You have no doubt heard of the F-35 or F-22 and wondered why these aircraft are so damn expensive, and why they are so controversial. I can't seek to answer those questions for you, but I can help to explain the academics behind fifth generation aircraft and their low observable (or "stealth") technology.
A reminder that I do not speak for anyone other than myself as defined in the site's Terms of Service, paragraph three. Furthermore, all of the information contained below is open source, albeit in highly disparate sources; I will credit sources where appropriate. Additionally, though I may use an air frame as an example (i.e. F-35, F-22, C-130), and may cite random figures (e.g. 30 meters squared), there is absolutely no math taking place in this blog post and all figures are completely and totally made up for the sole purposes of academic instruction. There may be math conducted in many of my sources, however, so if that's what you're looking for then you should click on the links throughout this post.
To repeat myself: All figures are completely and totally made up for the sole purposes of academic instruction.
Alright, so now that I've ensured that I'm not sued, fired, or imprisoned let's move on to why you're actually reading this blog post. Before we can look at low observable (LO)/stealth aircraft, we have to understand radar. Radar stands for Radio Detection and Ranging and utilizes radio waves to detect and analyze objects in the distance.
There are a lot of factors that come into play here (i.e. pulse width, duty cycle, pulse repetition frequency, and scan type), but you're here to learn about stealth aircraft and not radar, so we're going to gloss over these (click here or here for more detail). The radar dish will then remain idle for a time to receive any returns that might be coming, and analyze these returns to determine what it's seeing. The strength of that return is known as the radar cross section (RCS), and plays a pivotal role in a radar's ability to determine what objects are birds and which are planes.
Again, there is a whole lot of math and quite a few factors at play for determining the RCS of an object that we're just going to gloss over. The main factors that we're going to touch on are: Shape and Size (Material is also a big factor, but is outside the scope of this post).
These factors all go together to determine the RCS, which is a representative number that determines at what range a radar can detect an object. The RCS is represented in meters squared and the smaller the number, the closer the aircraft has to be to be detected by a radar.
To help illustrate this, consider that you placed a Volvo (10 meters squared) and a coffee mug (.0025 meters squared) at the end of a football field. Most of us could see the Volvo from the end field, and those of us with really good eyesight might even see the coffee mug. However, for some of us, we might need to move the coffee mug closer to us; restricting our visual range for observing that object. Radar works in much the same fashion; the smaller the RCS, the smaller the object is to the radar and the closer it must be to be observed.
This is fairly important for several reasons, not least of which is the simple fact that you cannot shoot what you do not know exists. Hollywood movies like to highlight the importance of "heat seeking missiles," but most modern warfare is conducted now beyond visual range and relies heavily on radar guided missiles. These are an impressive jump in technology, but they do rely heavily on your ability to detect the target on your radar.
Low Observable Aircraft
& the New Arms Race
LO aircraft are designed to take advantage of shape, material, and size in order to reduce their radar cross section to as low as is humanly possible. They also use radar jamming to further restrict enemy aircraft or surface to air missiles (SAMs) from locating them. The primary method of employment for these LO aircraft is to neutralize enemy aircraft and SAMs before the adversary even knows that LO aircraft is in the area.
This relies pretty heavily on the beyond visual range tactics that I briefly mentioned earlier and neutralizing enemy aircraft before they have the opportunity to even fire. This has been the standard training and operational method within the USAF since Desert Storm as monumental gains in proficiency and technology have made it more efficient than relying on WWII era dog fighting.
While air-to-air kills have been fairly infrequent (AQI and ISIL don't exactly have an air force), the primary role of air superiority fighters (e.g. F-22) and multirole fighters (e.g. F-35) was never to combat insurgents, but rather near peer states (i.e. China or Russia). As Lockheed Martin and the US government export the F-35 to allied nations who might get a lot of use out of them, their primary role within the US remains to be seen.
More likely than not, the existence of fifth generation aircraft is signaling the start of a new arms race in which the four major super powers (European Union, United States, Russia, and China) are modernizing their air forces to ensure their pilots are able to fly longer and strike further against any adversary they may encounter. This recent push to modernize is likely an attempt for those powers to retain their competitive edge in a global deterrent based strategy similar to that of the Cold War. However, unlike the Cold War, these weapons can be used and exported without fearing for their direct contribution to humanity's destruction.
It is, of course, impossible to know exactly what any political leader is thinking or how these aircraft will actually be used (if ever), so it remains to be seen if the significant (but not unheard of) investment in modernization will ever see a return, assuming that the general population can even determine what constitutes a "return." Is a return on investment for something like this measured in the number of air-to-surface strikes, air-to-air kills, number of adversary actions deterred, or the numbers of aviation technologies advanced?
It's fairly easy to gauge public opinion on something like this, especially in today's hyper-connected world, but it's much harder to measure the effect of a new technology until many decades after its existence.