BACK TO BASICS: STEALTH AND COUNTERMEASURES



Welcome to "Back to Basics"; an ongoing series in which we will attempt to "get back to basics".  Each week (or so) we will examine one crucial aspect of a fighter and how the fighters vying for Canada's FFCP compare. 

For a combat aircraft, speed and maneuverability are important factors in its survivability.  Once detected, a pilot may need to push an aircraft to its limits to avoid enemy fire.  Of course, the simplest way to avoid enemy fire is not get detected in the first place.  

Despite its widespread use in all the latest material, the concept of a stealthy aircraft is nothing new.  It began when combat aircraft were first painted in a disruptive camouflage pattern in WWI.  While this may seem basic by today's standards, one must remember that the most effective detection equipment of the day was the Mark I Eyeball.  Up until partway through WWII, one could avoid detection by utilizing cloud cover, flying out of the sun, or simply flying at night.  

The introduction of the radar changed all that however.  Aircraft detection was no longer limited by the constraints of the human eye.  The use of radar did not go unchallenged for long however...



One could argue that Germany's Horton Ho. 229 classifies as the world's first "stealth" bomber.  Utilizing a flying wing design similar to the B-2 bomber and utilizing radar-absorbing wooden construction, the aircraft reported had a much lower radar cross section than the smaller Bf 109.  

The Ho. 229 never saw production, however.  There is also some debate as to whether its stealthy design was intentional or not.  Its use of wood was more than likely decided by the lack of steel available to Germany in the later days of WW2.  

A far more effective foil against radar was just that:  FOIL.  

Radar of the day could be overwhelmed by dispensing strips of aluminum wire or foil backed paper.  This countermeasure, known as "chaff", puffs out a cloud of highly reflective material, obscuring the radar's view.  (This greatly simplify things)

To counter this, radar could differentiate chaff from its intended target by measuring the doppler shift.  

And thus began the continuing saga of radar, countermeasures, and counter-countermeasures.

F-4G mounting anti-radar missile and an ECM pod.
An in-depth discussion of stealth and countermeasures would fill volumes only to brush upon the subject.  Certainly more than we can discuss here in a single blog post.  Complicating matters is the fact that the technology behind it is constantly changing and evolving.  This forces us to take an overly simplistic view of the subject.  

In the broadest sense, there are two ways to detect an aircraft;  Active and passive.  

Active detection involves some outside source acting on the aircraft, usually electromagnetic radiation from a radar installation of some sort.  (RF signature)

Passive detection utilizes energy given off by the aircraft itself.  This usually means the infrared, or heat, radiation.  (IR signature).  

Similarly, an aircraft can "disguise" itself utilizing passive or active methods.

Passive countermeasures (ie "Stealth) concentrate on reducing the emissions produced or reflected by an aircraft.  For radar, this is done by absorbing radar signals, reflecting those signals away from their source.  For infrared detection, this is done by reducing the IR signature by actively cooling hotter parts of the aircraft or tucking the engine exhaust away and out of sight (like the B-2).  

Active countermeasures usually concentrate on overwhelming enemy detection equipment, obscuring the true picture by providing additional false targets.  For radar this is done by broadcasting false radar signals, or jamming.  It can also be done by providing false targets by use of chaff or decoys.  For infrared detection this can be done by providing confusing the sensor by use of flares or even lasers.  

To use an analogy to put things in even simpler terms, stealth is akin to a ninja sneaking into a room.  Active countermeasures is more like throwing a flash-bang grenade into it.  

Saab's Arexis jammer pod
Ranking the stealth and countermeasure capabilities of the Canada's FFCP contenders is no easy task.  While it may seem obvious at first glance, there are A LOT of caveats that come up.  Stealth, countermeasures, and electronic warfare are basically "black arts", with specific information about each aircraft being sparse at best.  Each aircraft broaches the subject in different ways as well.  

While I typically rank these worst-to-best based strictly on my humble opinion, I cannot do the same here.  While the F-35 is clearly the most stealthy, the EA-18 has the most powerful jamming capability...  But it is a specialized variant of the Super Hornet that Canada may not even procure.

Consider the rankings here accompanied by a healthy disclaimer, shrugged shoulders and a hearty:  "I guess?"

EA-18G Growler

Let me make this abundantly clear:  The EA-18G Growler does not belong on the bottom of this list.  It could easily be placed at the top.  With the addition of the upcoming Next Generation Jammer (NGJ), it likely would.  

At the present, the EA-18G does not appear to be included in Boeing's offer to Canada.  Perhaps, if it is selected, Canada could pursue a similar path as Australia and take advantage of a mixed fleet of Super Hornets and Growlers.  It could also look into the "hybrid" concept proposed by Boeing that utilizes the sensor suite of the Growler without the jamming capability.  

As it currently stands, however, Canada seems to be concentrating on the "plain-Jane" Block III Super Hornet.  Certainly no slouch, it still stands as a vast improvement over the CF-18 when it comes to stealth and countermeasures.

Despite being a larger aircraft, the Super Hornet has a smaller RCS (radar cross section) than the legacy CF-18.  This is thanks to the liberal use of radar absorbent material (RAM) and tweaks to its overall design (like the intakes that match the angle of the tail fins).  The use of an AESA radar also greatly reduces the RCS of the aircraft, while simultaneously reducing radar emissions.  

When it comes to active countermeasures, the (non-Growler) Super Hornet seems unspectacular.  There is nothing specifically wrong with it, it just does not stand out in any particular way.  The Harris AN/ALQ-214(V4) provides the usual signal jamming, towed decoy, and the like.  It is a similar system to that utilized by many American fighters.  It does lack a missile approach warning (MAW) system, a glaring omission for a modern combat fighter.  

In its default mode, the F/A-18E/F Block III is has perfectly fine stealth and countermeasure capabilities...  Just nothing really noteworthy.  


Gripen E EW suite

One would be excused for thinking the modest Saab Gripen to be lacking in stealth and countermeasures.  Saab intentionally left out any pretense to stealth during its design, knowing that stealth invariably adds cost.  Instead, Saab decided to utilize Sweden's proficiency with radio transmitters.  (Remember that telecommunications pioneer Ericsson is a Swedish company.)

Despite not having any typical stealth characteristics, the Gripen does have a relatively small RCS.  This is almost coincidental thank to other design features of the airplane.  Most obviously, its small size and frontal area come to play here.  The Gripen also tucks away its engine fan, which would normally light up like a disco ball on radar.   It also utilizes plenty of composites in its construction to save weight, which also happen to reflect less radar signal.  The Gripen's smaller size and single engine also happens to emit less heat.  

For its E variant, Saab decided to place a great deal of focus on the Gripen's electronic warfare suite.  Indeed, one of the most recognizable feature of the "Echo" variant are the large "Q-tip" shaped wingtip pods.  These pods act as built in ECM pods, both detecting radar signals and (soon) jamming them.  Saab has gone to great efforts to advertise the fact that they are the first to utilize gallium nitride (GaN) in their radar and EW systems, allowing for higher power and efficiency.  To further enhance survivability, Britecloud decoys can be deployed, as can the usual chaff and flares.  The Gripen also incorporates MAW sensors, a feature lacking in the Super Hornet.  

Saab has even developed its own electronic warfare pod.  This EW pod, compatible with the Gripen E, offers capabilities beyond self-defense.  Much like the AN/ALQ-99 or NGJ found on the EA-18 Super Hornet, the Arexis low-band jammer acts as a "escort jammer".  This protects not only the aircraft carrying it, but the aircraft around it, turning the Gripen into a sort of "mini-Growler".  

While it may lack the JSF's devotion to stealth or the Super Hornet's Growler variant, the Gripen E does offer a rather unique middle ground between the two.  


F-35 EW suite

The F-35 Lightning II is far and away the stealthiest aircraft available to Canada.  

Unlike the others, the F-35 was designed with stealth as a priority.  It is the only FFCP candidate with all-aspect stealth, internal weapon carriage, and the like.  One can argue the merits of stealth for Canada's needs, but no one can argue that the JSF is definitely the stealthiest aircraft on offer.  

Even without stealth, the F-35 does have an impressive EW suite.  Much like its stealth design, most of its countermeasures are built into the airframe rather than being incorporated into external pods.  Integrated into various parts of the aircraft, the AN/ASQ-239 turns the entire aircraft into a ECM pod.  Even the F-35's AN/APG-81 radar can be used to transmit a powerful enough signal to act as a stand-off jammer.  Keep in mind that the F-35's reduced RCS also makes it easier to obfuscate through radar jamming.  

The F-35's stealthiness is not without its weaknesses, however.

Even with its recessed engine nozzle, the F-35 produces a substantial amount of heat from its large, single engine.  If the JSF ever got close enough to be detected by IRST, its stealth features would quickly become irrelevant.  It should also be known that the F-35's stealth focuses on X-band radar.  Different wavelengths, like VHF can be used to much better effect.  There are also emerging technologies, like passive radar, that limit the F-35's stealth as well.  

Still, the F-35 remains the stealthiest aircraft available, while also mounting an impressive EW suite.  There is also the possibility of it mounting a version of the NGJ as well, possibly internally.    


"We're gonna shoot a SAM site before it shoots us? YGBSM!"
No pilot in their right mind would intentionally fly into heavily contested airspace without some sort of protection.  Even with protection, it is not a welcome subject.  In the skies over Vietnam, specially equipped aircraft were tasked with doing just that.  Their mission was to fly toward enemy radar and missile batteries with the intent of clearing a path for others.  These aircraft, known as "Wild Weasels" were tasked with suppression of enemy air defenses, or SEAD.  This soon received the motto ''YGBSM" as in "You Gotta Be Shitting Me!"

Such is the grim reality of air combat.  

The reality is constantly changing, however.  While much attention is placed on hardware, it is important to remember that software plays just as important of a role.  Radar signals are interpreted by computers, computers that can be continually upgraded with more sophisticated algorithms that not only increase the sensitivity and range, but also help distinguish false signals.  Such is the cat-and-mouse game of electronic warfare:  Every advancement seems to be met by a new countermeasure.  

Stealth may only play a part in an aircraft's survivability.  How large a part remains to be seen.  What is for certain is that, for the foreseeable future, adaptability will be key.  New threats will arise, with new counters for those threats.  Stagnation will result in obsolescence.  



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