Thursday, April 5, 2012

Hobbyking Micro-Quad build, part 3

I hooked up the battery, bound the transmitter, and tested to see which motors needed to be reversed. I had tried to think of some clever way to determine the motor rotation prior to soldering the motors, but couldn't think of any.
It turned out not to be a problem.  It's only a couple of seconds to desolder and resolder the wires in a swapped configuration.  I found it most convenient to leave the middle wire soldered and swap the left and right wires.  In this picture you can see the swapped state.
Here's how I attached the receiver.  Instead of using four 3-strand servo connectors, I used two.  You can do this because you only need one power connection.  The cable on pin 4 is connecting the signal, power, and ground wires.  The cable for positions 1-3 is connected to the signal pins only.  I made these cables with my crimping kit.
Note that I had to cross two of the signal wires where the attach to the control board.
(UPDATE:  Ignore everything below. I spent way too long trying out all kinds of things for the props.  I ended up using a hammer and banging the props directly onto the motor shaft. Works great!)

Previously I thought I could just use the prop savers to hold the prop in place without having to hollow out a hole in the pro to match the prop saver dimensions.  This turned out to be a false hope, as the blades wiggled vigorously as soon as power was applied.  I reversed the prop savers from their previous orientation so that the small end of the prop saver was exposed.  It should just line up with the end of the propeller shaft.

I used a 5/32'' drill bit to ream out the prop hole.  For strength, I didn't drill all the way through the prop, but just enough so that the prop would fit onto the prop saver. Holding the drill bit in some vice grips worked nicely.  Trying to use the electric drill broke the test prop.
I had some crud that didn't separate cleanly when the drill bit was removed... some tweezers took cleaned things up nicely.
Here's the props mounted on the prop saver using therabands.

Note: balance the props before you ream them out.  The small prop hole fits nicely onto a paper clip, but once the hole has been reamed out the balance is thrown off by the uneven connection between the paper clip and the inside of the hole.
I used gorilla superglue (with the embedded rubber cement) to glue things up.  Here's how much glue I used for the joints.
I applied it to one side, mated and jiggled the two sides to spread the glue, and then mated the joint to the proper position until the glue cured enough to hold the joint.
I cut some craft sticks to wipe off the excess glue from the joints.
Here's how much glue I used for the arm supports.  I also applied a bead of glue along the edge.
In order to keep my fingers out of the mess as I aligned the pieces, I held everything together with pliers.  I still got some on my fingers and blobbed some glue over the body.  If I did this again I would try dry-fitting everything and then wicking thin CA into the joints.  The Gorilla CA was a bit too thick for wiking.
To save weight and space, I took the Orange receiver out of its case and wrapped it in 3/4'' shrink tube.
I had to swap the mounting holes for the legs so that they didn't interfere with the mounting of the board.  If you're flying in X configuration, be sure your legs are lined up with the arms.
Here you can see that this allows plenty of room for the board.  There was vibrations even with this configurations.  I later added two more layers of gyro tape and the anti-vibration pad that came with the kit.

to be continued...

Note: If you're using kapteinkuk XCopter 4.7, the numbering of the rotors has changed:

 ;   View from above
 ;      Forward
 ; M1,CW     M3,CCW
 ;   *         *
 ;    \       /
 ;     \    /
 ;      \ /
 ;       +
 ;      / \
 ;     /    \
 ;    /       \
;   *         *
; M2,CCW    M4,CW

No comments:

Post a Comment