Hello friends!
First, let me state outright that this is not meant to be a detailed tutorial on flight log analysis; that guide can be found in sar104's post here and a great deal more can be learned from reading the whole thread there. I have immense appreciation for what sar104, Budwalker, msinger and a few other members have put in this forum on the topic of analyzing and understanding flight logs and I cannot thank them enough for their dedication and patience in helping fellow members, myself included, to gain very valuable insights on the mysterious aspects of flight log analysis. I have however observed that these wise men (and women if such is the case) can be very cryptic in their verbiage leaving the common man and woman among us scratching our heads. As a newbie pilot, it took me a while to understand many of the terms and parameters involved in flight log analysis and how they relate with one another. Perhaps, I thought, I can make this journey a little easier for other newbies and that - my friends - is the whole reason for this post.
Sar104 has listed some of the most frequently looked at parameters in flight log analysis in the post I linked earlier but I will paste a copy of these here for convenience.
For this first post, I want to focus on Number 13 - the recorded stick inputs of the pilot. Let's say I want to see the stick commands of the pilot and how the AC responded to these commands. We the common folk talk of left and right sticks and pushing these up,down, left, and right. But there are no such terms in the logs. These commands along with the resulting behavior of the AC are expressed in technical terms which may be self evident to someone familiar with aviation but are completely alien and cryptic to most of us. So let's get on with simplifying them.
Remote Controller Stick inputs
The stick inputs from the pilot are recorded in the log as "RC.aileron", "RC:elevator", "RC:rudder", and "RC:throttle" and can be accessed under the "RC" category of the time-series-signals in CsvView as shown below.
But what are aileron, elevator, throttle, rudder and how do I relate them with the pilot's input on the RC sticks? (What follows assumes a Mode 2 stick configuration)
Aileron = aileron describes the left and right movements of the right stick; in other words, the movement of the right stick along the x–axis. It commands the roll movement of the AC. In simple terms, roll moves the AC left and right. It does this by speeding up the rotors on one side and slowing them down on the other .
Elevator = elevator describes the up and down movement of the right stick; or the movement of the right stick along the y–axis. It commands pitch; or the forward and backward movement of the AC. It does this by speeding up the front rotors and slowing down the back rotors, and vice versa.
Rudder = rudder describes the left and right movements of the left stick; or the movement of the left stick along the x–axis. It commands yaw: yaw rotates the AC by speeding up all of the rotors spinning in on direction and slowing down all of the rotors spinning in the opposite direction (note here that quad copters have two rotors which rotate CW and two which rotate CCW).
Throttle = describes the up and down movement of the left stick; or the movement of the left stick along the y–axis. It commands climb/decent. It controls the vertical movement of the AC. It does this by varying the overall speed of the rotors; the faster the rotors spin, the greater the lift, and vice-versa.
So that is it folks! You can now plot these stick commands along with their corresponding effect on the AC's flight behavior (by expanding the "OSD" category in CsvView and selecting the relevant fields as shown below) and see if the AC performed as commanded by the pilot.
As a demonstration, here are a few graphs from CsvView
RC:throttle and OSD:height (you can see right away there were no uncommanded descents - sorry MM owners, I couldn't restrain myself there )
RC:elevator and OSD: pitch
RC:rudder and OSD:yaw
First, let me state outright that this is not meant to be a detailed tutorial on flight log analysis; that guide can be found in sar104's post here and a great deal more can be learned from reading the whole thread there. I have immense appreciation for what sar104, Budwalker, msinger and a few other members have put in this forum on the topic of analyzing and understanding flight logs and I cannot thank them enough for their dedication and patience in helping fellow members, myself included, to gain very valuable insights on the mysterious aspects of flight log analysis. I have however observed that these wise men (and women if such is the case) can be very cryptic in their verbiage leaving the common man and woman among us scratching our heads. As a newbie pilot, it took me a while to understand many of the terms and parameters involved in flight log analysis and how they relate with one another. Perhaps, I thought, I can make this journey a little easier for other newbies and that - my friends - is the whole reason for this post.
Sar104 has listed some of the most frequently looked at parameters in flight log analysis in the post I linked earlier but I will paste a copy of these here for convenience.
For this first post, I want to focus on Number 13 - the recorded stick inputs of the pilot. Let's say I want to see the stick commands of the pilot and how the AC responded to these commands. We the common folk talk of left and right sticks and pushing these up,down, left, and right. But there are no such terms in the logs. These commands along with the resulting behavior of the AC are expressed in technical terms which may be self evident to someone familiar with aviation but are completely alien and cryptic to most of us. So let's get on with simplifying them.
Remote Controller Stick inputs
The stick inputs from the pilot are recorded in the log as "RC.aileron", "RC:elevator", "RC:rudder", and "RC:throttle" and can be accessed under the "RC" category of the time-series-signals in CsvView as shown below.
But what are aileron, elevator, throttle, rudder and how do I relate them with the pilot's input on the RC sticks? (What follows assumes a Mode 2 stick configuration)
Aileron = aileron describes the left and right movements of the right stick; in other words, the movement of the right stick along the x–axis. It commands the roll movement of the AC. In simple terms, roll moves the AC left and right. It does this by speeding up the rotors on one side and slowing them down on the other .
Elevator = elevator describes the up and down movement of the right stick; or the movement of the right stick along the y–axis. It commands pitch; or the forward and backward movement of the AC. It does this by speeding up the front rotors and slowing down the back rotors, and vice versa.
Rudder = rudder describes the left and right movements of the left stick; or the movement of the left stick along the x–axis. It commands yaw: yaw rotates the AC by speeding up all of the rotors spinning in on direction and slowing down all of the rotors spinning in the opposite direction (note here that quad copters have two rotors which rotate CW and two which rotate CCW).
Throttle = describes the up and down movement of the left stick; or the movement of the left stick along the y–axis. It commands climb/decent. It controls the vertical movement of the AC. It does this by varying the overall speed of the rotors; the faster the rotors spin, the greater the lift, and vice-versa.
So that is it folks! You can now plot these stick commands along with their corresponding effect on the AC's flight behavior (by expanding the "OSD" category in CsvView and selecting the relevant fields as shown below) and see if the AC performed as commanded by the pilot.
As a demonstration, here are a few graphs from CsvView
RC:throttle and OSD:height (you can see right away there were no uncommanded descents - sorry MM owners, I couldn't restrain myself there )
RC:elevator and OSD: pitch
RC:rudder and OSD:yaw
