is a beta 1.7c version of the EngineSim program, and you are invited
to participate in the beta testing. If you find errors in the program or
would like to suggest improvements, please send an e-mail to Thomas.J.Benson@nasa.gov.
With this software you can investigate how a
jet (or turbine)
engine produces thrust
by interactively changing the values of different engine parameters.
Recently (2013), there have been several security patches added to the Java Runtime Environment (JRE).
As a result of the security patches, EngineSim does not always perform as it did in the past. One patch
does not allow the display of .gif images from a local directory. So you would not be able to see the engine
animations in Tunnel Test Mode or any of the component pictures on the output panel at the lower right.
We will continue to monitor these changes to the JRE and modify the code as necessary.
Because of IT
security concerns, many users are currently experiencing problems running EngineSim.
security settings that you can adjust that may correct
There are several different versions of EngineSim which
require different levels of experience with the package,
knowledge of jet engines, and computer technology.
This web page contains the on-line version of the program.
It includes an on-line user's manual which describes the
various options available in the program and includes hyperlinks to
pages in the
Beginner's Guide to Propulsion
describing the math and science of the jet engine.
More experienced users can select a
version of the program which does not include
these instructions and loads faster on your computer.
You can download these versions of the program to your computer
by clicking on this yellow button:
With the downloaded version, you can run the program off-line and do not
have to be connected to the Internet.
You can also investigate the effects of engine performance on aircraft
range by using another interactive applet
Undergraduate Version - EngineSimU
There are special
versions of EngineSim
for undergraduate students who are studying the basics of turbine propulsion.
These versions let you reset the limits on many of the design variables. There
are on-line and off-line applet versions of the program and an off-line
application version. With the application version, you can save your design to
a file, input a previous design from a file,
and obtain output files for printing. To run the application version, you must
have the Java Developers Kit (JDK) installed on your computer.
This program is designed to be interactive, so you have to work with the program.
There are several different types of widgets that you use to work with the program.
There are a variety of choices which you must make regarding the analysis and the display
of results by using a choice box.
A choice box has a descriptive word displayed and an arrow at the right of the
box. To make a choice, click on either the arrow or the current choice word, hold down,
and drag to make your selection. The new selection is indicated by a change in the word.
A recent security patch has changed the way that choice boxes operate.
This can result in a condition where you can't change from Imperial to Metric units.
To overcome this problem, we have included an Override option on the choice boxes
on the control panel. If you get stuck, click on Override then click on your choice;
it will then work correctly.
The current values of the design variables are presented to you in text boxes.
By convention, a white box with
black numbers is an input box and you can change the value of the number. A black box with
yellow or red numbers is an output box and the value has been computed by the program.
To change the value in an input box, select the box by moving the cursor into the box
and clicking the mouse, then backspace over the old number, enter a new number,
then hit the Enter key on your keyboard. You must hit Enter
to send the new value to the program.
For most input variables you can also use a slider located next to the input box.
Click on the slider bar, hold down and drag the slider bar to change values, or
you can click on the arrows at either end of the slider.
If you experience difficulties when using the sliders to change variables,
simply click away from the slider and then back to it.
the arrows on the end of the sliders disappear, click in the areas
where the left and right arrow images should appear, and they
Some graphics decisions are selected by pushing buttons.
To push a button, move the cursor over the button and click the mouse.
If you see only a grey box at the top of this page, be sure that Java is
enabled in your browser. If Java is enabled, and you are using the Windows XP
operating system, you need to get a newer version of Java. Go to this link:
try the "Download It Now" button, and then select "Yes" when the download box from Sun
program screen is divided into four main parts:
top left side of the screen is a graphic of the engine you are
designing or testing. In the Design Mode, the drawing is a schematic,
while in Tunnel Test Mode the drawing is an animation.
upper right side of the screen are choice buttons which
control the analysis. You can select the type of analysis,
the type of output to be displayed,
and the units to be used in the calculations.
You will always see the overall
engine performance displayed as thrust, fuel flow, airflow,
and computed engine weight.
lower right side of the screen are the results of engine performance
calculations. The output can be presented as numerical values
of certain parameters, graphs of engine performance, or as photos
of the engine parts with descriptions of their purpose. You
select the type of output displayed by using the red choice
button labeled "Output:" on the upper right panel.
lower left side of the screen various input panels are displayed.
You can select the input panel by clicking on the name or the
component in the graphic at the upper left.
can choose from four different types of
engines: a simple turbojet, a jet
with afterburner, a turbofan engine,
or a ramjet. Selections are made on the
graphics window by clicking on the engine name. The chosen engine
is shown in yellow. Depending on the engine type, different input panels appear
at the lower left.
The design process begins by selecting the design Flight Conditions.
The Flight input panel lets you change the Mach number, airspeed, altitude, pressure,
temperature, and throttle and afterburner settings. There are several different
combinations of these variables available for input using the choice button
on the input panel. The pressure and temperature are computed as functions
of the altitude by using a Standard Day atmospheric model.
variables for each engine component can also be varied.
The components and variables include the Inlet (pressure recovery), Fan (pressure
ratio, efficiency, and bypass ratio), Compressor (CPR, compressor
efficiency), Burner (fuel,maximum temperature, efficiency, pressure ratio),
Turbine (turbine efficiency) and Nozzle (maximum temperature, efficiency,
A8/A2). As you choose a different component the part of the engine
being affected is highlighted in the graphic by changing from its
default color to yellow. If you change the Output Display to "Pictures"
you can view an actual photograph and description of each engine
Size can be specified by either the frontal area or the diameter.
As the engine size changes, the grid background changes in
proportion to the size. The distance between any
two grid lines is 1 foot.
The program will calculate an average weight
of the engine that you design. The thrust to
weight ratio of the engine is displayed in the numerical output
and is a measure of the efficiency of the engine. The weight depends
on the type and design of the engine, the size
of the engine, and the component materials. The program
begins with standard materials for the components, but you can change
the materials and see the effects on weight of the engine. Just
push the blue Materials choice button on any component input panel.
You can also select to define your own material by choosing My Material
from the menu. Just type in your own values for material density
and temperature limit.
The program will check the temperature throughout
the engine design against the material limits. If you exceed a limit,
a flashing warning will occur in the schematic. You can see the
temperature limits by choosing "Graphs" in the Output display on the control panel.
Then select Temperature as the type of graphics display.
You can also find which component is exceeding the temperature limits by
selecting "Component Performance" on the Output display and looking
for the red temperature display.
(For the afterburner and the ramjet, the graphical temperature limits
are based on the flow temperature, not on the material temperature,
and are slightly higher than the material limits. Cooling airflow
is often used along the walls of these components to keep the material
temperature within limits.)
CONTROL PANEL CHOICES:
Mode, Units, Output Display
program works in two modes: Design or Tunnel Test Mode. In the Design
Mode, you can change design variables including the flight conditions,
the engine size, the inlet performance,
the turbo machinery compressor and turbine
performance, the combustors or burner
performance, or the nozzle performance.
For a turbofan engine design you can
also vary the fan performance and the bypass ratio.
In Design Mode, any change in an input parameter produces a new engine
You have to be very careful when drawing conclusions about
the effects of input variables on performance because you are not comparing the effects
on the same engine; you are comparing one engine against another engine.
In Tunnel Test Mode, you are only working with one engine.
You can vary only the flight conditions and you can not change
any of the component design parameters except the throttle setting.
The values of some of the performance parameters like inlet recovery and nozzle area
may change according to choices that you made during design.
In Tunnel Test Mode you are evaluating the
of the engine model which you specified in Design Mode.
You can use any of the output panels to see how the various engine parameters
change with speed, altitude, or throttle setting.
You can also load models
of real turbine engines for comparison with your design.
You can always reload your design to continue testing. In Design Mode,
you can use the existing engine models as good starting points for
calculations can be performed in either Metric or Imperial (English) units.
You can always return to the default conditions by pushing the red Reset
button at the upper right.
red Output menu allows you to change the contents of the
output window on the lower right side of the screen. You can choose
to display output boxes with numerical values of the engine
and component performance,
as described below. Or you can display photographs and descriptions
of each engine part. Or you can display graphs of the variation of the value
of pressure and temperature at various stations
through the engine. You can also display a T-s Plot or a P-v
which are used by engineers to determine engine performance.
generate your own performance plots, select "Generate" from the
graphics window. The input panel will now display some additional
buttons and sliders to generate a plot. Choose the variables to
be plotted using the pulldown menus and then push the "Begin" data
button. Set the value of the independent variable by using the slider
or the type-in box. Push the blue "Take Data" button and a data
point will appear on the graph. Set a new value for the variable
and take another data point (up to 25 points in any order). When
you are finished, push the "End" button and a line will be drawn
through your data points. To start a new graph, push "Begin" and
your old graph will vanish. When you are finished, push the red
"Exit" button and you will return to free stream conditions.
There are two additional performance panels that are displayed at the lower right.
The Engine Performance output panel shows the
the engine pressure
ratio (EPR) and engine temperature ratio
(ETR), gross thrust, and ram drag. Additional component performance
parameters, such as the nozzle pressure ratio (NPR),
compressor pressure ratio (CPR) , engine thermal efficiency,
nozzle exit velocity (V exit), free stream dynamic
pressure (q0), and specific impulse (ISP) are displayed.
Nozzle exit pressure (Pexit) and fan nozzle exit pressure (P fan exit)
and the compressor face Mach number (M2) are also displayed.
The Component Performance output panel shows the variation of
total pressure and temperature at various stages through the engine.
NASA Glenn Educational Programs Office will continue to improve and update
EngineSim based on user input. Changes from previous versions of
the program include:
On 5 Dec
13 version 1.7c was released. This version has been updated
to overcome some problems in the use of choice boxes caused
by recent Java security patches.
On 18 Oct
12 version 1.7b was released. This version has been updated
to include the compressor pressure ratio on the output panel.
This will help users to see the difference between Design Mode and
Tunnel Test Mode.
On 26 Oct
05 version 1.7a was released. This version has been re-sized
to fit the NASA portal. Some additional output variables have
been added and a correction to the gross thrust calculation was
made. The logic for moving the engine graphic was also changed.
On 20 Feb
04 version 1.6e was released. This version has a cleaner look
by moving the units into the output boxes. Engine thermal
efficiency is now output instead of compressor face Mach number.
On 11 Dec
03 version 1.6d was released. This version has separate input
panels for the ramjet burner and nozzle and allows the user
to specify the ramjet fuel.
On 25 Nov
03 version 1.6c was released. This version lets the user move
the engine graphic. The user can also specify any fuel by giving
the fuel heating value. A bug related to the nozzle total temperature
has been fixed.
On 17 Oct
03 version 1.6b was released. This version has a slightly
modified graphics window for resizing the application.
Tabs are also added to the printed output of the application.
On 15 Sep
03 version 1.6a was released. This version includes the component
output panel, additional input and output variables,
and some new input options for the flight conditions.
This is the first version which is available as a Java application.
The application permits the user to save results between sessions
and is run off-line.
There are minor changes to the layout of the program
and bugs in the weight calculations are corrected.
On 6 Jun
03 version 1.5h was released. This version corrects a bug
in the loading of existing engine models. Materials information is
now included in the upload.
On 29 Apr
03 version 1.5g was released. This version corrects a bug
in the ramjet temperature calculations.
On 18 Mar
03 version 1.5f was released. This version includes a correction
to the weight calculation when you change compressor face area.
On 17 Sep
01 a special version for undergraduates was released. This version includes
the ability to reset most of the limits in the program.
On 22 Aug
01 version 1.5b was released. This version includes more corrections
to the ramjet analysis and some slight changes to the variable limits.
A "sleek" version of the program is now available for experienced users.
On 19 Apr
01 version 1.5 was released. This version includes improved graphics
and a more consistent input environment. There are also corrections
to the ramjet analysis from previous versions.
On 13 Oct
00 version 1.4 was released. This version includes material properties
for each component and a calculation of the engine weight. Temperature
limits for each component are also checked.
On 26 Sept
00 version 1.3 was released. This version uses the "card format"
for input and output. Component input panels are invoked from
the engine graphic. Optional photos of the components are included
on the output panel.
On 31 Mar
00 version 1.2 was released. This version includes a ramjet
On 2 Dec
99 version 1.1 was released. This version includes a variety
of plots and an optional animation displays. This applet enables
the student to interactively observe the effects of engine component
performance on thrust and fuel consumption.
the following conditions in EngineSim:
Airspeed should be 0, the Altitude 0, and the Throttle 100. Record
(F net) ___________and the Fuel Flow __________.
Now go ahead and change the altitude to 10,000 ft. and the Airspeed
to 350. Did the thrust increase or decrease? Did the fuel flow increase
or decrease? Thrust ________ Fuel Flow__.
What happens when you choose a different engine? Choose a jet with
afterburner and record the thrust ___________ and the fuel flow
Choose a turbofan engine and record the thrust _____________ and
the fuel flow________.
What can you conclude about the effect of an increase in altitude
and airspeed on thrust? __________________________________ On fuel
Which engine is most fuel efficient? _______________________________