Nice new build, based on 1/2 ally tube, RCT 750 kv motors, 30 amp 4S ESC's, 10 by 4.5 props.

Overall width 680mm , length 840mm


About 5 hours work in it so far, the centre section and motor mounts are pre made for me out of 2.5mm fibreglass

The aluminium is all hand cut and drilled (lots of holes) !!

Nuts/bolts 3mm and 4mm

ESC's were stripped so they could be "daisy chained" on the input side, and have the motor wires direct soldered on the output side.


They are mounted on the side pods, as this keeps the high current DC (and associated mag fields) far away from the Magnetometer , about 120mm seperation



FC is an ardu, with mag, gps and sonar.

Now to get into the code, and do a custom mix, will take the Y6 code, as its close , and modify it, will do one version for the Vtail 8 (needs 5 channels) and a version for the Vtil Y6/Y4 (needs 4 channels)


Batteries will be 4S 12000 mah (good for about 10 kg total thrust) and carrying a maximum of 1kg DLSR

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Comment by Sebastian Gralla on August 28, 2011 at 8:03am

bad wiring on the power side, black and red wire should be on the same side, and use thicker wires!

Comment by Mathew Wellington on August 29, 2011 at 2:43am
Why would you like the black and red on the same side ? it defeats the purpose of the "daisy chain setup"

those wires will carry on average 25 amps, and are rated at 50 amps, i am sure on the short run they will be fine :)
Comment by Sebastian Gralla on August 29, 2011 at 8:52am

because all current flows in one direction on your setup, which makes a big magnetic field -> your compass will not work correctly

i wouldn't trust these wires, but it's your copter which falls from the sky ;)

Comment by Chuck on August 29, 2011 at 11:02am

That doesn't make any sense to me.  Power flows one direction through each ESC.

it isn't going to flow through all four ESCs as a complete loop.  Just four small loops.

I don't see where it makes any difference what side the beginning is. 

If you're paranoid, just flip two of them over.

Looks like 12 gauge main feeds.  41 amps.  If they aren't melting at full throttle it will be fine.

Comment by Mathew Wellington on August 29, 2011 at 11:28pm

Makes me laugh, the only comments are to do with power wiring - you would think with my background in electronics I might get the basics correct.


No comments on airframe design, coding the ardu........... sigh ......... :)


@chuck - by feeding the first esc direct from the battery, and then sucessivly feeding each ESC from the last, each ESC in the system will progressivly get less available voltage.

by daisy chaining, one to the other, with the negative lead from one direction and the positive from the other, we should get the same average voltage on all ESC's (daisy chain is probably the wrong term)


@sebastian - please draw me a picture of how you expect the magnetic field to develop.

i would have though as i have two seperate banks of ESC's about 240mm apart, fed from seperate batteries, seperate power leads, powerleads run together to cancel any fields, and certainly no power carrying conductors circling the APM - i should probably post a picture

Comment by Denny Rowland on August 30, 2011 at 12:11am

I have to say Mat I could not follow the logic of not having the daisy chain. Saves some weight. Is a power distribution board not  flowing in one direction also?

Comment by Mathew Wellington on September 1, 2011 at 1:35am

Thanks Denny, yep a distribution board could have a circulating magnetic field :)


OK, i think the motor code is right, modified a Y6 one


front two motors from CH_1

left middle motors CH_2

right middle motors CH_3

Left Rear Motor CH_4 (does left yaw control)

right rear motor CH_7 (does Right yaw control)


/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#if FRAME_CONFIG == Y6_FRAME//matts Vtail 8 mix
static void output_motors_armed(){ int out_min = g.rc_3.radio_min; int out_max = g.rc_3.radio_max;
// Throttle is 0 to 1000 only g.rc_3.servo_out = constrain(g.rc_3.servo_out, 0, 1000);
if(g.rc_3.servo_out > 0) out_min = g.rc_3.radio_min + MINIMUM_THROTTLE;
g.rc_1.calc_pwm(); g.rc_2.calc_pwm(); g.rc_3.calc_pwm(); g.rc_4.calc_pwm();
int roll_out =  g.rc_1.pwm_out; int pitch_out =  g.rc_2.pwm_out;
//left motor_out[CH_2] =  g.rc_3.radio_out + roll_out; // dual motors
//right motor_out[CH_3] =  g.rc_3.radio_out - roll_out; //dual motors
        //front        motor_out[CH_1]         =  g.rc_3.radio_out + pitch_out;              //dual motors
//back motor_out[CH_7]         =  g.rc_3.radio_out - pitch_out;       // CCW Right Rear motor_out[CH_4] =  g.rc_3.radio_out - pitch_out; // CW Left Rear
// Yaw motor_out[CH_4] += g.rc_4.pwm_out; // CCW Yaw right motor_out[CH_7] -= g.rc_4.pwm_out;  // CW Yaw left
// limit output so motors don't stop motor_out[CH_1] = max(motor_out[CH_1],  out_min); motor_out[CH_2] = max(motor_out[CH_2],  out_min); motor_out[CH_3] = max(motor_out[CH_3],  out_min); motor_out[CH_4] = max(motor_out[CH_4],  out_min); motor_out[CH_7] = max(motor_out[CH_7],  out_min); motor_out[CH_1] = min(motor_out[CH_1], out_max); motor_out[CH_2] = min(motor_out[CH_2], out_max); motor_out[CH_3] = min(motor_out[CH_3], out_max); motor_out[CH_4] = min(motor_out[CH_4], out_max); motor_out[CH_7] = min(motor_out[CH_7],  out_max); #if CUT_MOTORS == ENABLED // Send commands to motors if(g.rc_3.servo_out > 0){ APM_RC.OutputCh(CH_1, motor_out[CH_1]); APM_RC.OutputCh(CH_2, motor_out[CH_2]); APM_RC.OutputCh(CH_3, motor_out[CH_3]); APM_RC.OutputCh(CH_4, motor_out[CH_4]); APM_RC.OutputCh(CH_7, motor_out[CH_7]); // InstantPWM APM_RC.Force_Out0_Out1(); APM_RC.Force_Out6_Out7(); APM_RC.Force_Out2_Out3(); }else{ APM_RC.OutputCh(CH_1, g.rc_3.radio_min); APM_RC.OutputCh(CH_2, g.rc_3.radio_min); APM_RC.OutputCh(CH_3, g.rc_3.radio_min); APM_RC.OutputCh(CH_4, g.rc_3.radio_min); APM_RC.OutputCh(CH_7, g.rc_3.radio_min); } #else APM_RC.OutputCh(CH_1, motor_out[CH_1]); APM_RC.OutputCh(CH_2, motor_out[CH_2]); APM_RC.OutputCh(CH_3, motor_out[CH_3]); APM_RC.OutputCh(CH_4, motor_out[CH_4]); APM_RC.OutputCh(CH_7, motor_out[CH_7]); // Instan

Comment by Mathew Wellington on September 10, 2011 at 9:00pm


Comment by Jeff E on September 10, 2011 at 10:41pm

Wow great progress...I personally like the cover of the APM :D


Hope to see your gimbal and the frame in action...

Comment by Aaron Franzen on November 15, 2011 at 7:13pm



Looks good.  How is have things progressed since September?  I'm hoping to put together a multirotor for aerial photogrammetry, and am interested in something similar to your layout.  I am new to all of this, and I'm contemplating building something like the butterflycopter shown in the video here:  kkmulti


I have two questions I'm hoping to figure out.  First, where did you find the code to modify regarding the motor arrangement?  I've been searching the code, and haven't found it yet.


Also, does anyone know of a document that describes how to define motor layout?  I know the AeroQuad folks are working on a mixing table for defining new arrangements.  I'd like to have the option to use more rotors, like the ten in the link before.


Anyhow, good work.  If anyone can help with those questions, please let us all know.


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