/lgr/ dowloaded: April 12, 2013.)
Again, the TALON system can be used on any platform which is interoperable with
the 70 mm unguided Hydra rockets. The system is semi-active too, i.e. laser target
designation must be performed just like in the APKWS II. BAE or DAGR systems, and
essentially the role and missions are also the same.
Conclusions, possibilities of application in Hungary
By replacing the legacy fleet of Russian Mi helicopters, our country is expected to
procure western helicopters, which would also involve the application of the 70 mm Hydra
rockets. In view of the defence budget available it is only confirmed that the helicopters are
to be fitted with such weapon systems, approved under professional considerations, which
provide the capability of precision strikes. The most efficient form for this can be APKWS
system presented here. The evaluation of the concrete offers will identify the most suitable
option from among the weapons discussed or a more recent system should be procured or
developed. However, there is no doubt that as many as possible of the lements of the
unguided rockets and the low-cost guided missile systems shall be identical, as this is already
the existing reality.
The subject of my study is the armament of light-weight or medium multi-role
helicopters, to be procured as a compromise, and not the analysis of the antitank capabilities
of a combat helicopter. By the same token, naturally, the guided anti-tank missile capability,
in the conventional meaning of the role, will also be required carried on combat or transport
helicopters.
Hungary's NATO partnership system is based upon cooperation and collective
undertaking of missions. The feasibility of interoperability with the partner countries must be
an essential criterion when deciding on any defence procurement. The laser target designation
devices and the precision coded strike weapons satisfy these requirements.
The Jas-39 EBS HU Gripen fighters currently in use at this point are not able to
employ the low-cost guided rocket systems, however, they have the capabilities for laser
target designation and air to ground operations. This is why the integration of APKWS II
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should be considered, similarly to the fighters of the US armed forces for cooperation with
the JTAC noted earlier, in order to perform CAS missions (Close Air Support).
References:
1. Advanced Precision Kill Weapon System (APKWS™) BAE Systems:
http://www.baesystems.com/product/BAES_027112 , downloaded: April 04, 2013.
2.
DAGR
Direct
Attack
Guided
Rocket
System
http://www.lockheedmartin.com/us/products/DAGR.html, downloaded: November 26, 2012
3. BALI Tamás alezredes: A Légierő helye és szerepe a tűztámogatási feladatokban –
Repüléstudomány Közlemények, XXIV. évfolyam, 2012. 1. szám.
4. Defense Industry Daily: APKWS II: Laser-Guided Hydra Rockets in Production At Last
http://www.defenseindustrydaily.com/apkws-ii-hellfire-jr-hydra-rockets-enter-sdd-phase02193/ downloaded: April 04, 2013.
5. TALON Laser-Guided Rocket (LGR) http://www.raytheon.com/capabilities/products/lgr/
downloaded: April 12, 2013.
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