Heli-Headspeed is a tachometer software that acoustically measures the rotations per minute (RPM) of your RC model helicopter blades. For this purpose the blade sound is recorded and its frequency spectrum analyzed. It works with all electric and nitro model helicopters with two blades.
The software comes in a PC and a mobile phone version that runs on all Android phones and a lot of Java-enabled phones.
No need to install additional equipment on the heli, no need to buy an expensive optical tacho, it is easy to use, accurate, and works from a save distance to the helicopter.
Usage
The process is simple:
- select the expected RPM range
- click the measure button
The heli must be close enough to allow for clean recording of the blade sound, 2-3m distance to the heli should work well.
Mobile Phone Version
There are mobile phone versions for the following phone types:
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Android based phones.
The app can be installed from the Android market. Search for Heli-Headspeed in the market, use this Android market link or pick up a QR-code from e.g. AndroidPIT.
The software continuously measures the head speed and displays results in a graph. You can use the touch screen or the cursor keys to navigate in the graph and get a precise reading of individual points of the measurement. All measurements are saved in a history and are available for later comparison.
The software should run on all Android phones with Android OS version >= 1.5.
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Java enabled phones.
This version is JavaME based. This is a Java environment present on a lot of mobile phones. However not all mobiles are able to record sound in audio/x-wav format, but e.g. most of the newer Nokia and Sony Ericsson models can. Here is a list of phones that should work. Probably also others but it is nearly impossible to find such information on the web. You can simply try the software, it will tell you if your phone is not able to support the required audio format.
There are two ways of installing it on your mobile:
- point your phones browser to this URL:
http://digitizeit.de/heli/mobile/HeliHeadspeed.jad
It should install automatically. - Download these two files, copy them onto your mobile using USB, Bluetooth, whatever:
They can then be installed using your mobile phones file browser.
The phone will ask you to send the audio format and your phone model to my server, nothing else. I want to use this data to make a phone compatibility list. Please allow the app to do so.
The software likely does not work on Windows Mobile, check here for an alternative.
- point your phones browser to this URL:
PC Version
The PC version is Java Web Start based and runs on Windows, Mac and Linux. It can be launched directly from this website. This version features a mode for nitro helis in additon to the mode for electric helis. The nitro mode requires that you enter the gear ratio and works only with nitro helis!
In addition to live recording of the blade noise the PC version allows to read a .wav file. The measured RPM is displayed as a graph.
Launch Heli-Headspeed (Java Web Start must be installed, most likely you already have it).
If you like the software, you could send me some Bitcoins to: 17ihFp4NaZfMy7fnuassWdvSqzGRx3HoB4
About
Why such a software? If you start flying RC-helicopters at some point you need to adjust the RPM of the blades. There are a couple of possibilities to measure this number:
- buy an optical tachometer
- buy a data logger
- analyze the blade sound
The first two require additional equipment, the sound method however can be used with any notebook and a lot of mobile phones.
It is even possible to extract the rotor head speed out of YouTube videos.
The method is based on an analysis of the rotor blade frequency spectrum.
Basically it boils down to the fact that each blade makes a sound when it hits the turbulence of the preceding blade.
This software extracts the rotor head RPM out of the spectrum.
It is important to have sound with good quality. Compressed audio formats, e.g. mp3, often filter low frequencies too much.
Copying
Although the software on this site is mostly free it is still copyrighted by me. The files must not be hosted elsewhere or made available for distribution by other means.
Related Software
HeliPort is a free Windows and Windows Mobile program containing several applications for R/C helicopters. It includes an audio tachometer, several calculators, loggers, a real-time GPS logger and more. I think you will find it useful and of high quality.