MotoCalc Technical Support
MotoCalc and Microsoft® Windows 10
In order for MotoCalc to work properly with
Microsoft Windows 10, you should be using
Before you contact us, please check the list of
frequently asked questions below. The answer you are
looking for may already be there.
If you need to contact us, the method that will get you the answers you need
the fastest is to select
E-mail Technical Support from MotoCalc's Help menu.
When e-mailing, please try to provide as much
information as possible. If you are having trouble with a particular aircraft,
please include the project in your message by making sure that the
Automatically attach current project to e-mail check box is checked.
That way, we can reproduce the problem here and see exactly what you are
If for some reason you aren't able to use the built-in e-mail-to-support
feature, please see our contact page.
Frequently Asked Questions
The following are some common questions we get
in technical support, and the answers to those questions.
Some of the answers refer to sections of MotoCalc's on-line manual, which
you can access via the Help menu in MotoCalc, or
view it here.
Where did the motor temperature column go in MotoCalc
Why does the current go down as the airspeed goes
up. Doesn't it take more power to go faster, not less
How do I use MotoCalc for a multi-motored aircraft
or ganged motors operating each propeller?
How do I use MotoCalc to predict the performance
of a biplane?
Can I use MotoCalc to predict the performance
of a helicopter?
How can I change the project that's displayed
when MotoCalc first starts up?
How do I determine the parameters for a new motor,
cell type, etc., and add it to MotoCalc?
How does adjusting the motor timing affect performance
relative to MotoCalc's predictions?
Why are the predicted level flight times so long?
Why are they sometimes even longer than those predicted by earlier
versions (before version 5) of MotoCalc?
Why does MotoCalc not need to know the number
of blades of a ducted fan?
How do I determine the coefficients for a ducted
How do I move my copy of MotoCalc to a new computer?
How do I get updates to the data provided with
How do I get data updates if the computer I use
MotoCalc on is not on the Internet, or if my firewall will not
allow MotoCalc to connect to the Internet?
I've purchased a new computer, or I use more than
one computer on a regular basis. Do I need to purchase additional
Is MotoCalc available for the Macintosh or Linux?
Where did the motor temperature
column go in MotoCalc 7 and 8?
The temperature data is still there, but in a less obvious, yet
more meaningful way. Instead of appearing as a column on the static
and in-flight analysis, it only appears on the Stats line of an
in-flight analysis, next to the level and opt flying speeds. Furthermore,
that temperature represents the temperature at the specified throttle
setting (i.e. basically cruise throttle settings, the only ones
that make sense for computing steady-state temperature).
The previous method of computing the full-throttle
steady-state temperature was not as meaningful, because most motors
would not reach this temperature during the period of time that
a battery could actually operate the motor at full throttle.
Even in a Limited Motor Run (LMR) model, which is
operated at full power, the new method gives more meaningful results.
The temperature that MotoCalc computes, both in version 6 and
now in version 7, is steady-state temperature. This is the temperature
that the motor reaches after operating for some period of time
(generally 5 to 20 minutes, depending on the motor).
Few pilots operate a motor at full throttle for this
length of time. Thus, steady state temperature is never reached.
In a sport type aircraft, calculating the steady-state temperature
at a "cruise" throttle setting makes a lot more sense.
If a model really does require full power to remain airborne,
MotoCalc will know this, and cruise throttle will be full
In an LMR model, calculating steady state temperature
doesn't really make sense at all, since the motor is run for such
very short time periods, with long rests in between. However,
using the "cruise" method will still give you a more
meaningful result than the old full throttle method, because effectively,
you are operating at cruise power on average. Think of the short
bursts of power with long rests in between as a very low
rate speed control.
Nothing was lost in MotoCalc 7 with regard to temperature
calculations. If anything, the results are now more meaningful,
even for LMR applications.
In MotoCalc 8, full throttle temperature has returned,
but it only appears in the "Possible Power System Problems"
section of the MotOpinion report, and then only if there's a possible
problem. For instance, if your plane will maintain level flight
at half throttle, but might overheat the motor at full throttle,
a note to this effect will appear.
Current Versus AirpseedQuestion:
Why does the current go down as the airspeed
goes up. Doesn't it take more power to go faster, not less
Yes and no. Remember that the predictions are all for a given
throttle setting. If you just let the plane fly, it will settle
in to a certain speed, and the amount of power consumed will be
reduced because the propeller will unload. Now if you want to
make it go faster, you have to put in some down elevator. This
increases the speed of the plane, reduces the rate of climb, and
thus further reduces the load on the propeller.
How do I use MotoCalc for a multi-motored aircraft or ganged motors
operating each propeller?
The Drive System section of the MotoCalc Workbench
window has three fields for this: Series Motors,
Parallel Motors, and Num Props.
If your motors are wired in series, enter the number of motors
into the Series Motors field. If they are wired in parallel,
enter the number into the Parallel Motors field. If you
have a series/parallel or parallel/series set-up, enter the appropriate
numbers into both fields. The total number of motors is then the
product of these two numbers. The Num Props field indicates
the number of propellers (for propeller drive systems only of
course), which by default is assumed to be the same as the number
of motors but can be less for ganged drive systems (multiple motors
driving each propeller).
An easy way to do most of the above is to use the
Wiring Wizard, which lets you lay out your
motor, battery, and speed control wiring graphically, and then
automatically fill in the appropriate fields (except the Num
Props field) in the MotoCalc Workbench window.
How do I use MotoCalc to predict the performance of a biplane?
Everything is done the same way as for any other plane, except
for the following: In the Wing Span field of the Airframe
section, enter the average span of the two wings. In the Wing
Area field, enter the total wing area of both wings. This
will cause MotoCalc to think you have a plane with one very low
aspect ratio wing, which will closely approximate the lift and
drag characteristics of the biplane, with its two medium aspect
ratio wings and four wing tips. If your biplane has struts or
bracing wires, be sure to select the appropriate item in the Protrusions
section of the Lift and Drag Coefficient Estimator window.
Can I use MotoCalc to predict the performance of a helicopter?
MotoCalc does not, as yet, provide support for helicopter performance
modeling. However, you can make use of it to do some rudimentary
The MotoWizard and MotOpinion features won't be
of much use, but if you can determine the blade pitch at 75% diameter,
you can use this, and the rotor diameter, as the propeller pitch
and diameter in MotoCalc's main input window. Then, you can experiment
with different gear ratios for a given motor and battery to find
a combination that will provide a higher static thrust than the
helicopter's weight. Note that this will still only be approximate,
because a helicopter rotor has a variable (with respect to time),
yet constant (with respect to distance from the hub) blade angle,
whereas a propeller has a variable blade angle but constant pitch.
How can I change the project that's displayed when MotoCalc first
When starting up, MotoCalc always loads the project that was open
when you last exited from MotoCalc.
Adding New ComponentsQuestion:
How do I determine the parameters for a new motor, cell type,
etc., and add it to MotoCalc?
First, you have to determine the appropriate parameters for the
type of component you wish to add.
For motors, please refer to Measuring Motor Constants,
Entering Motor Data from Tests, Entering
Motor Data from a Catalog, or Using the Motor
Designer. For cells, please see Measuring
For gearboxes, just enter the gear ratio as provided
by the manufacturer, and specify the gearbox efficiency.
For propellers, specify the diameter and pitch, and
the propeller's power and thrust constants. The Propeller Constant
Estimator can help with the latter two.
For ducted fans, it is easiest to use the Fan
Data for speed controls is generally provided by
the manufacturer. Check the documentation that came with the speed
control, or the manufacturer's web site.
Airframe information is easily measured. Please see
Lift and Drag Coefficient Estimator.
Once you have the data you need, simply enter it
into the fields in the appropriate section of MotoCalc's Workbench
window, give the component a descriptive name, and click the Save
button in that section. The data is now a permanent part of your
How does adjusting the motor timing affect performance relative
to MotoCalc's predictions?
The motor parameters (motor constant, no-load current, and armature
resistance) of a motor are measured with the timing set to neutral.
However, the predictions that MotoCalc makes assume that the timing
is set appropriately for the predicted operating conditions. So
if you set the timing properly, the motor should operate as predicted.
Otherwise, the predictions will be off.
Level Flight TimesQuestion:
Why are the predicted level flight times so long? Why are they
sometimes even longer than those predicted by earlier versions
(before version 5) of MotoCalc?
The predicted level flight time is the absolute longest time that
the plane could maintain hands-off level flight at the indicated
speed and throttle setting. This assumes that the plane is launched
into level flight (i.e. no power is used for climbing), at the
right speed (i.e. no power is used to accelerate). Actual start
to finish flight times could be shorter (due to increased power
needed for take-off, climb-out, turning, aerobatics, etc.) or
longer (due to assistance from thermals). The predicted flight
time is only a rough guide line. MotoCalc 5 and up will predict
even longer level flight times for high-rate speed controls, since
these operate more efficiently than low-rate (frame-rate) controls.
Earlier versions of MotoCalc computed level flight times based
on the (inefficient) way a low-rate control operates. MotoCalc
6 and up generally produce lower predictions than version 5, due
to a more accurate mathematical model for in-flight propeller
unloading (MotoCalc 5 was overly optimistic).
Number of Fan BladesQuestion:
Why does MotoCalc not need to know the number of blades of a ducted
The mathematical model used by MotoCalc for ducted fan calculations
is based on the fan's swept area (rotor area minus hub area) and
the pitch. In this simplified model, the number of blades does
not matter. The differences in efficiency for different numbers
of blades can be adjusted for in the Power Coeff and Thrust
Ducted Fan Coefficients
How do I determine the coefficients for a ducted fan?
This requires either doing some tests, or finding published test
data. Then, use the Fan Coefficient Estimator
to compute the coefficients from this data.
Moving MotoCalc to a New ComputerQuestion:
How do I move my copy of MotoCalc to a new computer?
If you simply want to run MotoCalc on your new computer without preserving
any components or projects that you've entered, just install MotoCalc on the
new machine, either from your CD if you purchased it on physical media, or
from a downloaded installer (www.motocalc.com). If you do not have a CD,
please contact Capable Computing for a new license key (at no charge).
Please note that in order for us to create a new key, you will need to
provide the serial number that MotoCalc displays (in the Registration
Reminder window) on the new computer.
If you also want to preserve the components and
projects you've created, follow the steps above, and then copy
the following files from the MotoCalc user data folder on your old machine
to your new machine (using a disk, CD, USB stick, local area network,
e-mail, or whatever method you prefer):
Notes.lst (may not be present)
The location of these files depends on which versions of Windows and MotoCalc
you are using:
- MotoCalc 8.08 or newer with Windows Vista, 7, 8, or newer:
- MotoCalc 8.07 or older with Windows Vista, 7, 8, or newer, on a 64-bit computer:
C:\Users\YourUserName\AppData\Local\VirtualStore\Program Files (x86)\MotoCalc8
- MotoCalc 8.07 or older with Windows Vista, 7, 8, or newer, on a 32-bit computer:
- MotoCalc 8.08 or newer with Windows 95, 98, 2000, or XP:
C:\Documents and Settings\YourUserName\Application Data\MotoCalc 8
- MotoCalc 8.07 or older with Windows 95, 98, 2000, or XP:
Please note that some of these folders may be hidden by Windows. You
will have to make them visible in Windows Explorer by enabling
Show hidden files and folders in the View tab of the
Folder Options page (accessible by pressing Alt+T and
then selecting Folder options... in Windows Explorer).
On-line Data UpdatesQuestion:
How do I get updates to the data provided with MotoCalc?
Very easily. To update only one part of the database, click the
Open button in the appropriate section of the MotoCalc
Workbench window, and then click the Update... button in
the database browser for each type of component (motor, cell,
speed control, etc.). See Updating a Database Table
for more information.
To update the entire database at once, select Update
All... from the MotoCalc window's Update menu.
Both of the above methods assume that your computer
is connected to the Internet. If it is not, see the next question.
Off-line Data UpdatesQuestion:
How do I get data updates if the computer I use MotoCalc on is
not on the Internet or if my firewall will not allow MotoCalc
to connect to the Internet?
First, if the problem is a firewall, you can probably get MotoCalc
to connect to the Internet either by configuring the firewall
to allow it to do so, or by setting up MotoCalc to use a proxy
(please see Internet Connection Proxy).
If that fails, go to the MotoCalc web site's data
page at http://www.motocalc.com/data.htm
with a web browser on a computer that can access the Internet,
and visit each component page for the data you wish to update.
Use your browser's Save As command (usually on the File
menu) to save each page to a location on your computer (or to a USB
stick or other removable media you can later take to the computer
with MotoCalc on it. on it).
Then, in each component browser in MotoCalc, click
the Import... button, browse to the saved HTML file, and
click OK to import the data.
New or Second ComputerQuestion:
I've purchased a new computer, or I use more than one computer
on a regular basis. Do I need to purchase additional MotoCalc
No. Please see the appropriate section in
the Registration section of the manual.
MotoCalc for Macintosh or LinuxQuestion:
Is MotoCalc available for Macintosh or Linux?
There is no version specifically for Macintosh or Linux at this time, and we
currently do not have any plans to produce one. However, many customers
report that they are successfully running MotoCalc using
WINE, a free Windows
compatibility layer that allows Windows applications to run directly in Mac
OS X or Linux without requiring you to buy a copy of Windows. Since we
cannot guarantee compatibility, we suggest you download and try MotoCalc for
a free 30 day evaluation before purchasing.