The non-traditional design approach of the F-22 was driven by the reality of smaller military budgets, fewer aircraft and a requirement to make those few aircraft far more lethal than their predecessors.
An important aspect to increasing the lethability of the aircraft was the elimination of "housekeeping," a reduction of many system operations responsibilities that have classically taken a significant portion of the pilot's attention in the cockpit.
This allows pilots to fly with "carefree abandon."
Reduced complexity
The question was asked, "Why should an airplane be any more complex to operate than your car?" "Is there really a need for all those little switches, knobs and dials in the cockpit?"
As with a car, the basic approach was to make the operation of the F-22 a true "kick the tires and light the fires" machine. All switches, even the most traditional functions, had to earn their way into the cockpit.
The cockpit displays have been set up to be intuitive to the pilot. Confirmed enemy aircraft are red triangles, friendly aircraft are green circles, unknown aircraft are yellow squares and wing men are shown as blue F-22s.
Pilots now become tacticians and information managers, making decisions on data delivered clearly and in a timely manner by the F-22's integrated avionics system.
Extension of the cockpit
One of the primary design principles is really an extension of the philosophy for the cockpit itself. The design philosophy was established up front, with engineers and pilots working closely together.
"Carefree abandon" translates into the ability of the fighter pilot to do whatever he wishes with the F-22, without fear of loss of control, loss of thrust or aircraft structural overstress.
Specifically, this has resulted in an unlimited angle of attack (AOA) capability for the aircraft's basic combat configuration (for example, all internal carriage of weapons and no external stores). There are no AOA limiters, and, most importantly, no restrictions on flightpath.
The pilot can run the airplane out of speed and maneuver in the post stall regime with integrated flight controls and thrust vectoring. The F-22 responds smoothly to the pilot and can change flight condition at his command.
'Carefree' also applies to structural limits on the airplane, and this is handled two ways.
First, all the traditional limitations seen in flight manuals have been coded into onboard computers. For example, some components (such as landing gear and air refueling doors) have speed limits. The pilot is never prevented from exceeding those limits.
If the pilot exceeds a limit, either intentionally or unintentionally, he gets a message with an aural warning to tell him that a limit is being exceeded.
In addition to overspeed warnings to the pilot, the flight control system provides load limiting for all pilot inputs as a function of aircraft gross weight.
Second, the flight control system provides automatic load limiting for all pilot inputs as a function of aircraft gross weight. The pilot gets the maximum performance the aircraft is capable of achieving at any time when full roll, pitch or yaw commands are used.
The pilot can 'yank and bank' all he wants without fear of 'hurting' the airplane.
These flying qualities are backed by more than 8,000 hours of stability and control wind tunnel testing (during the Engineering and Manufacturing Development testing phase alone), thoroughly tailored flight control laws and countless handling quality simulation evaluations – all of which will be demonstrated during the coming flight test program.
Information from the web sites of Lockheed Martin, Boeing and Pratt & Whitney were used in this story.