We take a look at the new SAAB supersonic killer drone
Swedish defence company SAAB has revealed a radically shaped supersonic uncrewed combat air vehicle study. Jim Smith takes a look at what this means and what its shapes reveals.
The Uncrewed Air Combat System was reported at the International Congress on Aerospace Sciences (ICAS).
Background
3 years ago, I wrote an article for Hush-Kit about aerospace futures, which highlighted, among other things, the emergence of a systems-of-systems approach to air combat, which would integrated crewed uncrewed systems, onboard and offboard sensors and weapons systems, to create a survivable and persistent air combat capability. Here, I am using air combat in the fullest sense – not just air defence and strike, but also the enabling capabilities of surveillance, target location, air-to-air refuelling, communication and decision-making.
This article sought to identify the attributes, system elements and technologies which would be required to deliver such an air combat approach, and the recent appearance of the SAAB and BAE Systems work, along with other projects being delivered for the USAF and USN, in the UK, France, China and Australia serve to Illustrate the progress being made in this area.
In a broader warfighting context, the extensive role being played by uncrewed systems, at all levels of sophistication, in the Ukraine conflict with Russia, simply illustrates the key role such systems will play in the future Land, Sea, Air, and doubtless Space domains. Here’s a link to that article:
in addition to system aspects, this article suggests that three classes of platform will be required:
Persistent and or survivable uncrewed platforms ( for example, delivering surveillance, communications, EW and ELINT support, and some strike missions);
Attritable uncrewed platforms (current examples include weapons dropping commercial drones, seaborne attack using drone craft, and cruise missiles and other stand-off weapons); and
Crewed platforms, for use where real-time, on-the-spot, human decision-making is required.
SAAB UCAV
The SAAB UCAV (fittingly) has a somewhat Draken-like planform, with a highly swept inner wing forming a long strake ahead of an outer wing with lower leading edge sweep. The concept shown has an upper-surface engine intake, single-engine and butterfly tail surfaces, supplemented by elevons and flaps at the trailing edge. Under wing bays are shown on the wind-tunnel model, and appear generous in size in proportion to the vehicle as a whole, although the absolute scale is unknown.
To understand a vehicle like this, my approach is to see what can be inferred from the information available about what might be the design requirements for the platform, and then see what inferences can be drawn about its intended use. From the two figures showing aerodynamic information, we can see that these focus on two areas – supersonic wave drag, and vortex-fin interference.
The plot of area distribution is shown for three Mach numbers, Mach 1.0, Mach 1.4 and Mach 1.7, and these are compared with the distribution of a Sears-Haack minimum wave drag body. The comparison suggests thar the design Mach number for the concept appears to be likely to be close to Mach 1.7, because the distribution at this Mach number is pretty close to optimal. Additionally, a fixed intake of the sort depicted in the slides would perform reasonably well up to about this Mach number, but would probably be less efficient at higher speed.
The other aerodynamic slides relate to the flow about the upper surface of the vehicle at lower speeds. Specific data is shown on the interaction of the leading edge, forebody, and strake vortices, and their interaction with the butterfly fin empennage. This is unsurprising, since vortex lift from the forebody and strake will be important in enabling the UCAV to operate from reasonable runway length, and because undesirable vortex-fin interactions can lead to airframe damage and flight limitations. The figures show benign characteristics, at least at the (unstated) incidence and Mach number for which the figures apply.
The intake is mounted on the upper surface, with large bays in the flat under-surface of the fuselage. It is not evident what purpose the bays are intended for, gut the illustration with an open bay in the wind tunnel suggests their use as weapons bays. Current technologies suggest that the bays could be used for both air to surface and air-to-air weapons, and the relatively large volume of the fuselage suggests a reasonable range, or endurance, could be achieved. The supersonic capability of the design does, however, suggest that this is a penetrating, rather than a loitering system.
Potential Applications
What, then, might be the purpose of such a concept? As a flexible system, in a strike mission, such a UCAV could be used as a penetration aid, with the intent of striking threat radar, communications, electronic warfare, and defensive systems. It could also be used to deploy decoys and jammers to help conceal the location and intent of a crewed strike package, or be used on a one-way mission to increase the reach available against deep threats.
Use in an anti-air mission would also be possible, particularly if armed with a long-range weapon such as Meteor. Penetration of threat airspace might be aimed at deliberately provoking a response, with weapons release (or the use of smart decoys) making the UCAV threat un-ignorable, and forcing threat fighters to both expend weapons and manoeuvre aggressively, reducing their ability to respond to a follow up attack by crewed fighters.
Another possibility, though, would be a loyal wingman role, where cooperative use of passive sensors such as Infra-red Seeker Trackers or ESM equipment could allow triangulation and geolocation of ground-based targets; or tracking of aircraft through their heat signatures. Similarly, use of an active radar could allow either third-party targeting, or bistatic location of LO targets.
Use of the bays for other purposes, sech as active EW attack systems or tactical reconnaissance systems would also be possible.
Overall, the SAAB design looks like a starting point from which a family of flexible multi-purpose systems could be evolved. Of course, the concept shown at ICAS has been developed to research and understand the potential of this sort of vehicle, the problems which might need to be resolved, and the capability which might be available. As such, further development and system integration would be required before the appearance of a possible product, and the use of such a product would depend on future scenarios, and the capability of future weapons systems.
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Jim Smith
Jim Smith had significant technical roles in the development of the UK’s leading military aviation programmes from ASRAAM and Nimrod, to the JSF and Eurofighter Typhoon. He was also Britain’s technical liaison to the British Embassy in Washington, covering several projects including the Advanced Tactical Fighter contest. His latest book is available here.
Feb 2024
Hush-Kit 
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