Hypersonic Control Effectors

Over the past 50 years, research in hypersonic vehicle design has been focused on the development of continuous air breathing hypersonic vehicles. Recently, however, hypersonic vehicle technology has been demonstrated utilising hypersonic boost gliders. Hypersonic boost glide systems are 2 stage systems, utilising a rocket to ascend to high altitudes and Mach numbers, before detaching and gliding to its target, still at hypersonic speeds. One advantage of a gliding trajectory is its unpredictability due to continuous manoeuvring which makes interception of these vehicles difficult.

This project aims to understand the dynamics and control of hypersonic boost glide vehicles. It will do so by performing controlled free flight experiments in the Oxford High Density Tunnel (HDT) to attain the steady and unsteady aerodynamic coefficients of a boost glide concept. Knowledge of these coefficients will allow the stability and manoeuvrability of the vehicles to be assessed, and the potential flight envelope of these gliders to be established. The project will also investigate the effectiveness of different aerodynamic control surfaces such as elevons, body flaps and rudders.

Experiments performed in HDT for determining aerodynamic coefficients have traditionally used sting mounted models, where the model is rigidly attached to the test section. However, these models experience significant interference from the sting, which increases the uncertainty in the results. In recent years, a free flight testing technique has been developed in HDT, where the experimental model is dropped into the core flow of the tunnel during the test time. This eliminates interference from the sting and allows for much more accurate data to be obtained. Currently, the biggest limitation of free flight testing is that models are prone to hitting the tunnel walls and suffering damage, potentially ending testing prematurely. This project will develop a novel free flight model complete with a non-linear active control system, which will allow the model to control its position within the test section, preventing the model from colliding with the model walls. Employing a non-linear active control system would also allow the model to recover from any pitch or yaw instabilities caused by model release. The model will be able to move each of its control effectors independently, allowing for their effectiveness to each be assessed. Controlled free flight will also allow the use of larger free flight models within HDT, which will make it easier for future experiments to scale flight conditions appropriately, reducing the amount of compromises in experimental design.

This project falls within the EPSRC Engineering research area. It is performed in collaboration with DSTL.