The Messerschmitt Bf 109 first flew in 1935 as an air superiority fighter. Only a relatively small fuel load was envisaged and it was decided that performance could be optimised by the use of small wings whose high wing loading could be offset by leading-edge slots and trailing-edge flaps. The fuselage was slim and the cockpit cramped, this emphasis being carried over to the undercarriage, which was of narrow track. These design features were later to become the major drawbacks of the aircraft.

There are exceptions to every rule. Lockheed opted for a straight wing for its F-104 Starfighter, rather than the delta and swept wings of contemporary supersonic fighters. Among the penalties incurred with this choice were the need for ‘blown’ flaps (air tapped off the engine and exhausted over the flap to energise the airflow) for high AoA conditions (such as landing) and a remarkably thin wing having a dangerously sharp leading edge.

With the vogue for canard configurations, such as the Saab Gripen seen here, aircraft design has turned full circle. The Wright Flier was also an unstable canard. However, there the similarity ends with current fighters being designed to ensure favourable interaction between canard and foreplane vortices to increase total lift.

Top: Lift forces with a conventionally tailplane configuration, (MiG-29 Fulcrum) showing the tailplane download to trim under normal and high AoA flight.
Bottom: Lift forces of a canard configured aircraft (Rafale C) showing the positive lift from both canard and mainplane.

Illustration of the vortex flow from the foreplanes and mainplane of the Rafale at high AoA.

This plan view of the Northrop N-156F (prototype of the F-5 Freedom Fighter) illustrates the waisted fuselage and wing root leading edge extensions to conform to the area rule. The leading-edge extensions also provided significant increased lift at high AoA.

The Bristol M.1C Bullet which first flew in 1916 was an aerodynamically clean monoplane and achieved 114kts with only 80kW from its le Rhone rotary engine. However, it succumbed to technical opposition by virtue of the monoplane’s supposed lack of structural integrity. Only 125 were built and relegated to operations in secondary theatres of war.

One of the most influential aircraft evolved in Germany during the early 1930s was the Heinkel He 70. Among its many aerodynamic refinements was a smooth, oval section monocoque fuselage, retractable undercarriage and an elliptical plan form wing. The latter was chosen to minimise induced drag.

That the delta was a viable planform for both subsonic and supersonic designs is shown by the appearance, throughout the 1950s, of a succession of tailless and tailed deltas, including the F4D Skyray (seen here), F-102A Delta Dagger, Javelin, MiG-21, Draken and F-106A Delta Dart.

Addition of leading edge slats to the later model F-4Es greatly improved the turn rate and radii over the early models. The slats also improve stability and handling qualities.