I have a hypothetical question: if I'm going to build a scratch built multicopter, where in the huge amount of information on this site will I find the information I need to determine motor/esc/battery/ voltage /prop pitch and diameter matching to frame and cargo weight for the copter (should be formulas?)? I am sure this has been addressed, I just can't find it. I realize there are variables in there that can't be accounted for completely, but there should be a method for ball-parking it.
Also, I have a problem in the Mission Planner. I'm attempting to set up and run the Channel 6 roll/pitch P adjustment as described. However, when I put in the parameters as instructed, write them to the APM; the numbers that come back are strange. I can adjust my channel 6 knob on the xmitter to mid or low end but I'll get the high end number back no matter where the knob is set. However, If I repeatedly refresh the screen, the number will eventually show the setting that is consistent with the knob position. It takes 3 or four refreshes, tho. And, If I refresh again, it goes back to the high number again. Is this indicative of another problem that may be preventing me from properly adjusting the roll/pitch P? Could there be a serious problem somewhere? The reason I ask is I can't get my tricopter to level without active user input from the xmitter. It always rolls on takeoff and I have to correct it manually (fly it) or it will completely flip. I can hold the correction and get a sloppy hover, but then the copter rises or drops (slowly) but won't hold an altitude in stabilization mode- which is the only mode I'm using now during setup. Any suggestions or recommendations here? BTW, I have no problem with Yaw at all.
Scratch Tricopter frame with functioning Yaw control servo setup
Using APM 2.5+
no ext compass
Futaba 7c 2.4ghz comp radio system
Detrum 60a ESC
Tacon Bigfoot 10 motors
APM power modules
Thanks for any help in advance.