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Nozzles are one of the most efficient ways of producing thrust. Most of the modern day launch vehicles use a conventional Converging-Diverging nozzle (CD nozzle). One of the critical drawbacks of using these nozzles is in their inability to provide the same efficiency under varying conditions of the course of the flight. CD nozzles when developed are designed to work at a certain range of altitudes, i.e. either at sea level or under near vacuum conditions. Hence, a sea level optimized nozzle can’t provide the same efficiency at higher altitudes and vice versa. Thus, modern day rockets have multiple stages (usually 2), with the first stage having a sea level optimized nozzle which lifts the rocket from the launch pad and takes it to an altitude before being ejected along with first stage and the second stage having vacuum optimized nozzle which propels the payload in vacuum of space to a desired orbit. This results in higher operating costs for a single launch, makes the process of payload deployment more complicated. The problem of having to use multiple nozzles can be solved by using an altitude compensating nozzle, with aerospike nozzle being one of them. These nozzles under operation provide the same efficiency throughout the course of flight under varying ambient conditions. This makes possible the development of a single stage to orbit vehicle, SSTO having a single aerospike nozzle. An SSTO vehicle unlike modern rockets doesn’t have components which require to be jettisoned during its flight and thus retains its expensive hardware even after being recovered. Hence, an SSTO vehicle results in less operating costs, having optimum payload capability. An SSTO having aerospike when developed properly is highly versatile it terms of thrust vectoring, and it has the potential of being completely reusable, by using a compact single structure similar to space shuttle and using aerodynamic re-entry. This paper analyses the performance of aerospike by comparison with CD nozzle using CFD (Computational Fluid Dynamics).

Modern day aerodynamics has applications in various domains ranging from design of ballistic shells to ground vehicles exceeding sonic speeds. The conceptual design and analysis of such extreme applications require test beds of the same calibre which are able to comply with the complexity of the working mechanism. Wind tunnel is one such apparatus where scale models of the prototypes can be tested. Alike all apparatus even wind tunnels has to be calibrated on a regular basis which ensures that the readings obtained from the instrument are acceptable and the error margin are within the limitations. Thus there is a need for instruments which can accurately measure the various properties of the wind tunnel, namely the flow angularity, velocity distribution, speed setting etc. Taking into account the various requirements a claw yaw is designed, simulated and tested in a wind tunnel and the results are discussed.