The split S is an

Aerobatic maneuver Aerobatic maneuvers are flight paths putting aircraft in unusual attitudes, in air shows, dogfights or competition aerobatics. Aerobatics can be performed by a single aircraft or in formation with several others. Nearly all aircraft are capab ...

and an air combat maneuver mostly used to disengage from combat. To execute a split S, the pilot half-rolls their aircraft inverted and executes a descending half-loop, resulting in level flight in the opposite direction at a lower altitude.

Description

The split S is taught to be used in

dogfight A dogfight, or dog fight, is an aerial battle between fighter aircraft conducted at close range. Dogfighting first occurred in Mexico in 1913, shortly after the invention of the airplane. Until at least 1992, it was a component in every majo ...

ing when the pilot has the opportunity to withdraw from battle. It can be an effective tactic to prevent an enemy behind (between four o'clock and eight o'clock positions) from gaining a

missile lock-on Lock-on is a feature of many radar systems that allow it to automatically follow a selected target. Lock-on was first designed for the AI Mk. IX radar in the UK, where it was known as lock-follow or auto-follow. Its first operational use was in t ...

while one is disengaging from a fight. The split S is contrasted with the

Immelmann turn The term Immelmann turn, named after German World War I Eindecker fighter ace Lieutnant Max Immelmann, refers to two different aircraft maneuvers. In World War I aerial combat, an Immelmann turn was a maneuver used after an attack on another a ...

, which is an ascending half-loop that finishes with a half-roll out, resulting in level flight in the opposite direction at a higher altitude. The split S is also called a reversed Immelmann turn and can also be written with a hyphen: split-S. In basic terms, the Immelmann and split S are very similar, both accomplishing the same reversal in course, but the split S exchanges altitude to gain speed, while the Immelmann turn exchanges speed to gain altitude. The split S, being a descending maneuver, means that the pilot must ensure that it is started high enough to complete the half-loop; the exact minimum altitude depends on factors like the aircraft's speed, weight and maneuverability, likewise the terrain below the plane. Misjudgements can arise from a lack of situational awareness or from an error in reading instruments. The reasons for starting the split S maneuver from the inverted position include the fact that people tolerate acceleration ("g-force") applied from head to feet several times better than the reverse direction, as much as 9g versus 3g. Most combat aircraft frames are also designed to pull more Gs in their positive aspects (upward to the aircraft), rather than negative (downward to the aircraft). A much tighter maneuver is therefore possible with the half roll. The split S without a beginning half-roll was a standard maneuver in early World War II by German pilots seeking to evade British fighters. The

Merlin engine Merlin engine may refer to: *Rolls-Royce Merlin, an aircraft engine *Merlin (rocket engine family) Merlin ( cy, Myrddin, kw, Marzhin, br, Merzhin) is a mythical figure prominently featured in the legend of King Arthur and best known as a mag ...

used in British fighters was carburetted, and the float valves would malfunction under negative

g-force The gravitational force equivalent, or, more commonly, g-force, is a measurement of the type of force per unit mass – typically acceleration – that causes a perception of weight, with a g-force of 1 g (not gram in mass measure ...

leading to reduced power or a stalled engine (The German fighters were not subject to this problem since they used

fuel injection Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All comp ...

). This could be prevented by rolling the aircraft before starting the dive, but doing so took up enough time to give the German pilots an excellent chance of escaping. The beginnings of a solution was provided by "

Miss Shilling's orifice Miss Shilling's orifice was a very simple technical device made to counter engine cut-out in early Spitfire and Hurricane fighter aeroplanes during the Battle of Britain. While it was officially called the R.A.E. restrictor, it was referred to ...

", a fuel-flow restriction device, and was finally solved by changing from the original S.U. carburettors to Bendix-Stromberg pressure carburettors, and later to S.U. injection carburettors.

References

External links

Aerobatic manoeuvre website
{{Aerobatics Aerial maneuvers Articles containing video clips

Description

See also

References

External links