2. AEROSPACE PROPULSION AEROSPACE 410 ENGINE INTAKE AND NOZZLE SYSTEM
FOR A SUPERSONIC TRANSPORT PLANE
CONCORDE
SUBSONIC-SONIC-SUPERSONIC OPERATION
Dr. Cengiz Camci

4. The Rolls-Royce/Snecma Olympus engines that are
fitted to Concorde are a highly developed version
of the Bristol-Siddeley Olympus that was fitted to
the Vulcan bomber, which generated 11,000Lbs of
thrust.

8. The Olympus engines are 2 spool engines. The inner shaft
revolves within the outer shaft. The engine consists of
14 compressor stages, 7 on each shaft, driven by their
respective turbine systems. At supersonic speeds when
the air approaches the combustion chamber is is very hot
due to the high level of compression of 80:1.

9. The darker (black areas) are the areas more susceptible
to heat and are thus constructed out of the nickel-alloy.
To protect the later compression stages the last 4 stages
are constructed of a nickel-bassed alloy, the nickel alloy
is usually reserved only for the turbine area.

10. Concorde is the only civil airliner in service
with a 'military style' afterburner system installed to
produce more power at key stages of the flight.
The reheat system, as it is officially known, injects fuel
into the exhaust, and provides 6,000Lb of the total
available thrust per engine at take off.

14. This hotter faster exhaust that is used on take off and is what
is mainly responsible for the additional noise that Concorde
makes. The reheats are turned off shortly after take off
when Concorde reaches the noise abatement area.

15. SUPERSONIC TRANSPORT CONCORDE
MACH INLET FOR THE
SUPERSONIC TRANSPORT CONCORDE

17. ramps spill doors delta vortex forming at low speed
high angle of attack
CCW
ramps
spill
doors

18. AIR FLOW and INTAKES
To further improve engine system performance,
the air flow through the engine area is changed
at different speeds via a variable geometry
intake control system. Altering this airflow changes
the amount of air available to the
engine and the amount of air that
in itself is producing thrust via
the complex ramp and nozzle
assemblies.

19. ramps
ramps
spill
doors

20. The air intake ramp assemblies main job is
to slow down the air being received at the engine
face to subsonic speeds before it then enters
the engines.
At supersonic speeds the engine
would be unstable if the air being feed to it was also
at a supersonic speed so it is slowed down before it
gets there.

21. Subsonic Speeds (take off/subsonic cruise)
At take-off the engines need maximum airflow,
therefore the ramps are fully retracted and
the auxiliary inlet vane is wide open.
The auxiliary inlet begins to close as the
Mach number builds and it completely closed
by the time the aircraft reaches Mach 0.93.

22. At slow speeds all the air into the engine is primary airflow
SUBSONIC CRUISE
Secondary
Exhaust
buckets
At slow speeds all the air into the engine is primary airflow
and the secondary air doors are kept closed. Keeping them
closed also prevents the engine ingesting any of its
own exhaust gas.
At around Mach 0.55 the secondary exhaust buckets begin
to open as a function of Mach number to be fully open when
The aircraft is at M=1.1

23. Shortly after take off the aircraft enters the noise
Abatement procedure where the re-heats are turned off
and the power is reduced.

24. The secondary nozzles are opened further to allow
more air to enter, therefore quietening down the exhaust.
The secondary air doors also open at this stage to allow air
to by pass the engine.
The ramps begin move into position at Mach 1.3
which shock wave start to form on the intakes.

25. SUPERSONIC SPEEDS
At the supersonic cruse speed of Mach 2.0 the ramps have
moved over half their amount of available travel,
slowing down the air by producing a supersonic shockwave
(yellow lines) at the engine intake lip.

26. SUPERSONIC CRUISE
Some of the inlet fluid from the shock-boundary layer
interaction zone is removed in the ramp area

27. Back to low speeds
When the throttles are brought back to start the decent
the spill door is opened to dump out excess air
that is no longer needed by the engine, this allows the ramp
to go down to their maximum level of travel.
As the speed is lowered the spill doors are closed and the
ramps begin to move back
so by M=1.3 are again fully retracted.

28. ENGINE FAILURE
Should an engine fail and
need to be shut down during supersonic cruise,
the ramps move fully down and the
spill door opens to dump out excess air that is no longer
required by the failed engine.
The procedure lessens the
chances of surges on the engine.

29. ENGINE FAILURE

30. THRUST REVERSAL
After touch down the engines move to reverse power mode.
The main effect of this is that the secondary
nozzle buckets move to the closed position directing
airflow forwards to slow the aircraft down.

31. SUBSONIC FLIGHT

32. ENGINE 4 ENGINE ROTATING STALL PROBLEM
The main issue is that at slow airspeeds the engine
suffers vibrations on the low pressure compressor blades
from air vortices, that are created by the wing leading edge
sections, entering it from both the air intake and fully open
Spill door that moving in an anti-clockwise direction,
which is the opposite direction to the engine's direction
of rotation.
The effect is not seen on engine No1, as the vortices travel in
the same direction as the aircraft.
The No4 engine is limited on take off to 88% N1 at speeds
below 60 Knots.

33. Engine rotational direction is clockwise
VORTICAL STRUCTURES
OF FLOW at engine inlet
IS IN COUNTER CLOCKWISE
DIRECTION 1 4
If you stand underneath or behind Concorde during
take off it can be clearly seen that the no4 spill door is
not as open as the other three.
The reheat flame on engine 4 is also not as bright or stable
as the other three during the initial take off roll, until the aircraft
is around 60 knts when it matches the others.