Sunday, September 23, 2018

Starting RMAV (Remotely Manned Arial Vehicle)

I'd wanted to build a quad-copter.  Out of curiosity, I found a carbon fiber frame on a Chinese website for $30, and I ordered it.  I took it into the office (we have a guy that loves anything RC), and he talked about it being just like the one he paid $100 for.  After realizing I had a Chinese knock-off, I decided to keep building.  I'd like to buy one of those $100 frames just so the guy gets credit, but that will come when my wife thinks FPV is cool and takes over mine.  The gentleman that designed and built the kit is known by the moniker "Ummagawd" and is involved with Rotor Riot.

QUICK NOTE - Buy the $100 frames.  After having to break out the dremel with the grinding wheels to clear some space for the receiver and the video transmitter and getting carbon fiber all over the place, I'd strongly suggest getting the good frame that has pockets designed for that.  Still, this little project got me started into building a drone.

Anyway, here we go for a quick parts list :

I think green is cool.  So, I ordered green tubes (I needed 34mm and a 28mm tubes) and green cone washers.  The 34mm tubes didn't come in the size required for the quad frame, so I needed to turn them from 35mm down to 34mm down on the lathe.  Being cheap aluminum, the first one bent.  I chucked up the second one closer to the collet, and was successful :

My quad now has KV2600 T-Motors in green.  Since then, I've added the flight stack, and added some heat shrink tubing to secure the motor wires to the arms.  I've also added green antenna tubes in order to get a little more complete.  My propellers are a 3-blade HQ with a pitch of 4.3.  I know they sell 4.8 for quick response, but I'd like something a tad bit more gentle.

The above picture was taken before the green lock nuts arrived.  As of October 28, 2018, I have picked up an orange RunCam Swift 2 camera, and I removed the case and painted it some random color.

After painting the camera body, I installed it, and then realized I did not like the running of the antenna tubes.  I re-ran them along the front arms and left them relatively straight to increase the signal reception.  This gave me a little cleaner look as well (a nice side effect) :

Additionally, I have finally picked up the following, and I am preparing to install them.  On the left is the Spectrum SPM4648 DSMX receiver.  In the middle is the Lumenier AXII 5.8Ghz U.FL RHCP antenna for the video transmitter.  On the right is the ImmersionRC Tramp HV 5.8Ghz video transmitter.  On the bottom is the Spectrum SPM USB Simulator (so I can fly the quad without flying it using the ImmersionRC flight simulator).

Along with the Spectrum DX6, all I need is a battery, a charger, and some optional Fat Shark dominators for the first person view.

Progress is slow, but is coming along nicely.  I took the frame apart to start clearing out the area for the receiver and the video transmitter.  Note, it is worth it to simply get the pricier frame from Ummagawd because it has all of this cut out and in place.

Once that was cleared out, it was time to start re-assembling everything.  I'm using the HobbyWing XRotor series of flight stacks (F4 G2) :

Make sure when you install it that the arrow by the battery soldering pads points toward the camera (this is the "front" of the quad).  Next is to solder the cable to the controller that connects to the receiver.  For the Spectrum receiver (again, SPM4648), there are three wires from the connector.  Black should get soldered to the ground spot on the controller, the orange goes to 3.3v (do NOT do 5v).  And the gray should be soldered to the Rx spot right next to the orange cable.  Don't use the SBUS unless you are using an SBUS receiver.  Each receiver behaves differently.  The Rx are received UART connections (think of your old modems).  The Tx ports are for sending data to something else (e.g. an additional transmitter).

Next, I need to solder the motors to the controller, slide the receiver into position and install the flight controller, and the battery connector cable.  After that was soldering the receiver wires to the board :

Set up the antenna (remove the pigtail on there, clip the new antenna into place, and use hot glue to seal it up and keep it in place) :

Get the wires into position for all of the cables (including the transmitter we just hot glued) :

Make sure everything fits before closing it up.  Use enough Loctite to keep it from coming apart mid-flight on you.

The completed hardware quad :

Next up is to program the receiver.  After that, I just need a battery or two, and a charger before I can fly, and then some FPV fat shark dominators to do the first person view flights.  Kinda excited to get this thing done.

No comments:

Post a Comment