The F-22 on its first flight over Georgia, showing off its remarkable Thrust/Weight ratio.
Note the clean, smooth exterior for both aerodynamics and Stealth.
The F-22 program involves more than 15,000 people, working for over 1,400 companies
in 46 States. The main contractors are Lockheed Martin and Boeing. They share more or less
equally the construction tasks of the aircraft, manufacturing different sections which are
then assembled together by Lockheed Martin Aeronautical.
Lockheed Martin Aeronautical is responsible for overall program management, as well as building
the nose section and the forward fuselage including the cockpit and forward inlets; the leading
edges of the wings; the fins and stabilators; flaps; ailerons and landing gear. Lockheed
Martin Tactical Aircraft Systems is responsible for the center fuselage;
stores management; Integrated Nav and Electronic Warfare Systems (INEWS); the
Communication, Navigation and ID (CNI) systems, as well as weapons support systems. Boeing is responsible
for the wings; the aft fuselage; the radar installation; around 70% of the avionics software integration;
training; life-support; fire-protection systems; as well as flight-test development and management. Pratt & Whitney
is responsible for the 2 amazing F119-PW-100 engines.
The entire design of the F-22 is motivated by 4 factors:
All of these factors, when combined, give the F-22 a "First-look, first-shot, first-kill" capability. At 62 ft 1 in
long, the F-22 is roughly the same physical size as an F-15, but has a Radar Cross Section (RCS) that is reportedly as
little as 1/100 the size of an F-15's. This is done through several factors: The aircraft is shaped to deflect radar
signals away from the source. For example, the highly reflective compressor blades are shielded from view by specially-designed inlet
ducts. Unlike the F-117, the F-22 is not "candy-coated" with Radar-Absorbent Materials (RAM). Instead, RAM is applied only to
radar hot spots such as forward fuelage "chine", the edges of the wing and tail, and the inlet ducts.
The F-22 has a different appearance than the YF-22 prototype. The wings and the horizontal tail both have a leading-edge
sweep angle of 42° (on the YF-22 they were 48°); the trailing edges of the wings are at a 17° forward angle inboard.
Outboard of the ailerons on the wings, they are 42° forward (on the YF-22 they were all straight from root to tip). Despite these changes,
the surface areas of the wings remains the same on both the YF-22 and the F-22: 840 sq. ft (78m2).
The vertical tail surfaces on the YF-22 were found to be
larger than neccessary, so on the production Raptor they are 22% smaller. On the F-22, radar-defeating diamond-shaped inlet ducts are mounted approimately 18" (46cm) closer to the aircraft's nose than in the YF-22.
The first aft fuselage, containing all environmental control systems, fuel, electrical, hydraulic and engine subsystems, was completed on October 15, 1996. It is 19 ft long, 12 ft wide, and weighs 5,000 lbs. By weight, it is 67% Titanium, 22% Aluminum, and 11% composite. The aft fuselage was designed entirely on the 3D CAD (Computer-Aided Desgin) progam CATIA. The aft fuselage has electron-welded boom structural subassemblies, the largest one being the forward boom which is 10 ft long and weighs 650 lbs. The use of welding means that the use of more traditional fasteners such as screws and rivets is reduced by as much as 3/4. The center fuselage incorporates 5 large Titanium bulkheads. The largest is a 6-ton forging measuring 12 ft across and 6 ft high. The center fuselage, by weight, is about 30% Titanium, 30% composites, and around 30% Aluminum.
Each wing, built by Boeing, is 16 ft (from the side of the fuselage) by 18 ft (leading to trailing edge at root) in size. Like other components,
the wing was also designed entirely on CATIA. After analysing battle simulations, designers decided to replace every fourth composite spar
with a Titanium one to increase the wings' resistance to battle damage. Weighing in at around 2,000 lbs each, the wings are desinged to be interchanble
from one F-22 to another, easing maintenace concerns in the field. The wing, by weight is about 47% Titanium. Each wing has 4 hardpoint attachments, each capable of carrying stores of up to 5,000
lbs. These pylons would not be used in most combat situations, of course, because it would negate the aircraft's Stealthiness, but could be used to carry
stores such as external fuel for long deployments. Capable of air-to-air refuelling, the F-22 can carry 11 tons of internal fuel--twice the amount an F-15
can carry. Unlike other fighters being put into production such as the French Rafale
or the Russian Su-37, the F-22 does not incorporate canard foreplanes for pitch authority at high angles of attack (AOA).
Canards are not included because they are extremely difficult to incorporate successfully into a Stealth design. Instead, the huge tailplanes, which have
nearly as much area as an F-16's wing, are quite sufficient for the job. The horizontal
tails have a span of 27 ft (8.84 m). They are contructed of an Alumiunum honeycomb,
with a bonded bismaeimide skin surface. In the 90 day flyoff, the YF-22 demonstrated controlled flight at a 60° AOA, executing
a 360° roll at that attitude. In wind tunnel tests,
AOAs of as much as 85° have been demonstrated. The large vertical tails, canted outward at 28° are mounted well forward of the rear of the plane. Both the leading and trailing
edges of the stabilizers are swept at 22.9°. They have a span (tip to tip) of 18 ft 2 in (5.97 m). The F-22's landing gear is the Menasco tricycle type and can take a 9.3 fps (3.05 m/s) vertical impact.
The F-22's wheelbase was reduced by approximately 18" (46cm) compared to the YF-22.
The tolerances evident on the F-22 are remarkable. Many of the pieces are built to within tolerances of a few ten-thousandths of an inch. The drilling and cutting actions are performed by robots using
lasers for guidance. This is neccessary in order to preserve the aircraft's strict Stealth characterisics. Overall, the F-22 is approximately, by weight, about 42% Titanium, 23% composites, and about 15%
Aluminum, the rest being other materials.
The F-22, even though it has been described as being "more complex than the human body", is remarkably easy to maintain. For example, on a 30-day overseas deployment, a squadron of 24 Raptors would need only half as much
maintenance personnel as an equivalent number of F-15s. The F-22s would need only 8 planeloads of diagnostic and maintenance equipment, compared with 18 planeloads for the F-15s. Most of the F-22's access panels are reachable
from ground level, and maintainers will require only 8 more tools than is found in the basic F-15 maintainer's kit.
"The absolute raw power is something else." That's how Paul Metz, who took the Raptor on its first flight, described the feel of the F-22. The engines that power the Raptor are two Pratt &
Whitney F119-PW-100 low-bypass turbofans. They are unique in many ways. Having been desinged on computer, the F119's compressor and turbine blades are shorter, thicker and twisted more sharply than the
blades in earlier turbofans such as the F100-PW-229 that powers the F-15E. The F119 has 3 stages in the fan area, 6 stages in the compressor, and 2 stages in the turbine. The F119 has has a low-bypass value,
with about 15%-20% of the air being sent through the bypass duct. The F119 is in the 35,000 lb (155 kN) thrust class. The exact figure is classified,
but many have speculated that the F119 has a thrust as high as 39,000 lbs, giving a single Raptor a thust level equivalent to the thrust generated by an entire squadron of Korean War-era
F-86 Sabres. So having as much as 78,000 lbs of thrust on tap means that the
F-22 will have a good thrust to weight ratio. The target ratio is 1.4. Even at its
estimated maximum take-off weight of 60,000 lbs (27,216 kg), the F-22 will still have
a thrust/weight ratio of 1.2 to 1.3. Having these ratios above 1 means that even fully loaded, the
Raptor could accelerate while going straight up.
The engines give the Raptor "supercruise" ability: the ability to sustain supersonic flight without the use of gas-guzzling afterburners. This means that unlike
today's fighters which can only go supersonic for a brief dash, the F-22 will fly most of its mission above Mach 1. During testing, the YF-22, powered by the YF119 version of the F119, sustained supercruise flight at Mach
1.58. The F119 has a lot fewer moving and static parts than on previous engines. It is made with advanced materials such as a high-strength, heat-resistant Titanium matrix known as Alloy C. Alloy C is used in the compressor
stators as well as in the afterburner and nozzle areas. The
1st Stage compressor fan stators are made of Bismalimide. The F119 has a 3rd Generation digital engine control system. The most siginificant feature of the F119 is its thrust-vectoring capability. Insead of the traditional
circular engine exhaust "turkey feathers" we're so used to seeing on fighters, the F-22's F119 uses a two-dimensional (2D) thrust vectoring system that deflects exhaust +/-20° in the vertical plane in less than a second.
This gives the Raptor enormous maneuverability in a dogfight situation, and also is a prime factor in giving it its high-AOA control, and low-speed handling capability: Paul Metz said that the F-22 can maintain controlled
flight at the cruising range "of a Piper Cub", and estimates say it can fly effectively at speeds as low as 80 knots. The F119's development program started in 1983, and the start of the Engineering Manufacturing Development (EMD)
program started in 1991. The YF119 flew with one of the two YF-22s in 1990. F119 production for operational F-22 service will start in 1999.