One of the main competitors for this replacement program is the Lockheed Martin F-35 Lightning II. The aircraft is described as a “5th Generation fighter, combining advanced stealth with fighter speed and agility, fully fused sensor information, network-enabled operations and advanced sustainment.”
For many the most important part of the proceeding description is “stealth”. It is the attribute which seems to set the F-35 apart from all its contemporaries. So just what is the big deal about Stealth?
It has never been easy to convey what low observable technologies actually do. Understanding them requires some grasp of physics, of radar phenomenology, of aircraft design, and of how missions are planned and executed. Rebecca Grants’ paper “The Radar Game”, issued by the Mitchell Institute in 2010, is still one of the most accessible discussions of the subject available.
The point of Stealth is to reduce an object’s detectability across the electromagnetic spectrum but most importantly to radar. In this case the goal is to minimize the electromagnetic energy reflected back to radar so that the signal cannot be used for fire control solutions.
Traditional aircraft are vulnerable to radar detection for all the reasons that increased their aerodynamic qualities and performance in the first place. That is things like metal skins, large vertical control surfaces, and big powerful engines.
There is also a wider electromagnetic spectrum to consider. While radar is the main focus here, survivability can depend on taking measures to reduce visual, acoustic, and infrared signatures as well as minimizing telltale communications and targeting emissions.
Among passive technologies the favorite is infrared search and track. While it is not as often in the headlines as radar, designers of all-aspect stealth aircraft have worked since the 1970s to minimize infrared hotspots on aircraft.
It is also true that electronic countermeasures will have a role to play. It will always take a combination of survivability measures to assure mission accomplishment.
It is important to remember that the goal of ‘Stealth’ is not to make an aircraft invisible. For example, it may be difficult to prevent a blip on the kinds of long-range, low frequency radars used for initial detection, however it takes much more than a blip on a “Tall King” radar to unravel a well-planned mission. An aircraft designed to be stealthy in relation to radar gains advantages in how close it can come to air defense systems; it does not get a free pass in the battlespace.
Having said all that, it is essential to understand the advantages, and limitations, that radar stealth can grant.
Aviation Week & SpaceTechnology has analysed, using open source material, the relative advantages of various aircraft in relation to radar cross section.
They suggest that, based on figures released by the manufacturer, that the Su-35 can detect a 3-m2 target at 400 km (250 mi.). Keep in mind that large “fourth-generation” fighters such as the F-15, Su-27 and Tornado have radar cross-sections (RCS) of 10-15 m2. The F-16 and “Gen-4.5” fighters—Typhoon, Rafale, Su-35 and Super Hornet are believed to be in the 1-3-m2 range. Of course the figure is larger if external stores are carried.
The F/A-18E/F, which Boeing says employs the most extensive RCS-reduction measures of any non-stealth fighter, is reported at 0.66-1.26 m2
Based on these figures, A.W. & S.T. estimates that aircraft such as the F-15, the Tornado or Su-27 would be detected at a range of 335 to 370 miles (540 to 600 kilometers). Aircraft such as the F-18, F-16, Su-35 and Typhoon would register at ranges of 185 to 200 miles (300 to 400 kilometers).
On the other hand the F-35 and F-22 RCSs are said to equal a golf ball and marble, respectively which means that the Su-35 cannot detect an F-35 until it is within 36 mi. and inside 22 mi. for an F-22. And the U.S. fighters can launch their medium-range AIM-120 AMRAAMs from more than 60 mi. away. Also, that detection range is for a maximum-power, narrow-angle search. In conventional search mode, the detection range is half as much.
As Aviation Week & Space Technology points out in that article, the same arguments can be applied to the efficacy of stealth aircraft in relation to ground based air defence systems.
The latest S-400 surface-to-air system is feared for many reasons, including its longest-range (380-km) missile, but it cannot fire until its Gravestone radar has a target. According to the manufacturer that radar can detect a 4-m2 target at 250 km (155 mi.). This is good against “reduced RCS” fighters, but the F-35 would not be seen until 21 mi. away and the F-22 13 mi. away. The kind of internally carried Small Diameter Bombs used by these aircraft can be dropped from more than 40 mi. away.
Given these figures it can be argued that stealth aircraft will have an advantage over the kinds of weapons systems current fielded by our potential opponents. A contrary conclusion would be that if “fourth generation” aircraft were to be provided with longer range weapons they could just as easily overcome those systems.
Complex technologies like stealth cost money to field and the price of excellence is nothing new. The premier US night fighter of late World War II was the P-61 Black Widow. Its power and performance came with a high price however. It is reported that with Northrop’s assembly line in full gear, a completely equipped P-61 cost $180,000 in 1943 dollars, three times the cost of a P-38 fighter and twice the price of a C-47 transport.
High technology still carries a substantial price tag; the question for the Canadian Fighter Replacement Program therefore becomes, will stealth aircraft pay back the investment in combat value? The answer to that question is a big deal indeed.
Replacing Canada’s CF-18 Fleet
F-35 Lightning II
The Radar Game
Measuring Stealth Technology's Performance
Conquering the Night Army Air Forces Night Fighters at War - Stephen L. McFarland