This web page describes the R/C Flight Data Recorder (RCFDR). You plug the FDR in to your receiver via Y-connectors and it will log 4 channels of receiver data, every 0.1 seconds, for about 20 minutes of total log time. It is approximately 3"x1" and weighs less than a servo. Power is from the receiver battery. Resolution for the pulse width is 7 micro-sec. More memory can easily be added to the unit to increase on-board storage. If you want to log more channels, simply plug in more units. Data is stored in non-volatile memory. No memory back-up batteries are needed. The RCFDR will log exactly what your servos are seeing in flight.
When you land (or crash), you use the PC software and interface cable to download the data from the FDR to the PC, via the PC's parallel port. Data is extracted from the FDR and stored as an ASCII text file. From there, you can analyze the raw data using something like an Excel spreadsheet. Data from the FDR consists of the measured pulse widths of each of the channels, recorded at .1sec intervals.
If you set one of the channels to go hi or low for fail-safe, you can use the FDR to analyze whether if it really did go into fail-safe or not, and for how long. See sample #4 below. The RCFDR is a must for those that just have to prove that it was fail-safe that made them crash their mega-buck jet or heli.
Four sample sets of data logged with the FDR can be viewed below.
The RCFDR is currently in the testing phase. Cost for the RCFDR, interface cable and PC software would probably be around $200.
Sample #1 output from 4 basic channels, plotted in MS Excel.
Sample #2 output from rudder channel, after gyro processing, plotted in MS Excel.
Sample #3 helicopter gyro and mixing data plotted in MS Excel.
Sample #4 Failsafe data plotted in MS Excel.
Download PC interface software.