F-15 An/Apg-63 Radar Case Study Report Essay

The Flying Leatherneck Aviation Museum is proud to celebrate the 35th Anniversary of the F/A-18 Hornet. Below is a snapshot of the aircraft and its significance throughout history:

The McDonnell Douglas (now Boeing) F/A-18 Hornet is a twin-engine supersonic, all-weather carrier-capable multi-role combat jet, designed to dogfight and attack ground targets (F/A designation for Fighter/Attack). Designed by McDonnell Douglas and Northrop, the F/A-18 was derived from the latter's YF-17 in the 1970s for use by the United States Navy and Marine Corps. The Hornet is also used by the air forces of several other nations. The U.S. Navy's Flight Demonstration Squadron, the Blue Angels has used the Hornet since 1986.

The F/A-18 has a top speed of Mach 1.8. It can carry a wide variety of bombs and missiles, including air-to-air and air-to-ground, supplemented by the 20 mm M61 Vulcan cannon. It is powered by two General Electric F404 turbofan engines, which give the aircraft a high thrust-to-weight ratio. The F/A-18 has excellent aerodynamic characteristics, primarily attributed to its leading edge extensions (LEX). The fighter's primary missions are fighter escort, fleet air defense, Suppression of Enemy Air Defenses (SEAD), air interdiction, close air support and aerial reconnaissance. Its versatility and reliability have proven it to be a valuable carrier asset, though it has been criticized for its lack of range and payload compared to its earlier contemporaries, such as the Grumman F-14 Tomcat in the fighter and strike fighter role, and the Grumman A-6 Intruder and LTV A-7 Corsair II in the attack role.

The F/A-18 Hornet provided the baseline design for the Boeing F/A-18E/F Super Hornet, a larger, evolutionary redesign of the F/A-18. Compared to the Hornet, the Super Hornet is larger, is heavier, and has improved range and payload. The F/A-18E/F was originally proposed as an alternative to an all-new aircraft to replace existing dedicated attack aircraft such as the A-6. The larger variant was also directed to replace the aging F-14 Tomcat, thus serving a complementary role with Hornets in the U.S. Navy, and serving a wider range of roles including refueling tanker. The Boeing EA-18G Growler electronic jamming platform was also developed from the F/A-18E/F Super Hornet.

Entry into service

McDonnell Douglas rolled out the first F/A-18A on 13 September 1978, in blue-on-white colors marked with "Navy" on the left and "Marines" on the right. Its first flight was on 18 November. In a break with tradition, the Navy pioneered the "principal site concept" with the F/A-18, where almost all testing was done at Naval Air Station Patuxent River, instead of near the site of manufacture, and using Navy and Marine Corps test pilots instead of civilians early in development. In March 1979, Lt. Cdr. John Padgett became the first Navy pilot to fly the F/A-18.

Following trials and operational testing by VX-4 and VX-5, Hornets began to fill the Fleet Replacement Squadrons (FRS) VFA-125, VFA-106, and VMFAT-101, where pilots are introduced to the F/A-18. The Hornet entered operational service with Marine Corps squadron VMFA-314 at MCAS El Toro on 7 January 1983,and with Navy squadron VFA-25 in March 1983, replacing F-4s and A-7Es, respectively.

The initial fleet reports were complimentary, indicating that the Hornet was extraordinarily reliable, a major change from its predecessor, the F-4J. Other squadrons that switched to F/A-18 are VFA-146 "Blue diamonds", and VFA-147 "Argonauts". In January 1985, the VFA-131 "Wildcats" and the VFA-132 "Privateers" moved from Naval Air Station Lemoore, California to Naval Air Station Cecil Field, Florida, and became the Atlantic Fleet's first F/A-18 squadrons.

The US Navy's Blue Angels Flight Demonstration Squadron switched to the F/A-18 Hornet in 1986, when it replaced the A-4 Skyhawk. The Blue Angels perform in F/A-18A and B models at air shows and other special events across the US and worldwide. Blue Angels pilots must have 1,350 hours and an aircraft carrier certification. The two-seat B model is typically used to give rides to VIPs, but can also fill in for other aircraft in the squadron in a normal show, if the need arises.

Combat operations

The F/A-18 first saw combat action in April 1986, when VFA-131, VFA-132, VMFA-314, and VMFA-323 Hornets from USS Coral Sea flew SEAD missions against Libyan air defenses during Operation Prairie Fire and an attack on Benghazi as part of Operation El Dorado Canyon.

During the Gulf War of 1991, the Navy deployed 106 F/A-18A/C Hornets and Marine Corps deployed 84 F/A-18A/C/D Hornets. F/A-18 pilots were credited with two kills during the Gulf War, both MiG-21s. On 17 January, the first day of the war, U.S. Navy pilots Lieutenant Commander Mark I. Fox and his wingman, Lieutenant Nick Mongilio were sent from the USS Saratoga in the Red Sea to bomb an airfield in southwestern Iraq. While en route, they were warned by an E-2C of approaching MiG-21 aircraft. The Hornets shot down the two MiGs with AIM-7 and AIM-9 missiles in a brief dogfight. The F/A-18s, each carrying four 2,000 lb (910 kg) bombs, then resumed their bombing run before returning to Saratoga.

The Hornet's survivability was demonstrated when a Hornet took hits in both engines and flew 125 mi (201 km) back to base. It was repaired and flying within a few days. F/A-18s flew 4,551 sorties with 10 Hornets damaged including two losses. The two losses were U.S. Navy F/A-18s and their pilots were lost. On 17 January 1991, Lieutenant Commander Scott Speicher of VFA-81 was shot down and killed in the crash of his aircraft. The other F/A-18, piloted by Lieutenant Robert Dwyer was lost over the North Persian Gulf after a successful mission to Iraq; he was officially listed as killed in action, body not recovered.

As the A-6 Intruder was retired in the 1990s, its role was filled by the F/A-18. The F/A-18 demonstrated its versatility and reliability during Operation Desert Storm, shooting down enemy fighters and subsequently bombing enemy targets with the same aircraft on the same mission. It broke records for tactical aircraft in availability, reliability, and maintainability.

Both U.S. Navy F/A-18A/C models and Marine F/A-18A/C/D models were used continuously in Operation Southern Watch and over Bosnia and Kosovo in the 1990s. U.S. Navy Hornets flew during Operation Enduring Freedom in 2001 from carriers operating in the North Arabian Sea. Both the F/A-18A/C and newer F/A-18E/F variants were used during Operation Iraqi Freedom in 2003, operating from aircraft carriers as well from an air base in Kuwait. Later in the conflict USMC A+, C, and primarily D models operated from bases within Iraq.

An F/A-18C was accidentally downed in a friendly fire incident by a Patriot missile when a pilot tried to evade two missiles fired at him and crashed.[29] Two others collided over Iraq in May 2005. In January 2007, two Navy F/A-18E/F Super Hornets collided in midair and crashed in the Persian Gulf.[30]

Non-U.S. service

Though U.S. Navy aircraft have generally not sold well on the export market, the F/A-18 has been purchased and is in operation with several foreign air services. Export Hornets are typically similar to U.S. models of a similar manufacture date. Since none of the customers operate aircraft carriers, all export models have been sold without the automatic carrier landing system, and Royal Australian Air Force further removed the catapult attachment on the nose gear.[22] Except for Canada, all export customers purchased their Hornets through the U.S. Navy, via the U.S. Foreign Military Sales (FMS) Program, where the Navy acts as the purchasing manager but incurs no financial gain or loss. Canada, the largest Hornet operator outside of the U.S., ordered its aircraft directly from the manufacturer.

Australia

Main article: McDonnell Douglas F/A-18 Hornet in Australian service

The Royal Australian Air Force purchased 57 F/A-18A fighters and 18 F/A-18B two-seat trainers to replace its Dassault Mirage IIIOs. Numerous options were considered for the replacement, notably the F-15A Eagle, the F-16 Falcon, and the then new F/A-18 Hornet. The F-15 was discounted because the version offered had no ground-attack capability. The F-16 was considered unsuitable largely due to having only one engine. Australia selected the F/A-18 in October 1981. Original differences between the Australian and US Navy's standard F/A-18 were the removed nose wheel tie bar for catapult launch (later re-fitted with a dummy version to remove nose wheel shimmy), addition of a high frequency radio, an Australian fatigue data analysis system, an improved video and voice recorder, and the use of ILS/VOR (Instrument Landing System/Very High Frequency Omnidirectional Range) instead of the carrier landing system.

The first two aircraft were produced in the US, with the remainder assembled in Australia at Government Aircraft Factories. F/A-18 deliveries to the RAAF began on 29 October 1984, and continued until May 1990. In 2001, Australia deployed four aircraft to Diego Garcia, in an air defense role, during coalition operations against the Taliban in Afghanistan. In 2003, 75 Squadron deployed 14 F/A-18s to Qatar as part of Operation Falconer and these aircraft saw action during the invasion of Iraq. Australia had 71 Hornets in service in 2006, after four were lost to crashes.

The fleet was upgraded beginning in the late 1990s to extend their service lives to 2015. They were expected to be retired then and replaced by the F-35 Lightning II. Several of the Australian Hornets have had refits applied to extend their service lives until the planned retirement date of 2020. In addition to the F/A-18A and F/A-18B Hornets, Australia has purchased 24 F/A-18F Super Hornets, with deliveries beginning in 2009.

Canada

Main article: McDonnell Douglas CF-18 Hornet

Canada was the first export customer for the Hornet, replacing the CF-104 Starfighter (air reconnaissance & strike), the McDonnell CF-101 Voodoo (air interception) and the CF-116 Freedom Fighter (ground attack). The Canadian Forces Air Command ordered 98 A models (Canadian designation CF-188A/CF-18A) and 40 B models (designation CF-188B/CF-18B).

In 1991, Canada committed 26 CF-18s to the Gulf War, based in Qatar. These aircraft primarily provided Combat Air Patrol duties, although late in the air war began to perform air strikes on Iraqi ground targets. On January 30, 1991, two CF-18s on CAP detected and attacked an Iraqi TNC-45 patrol boat. The vessel was repeatedly strafed and damaged by 20mm cannon fire, but an attempt to sink the ship with air to air missiles failed. The ship was subsequently sunk by American aircraft, but the Canadian CF-18s received partial credit for its destruction. In June 1999, 18 CF-18s were deployed to Aviano AB, Italy, where they participated in both the air-to-ground and air-to-air roles in the former Yugoslavia.

Sixty two CF-18A and 18 CF-18B aircraft took part in the Incremental Modernization Project which was completed in two phases. The program was launched in 2001 and the last updated aircraft was delivered in March 2010. The aims were to improve air-to-air and air-to-ground combat abilities, upgrade sensors and the defensive suite, and replace the datalinks and communications systems on board the CF-18 from the F/A-18A and F/A-18B standard to the current F/A-18C and D standard.

In July 2010 the Canadian government announced plans to replace the remaining CF-18 fleet with 65 F-35 Lightning IIs, with deliveries scheduled to start in 2016.

Finland

The Finnish Air Force (Suomen Ilmavoimat) ordered 64 F-18C/Ds (57 C models, seven D models) with delivery started on 7 June 1995. The Hornet replaced the MiG-21bis and Saab 35 Draken in Finnish service. The Finnish Hornets were initially to be used only for air defense, hence the F-18 designation. The F-18C includes the ASPJ (Airborne-Self-Protection-Jammer) jamming pod ALQ-165.[44] The US Navy later included the ALQ-165 on their F/A-18E/F Super Hornet procurement.

One fighter was destroyed in a mid-air collision in 2001. A damaged F-18C was rebuilt into a F-18D. To do so, a forward section of a Canadian CF-18B was purchased and incorporated. The modified fighter crashed during a test flight in January 2010. The cause of the crash was determined to be due to a faulty tailplane servo cylinder.

Finland is upgrading its fleet of F-18s with new avionics, including helmet mounted sights (HMS), new cockpit displays, sensors and standard NATO data link. Several of the 63 Hornets remaining are going to be fitted to carry air-to-ground ordnance such as the AGM-158 JASSM, in effect returning to the original F/A-18 multi-role configuration. The upgrade includes also the procurement and integration of new AIM-9X Sidewinder and AIM-120C-7 AMRAAM air-to-air missiles. This Mid-Life Upgrade (MLU) is estimated to cost between €1–1.6 billion and work is scheduled to be finished by 2016. After the upgrades the aircraft are to remain in active service until 2020–2025.

Kuwait

The Kuwait Air Force (Al Quwwat Aj Jawwaiya Al Kuwaitiya) ordered 32 F/A-18C and eight F/A-18D Hornets in 1988 and delivery started in October 1991.The F/A-18C/Ds replaced A-4KU Skyhawk. Kuwait Air Force Hornets have flown missions over Iraq during Operation Southern Watch in the 1990s. They have also participated in military exercises with the air forces of other Gulf nations. Kuwait had 39 F/A-18C/D Hornets in service in 2008.

Malaysia

The Royal Malaysian Air Force (Tentera Udara Diraja Malaysia) has eight F/A-18Ds. The air force split their order between the F/A-18 and the Mikoyan MiG-29. Three Hornets were employed together with five UK-made BAE Hawk 208 in an airstrike on the Royal Security Forces of the Sultanate of Sulu and North Borneo terrorist hideout on March 5, 2013, occupying part of Borneo, just before the joint forces of Malaysian Army and Royal Malaysia Police operatives launched an assault in the 2013 Lahad Datu standoff.

Spain

The Spanish Air Force (Ejército del Aire) ordered 60 EF-18A model and 12 EF-18B model Hornets (the "E" standing for "España", Spain), named respectively as C.15 and CE.15 by Spanish AF. Delivery of the Spanish version started on 22 November 1985. These fighters were upgraded to F-18A+/B+ standard, close to F/A-18C/D (plus version includes later mission and armament computers, databuses, data-storage set, new wiring, pylon modifications and software, new abilities as AN/AAS-38B NITE Hawk targeting FLIR pods).

In 1995 Spain obtained 24 ex-USN F/A-18A Hornets, with six more on option. These were delivered from December 1995 until December 1999. Before delivery, they were modified to EF-18A+ standard. This was the first sale of USN surplus Hornets.

Spanish Hornets operate as an all-weather interceptor 60% of the time and as an all-weather day/night attack aircraft for the remainder. In case of war, each of the front-line squadrons would take a primary role: 121 is tasked with tactical air support and maritime operations; 151 and 122 are assigned to all-weather interception and air combat roles; and 152 is assigned the SEAD mission. Air refueling is provided by KC-130Hs and Boeing 707TTs. Pilot conversion to EF-18 is centralized in 153 Squadron (Ala 15). Squadron 462's role is air defense of the Canary Islands, being responsible for fighter and attack missions from Gando AB.

Spanish Air Force EF-18 Hornets have flown Ground Attack, SEAD, combat air patrol (CAP) combat missions in Bosnia and Kosovo, under NATO command, in Aviano detachment (Italy). They shared the base with Canadian and USMC F/A-18s. Six Spanish Hornets had been lost in accidents by 2003.

Over Yugoslavia, eight EF-18s, based at Aviano AB, participated in bombing raids in Operation Allied Force in 1999. Over Bosnia, they also performed missions for air-to-air combat air patrol, close air support air-to-ground, photo reconnaissance, forward air controller-airborne, and tactical air controller-airborne. Over Libya, four Spanish Hornets participated in enforcing a no-fly zone.

Switzerland

The Swiss Air Force purchased 26 C models and eight D models. One D model was lost in a crash. Delivery of the aircraft started on 25 January 1996.

In late 2007 Switzerland requested to be included in F/A-18C/D Upgrade 25 Program, to extend the useful life of its F/A-18C/Ds. The program includes significant upgrades to the avionics and mission computer, 20 ATFLIR surveillance and targeting pods, and 44 sets of AN/ALR-67v3 ECM equipment. In October 2008 the Swiss Hornet fleet reached the 50,000 flight hour milestone.

Potential operators

The F/A-18C and F/A-18D were considered by the French Navy (Marine Nationale) during the 1980s for deployment on their aircraft carriers Clemenceau and Foch and again in the 1990s for the later nuclear-powered Charles de Gaulle, in the event that the Dassault Rafale M was not brought into service when originally planned.

Austria, Chile, Czech Republic, Hungary, Philippines, Poland, and Singapore evaluated the Hornet but did not purchase it. Thailand ordered four C and four D model Hornets but the Asian financial crisis in the late 1990s resulted in the order being canceled. The U.S. DoD then purchased the Hornets in production for the Marine Corps.

The F/A-18A and F-18L land-based version competed for a fighter contract from Greece in the 1980s. The Greek government chose F-16 and Mirage 2000 instead.

Variants

A/B

The F/A-18A is the single-seat variant and the F/A-18B is the two-seat variant. The space for the two-seat cockpit is provided by a relocation of avionic equipment and a 6% reduction in internal fuel; two-seat Hornets are otherwise fully combat-capable. The B model is used primarily for training.

In 1992, the original Hughes AN/APG-65 radar was replaced with the Hughes (now Raytheon) AN/APG-73, a faster and more capable radar. A model Hornets that have been upgraded to the AN/APG-73 are designated F/A-18A+.

C/D

The F/A-18C is the single-seat variant and the F/A-18D is the two-seat variant. The D-model can be configured for training or as an all-weather strike craft. The "missionized" D model's rear seat is configured for a Marine Corps Naval Flight Officer who functions as a Weapons and Sensors Officer to assist in operating the weapons systems. The F/A-18D is primarily operated by the U.S. Marine Corps in the night attack and Forward Air Controller (Airborne) (FAC(A)) roles.

The F/A-18C and D models are the result of a block upgrade in 1987 incorporating upgraded radar, avionics, and the capacity to carry new missiles such as the AIM-120 AMRAAM air-to-air missile and AGM-65 Maverick and AGM-84 Harpoon air-to-surface missiles. Other upgrades include the Martin-Baker NACES (Navy Aircrew Common Ejection Seat), and a self-protection jammer. A synthetic aperture ground mapping radar enables the pilot to locate targets in poor visibility conditions. C and D models delivered since 1989 also have improved night attack abilities, consisting of the Hughes AN/AAR-50 thermal navigation pod, the Loral AN/AAS-38 NITE Hawk FLIR (forward looking infrared array) targeting pod, night vision goggles, and two full-color (formerly monochrome) multi-function display (MFDs) and a color moving map.

In addition, 60 D-model Hornets are configured as the night attack F/A-18D (RC) with ability for reconnaissance.These could be outfitted with the ATARS electro-optical sensor package that includes a sensor pod and equipment mounted in the place of the M61 cannon.

Beginning in 1992, the F404-GE-402 enhanced performance engine, providing approximately 10% more maximum static thrust became the standard Hornet engine.Since 1993, the AAS-38A NITE Hawk added a designator/ranger laser, allowing it to self-mark targets. The later AAS-38B added the ability to strike targets designated by lasers from other aircraft.

Production of the F/A-18C ended in 1999. In 2000, the last F/A-18D was delivered to the U.S. Marine Corps.

E/F Super Hornet

Main article: F/A-18E/F Super Hornet

The single-seat F/A-18E and two-seat F/A-18F Super Hornets carry over the name and design concept of the original F/A-18, but have been extensively redesigned. The Super Hornet has a new, 25% larger airframe, larger rectangular air intakes, more powerful GE F414 engines based on F/A-18's F404, and upgraded avionics suite. Like the Marine Corps' F/A-18D, the Navy's F/A-18F carries a Naval Flight Officer as a second crewman in a Weapons Systems Officer (WSO) role. The Super Hornet aircraft is in production and has equipped 22 squadrons.

The EA-18G Growler is an electronic warfare version of the two-seat F/A-18F, which entered production in 2007. The Growler will replace the Navy's EA-6B Prowler and carries a Naval Flight Officer as a second crewman in an Electronic Countermeasures Officer (ECMO) role.

Australia is the only nation other than the United States to operate the Super Hornet.

Other US variants

F-18(R)
This was a proposed reconnaissance version of the F/A-18A. It included a sensor package that replaced the 20 mm cannon. The first of two prototypes flew in August 1984. Small numbers were produced.[65]
RF-18D
Proposed two-seat reconnaissance version for the US Marine Corps in the mid-1980s. It was to carry a radar reconnaissance pod. The system was canceled after it was unfunded in 1988. This ability was later realized on the F/A-18D(RC).[65]
TF-18A
Two-seat training version of the F/A-18A fighter, later redesignated F/A-18B.
F-18 HARV
Single-seat High Alpha Research Vehicle for NASA. High angles of attack using thrust vectoring, modifications to the flight controls, and forebody strakes
X-53 Active Aeroelastic Wing
A NASA F/A-18 has been modified to demonstrate the Active Aeroelastic Wing technology, and was designated X-53 in December 2006.

Export variants

These designations are not part of 1962 United States Tri-Service aircraft designation system.

F-18L
This was a lighter land-based version of the F/A-18 Hornet. It was designed to be a single-seat air-superiority fighter and ground-attack aircraft. It was originally intended to be assembled by Northrop as the export version of the F/A-18 Hornet. The F-18L was lighter via removing carrier landing capability. Despite the advantages, customers preferred the standard Hornet, and the F-18L never entered mass production.
(A)F/A-18A/B
  • (A)F/A-18A: Single-seat fighter/attack version for the Royal Australian Air Force.
  • (A)F/A-18B: Two-seat training version for the Royal Australian Air Force.
"F/A-18A" was the original company designation, designations of "AF-18A" & "ATF-18A" have also been applied. Assembled in Australia (excluding the first two (A)F/A-18Bs) by Aero-Space Technologies of Australia (ASTA) from 1985 through to 1990, from kits produced by McDonnell Douglas with increasing local content in the later aircraft. Originally the most notable differences between an Australian (A)F/A-18A/B and a US F/A-18A/B were the lack of a catapult attachment, replacing the carrier tailhook with a lighter land arresting hook, and the automatic carrier landing system with an Instrument Landing System. Australian Hornets have been involved in several major upgrade programs. This program called HUG (Hornet Upgrade) has had a few evolutions over the years. The first was to give Australian Hornets F/A-18C model avionics. The second and current upgrade program (HUG 2.2) updates the fleet's avionics even further.
CF-18 Hornet
  • CF-18A: Single-seat fighter/attack version for the Royal Canadian Air Force. The official Canadian designation is CF-188A Hornet.
  • CF-18B: Two-seat training and combat version for the Royal Canadian Air Force. The official Canadian designation is CF-188B Hornet.
EF-18 Hornet
  • EF-18A: Single-seat fighter/attack version for the Spanish Air Force. The Spanish Air Force designation is C.15.
  • EF-18B: Two-seat training version for the Spanish Air Force. The Spanish Air Force designation is CE.15.
KAF-18 Hornet
  • KAF-18C: Single-seat fighter/attack version for the Kuwait Air Force
  • KAF-18D: Two-seat training version for the Kuwait Air Force
F-18C/D Hornet
  • The Finnish Air Force uses F/A-18C/D Hornets, with a Finland-specific mid-life update. The first seven Hornets (D models) were produced by McDonnell Douglas.[44] The 57 single-seat F-18C model units were assembled by Patria in Finland.
F-18C/D Hornet
  • Switzerland uses F-18C/D,later Swiss specific mid-life update. The Swiss F-18s had no ground attack capability originally, until hardware was retrofitted.

F/A 18 Hornets on the flight deck of the Nimitz-class supercarrier USS Harry S. Truman (CVN-75)

The Blue Angels' No. 6 F/A-18A

An F/A-18C taking off from USS Kitty Hawk (CV-63)

Three RAAF F/A-18As in 2013

Canadian CF-188A Hornet off the coast of Hawaii. Note the "false cockpit" painted on the underside of the aircraft, intended to confuse enemy pilots during dogfights.

A Finnish Air Force F-18C at RIAT 2005

Spanish Air Force's EF-18

F/A-18D Hornet dual at Payerne

An F/A-18B Hornet assigned to the U.S. Naval Test Pilot School

A Marine F/A-18D of VMFAT-101 prepares for takeoff

A VFA-11 F/A-18F Super Hornet performing evasive maneuvers during an air power demonstration above USS Harry S. Truman (CVN-75)

X-53, NASA's modified F/A-18

 

The F-22 Raptor, the world’s premier air superiority aircraft, has been around for quite some time now.  Lockheed’s YF-22 design won the competition with Northrop’s radical YF-23 almost 26 years ago, but the end of the Cold War, and resulting lack of urgency with the reduction in the Russian threat, made for an extremely protracted development for the final design (given the complexity of airframe, engines and electronics, perhaps no bad thing).  Though its inordinate cost brought it under Congressional attack and prompted several cutbacks in estimated production run (which cutbacks, in this sort of vicious cycle, spur increases in unit cost), the F-22 entered service in 2005, itself a fairly long time ago in military aviation terms. That year, the first Raptors replaced F-15C Eagles of the First Tactical Fighter Wing at Langley, Virginia, and the capabilities of US fighter pilots leapt forward in a fashion that hadn’t been seen since the transition from piston engines to jets over 50 years earlier.

Now and then, a weapon will appear that changes all the rules, to the point of rendering all other weapons in its class obsolete.  One thinks immediately of the great naval revolutions spurred by H.M.S. Dreadnought, and the USS Nautilus, or, in the aviation world, the shock delivered by the ME-262.  The F-22 represents just such an advance, outclassing all current fighters in the same way that the first nuclear submarine outclassed its diesel-powered contemporaries.  Few in number, Raptors nevertheless dominate the skies more thoroughly than their predecessors – a tall boast for an aircraft that replaced the mighty F-15.  Speaking of which…

The Wondrous F-15 Eagle

To understand what it really means to render an F-15 hopelessly obsolete, one has to understand something of the still phenomenal performance of that classic fighter, now, incredibly, in its 41st year of operational service. Until quite recently, the Eagle was only marginally outclassed by a new and much later generation of foreign fighter aircraft – derivatives of the Soviet “Flanker” family (Sukhoi SU-35, for example), the French Dassault “Rafale”, and the Eurofighter “Typhoon”, produced by a consortium of Britain, Spain, Germany and Italy.  These new fighters, while extremely impressive, really offered only an incremental improvement on what the latest F-15s could do, and it’s arguable that new Eagles, with up-rated engines and advanced electronics, were barely outclassed at all – South Korea appears to have reached just that conclusion in selecting an advanced derivative of the Eagle as its next generation fighter in the early 2000s, favouring it over all foreign competition.  While there are those (myself included) who felt that the last (and sorely missed) F-14 Super Tomcats were the most impressive fighters of the US 4th generation, there was no denying the superlative qualities of the Eagle, both as an aerodynamic achievement and as a weapons system/electronics platform. It remains a formidable adversary to this day.

The F-15 was designed in light of the Air Force experience in Viet Nam.  In the early 1960s, the Air Force had adopted the phenomenal F-4 Phantom II, a naval fighter, as its primary tactical aircraft (it says something of the qualities of the F-4 that the boys in blue suits had to swallow their bile and adopt a Navy machine).  The Phantom had cleaned the clocks of Air Force F-106 interceptors in simulated fighter and interception combat, and was almost the equal of the F-105 Thunderchief in dropping ordnance on ground targets.  With its great maximum speed, blistering climb rate and acceleration, and armament of long-range radar-guided AIM-7 Sparrow missiles, the Phantom was expected to sweep clear the skies over North Viet Nam of any pesky but outdated MiGs.  However, as strike packages of US fighter-bombers encountered resistance from those supposedly obsolescent Soviet fighters, the Air Force received a nasty shock.

It turned out that a maximum speed of over Mach 2 had little relevance in the air combat over Viet Nam (as opposed to the Phantom’s primary design mission of blasting off from a carrier deck and rushing out to meet incoming Soviet bombers).  It did no good to flash by at 1,400 MPH and 40,000 feet when the task was to protect bomb-laden F-100s and F-105s, flying, of necessity, at lower levels and subsonic speeds.  When the strike aircraft were pounced upon at 15,000 feet and lower, the Phantoms had to be there with them to mix it up with the MiGs; in any case, supersonic flight required use of full afterburner, a fuel-gulping mode that would drain an F-4’s tanks dry in just a few minutes.  In Viet Nam, nearly all air combat took place at subsonic speeds.

At subsonic speed and low altitude, The Phantom was out of its element, and this was just where the light and agile aircraft available to North Viet Nam, MiG-17s, 19s and 21s, were at their best.  Struggling to stay with the light, agile MiGs in hard turns at 400 MPH speeds, Phantoms found themselves embroiled in close range visual dogfights, where all their electronics were so much deadweight.

The need to mix it up at visual range was partly due to the AIM-7 Sparrows, which, despite high expectations, did not really work.  Not only were the missiles terribly unreliable, they were likely to be out-maneuvered by the MiGs even if they functioned as advertised – Sparrow was designed with large, decidedly un-maneuverable bomber targets in mind.  Worst of all, it proved impossible to launch Sparrows at beyond visual range.  The Identification Friend or Foe (IFF) systems meant to facilitate long range shots proved as unreliable as the missiles, and faced with a “furball” of US and NVN fighters on the radar screen, an F-4 was every bit as likely to blast a friendly F-105 as a MiG-17.  Long range Sparrow shots were actually prohibited after several US fighters were shot down in “blue on blue” engagements.

 

A MiG-17, unlikely nemesis to the far more sophisticated F-4 Phantom.

So there were the enormous F-4s, forced to low altitudes and low subsonic speeds, firing off Sparrow missiles at close range with little chance of a hit, just to rid their airframes of the weight, trying to bank into tight turns with nimble little MiGs, and getting themselves shot down with appalling frequency by small silver fighters that were little more than sports planes mounting machine guns.

Quite the embarrassment.

Now, there was nothing inevitable to this.  Even given the failure of Sparrow, and the necessity for subsonic, medium altitude dogfighting, Phantoms could have, and should have, acquitted themselves much better than they did.  The key problem was pilot skill.  Neither Air Force nor Navy pilots, amazingly, had any training in visual dogfights against dissimilar aircraft (so obsessed were military planners with nuclear war scenarios, and so confident had they been in Sparrow).  It was not until the late 1960s, and the creation of the Navy’s Top Gun fighter school, that this was addressed by either service.  Graduates of Top Gun learned to exploit the Phantom’s advantages in speed, climb rate and acceleration, and they learned how to maneuver in ways to defeat a superior turning fighter.

In 1972, Navy Phantom pilots racked up a 13:1 kill ratio against the MiGs, and it was not long before the Air Force created its Red Flag training program to emulate what Top Gun was doing for the Navy.  Combined with new technology – leading edge wing slats for better maneuverability, up-rated engines, improved IFF and Sparrow missiles, new radars, and in the case of Air Force Phantoms, an internal 20 mm Gatling gun – well trained Phantom pilots of the 1970s were actually well able to take on any aircraft they were likely to meet in air combat.

A pair of F-4Es, the classic variant of the Phantom II. With up-rated engines, improved radars, better missiles, an internal cannon, and leading edge wing slats for improved maneuverability, F-4Es were well able to hold their own against any opposition on the Soviet side. The “fighter mafia”, however, craved utter dominance.

Still, the Air Force “fighter mafia” never got over the shock administered in the mid 1960s: Sweet Jesus, we were head-down in our cockpits, poring over garbled radar pictures and poking at useless buttons, while the little silver bastards were laughing and flaming our asses.

Thus the call rang out for an aircraft that would return to the classic fighter virtues of old, something akin to a high technology P-51 or F-86, something that could “turn and burn”, with superb pilot visibility, and the sort of turn rate that would always put you on the enemy’s tail where a cannon or a heat seeking missile – the staples of visual combat – needed to be to do the most good.  “Not a pound for air to ground” was the new slogan; no more hulking fighter-bombers!  The next fighter was to be a pure fighter, unencumbered by the compromises of multi-role mission requirements.

Just as this was going on, the boffins at Mikoyan were administering another dose of the jitters with their remarkable MiG-25 “Foxbat”, a Mach 3 fighter that beat the F-4 at its own game and flew too high and fast for even Phantoms to intercept.  “Foxbat shock” took hold in Western aviation circles, and commentary at the time was obsessed with the inability of the best available US fighters to stop MiG-25s from going anywhere they wanted.  Anxiety mounted as Foxbats flew out of Egypt and Syria and cruised with impunity over Israel, easily out-pacing the F-4s sent up to intercept them.  The mood soured further when a modified MiG-25 officially broke nearly all of the Phantom’s speed and time to climb records.  I remember an editorial at the front of Jane’s All the World’s Aircraft that struck an almost hysterical tone, as if the MiG-25 would drive all Western fighters from the sky.

Initially, no one grasped that the MiG-25 was, essentially, little more than the re-usable first stage of a missile system designed to intercept high-flying supersonic bombers, with very limited maneuverability and poor radar performance in “look down” mode.  Far from the super-fighter it was supposed to be, the MiG-25 actually had no use in almost any scenario save high altitude bomber interception, and posed little threat to US tactical air operations.  In the late 1960s and early 1970s, though, producing an aircraft that could defeat the MiG-25, while at the same time out-maneuvering any other aircraft, was the design goal.  This was terribly ambitious.  It meant achieving the apparently incompatible goals of a fighter with even more radar, missile capability, speed and climb rate than the 24 ton Phantom, yet one even handier in close combat than a seven ton MiG-17.

Somehow, that is exactly what McDonnell Douglas handed the Air Force when the F-15 first flew in 1972.

The Mig-25 “Foxbat”, erroneously cast in the role of airborne bogeyman by Western defence analysts in the 1960s and 1970s. It looked the business, but was a pure interceptor, designed to attack high level supersonic bombers. Despite its fearsome appearance, it posed no serious threat to Western tactical aircraft.

One crucial factor in the F-15’s performance was the advance in engine design achieved by Pratt and Whitney in the late 1960s.  Phantoms were powered by General Electric J-79 turbojets, producing 17,900 lbs. of thrust for an installed weight of about 4,200 lbs.  The engines therefore had a thrust:weight ratio of about 4.25:1, and this gave the Phantom itself a thrust:weight ratio of about 0.8:1, very high for its day.  By 1972, Pratt and Whitney had developed the revolutionary F-100 turbofan, which offered almost 24,000 lbs. of thrust for an installed weight of just over 3,000 lbs.  This gave the engine a thrust:weight ratio of almost 8:1, and allowed the F-15 to be both lighter and more powerful than the Phantom.  Indeed, at a takeoff weight of 44,500 lbs., with armament, an F-15 had more thrust than weight at wheels-up, with a ratio of about 1.1:1.  At combat weight, with half of the internal fuel burned away, an Eagle enjoyed an astonishing 1.3 lbs. of installed thrust for every pound of weight.

Taking off with more installed thrust than weight.

An F-15 blasts off the runway with characteristic brute power.

This unprecedented thrust : weight ratio – to this day, no aircraft in service or projected surpasses it, not even the F-22 – gave the Eagle phenomenal acceleration, speed and climb rate.  An Eagle could stand on its tail and climb vertically, straight up, and break the sound barrier while doing it; in Project Streak Eagle, a modified F-15 soon re-took all the time to climb records usurped by the Soviets, with an airframe that reached 20,000 feet – the typical operational altitude of a Mustang – in only 37 seconds, and 50,000 feet – the maximum operational altitude of most current fighters – in only 77 seconds.  An Eagle could accelerate from a leisurely subsonic cruise to 1,000 MPH in less than a minute, and could attain (albeit for short periods) a dash speed of just over Mach 2.5, more than 1,650 MPH.

To exploit all this thrust, McDonnell Douglas designed an airframe that would be the antithesis of the F-4.  A new concept in air combat, “specific excess power”, was now dominating fighter design thinking.  This held that what mattered most to an aircraft engaged in close combat was how much reserve energy it had at any given moment to change its flight path and begin a new maneuver.  Thus, it was not enough if a plane could turn tightly, if turning tightly cost it all its energy and forced it to slow down.  What was needed was an aircraft that could turn tightly and then, if necessary, pull vertical; an aircraft that could pull rapidly out of a dive and ascend faster than its foe; an aircraft that had the excess power, when needed, to accelerate out of whatever predicament it was in, no matter what it was doing at the time.

Obviously, high thrust : weight ratio was one element of specific excess power, but another had to be aerodynamic.  In the vernacular, the new fighter had to be “lightly loaded”, meaning that however heavy it was, it had to have a  wing loading at least as light as the fighters that opposed it, even if the opposition was a far smaller fighter.  Wing loading is the simple ratio of aircraft weight to total wing area, measured in lbs. per square foot.  A Phantom had a wing loading at combat weight of about 80 lbs. per square foot.  When contemplating a 22 ton fighter that had to have high specific excess power at all times, McDonnell aimed for and achieved a target of only 60 lbs. per square foot with the Eagle (about the same as the eight ton MiG-21), using a huge wing of over 600 square feet.

Other features, such as twin tails, and highly-swept, wedge-shaped intakes, assured that the Eagle had sparkling aerodynamic performance at all speeds and fairly high angles of attack.  Heeding the pleas of the fighter mafia, the Eagle was also given a large, high bubble canopy that hearkened back to the P-51 and F-86.  In an F-4, the pilot was buried in the fuselage beneath a flush canopy, the sills up around his shoulders, with poor downward and almost no rearward visibility.  In an Eagle, the pilot sat on top, with the cockpit sills down around his waist, as if mounted on a horse; an F-15 pilot could turn around and look straight back between the twin vertical tails.

It all made for astounding close combat performance at slow- medium speed.  At air show altitude, an Eagle was able to crank into a high-G turn at 300-400 MPH and go a full 360 degrees in a time of about 18 seconds and a radius of about 1500 feet, without losing speed or altitude, and then, at the end of the turn – and this is what caused dentures to fall out at the Paris and Farnborough air shows – immediately pull into steep rapid climbs.  This betrayed an awesome amount of excess power, unimaginable to the fighter pilots of only a decade earlier.

An F-15 maneuvers with typical gusto at an air show.

Eagles at air shows in the mid 1970s cavorted through routines that included rolling takeoffs using only 800 feet of runway (less tarmac than used up by a Spitfire), vertical climbs at rates exceeding 50,000 feet per minute, Immelman turns, and a host of other maneuvers that had  never before been achieved by a large and heavy supersonic fighter.

The Eagle could do things going straight up that the best Russian and European fighters couldn’t do going horizontal.

Under the skin, the Eagle possessed an extraordinary electronics suite, comprising, among other things, the new digital APG-63 pulse-doppler radar (then surpassed only by the F-14’s AWG-9 system among all the world’s fighters), comprehensive radar-warning and electronic countermeasures systems, and advanced “heads-up” displays that projected vital information directly onto the windscreen, using lasers, in front of the pilot’s field of view.  In close combat, under the big bubble canopy, Eagle pilots received projected laser symbology telling them where to look for the enemy, reminding them of their own and their target’s altitude, heading and airspeed, informing them of fuel state and armament remaining, and providing firing solutions and aiming points, all without once looking down in the cockpit.  At long ranges, the Eagle’s superb radar allowed the pilot to discern targets flying low in ground clutter, and to detect fighter-sized aircraft at ranges as great as 110 miles.

Even better, highly-secret work was done to overcome the limitations of IFF systems.  In a project called “NCTR”, for “Non-Cooperative Target Recognition”, the radar boffins laboured to provide a way for the APG-63 to distinguish enemies from friendlies at extreme range without relying on IFF.  It is still not known for certain how this was achieved, though it is widely reported that the APG-63, in NCTR mode, shines radar waves off the compressor discs of the jet engines of opposing fighters.  The modulation of jet engine compressors is, apparently, distinctive enough to identify aircraft type.  However it was done, NCTR was proved to work in the 1991 Gulf War, during which F-15s shot down dozens of aircraft at long range without once scoring a goal on their own net.

Meanwhile, dedicated efforts to improve the Sparrow had resulted in a much more accurate, maneuverable and reliable radar-guided missile, and the Eagle, able to accelerate rapidly to supersonic speed in order to impart energy to the missile at the moment of launch, was able to “snap-shoot” AIM-7s to ranges up to 70 miles, and altitudes of 90,000 feet.  In practice intercepts, even high-flying Mach 3 SR-71s were not entirely safe from F-15s.  Sparrow remained a semi-active homing missile, meaning that an Eagle, unlike the Tomcat with its Phoenix missiles, could engage only one target at a time (a limitation that would not be addressed until the 1990s).  For the moment, though, the important thing was that Sparrow now bid fair to work just as planned back in the 1960s.

There was no doubt, in short, that the F-15 could maneuver the tar out of any of the MiGs that had so vexed Phantom pilots in South East Asia, and blast any MiG-25 right off of its high altitude perch.

Another shot of an F-15 cranking through an air show routine, moisture condensing in the low pressure over the enormous wing.

This must have seemed quite terrifying to Soviet planners, who well understood the limitations of the Foxbat, and knew that in fact no Soviet super-fighter existed.  Indeed, while the MiG-25 was giving US planners conniption fits, the Soviets, taking a sober view of what Phantoms had really accomplished over Viet Nam and the Middle East, were striving to mass produce an aircraft that could compete with the F-4!  In the mid 1970s, they were deploying huge numbers of their swing-wing MiG-23, which we now know to have been a good match for the F-4E.  As the Israelis soon proved over Lebanon, MiG-23s, and indeed MiG-25s, provided little more than target practice for Eagles.  The US Air Force had let an overreaction to the Viet Nam experience, and an overestimate of the Foxbat’s performance, spur them into the development of an expensive super-fighter that was pure overkill when the Eagle was first deployed.

Thus began a crash program in the Soviet Union to match the Eagle.  It took them over 10 years; the amazing post-script to the story of the Air Force’s frantic effort to replace the Phantom is that it was not until 1986 that the Soviets had any aircraft in squadron service that was convincingly superior to the F-4E of 1967.

Replacing the F-15

The Americans had created a monster.  With an air force full of fighters that were mincemeat in the teeth of the F-15s, the Soviets had no choice but to come up with their own super-fighter.  The new Soviet plane had to do everything the Eagle could do, and better, if possible, and it also had to contend with the even more agile light fighters that followed the Eagle into service, the F-16 and the F-18.  Prototypes were flying as early as 1977, but beating the Eagle wasn’t easy.  Protracted development was needed to overcome the many design challenges.  Mikoyan produced a relatively small fighter in the F-18 class, the MiG-29, given the NATO reporting name “Fulcrum”.  Sukhoi produced a more imposing design for an air superiority fighter that was as big as an F-14, with the thrust:weight ratio of the Eagle, and aerodynamics borrowed liberally from all the US “teen series” fighters.  This became the SU-27, given the NATO reporting name “Flanker”.  These began deploying around 1986, 12 years after the Eagle.  The F-15 had given the Americans 12 years of unrivalled supremacy, a breathing space that no air power, not even the Americans, had ever before enjoyed.  It was a feeling the Americans had gotten used to.  Now, there were new kids on the block.

Both of the new Soviet fighters were just a little more agile than the Eagle, but only the Sukhoi was true competition for the US fighter across the whole spectrum of air combat.  It had a radar of nearly equivalent capabilities to the APG-63, and it also had a useful infra-red search and track system (something that the Eagle, though not the Tomcat, lacked).  It had long range, and was able to carry an equally large load of missiles that were at least as good as the Sparrows and Sidewinders that were the Eagle’s primary armament.  As has since been proved at air shows around the world, the Flanker could turn even tighter than an Eagle (though not much, about 1 to 2 seconds faster for a 360 degree turn at low level), and could sustain much higher angles of attack.  As if to rub it in, the Russians stripped down a Flanker, gave it up-rated engines, and broke all of the Streak Eagle’s time to climb records (though by a fairly small margin; the Americans certainly could have up-engined an Eagle and taken them right back).  The Eagle retained an advantage in maximum speed, and it had a narrow edge in the quality and reliability of its electronics.  Overall, the Flanker was obviously able to take on F-15s on equal terms.

New kids on the block: the MiG-29 “Fulcrum”, broadly equivalent to the F-18 Hornet.

Looking at the Flanker, American planners had to acknowledge that they had goaded the Soviets into producing a fighter that could go toe to toe with the F-15.  With the Cold War still freezing, and facing the prospect of a confrontation with superior numbers of equally potent super-fighters, the quest for something to surpass even the F-15 became an unquestioned defence priority.  Americans cannot stand to be outclassed in air combat.

New kids on the block: the SU-27 “Flanker”.  Bigger, more powerful, more sophisticated, and entirely more elegant than the MiG-29, the rather un-Russian SU-27 was the F-15’s equal in almost every measure, and surpassed the Eagle in some respects.  It became the new benchmark for US defence planners.

At the same time, surveying the air defence environment over the central European front, American planners became increasingly dismayed at the proliferation of layered Soviet surface to air missile systems.  The SAM belt became so thick over the likely combat zone, and the quality of Soviet late generation SAMs so daunting, that it began to seem as if battling with Flankers was going to be the least of our worries.  Among the new SAMs were such frightening weapons as the S-300 and S-400, huge, long-ranged and fantastically fast – some sources quote speeds as high as Mach 7 for these missiles.  The F-15 has many virtues, but low radar cross section is not one of them; the angular US fighter is very easy to spot on radar (“looks like a frigging barn coming over the horizon” is one quip I’ve  read).  This made the US fighters vulnerable to interception by SAMs at all operational altitudes.  The same could be said about any Soviet fighter, but Soviet fighters didn’t have to face the sort of SAM belt that F-15 pilots would be up against.  It actually became plausible that SAMs alone could cripple the US air superiority campaign, making it impossible for NATO strike aircraft to penetrate Soviet defences, and for F-15s to protect them.

An S-300 mobile SAM launcher, raised to the vertical firing position.

Against this backdrop, something strange was being proved over the skies of Lebanon and Iraq.  The fighter mafia had got it all wrong; the lessons derived from Viet Nam were not valid.  Having insisted on fighters that were able to engage other fighters in close combat, to turn hard until they were on the enemy’s tail for a cannon or heat-seeking missile shot, the US Air Force was realizing that Eagles in combat were doing no such thing.

The S-400. These SAMs are credited with a speed of over 2 kilometers per second, or about 5,000 MPH. An even more potent S-500 system is now entering service.

A good fighter pilot is a not a knight of the air.  He’s a sniper, an assassin, and only a reluctant pugilist (aviation writer Bill Sweetman – I think it was Bill! – has noted that the ideal of the Medieval knight has never meshed with the behaviour of real pilots, or for that matter any other combatants, “the peasant-whacking lance jockeys of the Middle Ages included”). Dogfights at close range are often likened to a knife fight in a phone booth.  They are unpredictable, for the most part fair, and therefore only for hotshots, and other such mental cases.

Taking advantage of their far-seeing radars, NCTR and the snap-shot technique for firing Sparrow missiles, F-15 pilots much preferred to pick off the enemy at long range, before the poor bastards even knew they were under attack.  Vectored by AWACS aircraft into firing position, F-15s of the Israeli and US Air Forces slaughtered Syrian and Iraqi fighters at beyond visual range; the majority of Eagle kills (104 so far, without loss) have been Sparrow kills, and nearly all of the US victories in the 1991 Gulf War were achieved with Sparrow.  The maneuverability of the F-15, so important to its designers, was almost irrelevant, as indeed was the unquestionably superb agility of the half dozen or so MiG-29s that F-15s dispatched over Iraq (not to mention the several Yugoslavian Fulcrums that were later downed over Kosovo).  It was almost certain that the Syrians and Iraqis would have been just as easily destroyed by F-4s, if the Phantoms had been given the Eagle’s radar, and the new engines needed for that rapid rush to supersonic speed that was crucial to the snap-shot.

You could turn and cavort all over the sky, but what mattered was who got the first look, and who took the first shot.

Gradually, the assumptions spawned by the Viet Nam experience gave way in the face of combat results.  The Americans were not about to abandon fighter agility, and would certainly not deploy a new fighter unless it was able to outmaneuver the SU-27 Flanker in close combat.  Anything less would have gone too much against the grain.  Yet, it now seemed obvious, close combat was not the point at all, was not even likely, especially as missiles improved.  The new AIM-120 AMRAAM (Advanced Medium Range Air to Air Missile) would soon give the Eagle, or any plane that carried it, the ability to fire multiple shots at long range against multiple targets (like Phoenix, AMRAAM carries its own active radar, albeit in a much smaller package with shorter range).

At the same time, new heat-seeking missiles were being deployed that could, at shorter ranges, acquire a target from all aspects – there was no need to “saddle up” in the enemy’s rear quarter for a shot straight into the afterburner can.  The Soviets were first out of the blocks with a highly potent heat-seeker, the AA-11 “Archer”, that could attack from a very broad envelope.  Using an AA-11, a Soviet pilot could not only shoot you head on, he could shoot you line abreast, aiming the seeker head of the missile with a turn of his head, employing a link to a sight mounted in his helmet.  As work began on a version of the Sidewinder that could match the AA-11 – the AIM-9X, now in widespread service – it became clear that turning fights to get behind the enemy were almost certainly a thing of the past.  This had been predicted in the Phantom’s heyday, but the failure of the missiles made it a false prophecy in South East Asia.  Now, the missiles were working.

All that mattered was who got the first look, and who took the first shot.

The F-22 Emerges

“First look, first shot, first kill” became the slogan for the Advanced Tactical Fighter, the program that led to the Lockheed F-22 Raptor.  The new fighter would maneuver better than anything that had come before it, but that was just the beginning.  Though the Air Force knew that it was useless to try to design a fighter that would out-perform the Eagle in the classic “brochure statistics” of maximum speed and climb rate (it is hard to imagine how present technology could achieve this, especially when the Eagle can always be given new engines), the requirements for the ATF were more subtle, and much more ambitious.  The new fighter was to synthesize a number of technologies in order to ensure that its pilot had a better grasp of the situation than his opponents, and saw his opponents before they saw him.  It was to be less vulnerable to their missiles than they were to its.  While no faster in maximum speed, it was to have a much higher average cruising speed, enabling it to cover more air space, faster, than enemy fighters.  It was also going to be able to operate with near impunity in spite of the worst that the Soviet SAM belt could throw at it. Making all this possible would be a breathtaking set of revolutionary developments:  stealth, thrust vectoring, supercruise flight, “sensor fusion”, information systems superiority, datalinks for “networked” warfare, and extremely high operational altitude.

Stealth

“Stealth” is the popular word for what aerospace technicians call “low observable” or “LO” technologies.  Stealth is not one, but several systems and technologies that make an aircraft more difficult to detect, not just by radar, but also by infra-red tracking systems.  The idea was born in the 1970s as a result of the heavy losses incurred by the Israeli Air Force in the early days of the Yom Kippur war of 1973.

The lightning victory achieved by the Israelis in the Six Day War of 1967 had encouraged a certain arrogance among those in the Israeli military.  That war, won largely on the back of a perfectly executed pre-emptive strike by the Israeli Air Force, had left Israel in charge of the Golan Heights and the Sinai desert; Syria and Egypt therefore had a score to settle (Jordan, despite losing the West Bank, wisely abandoned the game).  By 1973, the Arab nations were faced with an Israeli air force that had vastly upgraded its capabilities, with the purchase of both F-4E Phantoms and A-4M Skyhawks to supplement the Mirage IIICs that had been the key players in 1967.  The Mirage III was a neat little fighter, roughly equivalent to the MiG-21.  The Phantom, of course, was a whole other order of warplane, and the Skyhawk had already proved itself a tough and reliable tactical bomber in countless missions over Viet Nam.  The Israelis could be forgiven some arrogance.

Yet in 1973, they were thrown back on their heels.  In a coordinated, Soviet-style shock attack, the Syrians stormed into the Golan while the Egyptians – this was truly horrifying – threw modular plastic bridges (courtesy of their Soviet pals) across the Suez Canal, to rapidly create a bridgehead in the Sinai.  Skyhawks and Phantoms attacked relentlessly on both fronts, and took very, very heavy losses, particularly in their attempts to drop the bridge spans over the Suez.  Without the laser and GPS guided bombs that would one day be standard issue in all Western equipped air forces, the Israelis were forced into dive bombing attacks, the only reliable way to hit something long and narrow like a bridge with an unguided iron bomb.  As any Stuka pilot could tell you, a dive-bombing run is all well and good until you run into a determined air defence, at which point it becomes the surest way to get your ass shot to pieces.  A sophisticated and determined air defence was just what the Israelis now found themselves up against.

The problem was a then-new surface to air missile, the mobile Soviet SA-6, roughly equivalent to the US Hawk (and thus very good indeed).  The Americans had not encountered it in Viet Nam, and it was a bitter surprise, decimating the Phantoms and Skyhawks with losses that were just barely made good by rapid transfers of US aircraft (direct from squadron service in some cases) to Israel.  Trained pilots, however, were not so easily replaced.  Such were the losses that early on, it looked as if the vaunted Heyl Ha’Avir might be destroyed as an effective fighting force.  New tactics, and a hasty transfer of the latest Westinghouse electronic countermeasures equipment from the US, soon turned things around, yet it was not until Ariel Sharon made his famous, Inchon-like dash across the canal, chewing up the Egyptian SAM belt on the ground, that the Air Force could operate freely over the canal zone.

The mobile SA-6 SAM system, scourge of the Israeli Air Force in the early days of the Yom Kippur war, and a key stimulus to the development of stealth technology.

All of this was viewed with despair by Western planners, who contemplated confrontations with the Soviets in Europe.  A secret program to swing the pendulum back was initiated under the aegis of Lockheed’s famous Skunk Works, birthplace of the U-2 and SR-71.  In an odd twist, the designers at Lockheed had become aware of a paper by a Soviet scientist on radar wave propagation that offered a possible solution.  Though it would be an aerodynamic mess, it might be possible to design a tactical aircraft that did not return radar signals to hostile emitters.

By about 1977, Lockheed was flying a prototype stealth aircraft out of Area 51 in Nevada, under the code name “Have Blue”.  The design was influenced more by the laws governing radar wave reflections than aerodynamics; the key was to ensure that even very powerful radar waves shone at the aircraft would either be absorbed, or bounce off somewhere where the emitting radar’s receiver could not receive them.  This was achieved through the use of various radar absorbent materials (RAM), and by creating a skin for the aircraft that was faceted, like a cut gem.  A radar wave hitting the aircraft would encounter a myriad of facets pointing in different directions; only a few of those small facets, and perhaps none of them, would be aligned such that a radar wave could hit them and return to the radar receiver.  Those few aligned facets would, like all the others, be covered in RAM, and thus return a very weak signal.

It was a sound idea, but extremely difficult to get right in practice.  Radar waves are a form of light.  An object is not less visible to a powerful radar simply because it presents a relatively smaller reflective surface, any more than a mirror is any less visible to a flashlight in a darkened room simply because it is, say, only half as large as another mirror. To thwart a radar return, the aircraft had to present almost no reflective surfaces to be “seen” by the radar – the Have Blue prototype, it was discovered, returned a radar signal detectable at 50 miles if even a half dozen screw heads were not quite flush with the fuselage skin.

A rare shot of Lockheed’s Have Blue stealth demonstrator.

Practical, effective stealth was nevertheless achieved, but in an aircraft, the F-117, that was an aerodynamic basket case, subsonic, and not a fighter at all.  Its faceted shape made it so unstable that it was, in its early years, prior to the perfection of its subtle computer controlled “fly-by-wire” software, blessed with the nickname “Wobbly Goblin” (without fly-by-wire technology, that is, automatic computer-controlled actuation of control surfaces, the F-117 would not be able to fly at all).  It has been said that “they did everything but flip on their backs while taxiing down the runway”.  Owing to their poor performance, they had to be restricted to night operations; invisible to radar and obscure to infra-red sensors they may have been, but a chance daylight encounter with any cannon-armed fighter would spell doom.

The “Wobbly Goblin” in broad daylight, when anything with a machine gun would be lethal to it. Its gem-like facets were highly stealthy, but aerodynamically ludicrous. Only sophisticated fly-by-wire systems allowed the F-117 to keep out of its own way and fly. Yet the  advantages of stealth were proved beyond doubt in Desert Storm.

Contemplating the SAM belt over central Europe, not to mention the powerful air search radars of SU-27 Flankers, the Air Force knew it needed stealth to be central to the design of the new fighter.  Yet, adapting stealth technology to an aircraft that was aerodynamically superior to an F-15 posed what should have been insurmountable technical challenges.  It was rather like stating in 1962 that America would send men to the moon before 1970.  The technology didn’t exist; the means to invent the technology didn’t even exist.  Yet, with typical American elan, the problem was cracked.

Improved computer power was one thing that came to the rescue.  With more powerful computers, it became possible to devise computer models for stealthy radar wave propagation that would accommodate smooth, curved surfaces rather than flat, faceted ones.  At the same time, advances in RAM technology meant that practical, robust radar-absorbent materials could be developed for use on fighters that would not be prohibitive to maintain (F-117s, and B-2 bombers as well, have very delicate RAM surfaces that need careful maintenance in air-conditioned shelters, not the sort of thing you need on forward-deployed fighters).

A quick glance at a drawing of the F-22 reveals one aspect of the stealth philosophy at work.  All of the leading and trailing edges line up with each other (in the vernacular, the design is “edge-aligned”).  The leading edges of the wings match the leading edges of the intakes, and the tailplanes, and so on; same story with all the trailing edges.  This ensures that radar waves can only encounter sharp, flat surfaces at right angles if they are oriented at one specific direction from the aircraft.  In a fighter maneuvering in combat, such precise exposure to radar is certain to be brief.  The rest of the time, the radar waves will bounce off into space, away from the emitter, if not absorbed by RAM.

An F-22 seen in plan view. Note how all of the trailing and leading edges of wings, intakes and tailplanes line up with each other – “edge alignment”.

The stealth measures incorporated in the new fighter also include, among other things, changes to the fighter’s own radar and the way it emits signals, and reduction of the infra-red signature of its engines, both discussed separately below.  Just as important, true stealth demands that the aircraft be in “clean” condition at all times, with no angular missiles, bombs or external fuel tanks hanging off of equally angular pylons under the fuselage and wings.  This posed another significant challenge.  Fighters had been using external fuel tanks to extend their range since the days of the P-51, and huge external tanks and pylons were a feature of all US tactical aircraft when the F-22 was designed.

Carrying weapons and fuel externally allows an airframe to be much smaller and lighter.  Why build the drag and weight penalty into the structure of the aircraft, when external carriage allows the drag and weight to be dumped as soon as it’s expedient?  An Eagle, for example, almost never takes off without a large and heavy 600 gallon fuel tank slung under the center fuselage.  This centerline tank gives it the fuel to go all the way to the combat zone.  Once there, the tank is dumped, leaving behind an aircraft much smaller and lighter, and therefore with higher specific excess power, than a hypothetical rival that had to take off with an extra 600 gallon fuel tank inside.

If stealth was a priority, though, there was no way to get around the need to put that extra 600 gallon tank inside.  The missiles, too, would have to be mounted in weapons bays inside the fuselage, with doors that opened only briefly at launch.  Here, at least, the Air Force had some experience.  Remarkably, the challenge of forcing open and then slamming shut weapons bay doors into the teeth of a howling supersonic air flow, while thrusting missiles safely out of the bay and away from the aircraft before their motors fired, had been solved as far back as the 1950s.  The F-102 and F-106 had internal bays for their Falcon and Genie missiles, and the Avro Arrow was to have had an internal weapons bay as well.  It was therefore feasible to put weapons and fuel inside.  It did, however, force the design to be large.  The Air Force aimed for a 25 ton fighter and concluded, reluctantly, that the end result would almost certainly be a 30 ton fighter – before long, a 35 ton fighter. Somehow, a 35 ton aircraft was going to have to out-fly the 22 ton F-15.

An F-106 launches a nuclear-tipped “Genie” missile from its internal weapons bay.  The open bay doors can be seen on the underside of the fuselage.

An F-22 with its weapons bay doors extended – almost 50 years after the F-106, the old technology proved crucial to stealth.

There is much more that could be said, but in brief, the stealth technology that was developed for tactical bombers in the wake of the Yom Kippur War was successfully adapted for use in fighters that have conventional fighter virtues.  An F-22 actually has a radar return that is much smaller than an F-117, and probably on a par with the B-2, yet it sacrifices little in aerodynamic terms to achieve this.  This is an incredible accomplishment. It ensures that SAMs on the ground, and fighters in the air, will probably know nothing of the Raptor’s presence, or at least they will know of it too late to do anything about it.  This alone, other things being equal, would give the F-22 a decisive advantage over any other fighter that preceded it.

And, other things were not equal.

Supercruise

Most current operational fighters are capable of high supersonic speeds, but they are “supersonic” in the same way that U-Boats of WW II were “submarines”.  While most of a U-Boat’s features were determined by the requirement to submerge, they were actually submersible torpedo boats, rather than true submarine craft.  They spent nearly all of their time on the surface, even while attacking in many cases, and could submerge only for brief periods, usually in response to attack.  Once underwater, they were slow, vulnerable, and had a limited air supply.  The first priority of every submerged U-Boat, after surviving,  was to get back to the surface.  It was not until nuclear power was installed that submersibles became true submarines that spent all of their time underwater, where they were faster, safer, and completely combat effective.

In the same way, an F-15 or SU-27 can make brief forays to supersonic speed, and the need to do so determines much of their aerodynamic structure, yet they spend nearly all of their time at subsonic speeds.  The state of jet engine technology determines this – though extremely powerful, contemporary fighter powerplants develop the most power at subsonic speeds.  As speed increases, more and more air is rammed into their intakes, and the engines begin to overheat.  This is why supersonic fighters have complex “ramps” in their intakes, which move, counter-intuitively, to decrease the amount of air that flows into the engine as speed increases.  Otherwise the engines would start to melt!  The only way to go supersonic, then, is to add thrust at the back end through the use of afterburners – and afterburners do nothing more clever or difficult than dump raw fuel into the jet exhaust, which then ignites, creating rocket-like thrust.  A very high percentage of the thrust at supersonic speed must be produced by this method, yet dumping buckets of raw fuel into the jet exhaust consumes the fighter’s fuel supply at prodigious rates.  Any fighter that spends more than a couple of minutes at supersonic speed had better start figuring out where the nearest air-refueling tanker is.

A typical “supersonic” fighter is therefore a subsonic aircraft capable of brief excursions into the supersonic realm.

The Air Force had something truly revolutionary in mind for the new fighter.  They wanted it to spend almost all of its time over hostile territory at supersonic speeds in the Mach 1.5 to Mach 1.8 range, about 1,000 – 1,200 MPH.  Any fighter that travels at that speed for extended periods will cover a great deal of ground, making it possible to cover larger areas with fewer aircraft.  It would also be very difficult to intercept, even if it wasn’t stealthy – a plane that is zipping by at high altitude and 1,100 MPH, and can sustain that speed, is very hard to catch with an aircraft that can only accelerate to that speed for a couple of minutes before running low on fuel and breaking off the chase.  Interception problems for ground-based SAMs would also be multiplied by the higher speed.

Even better results would flow if the aircraft could fly for extended periods at higher altitudes than other fighters.  The Air Force wanted the new fighter to cruise supersonically at 65,000 feet, almost three miles higher than other jets are able to operate.  At those altitudes, even F-15s and SU-27s begin to wallow in the thin air, and lose power of maneuver; they also lack the pressurization needed to keep the pilot alive at that altitude.  The new fighter would have to be comfortable, fast, and maneuverable at a height where other fighters could only zoom up and dive away, like fish jumping out of a pond trying to catch a dragonfly.  Designers referred to this operational altitude as the “high-fast sanctuary”, a zone that had been exploited in the past by exotic designs such as the SR-71 and MiG-25, but nothing that possessed conventional fighter attributes.

Aerodynamics have a lot to do with the F-22’s ability to operate comfortably at high altitudes, in particular a huge wing that dwarfs even that of an F-15; Raptor pilots will also be fitted out in a new G-suit/pressure suit ensemble that will keep them breathing and lucid 12 miles up.  However, flying level up there also requires a great deal of thrust, and flying level up there at 1,100 MPH requires more thrust than most engines could produce even under full afterburner, let alone in “military power”, without afterburner.  Yet extended supercruise necessarily implied high engine thrust without recourse to afterburning.

65,000 foot supercruise thus became a problem for the engine designers, and Pratt and Whitney narrowly beat out General Electric with a powerplant that marks a watershed in fighter engine development: the F-119 turbofan.  This engine still has afterburners, and in full afterburner produces something on the order of 38,000 to 40,000 lbs. of thrust, more than both J-79s produced on the Phantom, and about five tons more thrust than is produced by even the most powerful engine now available for current fighters.  With an installed weight of about 4,000 lbs., this gives the engines themselves a thrust:weight ratio of 10:1, a significant improvement over the 8:1 ratio of the prior generation.  The real story, though, is how much thrust these engines produce without resorting to afterburner: over 25,000 lbs., more than the engines on an F-15C at full, fuel-guzzling afterburner, and almost twice what an Eagle’s engines can produce at full military power.  Without using afterburner, then, an F-22 has more thrust than an F-15, and a thrust:weight ratio that still approaches 1:1 at combat weight.

An F-119 engine on the test rig.  Here, the massive thrust is seen deflecting both upward and downward in a multiple exposure. The rear nozzle does not merely expand and contract, as on conventional engines, but also swivels up and down.  This is known as “thrust vectoring”, and greatly increases aircraft agility at both subsonic and supersonic speeds.

Moreover, the F-119 engine can sustain this high thrust, without afterburner, even as it tears through the sky at supersonic speeds with air being rammed into it at volumes and velocities that would liquefy the turbine blades on an Eagle’s powerplant.  It does this by running hot, far hotter than was possible in prior engines, the result of extremely subtle materials technology and cooling methods too complex to be discussed in detail here.  Suffice to say that with the F-119 engine, the Raptor has proved fully able to cruise along for extended periods at Mach 1.7 and 65,000 feet.

There was more.  A conventional fighter, straining to maintain supersonic speed at full thrust, is out of specific excess power with which to do anything else.  It is basically a straight-line missile at that point, if it wants to sustain the pace.  Any maneuver has to involve a loss of speed and a return to subsonic velocity.  With the F-119, a Raptor still has 13 tons of thrust in reserve while cruising at Mach 1.7, and can access this power with brief use of afterburners.  An F-22 can therefore maneuver at supersonic speed, yet remain supersonic – a first.

The new engines embody yet another advance: thrust vectoring.  The nozzles of the engine swivel up and down within a range of about 40 degrees, meaning that the Raptor can vector its engine thrust away from the centerline to point the nose in any direction more quickly than it could by relying on control surfaces alone.  The F-22 is thus able to “get around within its envelope” – to transition from one flight state to the next – much more quickly than non-vectoring fighters.  This has important implications for subsonic agility, as will be discussed.  When travelling at high altitude in supercruise, thrust vectoring, combined with the high available thrust, allows the Raptor to pull quite extreme maneuvers at supersonic speed, when other fighters could only go straight and level and wait to run out of fuel.

As an added bonus, Pratt and Whitney designed the vectoring nozzles to be rectangular, rather than circular.  While not ideal for a pressure vessel, the rectangular nozzles confer real benefits to the stealthiness of the aircraft; the hot air coming out is shaped into a flattened plume that disperses more rapidly than the efflux of a conventional engine, making the Raptor harder to detect with infra-red sensors.  In league with this, the limited use of afterburner itself confers infra-red stealthiness, as it is the red-hot afterburner efflux that really makes an aircraft vulnerable to long range detection by infra-red systems.

The F-119 in cross section.

Supercruise opens up whole new fields of tactical opportunity, and fighter pilots are only beginning to figure out how to exploit the radical new capability.  For example, an F-22, at ordinary cruise, is always in position to take a “snap-shot”.  Against a fighter cruising at subsonic speed, the Raptor is able to fire off a missile at high velocity immediately, whereas the subsonic fighter must either take a minute to accelerate itself to supersonic speed, or try to fire back at subsonic speed.  Yet, even if it detects the Raptor at the same time as it is detected – impossible, given the Raptor’s stealthiness – the opposing fighter will not be in a position to fire back.  Flying higher and faster, the missiles on the F-22 will have about 50% more range than the missiles on the opposing fighter, even if they are both armed with missiles that have the same “brochure” statistics for range and speed.  The Raptor will thus be launching at the enemy while the enemy is not yet in range to return fire.  By the time the enemy could accelerate to supersonic speed and get within range of the Raptor – again, assuming for the moment that it could detect the Raptor at all – it would be too late.

Combined with stealth, supercruise provides an unbeatable advantage over previous generations of jets.  Test pilots are now working out whole new ways of attacking.  Working in simulators, they game out scenarios in which the F-22 detects the enemy, or perhaps a whole formation of enemies, while still unseen by the enemies’ radar.  It is then a simple matter to loose off a few AIM-120 AMRAAMS towards them while they are still too far away to return fire, even if they know they are under attack (which they will not) and could pick up the Raptor on radar  (which they cannot).  Then, engaging the afterburners to provide the excess power needed for supersonic maneuvering, the Raptors could make tight, 6G thrust-vectoring turns at 1,200 MPH, circling behind the unwitting enemy.  As the missiles strike the first few targets,  and the remainder go to afterburner to escape, the Raptors are positioning themselves, still undetected, for an easy stern shot against the accelerating but still subsonic enemy, who is now looking forward, in the wrong direction, for signs of the foe.

If attacked from behind, assuming the attacker can see the F-22 at all, a Raptor can engage afterburner, accelerate to Mach 2, and pull into a turn that may be too tight for the high velocity missile to follow, while bringing the attacker to bear.

High altitude supercruise may even make the Raptor a better bomber than other aircraft, able to loft specially-designed weapons towards targets tens of miles away, while avoiding radar detection, or out-running the SAMs if detected at all.  A stealthy, supercruising aircraft with excess power of maneuver, exploiting the “high-fast sanctuary”… for anyone thinking of going up against F-22s, these capabilities are the stuff of nightmares.

And that’s still not all that the Raptor has in its bag of tricks.

Sensor Fusion, Information Superiority, and Networked Warfare

 

The cockpit displays of a prototype F-22, topped with a wide-angle head-up display. This is probably not representative of the current cockpit arrangement, pictures of which are notably absent from public sources.

In Viet Nam, the varied electronics of the F-4 imposed too much workload upon stressed pilots.  Electronic countermeasures boxes would squeal in their ears and display symbology on dedicated screens.  The radar had its own screen to be kept under close scrutiny.  Heat-seeking missiles would announce their ability to “see” the target by producing a loud “growl” (the “annunciator tone”) in the pilot’s earphones.  Fuel gauges, altimeters, throttle settings, artificial horizons, all manner of separate dials and gauges had to be checked repeatedly.  Pilots, overloaded by all this, were often shot down while trying to get a grip on all the screens and dials and gauges and squeals and growls, never even realizing they were being shot at. I recall seeing an interview in which ace pilot Robin Olds, legendary commander of the 8th Tactical Fighter Wing in Viet Nam, sat in the front seat of an F-4 and pointed to all the systems he would simply turn off before entering combat, the better to prevent information saturation.  He would even turn off the microphone of the radar intercept officer in the back seat.  “He could hear me, that’s all I cared about”.  Colonel Olds was a seasoned fighter jock, having become an ace flying over Europe in WW II.  He knew how crucial it was to focus when entering battle.  Far too many of his peers were shot down before they learned this lesson, killed, in effect, by the very systems meant to protect them.

This is hardly surprising; an ordinary person could scarcely park a car while monitoring such a diverse set of inputs, much less dodge MiGs, evade SAMs, and swerve through puffs of anti-aircraft artillery in a fast jet while experiencing Gs equal to six times the force of ordinary gravity.

In the 1970s, a new discipline emerged in fighter design, aiming to improve the pilot’s “situational awareness”.  The heads-up display, described above, was a great stride down this road, allowing pilots to keep their eyes where they belonged while receiving the most vital information and ignoring the rest.  By the 1980s, improvements in digital cockpit design made for very much improved cockpit arrangements, using multi-function computer screens with clear symbology to augment the heads-up display.  Dials and gauges were all but banished.  A groundbreaker in this category was the F-18, with a cockpit that set the standard for future fighters.

The F-18 cockpit. Superficially similar to that of the prototype F-22, it operates under different functional principles, and does not provide “sensor fusion” via its multi-function displays.

Yet, clear displays or not, even an F-18 forced the pilot to look in several places to build up a coherent picture of what was going on.  All fighter displays worked on the same old principles.  If there was a radar, you had a separate radar display.  Countermeasures had their own display.  Infra-red or TV sensors had still another display.  A single pilot, with lots on his mind and plenty to do, could still be overwhelmed.

The Raptor will cure this problem with a revolutionary concept known as “sensor fusion”.  Taking advantage of the huge strides being made in computer power, the Raptor will replace all the separate screens with a central display that tells him everything he needs to know at any given time.  Separate displays may show different information, but they are entirely secondary.  On the central display, the computers will assemble the information from all the various sensors and instruments – called “apertures” in the jargon – and amalgamate them into one processed input.  The radar image will be combined with electronic warfare information, and so on, so that what the pilot looks at is “synthetic data”, made clear and comprehensible, that tells him several things at once.  Colour and shape will be a key element of this new display strategy.  The human brain responds instinctively to these characteristics. For example, an enemy aircraft will appear as a red triangle.  A line drawn from the center of the triangle will indicate direction of flight.  The length of that line will indicate relative speed.  An advancing red triangle sporting a long line pointed straight at you like a lance is an intuitively alarming thing.

At the same time, to avoid overload, the F-22 will operate on the “dark cockpit” principle.  The on-board computers, monitoring all systems and serving as intermediary between the aircraft and the pilot, will take care of routine functions.  If there is nothing to report, most of the cockpit displays will actually go dark, showing nothing.  Only if something happens requiring the pilot’s attention – detection of a target or threat, internal damage, arrival at crucial way-points, fuel status reminders, and so on – will the computers ask the pilot for instructions.  The very powerful computers at the heart of the Raptor’s information systems will function eerily like a separate mind; an F-22 is practically a simple organism on which the pilot rides, taking orders and making routine decisions behind the scenes, rather than a mere machine.

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