Air International 2000-03
D.Baker - Reaching Those Parts That Others Can't /Technology/
Unlike some of its contemporary Western fighters, the MiG-29 achieves a high degree of agility by dint of clever aerodynamic design alone. That said, it lacks the 'carefree handling' bestowed by fly-by-wire systems.
Один из 80 F-16C Block 50, полученных Грецией в рамках предыдущих заказов
With the F-16, General Dynamics took the unprecedented step of intentionally violating the rule book and designing a combat aircraft inherently unstable in pitch to give an exceptionally high degree of agility. That this could be achieved, whilst retaining docile handling characteristics, is due solely to the fly-by-wire flight control system.
An aerodynamicist’s nightmare, the F-117 is a classic example of the use of fly-by-wire to relieve the aircraft designers from the constraints previously imposed by 'classic' aerodynamics to obtain adequate stability.
Software-related incidents such as the pilot-induced oscillation that caused the crash on landing of the YF-22, and two Gripen accidents led to the safety of fly-by-wire systems to be questioned. However, refined software validation techniques have significantly reduced the risk of similar occurrences. All safety-critical software changes on aircraft such as the F-22, illustrated here, will be subjected to rigorous testing.
Suggesting that aircraft design is as much an art as a science, the US favours aft-tail designs with aircraft such as the Lockheed Martin F-22 Raptor, while Western Europe and Russia pursue the foreplane-delta.
In spite of the US pioneering fly-by-wire technologies during the 1950s, it was not until the Boeing 777 flew in June 1994 that fly-by-wire entered the US commercial aviation market.
In 1988, the A320 became the first airliner with fly-by-wire to enter widespread airliner service. In addition to possessing relaxed static stability, the A320 flight control system controls outboard spoiler and aileron actuators to inhibit gust load response and thus give a smoother flight.
Pioneering aviators were largely ignorant of the laws of stability and control and really did fly ‘by the seat of their pants’. Their task was not eased by the aircraft of the day which, like this Bristol Boxkite, were often unstable and underpowered.
The Grumman X-29A displays its planform. Canard area is 20% of the wing area
A number of radical technologies were embodied in the X-29, the most significant being aeroelastic tailoring of the forward-swept wings to prevent their structural divergence. Without the benefit of a fly-by-wire control system, providing continuous inputs to the canard, the aircraft would not have been controllable.