Starting and ignition

Starting and ignition

rotation of the starter ceases. A typical air starting
system is shown in fig. 11-7.
12. A combustor starter is sometimes fitted to an
engine incorporating an air starter and is used to
supply power to the starter when an external supply
of air is not available. The starter unit has a small
combustion chamber into which high pressure air,
from an aircraft-mounted storage bottle, and fuel,
from the engine fuel system, are introduced. Control
valves regulate the air supply which pressurizes a
fuel accumulator to give sufficient fuel pressure for
atomization and also activates the continuous
ignition system. The fuel/air mixture is ignited in the
combustion chamber and the resultant gas is
directed onto the turbine of the air starter. An
electrical circuit is provided to shut off the air supply
which in turn terminates the fuel and ignition systems
on completion of the starting cycle.
13. Some turbo-jet engines are not fitted with starter
motors, but use air impingement onto the turbine
blades as a means of rotating the engine. The air is
obtained from an external source, or from an engine
that is running, and is directed through non-return
valves and nozzles onto the turbine blades. A typical
method of air impingement starting is shown in fig.
11-8.
Gas turbine
14. A gas turbine starter is used for some jet
engines and is completely self-contained. It has its
own fuel and ignition system, starting system (usually
electric or hydraulic) and self-contained oil system.
This type of starter is economical to operate and
provides a high power output for a comparatively low
weight.
15. The starter consists of a small, compact gas
turbine engine, usually featuring a turbine-driven
centrifugal compressor, a reverse flow combustion
system and a mechanically independent |free-power
turbine. The free-power turbine is connected to the
main engine via a two-stage epicyclic reduction gear,
automatic clutch and output shaft. A typical gas
turbine starter is shown in fig. 11-9.
16. On initiation of the starting cycle, the gas turbine
starter is rotated by its own starter motor until it
reaches self-sustaining speed, when the starting and
ignition systems are automatically switched off.
Acceleration then continues up to a controlled speed
of approximately 60,000 r.p.m. At the same time as
the gas turbine starter engine is accelerating, the
exhaust gas is being directed, via nozzle guide
vanes, onto the free-power turbine to provide the
drive to the main engine. Once the main engine
reaches self-sustaining speed, a cut-out switch
Starting and ignition

A triple-breech cartridge starter.

A triple-breech cartridge starter.
Cartridge
7. Cartridge starting is sometimes used on military
engines and provides a quick independent method of
starting. The starter motor is basically a small
impulse-type turbine that is driven by high velocity
gases from a burning cartridge. The power output of
the turbine is passed through a reduction gear and
an automatic disconnect mechanism to rotate the
engine. An electrically fired detonator initiates the
burning of the cartridge charge. As a cordite charge
provides the power supply for this type of starter, the
size of the charge required may well limit the use of
the cartridge starters. A triple-breech starter is
illustrated in fig. 11-4.
Iso-propyl-nitrate
8. This type of starter provides a high power output
and gives rapid starting characteristics. It has a
turbine that transmits power through a reduction gear
to the engine. In this instance, the turbine is rotated
by high pressure gases resulting from the
combustion of iso-propyl-nitrate. This fuel is sprayed
into a combustion chamber, which forms part of the
starter, where it is electrically ignited by a highenergy
ignition system. A pump supplies the fuel to
the combustion chamber from a storage tank and an
air pump scavenges the starter combustion chamber
of fumes before each start. Operation of the fuel and
air pumps, ignition systems, and cycle cancellation,
is electrically controlled by relays and time switches.
An iso-propyl-nitrate starting system is shown in fig.
11-5.
Air
9. Air starting is used on most commercial and
some military jet engines. It has many advantages
over other starting systems, and is comparatively
light, simple and economical to operate.
10. An air starter motor transmits power through a
reduction gear and clutch to the starter output shaft
which is connected to the engine. A typical air starter
motor is shown in fig. 11-6.
11. The starter turbine is rotated by air taken from
an external ground supply, an auxiliary power unit
(A.P.U.) or as a cross-feed from a running engine.
The air supply to the starter is controlled by an electrically
operated control and pressure reducing valve
that is opened when an engine start is selected and
is automatically closed at a predetermined starter
speed. The clutch also automatically disengages as
the engine accelerates up to idling r.p.m. and the
Starting and ignition
124

SAFETY RULES SUMMARY

SAFETY RULES SUMMARY
A set of safety rules was developed by Jim Rowell (http://www.mrplc.com,
"Industrial Control Safety; or How to Scare the Bejesus Out of Me"). These are summarized
below.
Grounding and Fuses
• Always ground power supplies and transformers.
• Ground all metal enclosures, casings, etc.
• All ground connections should be made with dedicated wires that are
exposed so that their presence is obvious.
• Use fuses for all AC power lines, but not on the neutrals or grounds.
• If ground fault interrupts are used they should respond faster than the control
system.
Hot vs. Neutral Wiring
• Use PNP wiring schemes for systems, especially for inputs that can initiate
actions.
• Loads should be wired so that the ground/neutral is always connected,
and the power is switched.
• Sourcing and sinking are often confused, so check the diagrams or look
for PNP/NPN markings.
AC / DC
• Use lower voltages when possible, preferably below 50V.
• For distant switches and sensors use DC.
Devices
• Use properly rated isolation transformers and power supplies for control
systems. Beware autotransformers.
• Use Positive or Force-Guided Relays and contacts can fail safely and prevent
operation in the event of a failure.
• Some ’relay replacement’ devices do not adequately isolate the inputs and
output and should not be used in safety critical applications.
Starts

INTRODUCTION

INTRODUCTION
If you know how to program in any high level language, such as Basic or C, you
will be comfortable with Structured Text (ST) programming. ST programming is part of
the IEC 61131 standard. An example program is shown in Figure 19.1. The program is
called main and is defined between the statements PROGRAM and END_PROGRAM.
Every program begins with statements the define the variables. In this case the variable i is
defined to be an integer. The program follows the variable declarations. This program
counts from 0 to 10 with a loop. When the example program starts the value of integer
memory i will be set to zero. The REPEAT and END_REPEAT statements define the loop.
The UNTIL statement defines when the loop must end. A line is present to increment the
value of i for each loop.

THE ALLEN-BRADLEY VERSION

THE ALLEN-BRADLEY VERSION
Allen Bradley only supports IL programming on the Micrologix 1000, and does
not plan to support it in the future. Examples of the equivalent ladder logic and IL programs
are shown in Figure 18.4 and Figure 18.5. The programs in Figure 18.4 show different
variations when there is only a single output. Multiple IL programs are given where
available. When looking at these examples recall the stack concept. When a LD or LDN
instruction is encountered it will put a value on the top of the stack. The ANB and ORB
instructions will remove the top two values from the stack, and replace them with a single
value that is the result of an Boolean operation. The AND and OR functions take one value
off the top of the stack, perform a Boolean operation and put the result on the top of the
stack. The equivalent programs (to the right) are shorter and will run faster.

Figure 18.5 shows the IL programs that are generated when there are multiple outputs.
This often requires that the stack be used to preserve values that would be lost nor-

mally using the MPS, MPP and MRD functions. The MPS instruction will store the current
value of the top of the stack. Consider the first example with two outputs, the value of A is
loaded on the stack with LD A. The instruction ST X examines the top of the stack, but
does not remove the value, so it is still available for ST Y. In the third example the value of
the top of the stack would not be correct when the second output rung was examined. So,
when the output branch occurs the value at the top of the stack is copied using MPS, and
pushed on the top of the stack. The copy is then ANDed with B and used to set X. After
this the value at the top is pulled off with the MPP instruction, leaving the value at the top
what is was before the first output rung. The last example shows multiple output rungs.
Before the first rung the value is copied on the stack using MPS. Before the last rung the
value at the top of the stack is discarded with the MPP instruction. But, the two center
instructions use MRD to copy the right value to the top of the stack - it could be replaced
with MPP then MPS.

INTRODUCTION

INTRODUCTION
In previous decades (and now) PLC manufacturers favored “proprietary” or
“closed” designs. This gave them control over the technology and customers. Essentially,
a proprietary architecture kept some of the details of a system secret. This tended to limit
customer choices and options. It was quite common to spend great sums of money to
install a control system, and then be unable to perform some simple task because the manufacturer
did not sell that type of solution. In these situations customers often had two
choices; wait for the next release of the hardware/software and hope for a solution, or pay
exorbitant fees to have custom work done by the manufacturer.
“Open” systems have been around for decades, but only recently has their value
been recognized. The most significant step occurred in 1981 when IBM broke from it’s
corporate tradition and released a personal computer that could use hardware and software
from other companies. Since that time IBM lost control of it’s child, but it has now
adopted the open system philosophy as a core business strategy. All of the details of an
open system are available for users and developers to use and modify. This has produced
very stable, flexible and inexpensive solutions. Controls manufacturers are also moving
toward open systems. One such effort involves Devicenet, which is discussed in a later
chapter.
A troubling trend that you should be aware of is that many manufacturers are mislabeling
closed and semi-closed systems as open. An easy acid test for this type of system
is the question “does the system allow me to choose alternate suppliers for all of the components?”
If even one component can only be purchased from a single source, the system
is not open. When you have a choice you should avoid “not-so-open” solutions.

ASSIGNMENT PROBLEMS

ASSIGNMENT PROBLEMS
2. Using 3 different methods write a program that will continuously cycle a pattern of 12 lights
connected to a PLC output card. The pattern should have one out of every three lights set. The
light patterns should appear to move endlessly in one direction.
3. Look at the manuals for the status memory in your PLC.
a) Describe how to run program 7 when a divide by zero error occurs.
b) Write the ladder logic needed to clear a PLC fault.
c) Describe how to set up a timed interrupt to run program 5 every 2 seconds.
4. Write a program that will run once every 5 seconds and calculate the average of the numbers
from F8:0 to F8:19, and store the result in F8:20. It will also determine the median and store it
in F8:21.
5.Write a program for SPC (Statistical Process Control) that will run once every 20 minutes using
timed interrupts. When the program runs it will calculate the average of the data values in
memory locations F8:0 to F8:39 (Note: these values are written into the PLC memory by
another PLC using DH+). The program will also find the range of the values by subtracting the
maximum from the minimum value. The average will be compared to upper (F8:50) and lower
(F8:51) limits. The range will also be compared to upper (F8:52) and lower (F8:53) limits. If
the average, or range values are outside the limits, the process will stop, and an ‘out of control’
light will be turned on. The process will use start and stop buttons, and when running it will set
memory bit B3:0/0.
6. Develop a ladder logic program to control a light display outside a theater. The display consists
of a row of 8 lights. When a patron walks past an optical sensor the lights will turn on in
sequence, moving in the same direction. Initially all lights are off. Once triggered the lights
turn on sequentially until all eight lights are on 1.6 seconds latter. After a delay of another 0.4
seconds the lights start to turn off until all are off, again moving in the same direction as the
patron. The effect is a moving light pattern that follows the patron as they walk into the theater.
7. Write the ladder logic diagram that would be required to execute the following data manipulation
for a preventative maintenance program.
i) Keep track of the number of times a motor was started with toggle switch #1.
ii) After 2000 motor starts turn on an indicator light on the operator panel.
iii) Provide the capability to change the number of motor starts being tracked, prior
to triggering of the indicator light. HINT: This capability will only require the
change of a value in a compare statement rather than the addition of new lines
of logic.
iv) Keep track of the number of minutes that the motor has run.
v) After 9000 minutes of operation turn the motor off automatically and also turn
on an indicator light on the operator panel.
8. Parts arrive at an oven on a conveyor belt and pass a barcode scanner. When the barcode scanner
reads a valid barcode it outputs the numeric code as 32 bits to I:001 and I:002 and sets

Block Transfer Functions

Block Transfer Functions
Simple input and output cards usa a single word. Writing one word to an output
card sets all of the outputs. Reading one word from an input card reads all of the inputs. As
a result the PLC is designed to send and receive one word to input and from output cards.
Later we will discuss more complex input and output cards (such as analog I/O) that
require more than one data word. To communicate multiple words, one word must be sent
at a time over multiple scans. To do this we use special functions called Block Transfer
Write (BTW) and Block Transfer Read (BTR).
Figure 16.21 shows a BTWfunction. The module type is defined from a given list,
in this case it is an Example Output Card. The next three lines indicate the card location as
00, 3 or 003, the module number should normally be zero (except when using two slot
addressing). This instruction is edge triggered, and special control memory BT10:1 is used
in this example to track the function progress (Note: regular control memory could have
also been used, but the function will behave differently). The instruction will send 10
words from N9:0 to N9:9 to the output card when A becomes true. The enabled bit
BT10:1/EN is used to block another start until the instruction is finished. If the instruction
e.g. Check for nuclear reactor overheat I:001/03 overheat sensor
O:010/01 reactor shutdown
IIN I:001
IOT

These added statements can allow the ladder logic to examine a critical
input, and adjust a critical output many times during the execution of
ladder logic that might take too long for safety.

Note:When these instructions are used the normal assumption that all inputs and
outputs are updated before and after the program scan is no longer valid.
plc advanced functions -
is restarted before it is done an error will occur. The length and contents of the memory
N9:0 to N9:9 are specific to the type of input and output card used, and will be discussed
later for specific cards. This instruction is not continuous, meaning that when done it will
stop. If it was continuous then when the previous write was done the next write would
begin.
Figure

Fault Detection and Interrupts

Fault Detection and Interrupts
The PLC can be set up to run programs automatically using interrupts. This is routinely
done for a few reasons;
• to deal with errors that occur (e.g. divide by zero)
• to run a program at a regular timed interval (e.g. SPC calculations)
• to respond when a long instruction is complete (e.g. analog input)
• when a certain input changed (e.g. panic button)
These interrupt driven programs are put in their own program file. The program
file number is then put in a status memory S2 location. Some other values are also put into
status memory to indicate the interrupt conditions.
A fault condition can stop a PLC. If the PLC is controlling a dangerous process
this could lead to significant damage to personnel and equipment. There are two types of
faults that occur; terminal (major) and warnings (minor). A minor fault will normally set
an error bit, but not stop the PLC. A major failure will normally stop the PLC, but an interrupt
can be used to run a program that can reset the fault bit in memory and continue operation
(or shut down safely). Not all major faults are recoverable. A complete list of these
faults is available in PLC processor manuals.
Figure 16.15 shows two programs. The default program (file 2) will set the interrupt
program file to 3 by moving it to S2:29 on the first scan. When A is true a compute
function will interpret the expression, using indirect addressing. If B becomes true then the
value in N7:0 will become negative. If A becomes true after this then the expression will
become N7:-10 +10. The negative value for the address will cause a fault, and program
file 3 will be run. In fault program status memory S2:12 is checked the error code 21,
which indicates a bad indirect address. If this code is found the index value N7:0 is set
back to zero, and S2:11 is cleared. As soon as S2:11 is cleared the fault routine will stop,
and the normal program will resume. If S2:11 is not cleared, the PLC will enter a fault
state and stop (the fault light on the front of the PLC will turn on).

ADVANCED LADDER LOGIC FUNCTIONS

ADVANCED LADDER LOGIC FUNCTIONS
 INTRODUCTION
This chapter covers advanced functions, but this definition is somewhat arbitrary.
The array functions in the last chapter could be classified as advanced functions. The functions
in this section tend to do things that are not oriented to simple data values. The list
functions will allow storage and recovery of bits and words. These functions are useful
when implementing buffered and queued systems. The program control functions will do
things that don’t follow the simple model of ladder logic execution - these functions recognize
the program is executed left-to-right top-to-bottom. Finally, the input output functions
will be discussed, and how they allow us to work around the normal input and output
scans.
16.2 LIST FUNCTIONS
 Shift Registers
Shift registers are oriented to single data bits. A shift register can only hold so
many bits, so when a new bit is put in, one must be removed. An example of a shift regis-
Topics:
Objectives:
• To understand shift registers, stacks and sequencers.
• To understand program control statements.
• To understand the use of interrupts.
• To understand the operation of immediate input and output instructions.
• To be prepared to use the block transfer instruction later.
• Be able to apply the advanced function in ladder logic design.
• Shift registers, stacks and sequencers
• Program control; branching, looping, subroutines, temporary ends and one shots
• Interrupts; timed, fault and input driven
• Immediate inputs and outputs
• Block transfer
• Conversion of State diagrams using program subroutines
• Design examples

ASSIGNMENT PROBLEMS

ASSIGNMENT PROBLEMS
1. Draw a schematic symbol for a solenoid controlled pneumatic valve and explain how the valve
operates.
2. We are to connect a PLC to detect boxes moving down an assembly line and divert larger
boxes. The line is 12 inches wide and slanted so the boxes fall to one side as they travel by.
One sensor will be mounted on the lower side of the conveyor to detect when a box is present.
A second sensor will be mounted on the upper side of the conveyor to determine when a larger
box is present. If the box is present, an output to a pneumatic solenoid will be actuated to divert
the box. Your job is to select a PLC, sensors, and solenoid valve. Details are expected with a
ladder wiring diagram. (Note: take advantage of manufacturers web sites.)
3. A PLC based system has 3 proximity sensors, a start button, and an E-stop as inputs. The system
controls a pneumatic system with a solenoid controlled valve. It also controls a robot with
a TTL output. Develop a complete wiring diagram including all safety elelemnts.
4. A system contains a pneumatic cylinder with two inductive proximity sensors that will detect
when the cylinder is fully advanced or retracted. The cylinder is controlled by a solenoid controlled
valve. Draw electrical and pneumatic schematics for a system.
5. Draw an electrical ladder wiring diagram for a PLC controlled system that contains 2 PNP sensors,
a NO pushbutton, a NC limit switch, a contactor controlled AC motor and an indicator
light. Include all safety circuitry

PNEUMATICS

Pneumatic systems are very common, and have much in common with hydraulic
systems with a few key differences. The reservoir is eliminated as there is no need to collect
and store the air between uses in the system. Also because air is a gas it is compressible
and regulators are not needed to recirculate flow. But, the compressibility also means
that the systems are not as stiff or strong. Pneumatic systems respond very quickly, and are
commonly used for low force applications in many locations on the factory floor.
Some basic characteristics of pneumatic systems are,
- stroke from a few millimeters to meters in length (longer strokes have more
springiness
- the actuators will give a bit - they are springy
- pressures are typically up to 85psi above normal atmosphere
- the weight of cylinders can be quite low
- additional equipment is required for a pressurized air supply- linear and rotatory
actuators are available.
- dampers can be used to cushion impact at ends of cylinder travel.
When designing pneumatic systems care must be taken to verify the operating
location. In particular the elevation above sea level will result in a dramatically different
air pressure. For example, at sea level the air pressure is about 14.7 psi, but at a height of
7,800 ft (Mexico City) the air pressure is 11.1 psi. Other operating environments, such as
in submersibles, the air pressure might be higher than at sea level.
Some symbols for pneumatic systems are shown in Figure 5.7. The flow control
valve is used to restrict the flow, typically to slow motions. The shuttle valve allows flow
in one direction, but blocks it in the other. The receiver tank allows pressurized air to be
accumulated. The dryer and filter help remove dust and moisture from the air, prolonging
the life of the valves and cylinders.

RELAYS

Although relays are rarely used for control logic, they are still essential for switching
large power loads. Some important terminology for relays is given below.
Contactor - Special relays for switching large current loads.
Motor Starter - Basically a contactor in series with an overload relay to cut off
when too much current is drawn.
Arc Suppression - when any relay is opened or closed an arc will jump. This
becomes a major problem with large relays. On relays switching AC this problem
can be overcome by opening the relay when the voltage goes to zero (while
crossing between negative and positive). When switching DC loads this problem
can be minimized by blowing pressurized gas across during opening to suppress
the arc formation.
AC coils - If a normal relay coil is driven by AC power the contacts will vibrate
open and closed at the frequency of the AC power. This problem is overcome
by adding a shading pole to the relay.
The most important consideration when selecting relays, or relay outputs on a
PLC, is the rated current and voltage. If the rated voltage is exceeded, the contacts will
wear out prematurely, or if the voltage is too high fire is possible. The rated current is the
maximum current that should be used. When this is exceeded the device will become too
hot, and it will fail sooner. The rated values are typically given for both AC and DC,
although DC ratings are lower than AC. If the actual loads used are below the rated values
the relays should work well indefinitely. If the values are exceeded a small amount the life
of the relay will be shortened accordingly. Exceeding the values significantly may lead to
immediate failure and permanent damage.
• Rated Voltage - The suggested operation voltage for the coil. Lower levels can
result in failure to operate, voltages above shorten life.
• Rated Current - The maximum current before contact damage occurs (welding or
melting).

Output Modules

As with input modules, output modules rarely supply any power, but instead act as
switches. External power supplies are connected to the output card and the card will
switch the power on or off for each output. Typical output voltages are listed below, and
roughly ordered by popularity.
120 Vac
24 Vdc
12-48 Vac
12-48 Vdc
5Vdc (TTL)
230 Vac
These cards typically have 8 to 16 outputs of the same type and can be purchased
with different current ratings. A common choice when purchasing output cards is relays,
transistors or triacs. Relays are the most flexible output devices. They are capable of
switching both AC and DC outputs. But, they are slower (about 10ms switching is typical),
they are bulkier, they cost more, and they will wear out after millions of cycles. Relay
outputs are often called dry contacts. Transistors are limited to DC outputs, and Triacs are
limited to AC outputs. Transistor and triac outputs are called switched outputs.
- Dry contacts - a separate relay is dedicated to each output. This allows mixed
voltages (AC or DC and voltage levels up to the maximum), as well as isolated
outputs to protect other outputs and the PLC. Response times are often greater
than 10ms. This method is the least sensitive to voltage variations and spikes.
- Switched outputs - a voltage is supplied to the PLC card, and the card switches it
to different outputs using solid state circuitry (transistors, triacs, etc.) Triacs are
well suited to AC devices requiring less than 1A. Transistor outputs use NPN or
PNP transistors up to 1A typically. Their response time is well under 1ms.

Internal air system

Internal air system
pressure and temperature. Therefore, to reduce
engine performance losses, the air is taken as early
as possible from the compressor commensurate with
the requirement of each particular function. The
cooling air is expelled overboard via a vent system or
into the engine main gas stream, at the highest
possible pressure, where a small performance
recovery is achieved.
COOLING
3. An important consideration at the design stage of
a gas turbine engine is the need to ensure that
certain parts of the engine, and in some instances
certain accessories, do not absorb heat to the extent
that is detrimental to their safe operation. The
principal areas which require air cooling are the
combustor and turbine. Refer to Part 4 for combustor
cooling techniques.
4. Cooling air is used to control the temperature of
the compressor shafts and discs by either cooling or
heating them. This ensures an even temperature distribution
and therefore improves engine efficiency by
controlling thermal growth and thus maintaining
minimum blade tip and seal clearances. Typical
cooling and sealing airflows are shown in fig. 9-1.
Turbine cooling
5. High thermal efficiency is dependent upon high
turbine entry temperature, which is limited by the
turbine blade and nozzle guide vane materials.
Continuous cooling of these components allows their
environmental operating temperature to exceed the
material’s melting point without affecting the blade
and vane integrity. Heat conduction from the turbine
blades to the turbine disc requires the discs to be
cooled and thus prevent thermal fatigue and uncontrolled
expansion and contraction rates.

Basic mechanics

Basic mechanics

INTRODUCTION

INTRODUCTION
1. The development of the gas turbine engine as an
aircraft power plant has been so rapid that it is
difficult to appreciate that prior to the 1950s very few
people had heard of this method of aircraft
propulsion. The possibility of using a reaction jet had
interested aircraft designers for a long time, but
initially the low speeds of early aircraft and the
unsuitably of a piston engine for producing the large

high velocity airflow necessary for the ‘jet’ presented many obstacles. Fig. 1-1 Lorin’s jet engine.
2. A French engineer, René Lorin, patented a jet propulsion engine (fig. 1-1) in 1913, but this was an athodyd (para. 11) and was at that period impossible to manufacture or use, since suitable heat resisting materials had not then been developed and, in the second place, jet propulsion would have been extremely inefficient at the low speeds of the aircraft of those days. However, today the modern ram jet is very similar to Lorin’s conception. but it was eleven years before his engine completed its first flight. The Whittle engine formed the basis of the modern gas turbine engine, and from it was developed the Rolls-Royce Welland, Derwent, Nene and Dart engines. The Derwent and Nene turbo-jet engines had world-wide military applications; the Dart turbo-propeller engine became world famous as the power plant for the Vickers Viscount aircraft. Although other aircraft may be fitted; with later engines termed twin-spool, triple-spool, by-pass,
3. In 1930 Frank Whittle was granted his first patent ducted fan, unducted fan and propfan, these are
for using a gas turbine to produce a propulsive jet, inevitable developments of Whittle’s early engine.

Rolls-Royce Trent 800

Rolls-Royce Trent 800

Developed from the RB211, the Trent covers a thrust range of 71,000 lb to 92,000 lb thrust, with the capability
to grow beyond 100,000 lb. The Trent 800 features a 110 inch diameter wide-chord fan, high flow compressors
and Full Authority Digital Engine Control (FADEC).
Detailed engineering design began in 1988 to meet the propulsion requirements of the Airbus A330 (Trent 700)
and Boeing 777 (Trent 800). The Trent first ran in August 1990, and in January 1994 a Trent 800 demonstrated
a world record thrust of 106,087 lb.
The engine entered service in March 1995 in the Airbus A330.