Defense Issues

Military and general security

Archive for the ‘Weapons Systems Analysis’ Category

Light combat vehicles with high-calibre weapons

Posted by picard578 on February 1, 2017

Requirement for wheeled armoured vehicles appeared between First and Second World Wars, and in 1930s Germany started serial production of such vehicles for its recon units. Widespread usage of wheeled armored vehicles only started after World War II. In 1970s, 1980s and 1990s, new generations of wheeled armored vehicles appear, responding to military requirements for increased mobility, protection and firepower. Still, wheeled armored vehicle development lags behind tracked AFV development due to their significantly inferior off-road mobility, inferior firepower and inferior protection due to lower carriage capability of configuration.

New lease of life wheeled vehicles were given as a result of an air-land battle doctrine, a response to 3:1 advantage in armored forces by the Eastern block. There are also requirements for infantry transport, quick strikes, anti-tank combat at low and medium range, anti-air defense, fire support etc. Light armoured vehicles are receiving large-calibre guns, anti-tank missiles and other heavy weapons, and are being integrated into combat units. Recon vehicles are adapted for frontline use in peacekeeping operations through improvements in firepower and armor, albeit at the cost of sacrificed mobility. Still, airborne forces typically lack sufficient protected firepower platform, especially since few to no militaries still operate light tanks that can be deployed via parachute. Read the rest of this entry »

Advertisements

Posted in weapons, Weapons Systems Analysis | Tagged: , , , , | 17 Comments »

Dassault Rafale vs Saab Gripen

Posted by picard578 on October 1, 2016

Introduction

Dassault Rafale and Saab Gripen are both multirole fighter aircraft of canard-delta configuration produced in Europe. Rafale was designed to replace seven different aircraft previously in French service, while Gripen was designed for guerilla warfare against a superior enemy. This comparison will use Gripen C. Read the rest of this entry »

Posted in weapons, Weapons Systems Analysis | Tagged: , , , , | 45 Comments »

A fighter for Canada

Posted by picard578 on December 21, 2015

Introduction

Canada is a Western country that at the first look has most at common with Russia. It is huge, but vast majority of its population is concentrated in a narrow swath of land to the south, near the US-Canadian border. It borders United States to the south and west, while to the east is rest of the NATO and to the north is inhospitable Arctic, with its vast natural riches and strategic importance.

Defense of northern Canada depends mostly on three or four forward operating locations – fourth one is the only with permanently assigned squadron, and that one consists of transport aircraft. Only the far east and south of Canada have proper air bases. CF-18s are based in Bagotville to the extreme south-east and Cold Lake to the south-west. Extreme north is patrolled by long-range patrol squadrons using CP-140 Aurora aircraft; no fighter aircraft are present there on a continuous basis, despite primary mission of Canadian fighter jets being to patrol Canadian airspace. Main warning system is a chain of radar stations making up the North Warning System (DEW Line). Read the rest of this entry »

Posted in Weapons Systems Analysis | Tagged: , , , , , , , , , , , , , , | 22 Comments »

Assessing the SAM threat

Posted by picard578 on February 15, 2015

Introduction

SAMs are the new boogeyman of the USAF, one which they are also using in their political games. They want the F-35 because, they say, legacy aircraft are “unsurvivable”. They want to retire the A-10 and leave ground troops without any support because, they say, it is unsurvivable. But how much truth there is in their assertions?

Historical overview

During the Vietnam war, SAMs saw extensive usage. They were used primarly to defend key targets but were also deployed in the field; many were also mobile (though level of mobility they had does not even begin to compare with modern SAMs, thanks to excessive times necessary to either deploy or pack up). Read the rest of this entry »

Posted in Historical Analysis, Weapons Systems Analysis | Tagged: , , , , | 117 Comments »

Comparing stealth fighters

Posted by picard578 on December 24, 2014

Introduction

A Christmas / New Year present for all of you.

***

This article will compare “stealth” fighters, regardless of wether they are in service. Aircraft compared are as follows: F-22, F-35, T-50 / PAK FA, J-20 and J-31. Following article will form a basis for comparision:

https://defenseissues.wordpress.com/2014/08/30/comparing-modern-fighter-aircraft/ Read the rest of this entry »

Posted in weapons, Weapons Systems Analysis | Tagged: , , , , , , , , , , , , | 47 Comments »

CDI: The F-22: expensive, irrelevant and counterproductive

Posted by picard578 on November 1, 2014

By PIERRE SPREY, JAMES STEVENSON and WINSLOW WHEELER

Special to the Star-Telegram

On Dec. 12, the Air Force announced with considerable fanfare at Langley Air Force Base in Virginia that its F-22 fighter had reached “full operational capability.” Air Combat Command commander Gen. John Corley called it a “key milestone.”

Brimming with pride, a spokesman for the manufacturer, Lockheed, stated: “The F-22 is ready for world-wide operations” — and then added, “… should it be called upon.”

His afterthought makes the point: There are, of course, two wars going on, and the F-22 has yet to fly a single sortie over the skies of Iraq or Afghanistan. Nor has the Air Force announced any intention of sending the F-22 to either theater.

The Air Force is quite right to keep the F-22 as far as possible from either conflict. The airplane is irrelevant to both, and were it to appear in those skies, it almost certainly would set U.S. and allied forces back. Read the rest of this entry »

Posted in Weapons Systems Analysis | Tagged: , , , , , | 57 Comments »

Air to air weapons effectiveness

Posted by picard578 on June 15, 2013

Measures of effectiveness

To determine effectiveness of weapons, first we must determine what are measures of that effectiveness. Weapons are designed to kill, and to preferably kill opponent before he can kill you. But opponent wants to do the same thing, so he will try to survive – which means prevent you from killing him, and kill you. Best way to achieve advantage is by surprise; further, weapons should be as resistant to countermeasures as possible.

Historically, engagements were always between flights and squadrons, more rarely entire wings. This means target saturation. It also means that pilot is always in danger of getting killed by somebody even as he tracks the target; resultantly, time required for tracking the enemy should be reduced to minimum. But even side with inferior weapons was able to win if it has superior personnell or superior numbers as Germans have proven in France in 1940 and USSR in 1941/2. But once USSR learned from mistakes, and adjusted both training and tactics correspondingly, its numerical superiority decided the war.

Thus most important aspect of weapon is how it affects user’s skill. Second is how many weapons can be sent to and supported in fight; only third is combat capability of weapon itself. Further, more expensive weapon is not necessarily more effective even when numbers are ignored. More on it here. As for aircraft weapons, their primary function is to kill enemy quickly, reliably and at minimal danger to the user.

Missile effectiveness Read the rest of this entry »

Posted in weapons, Weapons Systems Analysis | Tagged: , , , , , , , , , , , | 16 Comments »

Saab Gripen analysis

Posted by picard578 on February 16, 2013

Program history

SAAB Gripen is a result of relaxed-stability fighter rush initiated by (at the time) revolutionary F-16 fighter aircraft. It is not surprising that SAAB opted for delta-canard layout they themselves pioneered in 1960s, but other options were also evaluated (and rejected). This was influenced by testing programme of Viggen in late seventies, which verified benign high AoA characteristics of the layout. To Sweden, choice of small, cheap but highly capable fighter aircraft was obvious.

In 1979, after cancellation of too expensive B3LA project (a development of subsonic trainer and light attack aircraft), Swedish Air Force carried a reexamination of its requirements. Conclusion was that only affordable option was development of multirole aircraft capable of carrying out air superiority, ground attack and reconnaissance missions. Thus the JAS programme was born, drawing name from specified requirements (Jakt – fighter, Attack – attack, Spaning – reconnaissance).

In March 1980, Government endorsed the plan, but insisted that foreign contractors should be allowed to bid for the contract. As a response, Swedish (state-owned) aircraft industry formed a JAS Industry Group, comprising Saab-Scania, Volvo-Flygmotor, Ericsson Radio Systems and FFV to manage the bid by Swedish industry. Formal proposals were requested in 1981, and JAS IG submitted their proposal on 1 June 1981. After evaluation of proposals, it was decided to go forward with JAS proposal. On 30 June 1982, a fixed-price proposal was signed between the FMV and IG JAS for 5 prototypes and 30 JAS-39A aircraft. Following month, name Gripen was selected for the aircraft.

Ericsson was tasked with developing multi-mode radar, while FFV developed navigation and attack systems.

Mock-up of the final design was unveilled in early 1986. However, development of Flight Control System caused delays in final assembly of the aircraft, with first Gripen rolling out of assembly on 26 April 1987, after 7 years of development. First flight was achieved on 9 December 1988, but after its sixth flight, on 2 February 1989, aircraft veered off the runway and carwheeled. Following that, FCS was fixed, and on 4 May 1990, JAS-39-2 flew with new software. Fifth and final prototype flew on 23 October 1991. Testing showed drag to be 10% lower than predicted, and airfield performance was also better than specifications. In June 1992, contract for second batch of aircraft was approved.

On 4 March 1993, first production Gripen (JAS-39-101) made its flight, with second production aircraft delivered for service testing on 8 June 1993. It soon crashed during air display over Stockholm due to the pilot loosing control and having to eject. Following the accident, further flight testing was suspended until FCS was revised. Revisions included changes to canard deflection angles in combat mode. Testing continued on 29 December 1993.

One JAS-39A was converted from production line to serve as prototype for twin-seated trainer, JAS-39B. It features 65,5 cm fuselage stretch, and rear cockpit that is, except for lack of HUD, identical to the front one.

On 12 June 1995, SAAB and British Aerospace announced joint development of export variant. In 2001, joint venture was registered in Sweden as Gripen International. As Gripen was designed solely for Sweden’s needs, Export Baseline Standard was developed, resulting in C and D variant of the aircraft. Soon, Swedish Air Force decided to also acquire the new version, with last 20 aircraft of Batch 2 and 30 aircraft of Batch 3 conforming to EBS specification.

EBS featured retractable inflight refuelling probe on the port air intake, full-color English-language cockpit displays in Imperial units, new computers, night-vision compatible cockpit lightning, FLIR and reconnaissance pods, more powerful air conditioning system, OBOGS and stronger wings with NATO standard pylons.

In December 2004, BAe sold large portion of its stake in Gripen International to Saab, finally selling remaining 10% of their stake to Saab in June 2011. On 26 April 2007, Norway signed an agreement on common development of aircraft, with agreement between Saab and Thales Norway following in June, concerning development of communications systems. In June 2007, NATO Link 16 was added to datalink systems of Gripens in Swedish service.

On 23 April 2008, Gripen Demo (requested in 2007) was presented, serving as demonstrator for Gripen NG. On 27 May 2008 it had maiden flight, and demonstrated supercruise ability on 21 January 2008, flying at Mach 1,2 without reheat.

In 2010, Sweden awarded 4-year-contract for improving Gripen’s radar and other equipment. On 25 August 2012 Sweden announced plan to buy 40-60 Gripen NGs, following Switzerland’s decision to buy 22 Gripens of the same variant. On 17 January 2013, Sweden’s government approved decision to buy 60 Gripen E’s, with first deliveries in 2018.

Unlike with Viggen, Gripen’s test flights revealed no aerodynamic, structural or engine deficiencies; in fact, all of them were better than predicted. Only structural “fix” was added strake behind each canard surface.

Basic data (Gripen C)

Length: 14,1 m

Wing span: 8,4 m

Height: 4,5 m

Wing area: 25,54 m2; 30 m2 with canards

Wing loading:

326 or 383 kg/m2 with 100% fuel, 4 AMRAAM and 2 Sidewinder

287 or 337 kg/m2 with 50% fuel, 4 AMRAAM and 2 Sidewinder

266 or 313 kg/m2 with 50% fuel and 2 Sidewinder

(*depending on wether canards are counted)

Thrust-to-Weight ratio: (80,51 kN – 18 100 lbf – thrust)

0,95 with 50% fuel, 4 AMRAAM and 2 Sidewinder

Fuel fraction:

0,27 (6 622 kg empty, 2 400 kg fuel) – 2 270 kg fuel was for A version’s “peace setting”; C version has only war setting

Weight:

6 622 kg empty

7 997 kg with 50% fuel and 2 Sidewinder

8 605 kg with 50% fuel, 4 AMRAAM and 2 Sidewinder

14 000 kg max takeoff

Maximum AoA:

>100 degrees (aerodynamic limit)

50 degrees (FCS limit)

Speed:

Mach 2,0 dash

Mach 1,15 cruise

Combat radius:

Ground attack, lo-lo-lo: 650 km

PS-05/A:

Range: 120 km vs 5m2 target (80 km vs 1m2 target)

Operational G capability: 9 g

Flyaway cost: 38 to 44 million USD (in FY 2013 dollars)

Cost per flying hour: 4 700 USD

Design

General

Saab Gripen is designed as a lightweight, highly maneuverable fighter. Close-coupled canard + delta wing arrangement was chosen to optimize maneuvering performance while also providing acceptable strike capabilities. Testing programs have verified excellent recovery capabilities for both Gripen versions. Further, delta canard configuration has inherently good battle damage tolerance due to “overlapping” surfaces, as well as positive trim lift on all surfaces, high maximum lift coefficient, good air field performance, and spin recovery capability. Floating canard also offers stable aircraft if EFCS fails.

To minimize weight, 30% of the structure is carbon-fibre composite. Aircraft is inherently unstable, and SAAB claims that it is first inherently unstable canard fighter to enter production.

While Gripen has low wing loading and good lift at high angles of attack, as well as relatively short wingspan, its thrust to weight ratio is below 1 at combat weight. Aircraft has operational service life of 8 000 flight hours.

Fuselage

One of things that can be noticed is large degree of wing/body blending, similar to F-16, which results in higher lift during maneuvers, as well as little or no interference drag that usually originates from wing-body juncture. Only exception to that are intakes, which are in side arrangement, with flat surfaces used for mounting canards. Body itself, having a “waist” noticeably thinner than parts immediately in front or aft of it, is clearly designed for transonic maneuvre.

Two small strakes are visible on the upper fuselage, located just behind canard surfaces, and single strake can be seen at bottom of fuselage; their purpose is to help enhance directional and lateral stability at high angles of attack.

Canards

Saab Gripen has canards that are relatively large compared to the wing. Canards are positioned close in front and slightly above the wing, and are tilted upwards, with large sweep-back. Location of canards at sides of air intakes prevents obstruction of air flow.

Primary purpose of close-coupled canards is not to act as control surface, but to increase lift at high angles of attack, where aircraft relies mostly on vortices to provide lift, by strengthening vortices generated by the wing and preventing their breakdown. Size and angle of Gripen’s canards are used to achieve as good as possible separation – vertical and horizontal – between canard’s tip and wing’s lifting surface, thus allowing for maximum vortex lift during high-alpha maneuvers – improvement of lift due to the close coupled configuration could be up to 50%, when compared to lift produced by surfaces in isolation. While thrust vectoring only increases maneuverability at very low speeds, and in supersonic regime, close-coupled canards are effective at any speed, though level of effectiveness varies with speed. As such, aircraft with close-coupled canards can have smaller wings for same lift at higher AoA (improving roll rate), being able to turn tighter at any air speed than otherwise possible with same wing size and angle of attack value, and achieving higher instantenenous turn rate. This also means that aircraft will be able to have lower wing span for same wing sweep and lift values, improving roll rates; smaller wing and reduced angle of attack also mean reduced drag when turning, allowing fighter to maintain energy better. However, downwash from canards also reduces wing lift at low angles of attack, reducing maximum payload fighter can carry.

Compared to LEX, canards are more versatile. Aside from being able to act as a control surface, canards can adjust position so as to produce maximum lift at any given angle of attack.

While Gripen managed to achieve angles of attack between 100 and 110 degrees during flight testing, normal AoA limit is 50 degrees as extremely high AoAs have no tactical use. Further, position of canards contributs to the fuselage lift of the fuselage just behind the canards during the turn, and canards themselves create lift, both in level flight and in turn.

Canard also has advantage over tail as the control surface – as center of gravity for modern aircraft is towards rear of the aircraft, usage of canard results in longer moment arm.

Canards can be tilted forward to nearly 90 degrees in order to aid braking during landing.

Wing

Wing itself is standard delta wing, offering large surface area, large volume and high strength for its weight. Shape of the wing ensures creation of vortexes at high angles of attack by wing’s leading edge, improving lift; wings are also equipped with small LERXes to strengthen said vortices. Another high lift device are leading edge flaps, which are used to increase lift at high AoA. When deployed during high-alpha maneuvers, flaps improve lift; however, they can also cause vortex breakdown. They also redirect air flow towards root of the wing, countering the tendency of air flow over delta wing to move towards wing tip. While usage of flaps can reduce drag, it only happens at speeds near stall speed, while in most other cases they increase drag. When flaps are not deployed, dogtooth leading edge configuration results in creation of single strong vortice at each wing, helping lift by countering tendency of delta wings to move air flow towards wing’s tips, and leave rest of the wing in stall. Wing is neither anhedral or dihedral, being located at half of the hull height. Due to wing’s (lack of) thickness, external actuators are required to control elevons.

Due to the Gripen being aerodynamically unstable aircraft, usage of delta wing also results in large trimmed lift during level flight, improving maximum lift by 10-20%, possibly more. Combination of close-coupled canards and low wing loading further improves air field performance, allowing for STOL capability.

While mechanism of lift creation at high AoA create additional drag, they increase lift and thus turn rate. But what some ignore while talking about drag “penalty” of close-coupled arrangement is that flow separation, aside from causing loss of lift, also causes major increase in pressure drag.

Rail launchers are located at wing tips, improving weapons loadout and allowing two missiles to be carried with minimum increase in drag, as well as improving lift/drag ratio of the wing.

Air intakes

Gripen’s air intakes are two-dimensional intakes, similar to those used at RA-5C. Intakes are separated from aircraft’s surface by fuselage boundary layer splitter plate, and provide adequate handling of fuselage boundary layer. High-alpha testing revealed no deficiencies in intake performance.

Fin

Tail fin is small relative to fighter’s size, compared to that of other Eurocanards and F-16. This might theoretically result in problems at high AoA; but usual way to change direction of aircraft is to rotate around X axis and pull nose up, and Gripen has additions on lower surface that may make fin unnecessary for directional stability.

Cockpit

One of major downsides of Gripen is its cockpit. While it allows good forward and side visibility, rearward visibility is very limited. This is dictated by its strike requirements, where exhaust from cooling unit is located behind cockpit to hide it from ground-based IR sensors. While SAAB did attempt to attenuate the problem by installing mirrors on forward canopy frame, it is only a partial solution.

Cockpit originally featured three monochrome multi-function displays, and wide-angle holographic HUD. It also has HOTAS controls that allow pilot to select many functions without lifting hands off the control stick or throttle. Ejection seat, unlike in previous aircraft, is not SAAB’s, but from Martin-Baker.

Engine

Engine is based on General Electric F-404 engine. Version used in Gripen, lincense manufactured by Volvo, had thrust boosted from 16 000 to 18 000 lbf (that is, from 7 257 to 8 165 kgf).

Operational characteristics

Gripen is capable of taking off and landing on roads, and could be capable of using unpaved runways. It can take off from 800 meter long snow-covered landing strips. Landing distance is reduced to 500 meters through usage of canards as air brakes, which is activated automatically when nose wheel establishes ground contact, as well as usage of elevons and large air brakes located at each side of fuselage behind the wing.

Further, it can be maintained by team of one specialist and five minimally-trained conscripts, and has very good combat turnaround time – less than 10 minutes. Gripen requires 10 man hours of maintenance for each hour in the air, and mean time between failure is 7,6 flight hours. Engine can be changed on road by 5 people in less than one hour. Airplane’s on-board systems include built-in “self-test” capabilities, with data being downloaded to technician’s laptop. All service doors to critical systems are at head level or lower for the easy access. Result is that Gripen requires only 60% of maintenance work hours of Viggen.

Aside from providing superior agility, Gripen’s FBW system is capable of automatically compensating for combat damage, including disabled or destroyed control surfaces – for example, using canards if aelirons are disabled.

Handling

Due to its aerodynamic layout, Gripen can be “parked” at 70 to 80 degrees of alpha. When giving adverse aeliron input, flat spin starts at up to 90 degrees per second rotation, and can be stopped by pro aeliron input. Aircraft has demonstrated spin recovery capability for complete cg and AOR range, as well as control capability in superstall, allowing recovery. During the spin testing, in one occasion when spin entrance was gained by wild maneuvering in afterburner, surge in thrust was recorded at high AoA and side-slip angles, but was immediately followed by instant recovery to full power.

Aircraft has operational G load limit of 9, and ultimate limit of 13,5 Gs.

Weapons

Gripen is armed with single Mauser BK-27 cannon, housed in a fairing on port side of aircraft’s belly (can be seen here). It currently also uses Sidewinder IR AAMs, though these are to be replaced with IRIS-T missiles. BVR missile is AIM-120 AMRAAM, though aircraft is also capable of using MBDA Meteor, Matra Mica, and BAe Sky Flash (built in Sweden as Rb-71).

For anti-ship combat as well as ground attack, it can carry SAAB RBS-15 missile (though only Mk3 version of the missile supports land attack missions). Dedicated air-to-ground missiles are AGM-65 Maverick (built in Sweden as Rb-75).

Fact that Gripen uses revolver cannon is a large advantage over aircraft using Gattling guns: while Gattling guns typically take 0,5 seconds to achieve full rate of fire, revolver cannons take only 0,05 seconds. As such, while M61A1 will fire 25 rounds in first half of second, weighting total of 2,5 kg, BK-27 will fire 13,45 rounds, weighting total of 3,5 kg. Larger caliber also ensures greater damage-per-hit, important due to stronger airframes of modern fighters.

Aside for gun, Gripen also has 6 missile hardpoints on wings. Two of these are in wingtip configuration, ensuring minimal drag in flight, while other four are mounted on low-drag pylons. Another hardpoint is located at the bottom of aircraft’s hull in centerline configuration. It is usually used for fuel tank carriage, though it can also carry targeting pods as well as ground attack ammunitions.

Sensors & EW suite

Gripen is equipped with radar PS-05/A, that is capable of detecting targets with RCS of 5 m2 at distance of 120 kilometers, which translates into 80 kilometers against 1 m2 target.

EW suite is built around AR-830 Radar Warning Receiver, with receiveing antennas at front and back of missile launch rails. BOL dispensers are bult into ends of missile launch rails and have capacity of 160 chaff packs or flares; BOP/C dispensers are built into the fuselage, and BOP/B into end of the wing pylons. Lattermost can trail BO2D towed repeater RF decoy, which can be used at supersonic speeds.

Gripen’s limited sensory suite in versions so far is a large shortcoming in combat – namely, lack of IRST, which means that Gripen pilot will have to rely on visual detection (not possible during night, insufficient in bad visibility conditions) or on opponent using his own radar (relying on opponent being an idiot should never be part of any plan). This was realized by SAAB, and Gripen NG will be given IRST; earlier version of Gripen, however, will either have to be retrofitted with an internal IRST system, or settle for using FLIR pod for both air-to-air and air-to-ground missions (if possible). That is probably connected to the fact that Gripen was always intended as a defense weapons, and could thus rely on directions from the ground.

Signature reduction

While the fact that Gripen is relatively small aircraft automatically means smaller IR and visual signatures, there were some specific attempts made at further reduction. Just behind cockpit are located ducts, which are used to release exceess heat from heat exchangers, reducing Gripen’s IR signature as seen from ground.

As far as radar signature is concerned, care was taken to reduce frontal RCS, though side RCS is not likely to be large as long as radar emitter is not at precise 90 degrees angle relative to the aircraft, which would result in return from aircraft’s side surfaces – in particular tail, nose and intake surfaces.

Datalinks and communications

Flygvapnet pioneered the use of datalinks in the combat aircraft, fielding first versions on SAAB 35 Draken in mid 1960s. Gripen is equipped with four high-bandwidth, two-way data links, with range of around 500 kilometers. This allows for exchange of targeting information and other data, even when one of aircraft is on the ground. One Gripen can provide data for four other aircraft, as well as get access to ground C&C systems and SAAB-Ericsson 340B Erieye “mini-AWACs” aircraft. It can also allow fighters to quickly and accurately lock on to target by triangulation of data from several radars. Annother possibility includes one fighter jamming the target while another tracks it, or several fighters using different frequencies at the same time to penetrate jamming easier.

Gripen NG

For Gripen E, SAAB has stated that empty weight will be under 7 000 kg, and engine also apparently has 22 500 lbs of thrust. It also has 3 300 kg of internal fuel, achieving 1 300 km combat radius with 30 minutes loiter time in AtA configuration on internal fuel, or 1 800 km with no loiter time. OTIS IRST will also be added.

Gripen NG will be significantly cheaper than other 4,9 generation aircraft, such as Eurofighter Typhoon or Dassault Rafale, and with 22 ordered by Switzerland and 40-60 by Sweden itself, it has prospect to achieve success on export market as well. Some sources place flyaway cost at less than 50 million USD; my estimate is that it will likely be around 45 – 55 million USD per aircraft.

According to some reports, wing area is double of Gripen C’s, fuselage is 20% longer, but it is made out of carbon nanotube reinforced polymer composites, reducing weight compared to Gripen C. All images of Gripen NG to date, however, seem to be using Gripen C / Gripen Demo as basis (Gripen Demo is test aircraft built by using Gripen C airframe, and images that could indicate wing area don’t show any difference in fuselage dimensions). Another presentation also shows Gripen NG’s empty weight as 7 120 kg, and wing loading as 317 kg/m2 in combat configuration with 50% fuel. (Interesting point is that same presentation states that IRIS-T will be able to shoot down BVR missiles from other aircraft, though slide in question is not entirely clear). OTIS IRST will operate in 3 – 5 and 8 – 11 micron wavelengths.

Conclusion? I won’t draw conclusion about NG until it is airborne and in service.

Image of Gripen landing. Take note of air brakes and canard position:

JAS-39 Gripen landing

Posted in Weapons Systems Analysis | Tagged: , , , , , , , , , , , , | 50 Comments »

Why UAVs cannot replace fighter aircraft

Posted by picard578 on January 26, 2013

Despite all technocrate’s dreams, aerial combat between peer opponents was always visual-ranged. Reasons for that vary; main reasons are inadvisability of using active sensors, low probability of kill for BVR missiles, and IFF problems. All of these problems are far greater against numerically and technologically comparable (or simply numerically superior) opponent than against numerically and technologically inferior opponent. Thus, WVR combat is likely to remain standard for aerial warfare, along with its large accent placed on OODA loop.

OODA (Observation-Orientation-Decision-Action) loop is fundimental principle of air combat. Fighter pilot first observes situation; after that, he orients based on previously-avaliable and acquired information (nationality of opponent, cultural considerations likely to affect opponent’s actions in current situation, etc.), then decides on further course of action and acts based on that decision. In the next loop, he observes opponent’s reaction to his own action so far as well as new situation, with rest of loop proceeding as in first one, though “orientation” part takes far less importance unless new information comes into play. In any case, breaking opponent’s OODA loop or going through it faster than opponent is prerequisite for victory. Opponent’s OODA loop can be broken by denying him vital information (done through usage of passive sensors, small visual and IR signature of one’s own aircraft, employment of various forms of jamming and environment-based interference), as well as by going through the loop faster than him – be it through faster observation/orientation/decision or executing action faster than opponent, which requires maneuverable aircraft capable of quick transients from one maneuver to another.

OODA loop of UAV operator is always imperfect, and worse than that of fighter pilot. Major problem is a delay from two to five seconds between UAV recording image and image being seen by UAV operator. Total delay between drone’s sesors recording opponent’s action and drone finally reacting to it – delay between „observe“ and „act“ part of the loop – can therefore reach ten seconds. Due to this delay, unmanned vehicles will be completely incapable of being inside human-piloted fighter’s OODA loop, which is a prerequisite for victory in a dogfight. But there are even more shortcomings than that.

In particular, each part of OODA loop is in itself imperfect. Observation made solely with information from mechanical sensors is never perfect as we have yet to design sensor as good as human eye. Imperfect observation means that imperfection continues to snowball through latter three parts, ending in action with some measure of disconnection from reality – and that can continue through multiple loops.

 

While drones are much smaller and cheaper than manned fighters, it is only result of their mission. If modern drones are faced with SAMs, MANPADS or enemy fighters, engagement is a foregone conclusion – and one not in drone’s favor. Drone operators cannot detect threats to their aircraft, and if drone was to be designed to be as capable and survivable as manned jet fighter, it would be just as large and costly, if not more, due to the need for advanced computers and communication systems. Even current, relatively simple, drones have much higher operating costs than manned aircraft, and are as much as ten times as prone to crashing – and both shortcomings can only worsen with increased size and complexity required for aerial combat.

 

Gigantic data transfers required to operate drones can easily lead to communication systems being overburdened – single Global Hawk drone uses as much bandwidth as did all US forces in the invasion of Afghanistan. Bandwidth is also a hidden cost of UCAV – while UCAV itself may be cheap, it requires very expensive (on order of hundreds of millions USD) equipment for data transfers, and even with modern UCAVs performing relatively simple tasks, data transfers can take up lion’s share of 250-million-USD satellite’s bandwidth. As such, entire package (UCAV and equipment required to operate it, which is actually part of UCAV despite not being in the airframe) can rival or exceed cost of manned fighter, with latter being a certainity in any UCAV capable of air-to-air combat.

Further, increased bandwidth automatically means increased vulnerability to jamming and other forms of electronic countermeasures. Main way datalinks defend against jamming is by reducing data transfer speed in exchange for increased reliability; that, however, may not be an option for data-hungry UCAV. As such, UCAV’s will be incapable of executing missions in heavily jammed environment, unlike manned aircraft, especially since it is far easier to build very powerful spread-spectrum jammer than to create jam-resistant uplinks.

Drones are also vulnerable to computer viruses, which could take control of a drone and order it to do anything by simulating incoming traffic from its operator.

 

It is also important to realize that UCAV capable of matching or exceeding the aerodynamic performance, load carrying capability and combat radius of manned fighter would be exactly as large and heavy as fighter in question. This would mean similar production cost to manned fighter (not counting control and data transfer systems), but at far higher maintenance costs, as much as several times higher, which would make it impractical to replace manned fighters with UCAVs on one-for-one basis. Further, having UCAV brings no operating cost savings, since it actually requires more operating and maintenance personnell than manned fighter due to the greater complexity.

As a result of everything above, replacing a manned fighter would require a fully-functional AI with almost identical cogniscive capabilities to a human brain – a feat that is, at this point, completely beyond both our knowledge of human brain, as well as beyond our hardware capabilities, and will remain so for some time – interestingly, contrary to MIC technology advocates, computer science experts have a complete disagreement on wether true AI can be achieved by the 2040; in any case, past trends do not give any reasons for optimism in that regard. Even when that is achieved, such complex programs would present serious reliability, maintainability and implementation challenges, possibly to the point of making an AI UCAV basically unflyable.

Drones will, however, remain useful in intelligence gathering, a role they have been used in since Vietnam, as drone being shot down does not carry the risk of operator being captured for questioning, and is much more politically acceptable. While these advantages also exist in regards to manned combat aircraft, disadvantages are simply too large.

Posted in Weapons Systems Analysis | Tagged: , , , , , | 11 Comments »

AIM-120D vs MBDA Meteor

Posted by picard578 on December 15, 2012

Design requirements

AIM-120 was started as a project to replace painfully ineffective AIM-7 Sparrow and AIM-54 Phoenix (which are only effective against heavy bombers and (in case of later-iteration AIM-54) non-maneuvering fighters). It was to be relatively small BVR missile, so as to be able to be carried by the F-16.

Meteor is a result of joint European project to develop BVR missile to replace BAe Dynamics Skyflash. It was to be capable of shooting down a variety of targets, including low-RCS UAVs and cruise missiles, as well as maneuvering fighters of Flanker family. Another requirement was compatibility with Typhoon’s semi-recessed fuselage hardpoints, originally designed for AIM-120.

Effectiveness

AIM-120D is a further evolution of US AIM-120 BVR AAM series. It uses classic fuel+oxygen combustion mix, and does not rely on air flow from outside. In fact, it uses the same engine as AIM-120C, with improvements being mainly in electronics. However, it has been reported that engine malfunctions in cold environments – exactly where it is most likely to be used.

Meteor is a ramjet BVR AAM. As such, it does not carry onboard oxygen, but rather uses oxygen from surrounding air, allowing it to hold more fuel. Result is better acceleration, top speed, and range for a given missile size.

While Meteor may not have as large maximum range as AIM-120D (only figure I have for Meteor is “more than 100 km”, with 100 km being “optimal range”, versus public figure of 160 km for AIM-120D), it is faster, and thus more deadly at any range it can reach. This is important, as BVR missiles are never fired at maximum range due to meager Pk against fighter aircraft. However, range varies on altitude, with best range for both missile types being achieved in high-altitude rare-atmosphere conditions, where maneuverability is almost nonexistent; at sea level, range is not much more than visual. Velocity loss after burn-out also varies with altitude, with 25% of current velocity being lost every 150 s at 24 km, 25 s at 12 km and 5 s at sea level.

Range can be reduced even further if enemy uses jammers. Thus, large NEZ (no-escape zone) is far more important. (To explain terminology here, NEZ is NOT a zone where a hit is guaranteed; rather, it is a zone where enemy aircraft cannot outrun missile, waiting for it to run out of fuel, but rather has to outturn it). Higher speed allows it to reduce time to target, and thus opponent’s reaction time, as well as to retain energy for longer after engine has burned out.

In fact, Meteor’s NEZ was to be three times as large as that of AIM-120B. Active version of missile is equipped with radar Aster, designed to shoot down cruise missiles, which thus can be used against targets with low RCS.

However, both missiles are BVR, making their actual value questionable. In fact, jamming and IFF issues mean that BVR missiles are far more likely to be used as a WVR weapon than in their intended purpose. While AIM-120 did achieve 6 BVR kills out of 13 firings, all but one were against non-maneuvering targets with no ECM and no awareness of missile. By comparing difference in Pk between maneuvering and non-maneuvering targets for AIM-9, it can be concluded that AIM-120 will achieve Pk of at most 11%; however, it is larger and heavier than AIM-9, as well as more vulnerable to countermeasures, so even that is an optimistic estimate.

EDIT: Meteor is estimated to have a range of 250-300 km with ballistic flight path, which suggests an improvement over initially cited goal. That being said, best option is to wait for performance figures after it enters service.

Posted in Weapons Systems Analysis | Tagged: , , , , , , , , , | 21 Comments »