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Abstract:
The paper outlines a concept design of a Pakistan-centric UCAV design, the primary characteristics of which are an air-to-air role, low costs and a missile-launched platform. The UCAV is designed to play a supplemental role to PAF fighter jets. The concept explored is conceptually between a manned fighter and a guided missile. The missile launched design will allow the aircraft to be based anywhere and without dependence on an airfield, similar to mobile SAM systems.
Introduction
Unmanned Combat Air Vehicles (UCAVs) are a category of Unmanned Aerial Vehicles (UAVs) that are designed to fire munitions and are characterized by greater autonomy of operation. Key attributes coupled with UCAVs, as defined in conventional military jargon, include an unmanned counterpart of a manned attack or fighter aircraft. This necessitates such capabilities as range, high speeds and significant weapons load.
UCAVs are an emerging technology that has the potential to revolutionize air warfare. While the 5th generation of combat planes is today the pinnacle of military aviation, UCAVs present paradigms that can supplement if not supplant them. Subject Matter Experts (SMEs) who discuss a potential 6th generation inevitably mention unmanned aircraft as a possible key salient.
This paper focuses on UCAVs as primarily air-to-air combat vehicles focused on providing a simple, achievable solution as a complement and aid to PAF fighter aircraft. The proposed UCAV is a Pakistan-centric UCAV the primary characteristics of which include an air-to-air role, low-costs and a missile launched system.
The proposed UCAV will be optimized for a high-high air-to-air profile. The system is designed to play a supplemental role to PAF fighter jets rather than to replace manned combat aircraft. The UCAV concept explored is conceptually between a manned fighter and a guided missile. A missile launched design will allow the aircraft to be based anywhere and without dependence on an airfield, similar to mobile SAM systems. The solution is emphasized to be built on cheap, reliable and achievable technologies, judged to be within the reach of Pakistan’s industrial base. The UCAV is designed with BVR engagements in mind rather than attempting to outdo fighter pilots in dogfights.
UCAV Technology
When the term UCAV is used, we imagine Ryan Reynolds as the pilot in the action flick, the Green Lantern take on sci-fi –like artificial intelligence UCAVs. Or we imagine Jessica Biel and Josh Lucas take on similar machines in Stealth. We then rightly assume that such technologies are fantasies and beyond the scope of serious discourse when considering Pakistan’s capabilities.
The technologies needed for fielding real UCAVs are here, already proven and mature. Many of the technologies are in fact only waiting to be integrated together. Consider the example of autopilot computers that can now takeoff, fly to a destination and land the commercial aircraft. This technology has been available in the commercial airline industry for decades. Pilots can merely take control when something untoward happens.
An American Global Hawk today can take off, fly around the world, accomplish its ISR mission and come back to base making a perfect landing, all with no manual input. A JSF is being designed with the ability to visually track a large number of targets, identify and categorize them without any human input. Modern missiles, utilizing proven technologies and without Artificial Intelligence (AI), can defeat maneuvering fighters by employing multiple tactics, even being able to come back in case it missed the designated aircraft in its first pass. Again, all this is accomplished without input from a human operator.
Competing UCAV Paradigms: Unmanned F-35 vs. One-up Cruise Missile
Two paradigms of UCAVs are presently competing with each other. The first is broadly looking to build an F-35 like unmanned platform while the second seeks to build something a step above stand-off cruise missiles. The concept design proposed in this paper is closer to the second paradigm. It is worthy to note that Lockheed Martin’s “Skunk Works” shares a similar paradigm:
From a system of systems, cost and concept of operations standpoint, "we take the view that (a UCAV) should be more like a JASSM that comes back than an F-35 that's unmanned," Kacena says. JASSM is the Lockheed Martin AGM-158 Joint Air-to-Surface Stand-Off Missile in production for the USAF and USN. He adds: "We think (the UCAV) should be controlled from an aircraft (such as an F-22 or F-35) that goes into a high-threat environment and that they should carry and launch them from a low observability pylon. The challenge is to create a pilot workload that is no more arduous than launching an Advanced Medium Range Air-to-Air Missile.[1]
The China Factor
All indications are that the Chinese are taking UCAVs very seriously and may lead the world in this technology within the next decade. One informed expert accessible to this author comments that:
“…the Chinese will go the way faster than others because of their limited knowledge of air combats and the ability to produce fast and cheap. They never had good experience in modern war and always relied on quantity. In case of Pakistan, you need your pilots but you have to risk UCAV's to keep a front on the outside of your perimeter.”
Pakistan’s advanced missile technology base, the Babar Cruise Missile, the JF-17 program, the UAV prowess of Integrated Dynamics (among others) and close alliances with China and Turkey provide an ideal environment for such a venture. It appears that all the ingredients necessary for the successful development of such a UCAV are now present for a successful takeoff.
Pakistan’s Threat Scenario 2025
Before considering an active solution and the technologies relevant to that solution, it may be helpful to first consider the threat scenario Pakistan will face. Looking fifteen years ahead, an evident change in the quality of the threat in Pakistan’s neighborhood is evident.
India will begin to field PAKFA fighter jets from Russia and may also develop her own from technology bought from the Russians. While the latter may be discounted as another employment opportunity for DRDO and related third-rate Indian bureaucracies, PAKFA and any specific design built for India by the Russians will provide a challenge that would be wholly new to the subcontinent: a 5th Generation Fighter. Further, it may not be farfetched to imagine a JSF purchase as well, given the blossoming long-term partnership developing between India and the United States. Hillary Clinton is said to have made an “unbelievable offer” of $65 million apiece for a basic F-35[2]. Even if these F-35s are not purchased, the MRCA is expected to yield 126-200 high-end 4.5++ generation Rafale or Eurofighter aircraft.
The PAKFA is a clear threat to the aerial security of Pakistan. The aircraft was designed to counter the F-22 in air combat. The threat is perhaps best defined as reasonable stealth, super cruising, high altitude and high speed. The PAKFA takes BVR combat to a new level that the airframe of the JF-17, by design, cannot compete with. BVRs launched from a high-high profile would increase missile range and speed and reduce the threat range and effectiveness of Pakistani BVR launches in response. If we imagine that Pakistani AWACs and refuelers will be in the sky, such threats would be a menace for these major assets, particularly with longer ranged BVR missiles bought from Russia.
By 2025 India could possibly be fielding PAKFAs and other high-end platforms in the hundreds, drastically changing the military balance in the Subcontinent. Pakistan can either go bankrupt attempting to counter this new threat or she can become obsolete, back to a decade similar to the 1990s, but in a world that is rapidly destabilizing and closing around Pakistan. Or Pakistan can develop viable military strategies and programs to counter these threats, and, as concerns military aviation, Pakistan could seek some of those answers in UCAVs.
A Simplified & Yet Useful Missile-Launched UCAV (ML-UCAV)
The proposed UCAV is Pakistan-centric and has the primary characteristics of an air-to-air role, low-costs and a missile-launched system. The UCAV will be optimized for a high-high air-to-air profile. It is designed to play a supplemental role to PAF fighter jets rather than to replace manned combat aircraft. The missile-launched design will allow independence from airfields, similar to mobile SAM systems; this conception of a UCAV theoretically placed between manned aircraft and guided missiles.
The UCAV may be launched and placed into a high-high profile. The emphasis is to be built on cheap, reliable and achievable technologies, judged to be within the reach of Pakistan’s industrial capability.
A V/STOL capability has been explored by a number of previous concepts including the British Harrier and more recently the F-35 and V-22 Osprey. Among projects that were undertaken include the US Navy Convair XFY-1, the Dessault Balzac and Bell YF-109. These planes were designed to counter the vulnerability and restrictions of airfields, which were increasingly exposed to attacks. They could also potentially provide air defense for ships.
The concept was perhaps first conceived in the American Chance Vought V-173, a STOL fighter for the US Navy and the WWII era German Sanger Amerika Bomber[3], a rocket-powered aircraft launched from a rail and, like our proposal, designed for high-altitude and high-speed flight. The vulnerability spoken of here has only increased in recent years with the proliferation of PGM and cruise missiles, along with the particular geographical vicinity of the Indo-Pak scenario. Heavy piloting skill and workload coupled with the high-risk and danger posed during launch and recovery were key considerations why many of these projects went out of favor, despite the clear requirement.Key Requirements
We identify the following key requirements of such a solution:
- Mechanical simplicity (no pilot and all the pilot equipment like ejection seat, oxygen system, no landing gear, etc.)
- Engine:
- Simplified turbojet engine buildable in Pakistan
- Low cost
- Low Mean Time Before Failure (MTBF) to compensate for costs / complexity
- Designed for high altitude, high speed f-pole BVR combat
- Algorithms rather than Artificial Intelligence (AI)
- Network-centric, swarm & group tactics
- Smaller, low RCS, internal bay
- In-Flight Refueling (IFR) capability
These objectives may be achieved by the following characteristics as outlined below.
Aerodynamics
A well-swept, all-wing design with very large wing area optimized for a high-high profile. The air-intakes may be fixed, as the UCAV only needs to operate in a specific flight profile and the boosting rocket will get the UCAV to the right altitude / speed. This will allow superior and more efficient performance for a given engine technology. Simultaneously, a fixed inlet will save on weight, costs and complexity.
Human Input
The UCAVs will act as auxiliaries to manned combat aircraft. Input will be received if and when needed and the UCAV would also be capable of autonomous operations. The UCAV could be guided by AWACs, ground controllers and PAF fighters in the air. Regular manned fighters could give input but special two-seater JF-17s may also be created for added command and control.
This latter idea of an autonomous yet managed UCAV is a step that is needed before a next generation of UCAVs that are completely autonomous becomes viable. The solution provides the best of both worlds: the advantages of having a pilot who can utilize split second decisions around a complex air battle particularly near the battle area is combined with the advantages of higher G-force dexterity of UCAVs along with gains in stealth, agility and lack of casualty vulnerability.
We do not also wish to have a UCAV running loose with no idea where it is, what it can do and how to stop it.
Missile Launched
The basic configuration for the proposed UCAV is similar to the Babar Cruise Missile; truck mounted and boosted into its flight profile. The payload is larger and the missile needed to boost the payload to a high-high profile at close to 50,000 feet will also equivalently be larger. This will allow the PAF added strategic risk mitigation, as keeping UCAVs in airfields will put PAF assets in relatively fewer locations, all of which are essentially open to attack.
Threat mitigation is of vital importance given that Pakistani airfields being relatively close to the border and the neighborhood is bristling with PGMs and standoff munitions.
The missile-launched will also enable the aircraft to have a lower fuel-to-weight ratio as a significant fuel load is expended between takeoff and reaching combat altitude / speed. This can often be as high as 20-30% of fuel capacity. Since the UCAV will be placed in a high-high profile at 50,000 feet, this will provide a significant advantage in terms of reaching engineering parameters for the aircraft. Further, no compromises would be needed related to aerodynamic optimization; a turbojet optimized solely for a high-high profile would be highly efficient.
Recovery can be achieved by parachute and assisted with dispersed pre-designated locations with receiving nets. These can be coupled with nearby reload and quick turnaround capabilities.
Turbojet Engine
Turbojet engines are considered to be near obsolete in combat aircraft today. However, they have a number of characteristics which make them ideal for the proposed UCAV design. Firstly, turbojet engines are simpler to build and manufacture. The metallurgy and technology needed is less stringent. This is of key importance with respect to Pakistan, given that Pakistan does not have experience building aircraft engines.
On a second point, for a high altitude and high speed profile, a given size and weight of engine, holding everything else constant, turbojets match or exceed turbofan engines. The downside is that turbojet engines are significantly less efficient in other flight profiles which are invariably part of the traditional combat aircraft’s flight; takeoff, loiter, low-mid altitude flight, low speed flight and landing. Consider that for many older generation turbojet engines, to takeoff and reach combat speeds and altitude, 20%-30% of fuel is consumed. However the issue is resolved given that the UCAV will be put into its high-high flight profile by a missile delivery system.
The designated turbojet engine would not need to match the same MTBF (Mean Time Before Failure) which is often significantly smaller for a turbojet compared to a similarly classed turbofan. This is because UCAVs do not need training and regular interception duties in an auxiliary role for the PAF. This should also allow leeway in the materials utilized for manufacturing, significantly bringing costs down and increasing power-to-weight ratios.
Further, ceteris paribus, a turbojet engine exposes less frontal area than turbofan engines, an important characteristic for stealth. It may also be noted that the F-22 engines, while turbofans, are closer to turbojets than its other contemporary combat aircraft peers; the F-22 engines have very low aspect ratios and are designed with this feature specifically to take advantage of a high-high flight profile.
BVR Focus
The focus has been on emphasizing on high-high f-pole BVR engagement because UCAVs are still lacking in an ability to engage in within visual range air combat maneuvering. This also allows us to dispense with the need for artificial intelligence. Instead, it may be adequate to utilize algorithms and "blind computation" i.e. alpha beta pruning instead.
Nevertheless, a look at Artificial Neural Networks (ANN) may not be out of place, given that it has been successfully applied in a wide variety of industries including UAVs.[4]
Asymmetric Sensor Payload & Practical Stealth
To keep costs at a minimum, sensors such as radar and IRST can be carried in asymmetric sensor payloads; some UCAVs carrying one, while others carrying another. The sensors themselves are merely an addition as the UAVs would rely on other platforms to supplement their own sensors. Similarly, while stealth may be incorporated into the design from the ground up, it may prove to be financially prudent to be heavily biased towards costs over low observability.
Target Specifications
A broad set of target parameters indicating a technical sketch of the ML-UCAV’s needed capabilities are indicated below.
Combat load: 600-900 kg (4-6 BVR AAMs)
Wing loading: 300-330 kg/m2
Maximum speed: 2.00 – 2.25 Mach
Maximum g-load: 12-15 g
Combat Altitude: 15,000 – 20,000 m
Analysis
Given the ability today of remotely launching AAMs and the highly sensor rich environment over Pakistani air space in the timeframe of deployment, such auxiliaries would provide a cheap force multiplier for Pakistan. The strategy would allow Pakistan to take advantage of the technology changes that have taken place and utilize Pakistan’s technological and industrial strengths. UCAVs would also allow Pakistan to simultaneously counter both the numerical and qualitative enjoyed by the IAF. The high-high profile of the UCAV would allow ideal BVR conditions against not only conventional targets but also stealthy targets; given that stealth planes provide some of the worst RCS from the top.
Reliance on PAF airfields would also be lowered, with UCAV assets being flexibly deployed anywhere. The UCAV would balance the PAF manned fighter force by providing a high-high platform to synergize with the mid-low level optimized fighters such as JF-17 and F-16s. UCAVs would add a new dimension for the PAF to employ and the IAF to counter. As the RAND Corporation notes:
Aerospace power will tend to perform best when the desired outcome involves affecting adversary behavior rather than seizing and holding terrain.
This is exactly the outcome that the proposed UCAV is projected to achieve; providing a near-perfect combination of technological and operational.
On the down side, the proposed UCAVs would comparatively lack situational awareness. While we have attempted to moderate this factor with a BVR focus and a solution slaved to manned fighters, in the presence of a loss of communication in the battle space, perhaps instigated by enemy EW, the UCAVs can prove to be more vulnerable than their manned counterparts, who may still be able to improvise. Furthermore, in the event that the enemy is able to exploit a weakness, the UCAVs would be unable to respond until adequate software upgrades. On the other hand, since the UCAVs would only be employed during war, the opportunity to find those weaknesses, both for the home side and the enemy are limited. Ballistic launch of UCAVs also brings the hazard of being mistaken as a nuclear assault. The recognition of the existence of such weapons would make any possibilities of a misunderstanding a non-issue.
Expanding the arms race between India and Pakistan in a new dimension must also be carefully considered, given the strength of India’s IT sector and Israel’s UAV sector, the latter being a close ally of the former. This would mean going against the enemy on territory it has a relative technological and industrial advantage. Appendix I and II provide a SWOT analysis and a diagrammatic look at some of the strengths of this proposal.
Conclusion
UCAVs are an emerging technology that has the potential to revolutionize air warfare. While the 5th generation of combat planes is today the pinnacle of military aviation, UCAVs present paradigms that can complement manned fighters of the 4th and 5th generations. While most nations struggle to keep their 4th generation aircraft operational and can barely dream about 5th generation solutions, UCAVs provide an interesting paradigm shift that cannot be ignored by those entrusted with the defense of their nations. Our ML-UCAV concept provides many of the benefits of SAMs and manned fighters, while mitigating their disadvantages. For Pakistan, UCAVs may be the only realistic way to counter a large number of PAKFAs and possibly other 4th and 5th generation planes sitting across the border.
In the Grande Strategic view, PAF could use large numbers of UCAVs as a cheap and ideal counter for IAF’s quantitative and qualitative edge, while maximizing the limited financial resources available to the country. IAF would be put off-balance in attempting to assess an asymmetric threat that neither she nor the rest of the world has experienced. Combined with manned fighters, EW assets, Long Range SAMs and other assets, the UAVs would provide a force multiplier effect over the entire Pakistani IADS.
Armed with 4-6 BVRs, the UCAVs could prove to become the foot soldier of the sky, lightly armed and yet overwhelming in their numbers, guarding the parameters while allowing manned PAF fighters the flexibility to enter and exit the air battle at their choosing.