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.

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

Finished 3D Printed Hexacopter

Now using APM 2.6, 6HGPS and a CDR box for the electronics compartment.
Build files: https://www.thingiverse.com/thing:1168629
For hub close-ups http://blog.lowres.xyz/2015/11/hexacopter-new-central-hub-setup.html

Flying the Hexacopter

Putting the Hexacopter through its paces and playing around with the Gopro.
32 Minute flight time that day. Quite blustery too.

Oops Crash

Well I can not put it down to learning to fly, I forgot to hookup the low voltage alarm, and it just dropped out of the sky....from 30m :( Print a new hub/frame and should be good to go.

Hexacopter New Central Hub Setup

New improved hub to locate 16mm arms and 4mm pins to lock the arms in place.

Top level for hanging the two 5000mah batteries and fixing the electronics.

  Lower carriage for carrying camera.

Printed with PLA @ 25% Honeycomb fill.

Velco tabs for fixing the batteries in place.

Creating a Hexcopter Iteration 2

Creating a Hexcopter Iteration 2

After the first iteration, the results of which I am really happy as a first effort. There were some things that needed to improve:

• Less complicated central hub mechanism which does not rely on super glue to hold the Carbon Fiber arms into the Hub brackets.
• Really wanted to get GPS and flight planning, alt hold loiter and all those nice things, all things the KK board will not do.
• 17minute flight time was a bit on the short side and really wanted to get to over 30 minutes.

So:

• Redrew the central hub and instead of having the hing mechanism, replaced it with a solid 6 pronged part, including location holes for pins which would be used to hold the Ø16mm Arms.
• After checking round the 3DR APM flight computers looked like a good value purchase and I ended up buying a bundle from Banggood; APM 2.8, Power Module, GPS/Compass unit, Telemetry.
• Batteries, replace the single 4000mah battery with 2x 5000mah batteries connected in parallel. Try and keep the center of gravity just below the rotors.

Creating a Hexcopter Iteration 1

Creating a Hexcopter Iteration 1
First Flight using Hobbyking KK2.1.5 Board, 11" x 5 Props, S4 4000Mah Battery, span between motors is 710mm

 

The first flight, infact the first time flying a copter of any sort.... PID settings need some work...