250 Quadcopter, Full Build

a homemade 250 size quadcopter is not difficult to build. it just takes a bit of time to find and get he necessary components. The following components have been used in this project:

• 4 motors, 2206-2150kv, baby beast, hobbyking
• 4 esc's, 12 amps, afro
• 1 receiver, frsky tfr6
• 1 flight controller, naze32, flashed with cleanflight
• 1 analog video transmitter with antenna, immersionrc
• 1 fpv camera, cmos mini, hobbyking
• 1 hd camera, mobius
• 1 lipo alarm
• 1 power distribution cable, hobbyking
• 1 lipo battery, 1400 mah
• 1 "dirty" frame, laser cut from 6 mm poplar plywood
• 1 "clean" frame bottom, laser cut from 2 mm birch plywood
• 1 "clean" frame top, laser cut from 2mm birch plywood
• 2 motor mounts top, motors 1 and 3, 3d printed
• 2 motor mounts top, motors 2 and 4, 3d printed
• 2 motor mounts bottom, motors 1 and 3, 3d printed
• 2 motor mounts bottom, motors 2 and 4, 3d printed
• 6 vibration damping ball, 80 g, hobbyking
• 6 hex spacers, 29 mm, hobbyking
• 12 bolts, m3 x 6 mm
• 12 bolts, m3 x 20 mm (3 per motor is enough)
• 4 bolts, m3 x 16 (nylon)
• 8 nuts, m3 (nylon)
• 4 lock nuts, m4
• 4 propellers, 5030
• 1 alpha gel, 30 x 30 x 5
• 1 alpha gel, 60 x 20 x 5
• 2 velcro straps
• lots of zip ties

the base frame has to be cut from 6 mm poplar plywood. the remaining frame parts are cut from 2 mm birch plywood. if you don't have a laser cutting machine just print out the plans, glue them to the plywood and cut the frame parts with a fretsaw or a scroll saw.

the 2 mm adaptors for the vibration isolator are glued to the base frame. this is necessary because the vibration isolator do not fit the 6 mm thick plywood.

paint all frame parts so they are water-resistant. i like to use acrylic paint because the paint roller can be cleaned very easily with water.

to improve flight stability angled motor mounts are supposedly helpful. they are not a requirement and some might even dispute their effectiveness. but they can be made very easily by everyone who has access to a 3d printer.

attach the prop mounts to the motors. in order to keep the bolts from loosening under the vibrations of the motors i always use a thread locker similar to loctite.

mount the rubber vibration isolators to the base frame (the dirty side, i.e. the side with the vibrations from the motors). i don't use any glue to secure them, they are just held in place by a form fit.

each motor is bolted to the base frame with three (to save the weight of the fourth) m3x20 bolts and the two pieces of the motor mounts. care must be taken when orienting the motor mounts. the motor must be slanted towards the center of the base frame.

each esc's three adjacent connectors are connected to a motor. at this moment the rotation direction of the motors is arbitrary. this has to be checked later, when the flight controller is being configured. the esc's are fastened to the base frame with zip ties through the predrilled holes.

the power distribution cable is connected to each esc and attached to the frame with a zip tie. the power cable of an immersion rc video transmitter can be directly plugged to a special connector of the power distribution cable.

the naze32 acro flight controller is bolted to the lower plate of the clean side of the frame with nylon bolts.

the tiny fpv camera is attached to the frame with a zip tie. better check the orientation of the camera first.

the naze32 comes with a wire harness than makes it easy to connect it to the receiver.

the six hex spacers are bolted to the lower plate of the clean frame with m3x6 bolts.

mount the antenna to the video transmitter and fix the transmitter to the upper plate of the clean frame.

remove the red wire from the jst connectors of three esc's. this might not be necessary for esc's with a linear bec. i would do it anyway. the wire can be removed by lifting the little tab of the plastic connector casing while pulling on the cable. the freed connector has to be isolated with tape.

the connectors are then connected to the flight controller. see the naze32 documentation for detailed information.

install the cleanflight configuration software and connect the flight controller to the computer via a micro usb cable. the configuration software allows calibration of the esc's. additionally the rotation directions of the motors has to be checked. the rotation direction for a quadcopter is described in the naze32 documentation.

in case the rotation direction of a motor is found to be incorrect, simply swap two wires to the motor.

once the motor rotations are set, the bottom plate of the clean frame is connected with the bottom plate of the dirty frame with the rubber vibration isolators. this can be tricky but a pair of pliers and a screw driver help a lot.

connect the camera and the power supply to the video transmitter.

there are lots and lots of cables from esc's, video and others that need to be secured away from the propellers. more zip ties and tape can be very helpful...

bolt the top plate of the clean frame to the bottom part.

mount a prop with correct rotation direction to each motor. in case all prop adapter have a right-hand thread use lock nuts to avoid loosing propellers in mid-air.

strap the mobius camera to the top plate with a velcro strap. the separation of the dirty and the clean frame with vibration isolator eliminates already some vibration from the motors. alpha gel around the mobius camera reduces vibration further.

finally, we are done. charge your batteries and let's go test fly!

here you find the stl-files for 3d printing, pdf and corel files for laser cutting and the full 3d model for creo elements express (free cad software from ptc).