|CENTRE FOR HYPERSONICS|
|The HyShot Flight Program
is an experiment designed to develop a correlation between pressure measurements
made of supersonic combustion in The University of Queensland’s T4 shock
tunnel, and that which is observed in flight. This correlation will
be developed with a scramjet configuration that retains the essential components
for supersonic combustion. Two flights were made - one on 30 October 2001
and another on 30 July 2002. Supersonic combustion was achieved on
the second flight.
The HyShot Program uses a two stage Terrier-Orion Mk70 rocket to boost the payload and the empty Orion motor (the Orion motor remains attached to the payload) to an apogee of approximately 330km. As the spent motor and its attached payload falls back to Earth, they gather speed, and the trajectory is designed so that between 35km and 23km, they are travelling at Mach 7.6. It is during this part of the trajectory that the measurements of supersonic combustion are made.
Pressure measurements will be the primary means for obtaining the correlation. Approximately 40 measurements will be made in and around the engine. Gaseous Hydrogen will be used as the fuel. As the combustion process in the scramjet is dependant on the ambient pressure, a highly parabolic trajectory with a near vertical decent during the test time was chosen, so that a correlation could be developed over an envelope of ambient pressures. In addition to the scientific merits, a vertical trajectory is also more cost efficient and there are less structural difficulties resulting from the lower heat and dynamic loads. The approach being taken by The University of Queensland is new and if shown to be successful, will open a new era in flight testing hypersonic air-breathing engines.
The Mission begins with the rockets pointing to the sky in a near vertical position. The payload is shrouded beneath a nose cone to protect it during the ascent through the atmosphere. If suitable atmospheric conditions prevail, the launch sequence begins. A final check is made of all the operational equipment using the onboard telemetry system. The arm button is then activated to start the computer running. At T=0, the Terrier motor is fired. As the rocket leaves the launch pad, it pulls away the fuel lines and an umbilical chord which has enabled the scientists an engineers to control the payload systems whilst on the ground. The computer now has to control the experiment for the next 10 minutes by itself. With an acceleration of 22g (22 times the Earth’s gravitational force) the Terrier motor propels the system to 4000 km/hr after just 6 seconds. This motor is then jettisoned and the Orion motor and its payload coast for 9 seconds. The Orion motor is then fired and boosts the payload in 26 seconds to a speeds in excess of eight times that of sound (8300km/hr) and to an altitude of 56 km, approaching the edge of the atmosphere. Five seconds later the nose cone is blown off with compressed nitrogen. During the next 400 seconds, the rocket is maneuvered to point downwards, in readiness to re-enter the atmosphere. This is achieved by using a cold gas thruster which provides pulses of compressed nitrogen to gently nudge the spent Orion motor and the experiment into the correct orientation.
As the rocket and the experiment re-enter the atmosphere, the altitude is monitored by way of a Pitot probe. When it descends to 35km, hydrogen is supplied to the scramjet and the supersonic combustion experiment begins. Measurements of pressure and temperature in the combustor are transmitted back to three ground stations to be stored for later analysis. The flow of fuel is maintained for the next 5 seconds as the experiment descends to an altitude of 23 km. At this point the experiment is complete.
The Vertical Trajectory has one difficulty
in that only small aerodynamic forces act on the motor and its payload
during re-entry to the atmosphere. If the payload and the Orion motor
are not pointing downwards before re-entering the atmosphere, this lack
of air makes it difficult to turn the payload into the downwards direction
before reaching the altitude at which the experiment begins. To alleviate
this problem, the payload is rotated so that it is correctly oriented before
it re-enters the atmosphere. This is quite a difficult maneuver to perform
as the payload and its attached spent rocket motor are spinning at between
4 and 6 Hertz. This coupled with the fact that the system weighs
close to 600kg provides for a very large angular momentum vector, which
must be rotated through approximately 160 degrees. The method chosen
to perform this maneuver is called a Bang-Bang maneuver.
When the Terrier motor initially starts there are accelerations approaching
60g experienced by all the components. This acceleration is only
short lived and dies away to less than 30g after a half a second, but unless
the equipment on board can withstand this initial shock, the experiment
will fail in the first second of the flight. Hence, a vibration rig,
which is essentially a stiff beam, has been built to simulate this environment.
Different pieces of equipment can be bolted to the vibration rig and tested
to see if they can withstand the vibrations. Up to 30 kg at a time
can be placed on the rig. This allows complete testing of much of
the experimental structure at the one time.
Sponsorship for the HyShot Flight Program has been obtained from, The University of Queensland, Astrotech Space Operations, Defence Evaluation and Research Agency (DERA, UK), National Aeronautics and Space Agency (NASA, USA), Defence, Science and Technology Organisation (DSTO, Australia), Dept. of Defence (Australia), Dept. of Industry Science and Resources (Australia), The German Aerospace Centre (DLR, Germany), Seoul, National University (Korea), The Australian Research Council, Australian Space Research Institute (ASRI), Alesi Technologies (Australia), National Aerospace Laboratories (NAL, Japan), NQEA (Australia), Australian Research and Development Unit (ARDU, Australia), the Air Force Office of Scientific Research (AFOSR, USA) and Luxfer, Australia.
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The University of Queensland
Brisbane, Queensland 4072 Australia
Phone: +61 (7) 3365 3592
Created by: Centre for Hypersonics Web Editor
Authorised by: Director of Centre
Modified: 2 June 2003
© 2003 The University of Queensland