I just restored the site survey that some of you may remember from a few months ago. I think I took it down when I released the tutorials, since I felt that the menu was getting crowded. On hindsight, that was a bad idea. I did some editing of the questions, but they are just as relevant today as they were before.

Why is that? Well, I don’t bother asking questions about the new features I’m already working on. I also don’t ask about high priority work that is already on the schedule. But it is hard for me to gauge the level of interest in adding calculator support for helicopters or gas engines, for example.

It only takes about a minute to fill out. The answers will help me prioritize my to-do list. So take a look and let me know what you think!

Sometimes it takes a while after I implement a new feature before I fully understand how to use it. That has definitely been the case with the PowerEnergy per unit of time. Common units include the watt and horsepower. System Optimizer. After I finished writing the optimizer example tutorial, I thought hard about what it really meant. It became obvious to me that, for most calculator users, a lot of assumptions could be made about what they were trying to do.

The result is the new EZ Optimizer. It dramatically simplifies the process of optimizing a power system. It’s this simple:

1. select the airplane
2. bring up the EZ Optimizer
3. set the propeller maximum diameter that will fit
4. set the maximum number of cells to try
5. run the EZ Optimizer

That’s it! It’ll find the best LiPo pack and outrunner motor for your airplane. The best news is that, if you are not happy with the results, you can manually edit the filters and run the full optimizer directly. The filters give you about a million combinations, so running the optimizer is pretty quick.

The latest component database release contains:

• 4,112 components preloaded by me
• 2,283 components entered by other web site members
• 6,395 total airplanes, motors, etc

There’s now 1,236 preloaded airplanes and 1,383 motors.

I just released the first major update of the interactive tutorials since they were originally released four months ago. As I reworked and added to the tutorials, I carefully thought about what I could do to make the calculator easier to use. All of the calculator changes that I’ve released in the last couple of weeks have been as a result of this process.

There are changes in every slide, with two major additions. First, I added a quiz to test your knowledge of the calculator and website. After the quiz is over, you can go back and learn the correct answer to any questions you may have gotten wrong. Right now the quiz is just for fun.

But by far the biggest new feature is a brand new step-by-step example of optimizing a power system. This tutorial is almost as long as all the other tutorials combined, and it doubled the size of the tutorial flash file to 2MB. My goal was to answer every question that might come up during the optimization process.

I’ve been working on some new tutorials. It’s forcing me to step back and think about the different ways that the calculator can be used. I have also spent quite a bit of time during the last few days using the calculator and pushing it to its limits.

Invariably, I see many areas where I get new ideas to make it work better. Rewording and expanding ToolTips to make them clearer is very common. I have also made many small tweaks to the functionality.

I just released a larger new feature. Before, the filters only let you do “and” type of filters. I.e., “the propeller diameter must be less than 15 inches and greater than 10 inches”. That was good enough to be able to handle the simpler scenarios that I envisioned before.

Now you can create much more complex filters. For example, “electric or slow-flyer propellers less than 10 inches in diameter”. That was simply not possible before.

There are six new graphs in the calculator, including one that I have to call the first advanced graph.

A new propeller graph compares the Advance RatioRelates a propeller’s airspeed with the rotational frequency and diameter. It is closely related to the angle of attack of the propeller blades. with the Power-Speed CoefficientRelates the forward velocity with the power required to turn a propeller. It is closely related to a propeller’s efficiency. It is sometimes used to help determine the correct propeller diameter to use. . Both of these terms are in the glossary. If you don’t know what they mean, don’t worry about it. These quantities are very useful for conducting advanced propeller analyses.

Now you can! The latest calculator release includes about 20 different new features or changes. Highlights:

• Compare two components side-by-side. Want to see how two motors stack up to each other? Load both of them up on the same graph! Expect a short pause, since you are doubling the number of computations. To disable the charting of the second component, select <None>.
• Support for multiple motors in one power system. The motors have to be of the same type and have to be wired in parallel (probably what you want, anyway). To use with the optimizer, set the number of motors before you start it. The optimizer will keep the number of motors that you selected.
• More input values have now become optional. There is improved logic to estimate missing data. Of course, if you know what the value is supposed to be, then you are probably better off entering it.
• ComponentThe different entities that the calculator is designed to edit. Motors, propellers, airfoils, etc. names are now case-sensitive. Case-insensitive names were sometimes causing some confusion. In lists, now uppercase letters will show up before lower case letters.
• The location <Standard Atmosphere> has been renamed <None>. This means “nowhere specific” and is probably easier to understand.
• I moved the chart combo box to the bottom of the screen. There is now less need to scroll in the list.
• Many expanded explanations in ToolTips to address common questions.
• Clearly labelled the advice as advice. Some folks (that hadn’t looked at the tutorials) thought these were error messages.
• Close to 6,000 components in the database. If you only want to see the components that I preloaded, then set the filters to only include Edited By = carlos.

Since there were so many changes, I spent an extra two days just testing it. It’s looking great!

The calculator is now a widget that can be easily shared with others or added to your web site. This is a much better solution than trying to install the Flash SWF file I described earlier. To bring up the widget menu, click on the small “Widget” tab at the bottom of the calculator.

Note: the version you copy will be for whatever data server you are using at the moment, United States or Europe.

I’ve merged in all the logic for the special OEM version of the calculator back into the main calculator executable. To put a free version of the calculator on your website, either copy to your webserver or run from my server.

Again, the control is 1000x700. This version enables more functionality for free than before. Questions or comments? Please do not hesitate to contact me.

UPDATE: I no longer recommend using the SWF file directly. The widget I describe above is a much better solution. Please use that instead.

I just released a new version of the calculator.

ComponentThe different entities that the calculator is designed to edit. Motors, propellers, airfoils, etc. names are now identified with the account name of the person that last edited the data. If your account name is “mike” and you create a new airplane called “Whizbang”, then the name of the airplane will become “Whizbang [mike]”. Previously saved data is automatically converted to the new convention. The only exception is the data that I preloaded. Instead of seeing “Sig Kadet Senior [carlos]” you’ll just see “Sig Kadet Senior”.

I went through a lot of trouble to make sure the power system selected in an airplane is still valid even after the power systems get renamed. This also applies to the components (battery, motor, propeller, etc) inside a power system itself. If the calculator happens to make a mistake, I apologize. Errors should be very rare, but I have to assume they are possible.

A new command in the Administrative tab can be used to load another user’s data. With the new naming convention (see above), your personal data will never get overwritten this way. If you wish to copy one of these loaded components into your personal account’s data set, perform a small edit on it. This triggers the creation of a copy. This is probably harder for me to explain than for you to figure out, so just try it out in the calculator.