Tuesday, 8 December 2015

Mini Quad Rebuild 10mm arms

Mini Quad Rebuild 10mm arms

The original 9mm pultruded carbon fiber tubes were cheap tubes with no tortional strenght one crash and they cracked length wise. (unidirectional fibers)

The 10mm tubes are role wrapped and have much more torsional strength.

New motor ends needed to be 3d printed from PLA, luckly drilling out the central hub arm holes from 9 to 10mm went well using a bench press.

 The motors, distance between the holes is just under 10mm which means the tubes and the 3mm bolts have a bit of an interference fit.

Printed bungs on the ends of the tubes to help support the compression force when the motor ends are placed. 4mm Aluminum pegs fix the arms into the central hub.

4x 3mm bolts (22mm long) compress the two parts onto the end of the arms and fix the motor.

Saturday, 5 December 2015

Mini Quadcopter

Next project something smaller

Aim was for a smaller drone to run with my spare 4000mah S4 battery, bit odd I agree to build a quad copter around a battery.

  • So 4000mah battery.
  • Gemfan Bull Nose BN6045 Propellers 6 x 4.5
  • Spare Hobbyking KK2.1.5 flight computer.
  • Multistar Elite 2306-2150KV 'MINI MONSTER' Quad Racing Motor
  • Turnigy Multistar 30A Slim V2 ESC With BLHeli OPTO 2-6S
  • Arms 9mm Carbon Fiber tubes
  • All 3mm bolt/nuts
After the initial assembly and flight a problem emerged the 20 year old carbon tubes (originally used in kites) were still have excellent bending rigidity but their torsional strength is terrible, the first crash resulted in two of the arms cracking length wise and having no torsional strength anymore looking round the carbon vendors 9mm does not seem to be a section that is easy to get hold of, so looks like the 9mm tubes will need to be replaced with 10mm carbon with lateral wrap making its torsional strength much better. Not sure if I can drill out the frame or if its going to need to be reprinted.

Central frame from above
The battery compartment is central to the copter frame. Center of gravity is around the rotor height.

From below:
Needs to be printed with supports
Motor Ends Top:

Motor Ends Bottom:

Assembled without battery

With Battery:
Crazy wires, will need a clean up