Until a photo with an interesting caption appeared on the November 2012 issue of Air Force Magazine, few people had noticed that an F-35 display model at the Air Force Association Technology Expo 2012, had its weapon bays loaded with a brand new type of air-to-air missile: the Lockheed Martin “Cuda”.
Image credit: Air Force Magazine
“A Lockheed Martin model shows how its “’Cuda” concept for a small AMRAAM-class radar guided dogfight missile could triple the air-to-air internal loadout on an F-35. The missile is about the size of a Small Diameter Bomb and fits on an SDB-style rack.”
Photo caption aside, almost nothing is known about the “Cuda” missile.
“We are having some challenges getting information on Cuda cleared for public release,” Cheryl Amerine, Cuda POC at the Lockheed Martin Missiles and Fire Control, told The Aviationist.
“Cuda is a Lockheed Martin multi-role Hit-to-Kill (HTK) missile concept. Lockheed Martin has discussed the missile concept with the United States Air Force. The Cuda concept significantly increases the internal carriage capacity for 5th generation fighters (provides 2X to 3X capacity). Combat proven HTK technology has been in the US Army for over a decade. Bringing this proven HTK technology to the USAF will provide potentially transformational new capabilities and options for new CONOPS.”
The Hit-to-Kill missile technology Lockheed is designing for the USAF is still classified and some of the capabilities of the Cuda missile are being reviewed for public release. Still, something can be said based on the few details available.
First of all, the F-35 will carry kinetic energy interceptors: “hit-to-kill” weapons rely on the kinetic energy of the impact to destroy their target. That’s why some HTK missiles don’t carry any warhead (others use a lethality enhancer warhead).
Image courtesy of Lockheed Martin
HTK technologies can be used for missile defense (Scuds, rockets or even ballistic missiles). Is someone at the Pentagon studying the possibilty to use F-35s carrying clusters of Cudas as aerial anti-missile systems to intercept small rockets, SAMs (surface-to-air missiles)?
Second, that unlike Sidewinders, Cuda missiles, rather than being equipped with an IIR (Imaging Infra Red) seeker, will be radar-guided. This means they will be ejected from the internal bays in such a way the exposure of the stealth plane is reduced.
Third, the possible integration of the Cuda with the F-22: since a Raptor can carry eight SDB, it can theoretically carry up to eight Cuda, even if the perfect air-to-air loadout could be mix of AIM-120 AMRAAM, AIM-9X and Cuda missiles.
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Follow up: A LHM spokesperson has confirmed that it’s a MRAAM.
Given that they’re saying it’s an AMRAAM class weapon, I think that it’s safe to say that the range is >50km. It sounds like a combination of -9X agility, with MRAAM NEZs. If this can be achieved, and come it at an acceptable cost, it could vastly increase capabilities.
The yellow band is likely to indicate pyro in the divert motor section but could also be a small ‘lethality enhancer’ designed to breakup the missile body into tumbling chunks to maximize kinetic coupling to the target. From my studies of AShM, I would say at least half of target impact damage with the motor still burning is from high energy motor fragments acting as incendiaries and if the weapon motor burns back to front, that means opening up the forward edge of the motor case to kick out chunks of the HTPB.
Further to the range theories, the original illustrations of this missile were associated with the F-22 which has the advantage of a much higher launch Mach as altitude. AIM-4 Falcon off of dedicated interceptors like the 102 and particularly the Six had a 50% longer range (as well as proto ALASCA capability) than when carried by F-4D/E because the missile -system- was designed to be punched through the Mach before launch which is where 90% of your fineness ratio and body diameter as frontal crosssection issues arise. Once you put a shock on the tip, it’s more about forebody shaping and fin design containing the supersonic body flows and here the CUDA is noticeably better than the AIM-120.
From the aspect ratio of the fins, I would in fact suggest that this is a weapon which is either considerably higher Mach pointed than AIM-9X and/or expects to do all of it’s terminal steering off the Pif-Paf upfront because while the tail controls are still sizeable, the mid body wings are more strakes than wings.
The key differentiating point here may be that the weapon cannot in fact be fired ‘at advantage’ from F-35s because the ability of the Lightning to plow through the Mach in IRT without progressive drag rise slowing it to a crawl of acceleration compared to the Raptor is well documented with a 15 second drag rise problem on the A/B and a nearly 50 second problem with the C.
If, as the article suggests, the CUDA will have secondary roles that include SEAD (GBU-39 takes upwards of five minutes to accomplish midrange flyout because the wings deploy immediately and it isn’t powered like AASM, it is thus a -lousy- ARM replacement) and active missile intercept, for which the ability of a small weapon to be high-density loadout compatible is crucial in dealing with saturation attacks by systems like the SA-10/20/21 or Su-27 AA-12 ‘without running’; the seemingly contradictory requirements of absolute range and instantaneous ability to match inbound threat high terminal energy as a means to cancel trajectory offsets will be mandatory.
In hittile missile intercept, you must literally have enough energy on the missile body such that shunt motor divert doesn’t come ‘too late’ in the intercept closure to match random or deliberate terminal evasion gaming by the threat weapon, causing the weapon to be too slow to move across after deflecting into the vector (this may also be part of why the missile body is so short, to provide adequate stiffness).
That such an approach also works well for boost-coast trajectory mechanics in SEAD strike on ground targets can be seen if the weapon slides from Mach 6 to 80K instead of a direct shot of Mach 4 from 30K. Essential if you are going to remain medium level and yet outside the 20-series SAM WEZs.
Stealth allows the shots to be delivered preemptively rather than reactively, based on UAV or overhead cueing which means absolute range rather than shortest time of flight may still be a consideration, provided it’s not the basement level 250-300 knots of an SDB.
Air to Air, a subsonic F-35 would likely be pole inferior whether using AIM-120C and quite possibly with D to both R-77PD and Meteor equipped threats. Best case, all of the AMRAAMs launch ranges would still overlap with the AESA cueing distance for the Soviet OLS, French OSF or British PIRATE systems as much as the threat shots themselves.
This must be a consideration where focussed scan by a high power AESA can ‘pull’ a VLO threat from a jammer saturated background with particular waveform/PRF modes as peak power interactions (literally building an impedance load on the jet until it becomes a regenerative return) and ironically, this may be why less consideration is given to absolute range of the weapon than what I will call ‘first impact’ distance.
Here is why: If a rocket boosted weapon has a 40-60nm range from a Mach 1.5 launch and a 15-25nm range from a Mach 1.25 launch and a 12-15nm range from a Mach .85 launch, the overall concern is not one of how far the weapon will go but how close it must come before the target airframe, with essentially unlimited impulse as deep fuel tanks, cannot exceed it’s physical ability to alter it’s A-Pole trajectory point as seeker acquisition cube with energy gulping midcourse trajectory updating.
If motor ignition at launch gives you a 50nm IR blip and AB gives you a 25nm blip (and it may well be reversed or equal, depending on chosen operative wavelength and technology base) then the fact is that the target is going to be able to pump and move away from the point where the missile’s terminal energy would be sufficient to defeat it’s evasions.
Before it extends, it will fire a ramjet AAM whose lower cruise Mach (2.5-3) is compensated for by much more total impulse seconds which means it can make a slower transit and still be lethal when it arrives, probably MCG’d by a wingman. However; if a combination of tactics and stealth brings the launch point to the midrange position and the rocket AAM equipped aircraft fires a Mach 4-5 or even 6 capable shot at 15-25nm, it _does not matter_ who guides and who runs because the non-LO target cannot beat the much reduced time of flight as extension window and a threat’s Mach 3 ramjet weapon will either not reach terminals (because two can play the shoot and scoot game) before it loses seeker cube on the LO F-35.
Or, it will be shot down by a followon CUDA self-defense engagement.
In this, what you are essentially seeing is that it’s better for the VLO platform to delay launch to whatever point where IRST/Radar gets a natural skin pain and then accept the close in engagement with a hypervelocity round rather than play long-lance games over 40-60nm because the rocket’s peak Mach will beat the ramjet’s sustained Mach, _provided_ LO works to a given detection range threshold.
It is an interesting concept and the exact opposite of what one would assume likely in a gamed encounter between a low energy stealth plane and a high energy but widely separated (to provide safe BVR shot update and RCS aspect look angle) threat wall formation.
To which I would add that the Su-27, PAK-FA and MiG-35 as well as the Eurocanard Clones IRST mountings all have one thing in common: They are upper hemisphere biased towards an assumed higher altitude threat as the Raptor.
While there is no doubt some lookdown as a function of radome slope and arched spines, the overall effect is still one of opening a functionally huge virtual sill line as lower hemispher mask. Since the F-35 has small wings and a limited thrust trust resulting in roughly a 108lb/sqft wingloading an 1.02:1 T/Wr at gross mission weight, one must ponder how much of a mid/hi altitude band aircraft it is actually intended to be or whether it is in fact (at least for A2A) supposed to function as a snapup sniper that takes sensor handoff from other aircraft and then hides it’s burner sprint while using a CUDA’s high Mach to nail targets at hard crossing angles from offset orbit points, much closer in _and below_ the expected ‘medium altitude’ threat band of modern stealth.
Again reflecting the advantage of stealth + huge fuel fractions to early ingress entry at low level.
This certainly seems to be the emphasis of modern air combat training in Alaska wherein F-22s act as master sensor nodes and pass on data via suitably equipped RQ-4 BACN or ROBE KC-135 to secondary F-15/16/JAS-39/F/A-18 platforms which are full-signature displaced into the hidden mountainous terrain folds of the Alaska JPARC range complex.
(Time Index 3:39)
Such an approach would obviously work even better with a VLO asset, though there would be ‘hotside’ concerns to RCS shaping.
Finally, I believe the implication of the weapon being radar guided is a function of an overstated emphasis by the USAF on never employing IR weapons in LOAL pitbull mode without positive shot control. This obvious doesn’t apply in a world where the majority of ASRAAM, Python V and MICA-IR weapons are all comfortable with this capability and in fact use it to gain trans-merge options. An RAF Tornado F.3 shocked the blue force when it broke through their CAP and lofted an ASRAAM which killed an E-3 Sentry (albeit pyrhhicly, after the Tornado had been run down) from distances approaching what an MRM would have once been considered necessary to achieve. High altitude, high Mach, new sensor windows impervious to aero heating and strapdown autopilot that minimizes control surface trim drag in a lofted trajectory can do quite a bit to increase nominal range. In this it must be remembered that the early AAAM was in fact a 7″ booster can on a 5″ primary weapon and had well over 100nm absolute reach.
The USAF is of course more pragmatically concerned with maneuver combat and in this it must be noted that the IDFAF specifically trains to deconflict wingmen in the widebore HOBS shot environments of WVR combat so clearly it is possible to OTS fire a weapon across-circle at a target and steer the round into seeker acquisition under positive shot control.
We just don’t do it ourselves, yet, perhaps because the limited impulse of the Mk.36 motor of the early AIM-9X made such a concept rather functionally worthless.
I would have preferred to see a CUDA IIR capability for the simple reason that it makes A2G targeting simpler using onboard target fractal recognition softwarre derived from the EOTS or APG-81 imagery but we don’t know that this is not an MMW (35-94GHz) system similar the seeker once tested on ASRAAM and the scabbed Quickbolt system of AARGM. In which case it may be both capable of imaging and beyond conventional jammer/TRD spectrums in the I-J bands. The fact that they have essentially moved the guidance section into the radome area at the very least suggests a reduce array size if not a fullup MEMS seeker which is itself an impressive feat if it is operating in the K-M or W bands.
Again, AAAM used IIR underneath a frangible radome for aerodynamic reasons but did so in company with SARH so it may be that the USAF is thinking about either the requirements for a very high boost:coast weapon (up to Mach 6) and/or weather deck penetration rather than say, counter-LO for use against J-20 and PAK-FA specifically.
Finally, it must be considered that the F-35, being a less competent air to air platform than existing G4/4.5 airframes and operating in an imaging-seeker environment, is going to be the first to be equipped with TADIRCM. The F135 engine offers simply too huge a jet wake for conventional EXCM to work in a dogfight environment and the mass ejection of flares from a flat-plated airframe is not exactly a wise idea for any aircraft regardless. A high energy laser DIRCM which can ‘glaze the eyes’ of an EO weapon must thus be considered a valid option to prolonged maneuvering combat in which the F-35 is certain to lose the nose-point game anyway. The one precondition to this of course is that the aircraft have a functional alternative spectrum weapon and that may well be why CUDA is radar guided.
In any case, the notion that being ejected from a weapons bay mandates or rewards a particular guidance mode is a false one. It simply implies a tether and a wide angle SAIRST, a decent strapdown system on the missile and a functionally secure tether to steer the seeker into lane and the F-35 provides all of these things, in spades.
The yellow band just means it’s not a dummy warhead. They’re on all missiles. Green (I think) is a non live weapon for training.
Those classified “capabilities being reviewed for release” are the ability to intercept enemy air to air missiles and SAMs. The hit to kill technology and improving radar tech will allow intercepting enemy missiles while guiding your own missiles to the enemy aircraft. Even intercepting enemy ground launched SAMs may be possible
They’ll deploy small laser cannons in fighter aircraft way before they blow the money on these.
The AIM-9X has a ability(to my knowlege) to be fired then slaved to a target. Making this:
“Second, that unlike Sidewinders, Cuda missiles, rather than being equipped with an IIR (Imaging Infra Red) seeker, will be radar-guided. This means they will be ejected from the internal bays in such a way the exposure of the stealth plane is reduced.”
moot
It isn’t moot entirely because it allegedly has range comparable to the AIM-120D. Much longer range than an AIM-9.