A drag-reducing aerospike is a device (see nose cone design) used to reduce the forebody pressure

aerodynamic drag In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fl ...

of blunt bodies at supersonic speeds. The aerospike creates a

detached shock A bow shock, also called a detached shock or bowed normal shock, is a curved propagating disturbance wave characterized by an abrupt, nearly discontinuous, change in pressure, temperature, and density. It occurs when a supersonic flow encount ...

ahead of the body. Between the shock and the forebody a zone of recirculating flow occurs which acts like a more streamlined forebody profile, reducing the drag.

Development

This concept was used on the UGM-96 Trident I and is estimated to have increased the range by 550 km. The Trident aerospike consists of a flat circular plate mounted on an extensible boom which is deployed shortly after the missile breaks through the surface of the water after launch from the submarine. The use of the aerospike allowed a much blunter nose shape, providing increased internal volume for payload and propulsion without increasing the drag. This was required because the Trident I C-4 was fitted with a third propulsion stage to achieve the desired increase in range over the Poseidon C-3 missile it replaced. To fit within the existing submarine launch tubes the third-stage motor had to be mounted in the center of the post-boost vehicle with the reentry vehicles arranged around the motor. At the same time (middle 1970s) an aerospike was developed in KB Mashinostroyeniya (KBM) for the 9M39

surface-to-air missile A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground to destroy aircraft or other missiles. It is one type of anti-aircraft syst ...

9K38 Igla The 9K38 Igla (russian: Игла́, "needle", NATO reporting name SA-18 Grouse) is a Russian/Soviet man-portable infrared homing surface-to-air missile (SAM) system. A simplified, earlier version is known as the 9K310 Igla-1 (NATO: SA-16 Gi ...

MANPADS Man-portable air-defense systems (MANPADS or MPADS) are portable surface-to-air missiles. They are guided weapons and are a threat to low-flying aircraft, especially helicopters. Overview MANPADS were developed in the 1950s to provide military ...

(in order to diminish heating of

infrared homing Infrared homing is a passive weapon guidance system which uses the infrared (IR) light emission from a target to track and follow it seamlessly. Missiles which use infrared seeking are often referred to as "heat-seekers" since infrared is radi ...

seeker fairing and reduce wave drag), giving the name to the whole system (russian: игла means 'needle'). A simplified Igla-1 version with a different kind of target seeker featured a tripod instead of a 'needle' for the same purpose. Further development of this concept has resulted in the "air-spike". This is formed by concentrated energy, either from an electric arc torch or a pulsed laser, projected forwards from the body, which produces a region of low density hot air ahead of the body. This has the advantage over a structural aerospike that the air density is lower than that behind a shock wave providing increased drag reduction. In 1995 at the 33rd Aerospace Sciences Meeting, it was reported that tests were performed with an aerospike-protected missile dome to Mach 6, obtaining quantitative surface pressure and temperature-rise data on the feasibility of using aerospikes on

hypersonic In aerodynamics, a hypersonic speed is one that exceeds 5 times the speed of sound, often stated as starting at speeds of Mach 5 and above. The precise Mach number at which a craft can be said to be flying at hypersonic speed varies, since in ...

missiles.

Missiles with aerospikes

; USSR *

(MANPADS) ; US * UGM-96 Trident I * UGM-133 Trident II ; France *

M51 (missile) The M51 SLBM is a French submarine-launched ballistic missile, built by ArianeGroup, and deployed with the French Navy. Designed to replace the M45 (missile), M45 SLBM (In French terminology the MSBS – ''Mer-Sol-Balistique-Stratégique'' "Sea-gr ...

References

External links

* American Institute of Aeronautics and Astronautics *

National Aeronautics and Space Administration The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding th ...

Progress in Flight Physics Progress is the movement towards a refined, improved, or otherwise desired state. In the context of progressivism, it refers to the proposition that advancements in technology, science, and social organization have resulted, and by extension w ...

{{DEFAULTSORT:Drag-Reducing Aerospike Drag (physics) Aircraft components