Introduction: SexieHexie (Hexacopter With 8520 Motors)

About: I’m a retired Avionics repair technician ( depot level ) . I was also responsible for the quality control for the soldering shop . Sports to keep my old hardware in shape and Linux and embedded systems to keep…

This project is dedicated to the Belgian artist Panamarenco (link) who passed away december last year . He combined art with technics , especially flying objects . He will be missed ...

The supplies for this Hexa may look a bit strange but we're living special times , all model shops are closed due to the Covid-19 shit ... During the nineties I scratch-built many balsa R/C planes so there's still some WoodStock (:-) ) left . This brings us to the supplies :


For the airframe :

- 2mm light aircraft plywood ( we need a 60 by 60mm part )

-3mm plywood or paint mixing sticks for the motor mounts

-Carbon fiber rods , 4.8mm or smaller ( but check for decent stiffness )

-scrap Depron , balsa for battery holder , canopy ...

-lots of imagination and patience , work slowly and carefully :-)

Avionics :

Transmitter and receiver ( I use FlySky I6 and FS-RX2A Pro V1 receiver )

Flight controller board : F3 Evo brushed ( or any 6 motor board )

1S Lipo battery , approx 600mAh (25C or better )

6 8520 1S motors ( 3CW and 3 CCW ) with props (55mm)

Tools :

woodworking tools , dremel , drill , all you can get your hands on :-)

Step 1: Draw Plans ( or Print Them )

First we need building plans , they will simplify your work as you can build the airframe on them .

I made several drawings as they got dirty during the job . They can be drawn in a couple of minutes , if you use millimetric paper it's much easier :-)

Step 2: Building the Motor Mounts

Mine are made of paint mixing sticks , appox 3mm thick ( and very cheap ) . We pick the best one out of the pack ( verify if it's staight , weight , quality ) and size it to 16mm with a Proxxon circular saw . Sand it , draw a nice line in the middle and mark the holes for drilling with a hand tool .Draw the external lines . Take your artwork to the drill stand , put a 8.5mm drill into the machine and drill all holes ( it's wise to make some extra motor mounts , some holes will be out of center even if you work carefully ).Cut the parts apart with the circular saw if you have one ( borrow one , it'll save you lots of time ) . Sand all parts , carefully try if the motors fit ( they won't , so sand the hole very carefully until the motors fit snugly) .

Et voila , motor mounts : Check !

Step 3: Building the Baseplate , Mark CF Rod Positions

Very easy ! Start by cutting a 60 by 60mm plate from 2mm aircraft plywood , cut off the corners (see drawings ) , sand , and put it on top of the building plan . Draw the lines for the CF rods using the lines on the building plan ( I used 4.8mm rods so adjust to the size of your stuff ) and it's done !

Step 4: Assemble the Frame

Make sure your working surface is completely flat and equal , use a fuselage builder jig or balsa building plank if possible . If you're working on the kitchen table cover it because we'll use glue and we will spill :-)

Put two motor holders on the plan and cut a CF rod . Use Cyano glue ( superglue ) and glue the motor holders to the rod . Put the baseplate on the plan ( put some scrap balsa under it if the motor mounts are 4mm) and line the whole thing up with the plan , glue with Cyano .

Let dry , even superglue needs some time . Now you can assemble all the motor mounts , CF rods to the baseplate with Cyano . Take your time and work precisely , you'll have to adjust the CF rods (cut with a certain angle) to have a good fit .

Six motors will produce a fair amount of vibrations so we need to reinforce the CF-motor mount connection point . This is done by soft balsa strips (3mm thick) glued with white wood glue next to the CF rods . It will add some weight but losing a motor in flight is much worse !

At this point , the AUW ( All Up Weight ) is about 14 grams , quite acceptable .

Congrats , you have made yourself a nice airframe !

Step 5: Installing the Motors

This is an easy job . Because the motor mounts are ( or should be ) almost straight in all axes just put in the motors ( it's a good idea to test them first ) . Make sure to put the motors ( (CW and CCW) in the correct positions . I used a triangular tool to verify my job . If it's all OK fix the motors with a tiny drop of Superglue .

All up weight is now about 50 grams .

Step 6: Installing Avionics

I had to repair my Flight controller , the step-up converter was dead .

I removed/replaced this part : MT3608 booster

Found lots of info here :-)

Fix your Rx and flight controller to the baseplate with double tape or the sticky things that fix your GoPro to your motorcycle helmet ( I used these 3M things , they are great because they also absorb shocks to the flight controller ) . Make sure the FC is placed in the right direction ( arrow marking on the pcb ) .Take the drawing and F3_EVOmanual and solder the motor wires to the correct motor outputs .

The CW motors are on the left , the CCW on the right if the flight controller is facing forwards .

Take your time and check , check and doublecheck :-) . A short motor connection may ruin the FC ...

If you wish you can also install a buzzer for low batt warnings etc ...

Now it is time for a few tests . I assume the Rx is already bound to the transmitter and the FC has Betaflight 3.1.0 or more recent on board . Here's how I configured my flight controller :Speedy Bee configurator

Configure for X-hexacopter . When configuration is done check motor rotation direction , NO PROPS YET !

Step 7: Prepare for a Test Flight

Use rubber bands and a few pieces of wire to fix the battery . I made a "testing landing gear" with 6mm depron fixed to the motor mounts . Use UHU POR or the Depron will melt !

Almost done :-)

Step 8: Here We Go !

Make all necessary preflight checks , install a fresh charged battery and take off ! She flies like a quad but because of the 2 extra motors you should ease on the throttle :-)

When your hands are no longer trembling go for another battery and another battery and ...

Have lots of fun !

If any questions drop me a line , always at your service !


Step 9: Modifications , Corrections Etc ...

Despite the correct diameter of the holes in the motor mounts the CCW motors came loose , seems they are a little thinner than the red CW motors . Solution : reposition the motors , take som wire or wool or whatever and glue it at the underside of the motor mounts with cyano . Replace the depron test LG by one in medium 2,5mm balsa . She made several flights after these mod's , no problems so far !

Stay safe , and most of all : have great Fun !