Capable Computing Inc's MotoCalc Version 8.03

J. David Johnson explores the latest release of the greatest tool for EVERY electric modeler who isn't purchasing an all-in-one-box, or the manufacturer's recommended power package.



Requirements:See Article Text
or $10 additional to get a CD
System Requirements:a Pentium based processor
8Mb of free hard disk space
800x600 or higher screen resolution
Microsoft® Windows® 95, 98, ME, NT®, 2000, or XP.
Manufacturer:Capable Computing, Inc.
Available From:MotoCalc

What's New in 8.03?

The MotoCalc Site brags...

  • increased versatility of MotoWizard
  • Battery "C" rating
  • Parallel cell ranges supported
  • Flat and curved plate wings supported
  • Gearbox weight added
  • Direct Link to tech support
  • "Tip of the Day" to expand your usage
  • TONS more data -- 1300+ motors, etc!!
  • Internet proxy support
  • Easier look and feel

So, if you're a long-time MotoCalc user, there are just some of the reasons to choose to upgrade to 8.03! ITS FREE as a download, or a $10 CD! Now THAT'S great customer support!

There has never been a more exciting or enticing time to get into electric flight. With the advent of powerful brushless motors, a myriad of speed controller options, Lithium Polymer packs, safe, reliable charging solutions and a plethora of excellent quality airframes -- there's just so much to enjoy!

But coming with that is the somewhat complex task of selecting the appropriate power system for the airplane. With so many choices, it would be easy to pick a system that was underpowered, or drew too much current for the battery pack, ESC or motor, or offered too little flight time.

If only there was an easy way to "test out" a variety of options without spending a fortune on multiple setups. Well there is... and has been for some time: MotoCalc!

It's most recent version 8.03 costs only $39... less than the price of a single brushless motor. Yet it is a tool that will not only save you wasting money on unsatisfactory power sets, but also allow you to optimize your setup for best performance.

MotoCalc 8 requires a PC with the minimum requirements listed in the specifications table, above right.

It runs blazingly fast, with results and updates happening instantly.

At first glance, the program can seem daunting and "long-haired". Meaning one might think you'd have to be a rocket scientist to use or make sense of it. However, that's not the case at all! Yes, you can delve pretty deep into the variety settings available to calculate a myriad of situations... but for the electric beginner, it's a simple 6 step process with many presets.

Testing the software

For my test airframe I chose the AirfoilZ Yak54. Knowing the suggested motor/esc/battery combo was a great performer, I still wanted to look at another popular brand of motor... the Hi-Max Outrunner.

So we needed to begin entering the setup into MotoCalc, which is separated into 6 data sections: Motor, Battery, Filter, Drive System, Speed Control, and Airframe. In these 6 sections, I selected and described the components to "test".

In the motor section, there is a drop down with nearly 1600 motors to choose from... that's right 1600!!! Or you can create your own by simply entering the data from the motor's spec sheet and save it as a preset.

The battery section provides info on a variety of packs.. nearly 200 in all... and again, if a new pack comes along, simply input the data from it's spec sheet and save it as a preset for future use. Note that data is entered for ONE cell, then select the series and parallel configuration that will make up the pack.

It's easy to test a 2S against a 3s or 4s pack by simply changing the series count. The program will even calculate all 3 at one and compare them!

The filters section is perhaps one of the more advanced sections and, for newer users, it can be simply left "unchecked" so it's not used in the calculations. Basically filters are ways of setting limitations on a variety of settings... like max amps, minimum thrust required, min/max speed, minimum run time, etc. These settings allow you to tell MotoCalc your preferences that must be met.

Here the user selects the prop and gearbox (if used) from about 100 choices. Don't see an exact match? You can select a close prop, like an APC 11x4.7 slowflyer, then change the figures to create a 12x6 or 10x7. The gearbox ratio can easily be changed too. The modeler can try out a higher ratio with a larger prop, or a smaller prop and lower ratio, all without risking the motor or airframe! Again a range of ratios/props can be entered and have Motocalc compare them. It even supports ducted fans!

With over 125 speed controllers in the database... and many of them the most popular brands and sizes... you can easily select an ESC that you believe might work for the project. And yet again, you can enter in the spec data and save a preset for those that are newer releases or not listed.

Here you can enter in the data for your airframe. Wingspan, area and empty weight are key. The empty weight is the airframe ready to fly MINUS the motor, prop, esc and battery. Because each of those items are tracked in the various sections... Motocalc will adjust the weight of the RTF plane base on the selected options. If you pick a larger battery, the program will adjust the weight, and then calculate the differences in power to weight, speed, flight-time, etc.

You can select from the 60 or so presets and modify them from there, or start from scratch and enter in the data for your specific airframe.


Once each section has been set, MotoCalc can then compute a report based on those settings. The In-Flight Analysis results will show you a wide variety of data, from airspeed, to the amount of amps the motor is drawing, to thrust and watts calculations. Scrolling through the data you can look for the green bar which represents the level flight parameters. I tend to use this as a "bar" for how long of flight times to expect. This line represents the plane flying level without any gain or loss of speed... and though I use MORE throttle when doing 3D maneuvers, I also use less throttle in down-lines, some maneuvers, etc. So together it come closes to the prediction. As a safety margin, I might subtract 10-20% for aggressive 3D flights, and I have found this to be pretty accurate for my style of flying.

By going back and changing settings in the 6 sections and re-computing... you can see how each item interacts with the performance. AND this is what lets you determine the optimal load out for your airframe!

From this screen you can then select the "Opinion" button.

The MotOpinion screen basically puts all the info in the prior screen into easy to understand, English terms. Looking at each section, the software provides notes to the performance or problems with a selected power system and possible aerodynamic problems and results. If there are any calculable problems like the motor not being used efficiently or running too hot, this section will tell you possible ways to solve it, like... "Select a larger prop".

It will also note when the current draw is too much for your ESC.

Other Functions

MotoCalc boasts some other great functions, depending on your modeling experience and needs. One example is the wiring wizard, to help ensure that even multi-motor installs are wired up correctly and safely, with parallel and series setups all diagrammed and easily understood.

The graphing functions can really help to make a series of overwhelming figures suddenly so clear.

Their website indicates that even propeller data is easily added, thanks to coefficient estimators that allow the user to input actual bench testing data. (I didn't experiment with this function.)

Along with the in-flight data predictions mentioned previously, there is also the ability to do static predictions such as power loading, power loss, etc, without airframe information needed.

A review couldn't be complete without mentioning MotoWizard! Especially for the newer e-modeler, who isn't sure what power package to look at for his new model, or for converting a glow model to electric, this is a fantastic tool. Simply tell it the specifications of your model and the performance you desire, and it will recommend some power setups for you! Then ask MotOpinion to clarify the information provided, for a 'plain English' explanation.


MotoCalc is an essential tool for the electric flight enthusiast. I cannot tell you how much I've learned JUST USING the program, getting a grasp on the interactivity of the components and developing a better guesstimate on outfitting my planes. I have used MotoCalc on several projects from small 10oz foamies up to 13 lbs 1.60 size e-conversions. I have found the calculations to be surprisingly accurate.

It's important to note that along with this program, a good watt-meter should be employed to confirm the amp draw of any setup. These two tools together can and will help make your next e-project a successful and enjoyable experience.

I can honestly say that this will be the BEST $39 you could spend on e-flight enjoyment. Not convinced? There's EVEN a free 30 day trial!!

Last edited by AMCross; Nov 21, 2006 at 02:57 PM..
Thread Tools
Nov 23, 2006, 03:00 PM
Registered User
Fourdan's Avatar

MotoCalc and PC changing

Hello Stefan
I misunderstood the S/N principle to get the registration key
Now I know that the key is "associated" with the PC machine
My new key arrived
It's OK
Sorry for my first message
Louis the french tester
Last edited by Fourdan; Nov 24, 2006 at 10:16 AM.
Nov 23, 2006, 03:07 PM
MotoCalc Developer
stefanv's Avatar
Hi Louis:

Glad we got through to you! We always respond to new key requests promptly, so if you don't hear back, then something has probably intercepted our message.

Stefan Vorkoetter
Capable Computing, Inc.
Last edited by stefanv; Nov 24, 2006 at 02:30 PM.
Nov 23, 2006, 04:32 PM
Registered User
Hey Stefan!

One thing I've always wondered about with motocalc, is the lack of prop types. For instance, there is an APC prop type, but is it for E, Slow Fly, or some other? And where are the GWS props?

Sure would be nice to fill up the table with a bunch more named constants! Maybe even breakpoint tables, if straight constants fail to cover wide ranges of sizes and pitch for the same prop family...

Have you seen this thread here in the power section:

It has all kinds of data about different prop types, and thrust and power constants, and so on. Hopefully some of it could be adapted to motocalc.

All the best on this great product!

Long time motocalc subscriber,
Don Erway
Nov 23, 2006, 04:36 PM
MotoCalc Developer
stefanv's Avatar
We're going to be adding some new downloadable prop type data in the near future. Yes, I'm aware of that thread, and we'll be doing our own testing as well.

Last edited by stefanv; Nov 23, 2006 at 08:09 PM.
Nov 23, 2006, 06:25 PM
Registered User
Fourdan's Avatar
Last edited by Fourdan; Nov 24, 2006 at 03:16 PM.
Dec 02, 2006, 04:17 PM
Registered User

Does the lastest software support all the Tower Pro / Balsa Products motors and ESCs ?


Dec 04, 2006, 09:55 AM
MotoCalc Developer
stefanv's Avatar
Originally Posted by netdudeuk
Does the lastest software support all the Tower Pro / Balsa Products motors and ESCs ?
Not at the moment, but we're always adding new data, which you can add to your copy of MotoCalc with a single mouse click at any time in the future. We've contacted Balsa Products for detailed specs for their motors, and we'll add them as soon as we receive the data.

Dec 04, 2006, 12:26 PM
Registered User
Originally Posted by stefanv
Not at the moment, but we're always adding new data, which you can add to your copy of MotoCalc with a single mouse click at any time in the future. We've contacted Balsa Products for detailed specs for their motors, and we'll add them as soon as we receive the data.

That could be good for all concerned. People are more likely to get the software if they know that they can select lower cost motors as a result. It may only take a couple of motor purchases to be able to break even.

PS Please send me a license key for this cool business expansion tip !
Dec 09, 2006, 10:11 AM
MotoCalc Developer
stefanv's Avatar
Originally Posted by netdudeuk
People are more likely to get the software if they know that they can select lower cost motors as a result.
Indeed! Balsa Products has replied to us that they have the data, and will send it to us as soon as they've got it all compiled in one place. We've tried contacting TowerPro, but have not yet heard back. We're also in the process of getting data for all the Great Planes Ammo and Rimfire motors. As soon as we have any new data, it will be available for download into MotoCalc.

Stefan Vorkoetter
Capable Computing, Inc.
Dec 09, 2006, 10:18 AM
MotoCalc Developer
stefanv's Avatar

MotoCalc 8.04 Now Available

Please see the announcement.

Stefan Vorkoetter
Capable Computing, Inc.
Last edited by stefanv; Dec 09, 2006 at 10:27 AM.
Dec 09, 2006, 10:46 AM
Survival is Attitude!
Skonkworkstexas's Avatar
Stefan, The APC thin is my prop of choice, and I have had to extrapolate the diameter to between a 10 to 15% increase on the diameter in order for the test stand to agree with the readings. Very little changes on the Master Airscrew, and none on the GWS props. I attribute this to the high efficiency of the airfoil, and its low drag due to the thin cross-section. Have you seen this type of problem in the past?

Of greater importance to the reader, I built a Schumate F18 last year, and was trying to scale it to a greater degree. Running a 3s 2220 and outrunner, which was considered unpopular at the time, I went through 3 "recommended" motors, and found them unsuitable for the task. After the final crash on the second day of flight testing, I stopped flying, and started testing. I built test stands, bought the proper test equipment, and downloaded Motocalc. I had been told not to waste the time or expense with such software. Shortly into my investigation, I paid the money for the software.
I am convinced that if you fly ANYTHING past an RTF plane-ANYTHING........then the first thing you need is a "drawing board".......and MotoCalc is the board. A fatal mismatch cost me the plane, and the recommended motors I bought before MotoCalc are still in their boxes. The software, if properly loaded, and tweaked with the test stand results, primed me into future success, for a trifle of the cost. If I want to build a plane, the first question in my house is asked. "What does the computer say about the plane?" Motocalc is not my primary source of knowledge when building....Just the beginning, the middle, and the end, while supporting a successfully flying plane!
Welcome from the Skonkworks of Texas
Dave (Skonk)
Dec 09, 2006, 11:07 AM
Registered User
Dr Kiwi's Avatar
Well said, Dave!
Dec 09, 2006, 11:55 AM
Survival is Attitude!
Skonkworkstexas's Avatar
Even better said is a quote made by Mary Dilda, air racing champion, and owner of the T34 Mentor "Two of Hearts" at Reno fullscale air races:

"Car racers look for the perfect tire and suspension. In air racing we're looking for a propeller tuned to the airframe and balanced to the engine. Its a prop-engine mix, and it took seven years to find it."
Thrice gold winner, as quoted in Air & Space Smithsonian, January 2007 issue
Dec 09, 2006, 12:27 PM
Survival is Attitude!
Skonkworkstexas's Avatar
Stefan, have you tried, or have specs on Little Screamers motors?

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