Saturday, December 26, 2009

F-22 Raptor

I don't know why, but when visiting the museum I completely missed the F-22 Raptor, the most advanced fighter aircraft in the world. It is also the most expensive at 143 million dollars per copy. Builder Lockheed-Martin says that no other fighter in the world, current or projected, can touch it. As reference I am using a recnt picture by renzodionigi published on flickr. The exhibit is actually located in the Modern Flight Gallery, even though theme-wise it would rather belong into the (Post-) Cold War Gallery together with the other modern stealth/fighter jets.

Lockheed Martin F-22A Raptor

The F-122 Raptor participated in Toronto's Airshow in September this year. There I captured part of the routine with a series of images taken at one second intervals:

The F-22 Raptor is a fifth generation fighter that is considered a fourth-generation stealth aircraft by the USAF. Its dual afterburning Pratt & Whitney F119-PW-100 turbofans incorporate pitch axis thrust vectoring, 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, without external weapons, is estimated to be Mach 1.82 in supercruise mode; as demonstrated by General John P. Jumper, former US Air Force Chief of Staff, when his Raptor exceeded Mach 1.7 without afterburners on 13 January 2005. With afterburners, it is "greater than Mach 2.0" (1,317 mph, 2,120 km/h), according to Lockheed Martin; however, the Raptor can exceed its design speed limits, particularly at low altitudes, with max-speed alerts to help prevent the pilot from exceeding them. Former Lockheed F-22 chief test pilot Paul Metz stated that the Raptor has a fixed inlet. The absence of variable intake ramps generally limits speeds to approximately Mach 2.0. Such ramps would be used to prevent engine surge resulting in a compressor stall, but the intake itself may be designed to prevent this. Metz has also stated that the F-22 has a higher climb rate 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 US Air Force claims that the Raptor cannot be matched by any known or projected fighter types, and Lockheed Martin claims that, "the F-22 is the only aircraft that blends supercruise speed, super-agility, stealth and sensor fusion into a single air dominance platform."

The true top speed of the F-22 is unknown to the general public. The ability of the airframe to withstand the stress and heat is a further 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 (and its associated high fuel usage). This ability is now termed supercruise. This allows the aircraft to hit time-critical, fleeting or mobile targets that a subsonic aircraft would not have the speed to reach and an afterburner dependent aircraft would not have the fuel to reach. The F-22 is highly maneuverable, at both supersonic and subsonic speeds. It is extremely departure-resistant, enabling it to remain controllable at extreme pilot inputs. The Raptor'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. During June 2006 exercises in Alaska, F-22 pilots demonstrated that cruise altitude has a significant effect on combat performance, and routinely attributed their altitude advantage as a major factor in achieving an unblemished kill ratio against other US fighters and 4th/4.5th generation fighters.

To get an idea about the amazing maneuvers this airplane is capable of performing watch this 10 minute HD video posted by jaba149 on YouTube:

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