A 6th generation combat aircraft for Europe

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The normal ideas for a 6th generation fighter / combat aircraft follow the established triad of air dominance fighter (F-22 continuation), strike fighter (F-35 continuation) and bomber (B-21?).

The usual expectation is that more gadgets will be added (including lasers powerful enough to at least damage optical and thermal sensors). It's also widely believed that a 6th generation combat aircraft will be optionally manned if not outright unmanned, and cooperate with drone 'wingmen'.

I have my own thoughts about what would be sensible instead, and I only really pay attention to defence of Europe. So the scenarios are either an air power-supported land war in Eastern Europe (worst case vs. Russia, PRC and Turkey at the same time) or an air/sea war with land-based air power and air defences facing seaborne aerial threats (including quasiballistic missiles). The latter scenario is of lesser importance, as it relies on the U.S. turning full-blown fascist and hostile and they could alternatively use SpaceX Spaceships to haul warheads into low orbit for bombarding Europe (by the 2030's). So the main scenario is a land/air war in Eastern Europe.

There are many land-based, non-manned aviation alternatives to manned air power and even many ground alternatives to most unmanned airpower, such as firing quite cost-efficient surface/surface missiles at targets within 120...500 km.

A 6th generation combat aircraft would thus have to be able to hide on airbases and airports 500+ km away from the ground combat and it could best justify its huge expenses by filling unoccupied tactical niches. I will probably later publish a draft text on what can substitute for manned air power in what roles. For this blog post I'll just state that I think about a survivable radar platform for about 60,000 ft altitude, using radars both to find air targets and ground targets, albeit this may be done by different aircraft versions with different radar bands.

unofficial X-44 Manta depiction, (c) Fox 52

The platform would be roughly similar to the X-44 concept, albeit with more spaced turbofan engines and consequently a single centreline underbelly air inlet (to still have S-duct).

I chose the X-44 concept as a starting point because the entirely tailless design helps much with radar stealth.

The spacing would be necessary to enable having the same radar in the tail as in the nose (thrust vectoring might be limited by the radome). The radar would use a rotating ~45° angled AESA antenna, enabling semispheric coverage for each nose and tail radars and thus full spherical overall radar coverage. The aircraft could freely manoeuvre at 60,000 ft with supercruise speed (afterburners not needed, actually).

All missiles would be kept in a central rotating magazine weapons bay (or two) between the turbofans, similar to what some bombers have. There would be at least six missiles and a few free-flying DRFM decoys in there.

https://www.thedrive.com/the-war-zone/31799/proposed-facility-would-drastically-cut-down-time-required-to-arm-bombers-on-guam

The missiles would mostly be dual purpose missiles, capable of hard-killing incoming rockets and killing pursuing aircraft at similar ranges as today's best infra-red guided missiles. This entire aircraft's purpose would be more similar to today's AWACS (AEW) and J-STARS aircraft than to a F-22. 

Munitions would primarily be fired from the surface, but the bird's view at 60,000 ft is an important niche capability to make full use of such surface-based munitions.

The idea is to feed radar data from bird's view perspective into a networked air and ground war effort. This includes air contact data (detection by L-band radar) and ground contact and ground mapping data (X-band). A detected hostile fighter would not be engaged by this aircraft, but by ground-based missile launchers at command of a ground-based air war command. This aircraft concept would not be meant to fly over hostile ground, but it would be able to venture out to sea (Baltic or Black Sea, for example) and its stealth, flying performance (altitude, speed) and missile countermeasures would enable it to fly close enough to the ground battle for a useful field of view into hostiles-controlled terrain.

The X-band radar version (not both radar versions on one plane) could use leads given by the longer avelength L-band version to determine the vectors of aerial contacts more accurately than even the combined contact info of multiple L-band version aircraft. The X-band radar would still mostly look at the ground (or surface at sea) and at what flies or floats below the surface radar line of sight, though.

The countermeasures would include at least one laser powerful enough to render infrared, UV and visible light seekers on missiles near-useless and possibly even to badly damage the seeker of active radar-guided missiles. The dual purpose missiles would try to trigger the fuse of hostile missiles, but also try to damage or destroy said missiles (maybe even with EMP warhead against radar-guided missiles?).

The aircraft would transit about 500 km per sortie, so a useful on-station duration of one hour would require about 3,000 km range in a high-supercruise-high flight profile with full missile load. This range, the survivability features, the munitions bay and the two big radars would lead to an aircraft rather a bit larger than the F-22. This causes huge challenges on the ground, as hiding would be difficult. Moreover, such a highly complex aircraft would rather not permit sustaining more than one such two-hour sortie per day, and midair refuelling wouldn't help much to extend flying hours per day, but require much extra effort and permit more distant basing.

So assuming we would need 10 on station, that would be a total requirement for 240 aircraft + reserve for not ready aircraft (another 100 maybe) + attrition reserve. The required total might be 500, difficult to afford for such a niche capability. 10 on station might not even suffice to satisfactorily cover the entire span from North Cape to Suez Canal or Caucasus region for NATO. Maybe the cost would be prohibitive, ensuring that an approach with only low altitude drones and ground-based equipment replaces the air war even if the opposing forces still insist on air power as we know it.

S O

defence_and_freedom@gmx.de

 

edit: You may have read that L band is no magic bullet against RF stealth and requires huge antennas to  create a narrow beam main lobe. Wavelengths longer than X-band are not much used in fighters because they are indeed not so good at accurate 3D measurements. Whatever band would be used (could be UHF for LO air threat detection, actually) doesn't matter so much. Longer wavelengths are worse for angular resolution, but fine for ranging. Two radars may detect and track a target over time getting just 10...20° angular resolution, but accurate distance readings. Their own position would be known accurately. Fusing thee two tracks allows for computing the position of the contact even if there are many contacts at the same time in the same beam. The algorithms for this are fairly straightforward; you just need to rule out implausible movements. Finally, you get a position accurate enough that a high-powered X-band radar can stare at it, switch off filters for a short range band in its narrow beam and even a tiny echo would suffice to detect a LO cruise missile at a useful distance. Moreover, LO aircraft contacts can be confirmed with zoomed IIR cameras.

Finally, long wavelength radars can move their main lobe to determine when the contact doesn't generate such a strong echo any more (because the main lobe ends), they do not just get the ibinary info whether contact is detected by main lobe or not. (See here for basic info on radar lobes: https://basicsaboutaerodynamicsandavionics.wordpress.com/2016/08/11/radar-fundamentals-part-ii/ )

The requirement for having two long wavelength radars 'seeing' the same contact does add to the quantity of radars that need to be in action (and thus radar airraft on station), of course.

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