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+

MP 1.2.86

Arducopter 3.0.1

no ext compass

Futaba 7c 2.4ghz comp radio system

Detrum 60a ESC

Tacon Bigfoot 10 motors

10/6 props

APM power modules


Thanks for any help in advance.   


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  • When doing CH6 tuning, you need to hit "Refresh Params", not "Refresh Screen" to see the value being used based on the CH6 position.

    Watch Randy's Pre-flight and maiden-flight videos and do everything in them.

    Make sure you do an accelerometer calibration on a level surface, disable the trims on your transmitter, do a radio calibration, check your vibration levels and do an auto-auto trim sequence. Make sure your APM is level and square in your frame.

    Unless your tri is vey heavy for some reason, those motors and props should provide plenty of power on 4S.

    I'm guessing the steps above (probably the radio calibration or auto-trim) will fix your problem.

  • MR60

    This might help you for powering your craft

    Also i do not find it wise not to spend the neededbtime to familiarize yourself with the wiki documentation. If we'd just give you some sort of magic formula to build a drone without understanding the functionning, you would represent a danger for yourself and others flying a drone.
  • ".. need to determine motor/esc/battery/ voltage /prop pitch and diameter matching  to frame and cargo weight for the copter (should be formulas?)?  "

    look at link below:


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