Giovanni’s Weblog

Lockheed Martin… pfff!! what can i say?? simply beautiful… don’t you think so?. This time I’m gonna talk about the F-22 Raptor.

The F-22 Raptor is a fifth generation fighter aircraft which utilizes fourth generation Stealth technology. It was originally envisioned as an air superiority fighter for use against the Soviet Air Force, but is equipped for ground attack, electronic warfare and signals intelligence roles as well. Faced with a protracted development period, the prototype aircraft was designated YF-22 and, as F/A-22 during the three years before formally entering United States Air Force service in December 2005 as the F-22A. Lockheed Martin Aeronautics is the prime contractor and is responsible for the majority of the airframe, weapon systems and final assembly of the F-22. Along with Lockheed Martin, partner Boeing Integrated Defense Systems provides the wings, aft fuselage, avionics integration, and all of the pilot and maintenance training systems.

• Characteristics

The dual afterburning Pratt & Whitney F119-PW-100 turbofans incorporate thrust vectoring. Thrust vectoring is in the pitch axis only, with a range of ±20 degrees. The maximum thrust is classified, though most sources place it at about 35,000 lbf (156 kN) per engine. Maximum speed is estimated to be Mach 1.72 in supercruise mode and without external weapons; with afterburners, it is “greater than Mach 2.0″ (2,120 km/h), according to Lockheed Martin. The Raptor can easily exceed its design speed limits, particularly at low altitudes; max-speed alerts help prevent the pilot from exceeding the limits. General John P. Jumper, former U.S. Air Force Chief of Staff, flew the Raptor faster than Mach 1.7 without afterburners on 13 January 2005. The absence of variable intake ramps may make speeds greater than Mach 2.0 unreachable, but there is no evidence to prove this. Such ramps would be used to prevent engine surge, but the intake itself may be designed to prevent this. Former Lockheed Raptor chief test pilot Paul Metz stated that the Raptor has a fixed inlet. Metz has also stated that the F-22 has a top speed greater than 1600 mph (Mach 2.42) and its climb rate is faster than the F-15 Eagle due to advances in engine technology, despite the F-15’s thrust-to-weight ratio of about 1.2:1, with the F-22 having a ratio closer to 1:1.

The true top-speed of the F-22 is largely unknown to the general public, as engine power is only one factor. The ability of the airframe to withstand the stress and heat from friction is a key factor, especially in an aircraft using as many polymers as the F-22. However, while some aircraft are faster on paper, the internal carriage of its standard combat load allows the aircraft to reach comparatively higher performance with a heavy load over other modern aircraft due to its lack of drag from external stores. It is one of only a handful of aircraft that can sustain supersonic flight without the use of afterburner augmented thrust, i.e. supercruise. The fuel usage from using afterburners greatly reduces flight time.

The F-22 is highly maneuverable, at both supersonic and subsonic speeds. The F-22’s thrust vectoring nozzles allow the aircraft to turn tightly, and perform extremely high alpha (angle of attack) maneuvers such as the Herbst maneuver (or J-turn), Pugachev’s Cobra, and the Kulbit, though the J-Turn is more useful in combat. The F-22 is also capable of maintaining a constant angle of attack of over 60°, yet still having some control of roll. Cruise altitude is a huge factor in performance. During June 2006 exercises in Alaska, F-22 pilots routinely attributed their altitude advantage as major factor in an unblemished kill ratio.

There is a nice video of the F-22 Raptor Debut, enjoy!