F-22A Raptor Is considered to be the flagship fighter of USAF. And till now we can say it is the only in service Stealth fighter aircraft.
The history of Raptor’s evolution goes back to 80s. When the russian Su-27 flanker and Mig-29 fulcrum used to rule the sky. So USAF needed to replace their ageing and outdated F-16s and F-15s. To meet the requirement of modern era jet fighter and outmatch the Russian Flankers as well as Fulcrums an RFP was issued in July ’86 for a new generation fighter code named as Advanced Tactical Fighter. After having a through out demonstration phase 2 prototypes YF-22 and YF-23 are selected and project was handed to 2 primary contractor Boeing and Lockheed martin. After a whole lot of technical demonstration YF-22 was choosen over YF-23. The later was more stealthier and faster than former but lacks agility which the USAF required to outmatch the Flanker’s agility.
DESIGN CHANGES FROM YF-22 to F-22:
-Cockpit was moved forward by 178 mm to improve pilot Visibility
-Air intakes were moved back by 356 mm
-Wing’s leading edge sweep angle was changed from 48° to 42°
-The surface area of vertical stabilizer area was decreased by 20% to make it more stealthier.
-Wing and stabilator trailing edges were refined to improve aerodynamics, strength, and stealth
-Vertical stabilizer was shifted rearward
In this whole process the cost of the whole project is increased by considerable amount. Due to this the no of aircrafts requested is reduced to only 181 in 2006 which was originally 750 in 1994. The total cost of program was almost upto $70 billion exceeding the original $26 billion value for 750 F-22s. Now the fly-away cost of 1 F-22 is almost $160million making it the most costly fighter in the world.
But the aircraft gives good value for its money. Till date the Raptor can be declared as the most potent fighter aircraft taking all point of view in a combat situation.