Comment by Ed Stewart on October 17, 2010 at 7:23pm

Nice, thanks for the photo's, very clean install.

Comment by James Pistorino on October 17, 2010 at 9:11pm

I was building the same thing this weekend.

What size tubing are you using? How long are the arms?

I would be interested in learning where you got the aluminum tubing from.

Looks great and is an inspiration.

Comment by Schwabenkart on October 17, 2010 at 10:10pm

Curious, it's nearly the same design like my arducopter.

Mine consitst of 4 aluminium sqare tubes, size 12mm x 1. Length 480mm each.
I bought it at the local hardware store.

But it still doesn't fly and doesn't look so great than yours

Comment by Robert Beatty on October 18, 2010 at 12:48am

Here is the Bill of Materials and Build Instructions for the aluminum frame in these pictures. Please note that there are many different sizes and designs that might work. This is just one approach. Also, please note that I am very new to Arducopters. I am no expert. I'm just sharing what I've learned about building this particular frame, which seems to work well so far. The overall size of this ArduCopter is based on the DIY Drones "beta" frame design. I should also note that my aluminum Arducopter is built using mostly U.S.-style dimensions, but I'm sure metric equivalents can be found as well.

The raw material for the central frame pieces is "Aluminum 3003-H14 Sheet, 0.032" Thick, 12" x 12"". You can buy this from Amazon for $9.51 or elsewhere. The thickness is critical for the right combination of stiffness and lightness. Don't use 0.064 or 0.016, which are respectively too heavy and too flimsy.

The undercarriage material is "Aluminum 3003-H15 Perforated Sheet, ASTM-B209-04, Staggered 3/16" Round Perfs, 1/4" Center Spacing, 0.032" Thick, 12" Width, 24" Length". You can buy this from Amazon for $12.95 or elsewhere.

The aluminum rods are #6-32 aluminum threaded rod. You can buy this from Amazon for $2.64 or elsewhere.

The main fastener used in this design are Zinc plated Steel Machine Screws, Pan Head, Phillips Drive, #4-40, 3/4" long. You can buy these from Amazon for $4.50 for 100. You also need a box of #4-40 nuts.

Also purchase (4) Aluminum standoffs, Male/Female, #6-32 thread, 1/4" hex, Length 1/2". You can buy these from Allied Electronics for $0.37 each or elsewhere.

Also purchase (4) Aluminum standoffs, Male/Female, #6-32 thread, 1/4" hex, Length 1-1/2". You can buy these from Allied Electronics for $0.80 or elsewhere.

The arms are 6063 Aluminum Square Tube 1/2" x 1/2" x .050" wall thickness x 8.5" length aluminum square tube, which you can purchase from www.onlinemetals.com for $5.98 each. (They will cut them to that length for you, or you can buy a longer piece and cut them yourself). Please note that these arms are quite stout and quite heavy, weighing in at 35.1 grams each.

When I became interested in quadrotors, the DIY Drones Beta Kit was already sold out, but I did manage to get a few of the arms. Those arms are 0.019 inches thick and weigh only 11.2 grams, which is excellent. These arms will probably become available again on the U.S. DIY Drones Store when they release the production Arducopter kit. However, due to my very poor RC flying skills (never flown one in my life), I crashed my Arducopter early on and crumpled a couple of my original thin-walled arms, which led me to construct my own replacements out of the only material I could find, tubes with substantially thicker walls. My Arducopter currently has two of the thick-walled arms and two of the thin-walled arms. Even though it is lopsided in terms of arm weight, it still flies very well, which is a testament to the excellent Arducopter software, which must power the motors to balance it out. It's not even noticeable. However, of course, given a choice, it would be better to have all your arms the same wall-thickness and weight. If you want lightness and ease-of-manufacture, and they are available, buy the DIY Drone Arducopter arms. They are excellent and have most of the holes you need pre-drilled. If you want stoutness, buy the tube from onlinemetals or elsewhere and make them yourself. Just be very aware of your wall thickness.

Now that you have all your parts, here are the build instructions:

Cut your 4 arm tubes to 8.5" each with a hack saw, 4" mini-table saw, or some other method. On the motor end, use a 7/32" drill bit to drill two holes all the way through (top and bottom of the tube)(A bench-sized drill press is extremely useful here, rather than a hand drill). The position of these holes should match your motor mount. You will also need to use a large drill bit to drill a hole directly between these two mounting holes. The backshaft of your motor will stick down through this hole and will need good clearance on either side so that it doesn't rub. On the underside of the tube, use a large drill bit and a Dremel tool with a carbide router bit, or some other method, to cut out a large area where you'll put your cables. It should be nearly the whole width of the tube and about an inch long to fit your cables nicely, although exact size is not important here. Also use the 7/32" drill bit to drill two holes at the other end of tube. These will be used to clamp the arm between the two center pieces. Make sure your holes are on center with the length of the tube and in a consistent position to match up with holes you'll drill into the center pieces.

Cut the aluminum sheet into two 4.25" squares for your center frame pieces. Make it as square you can get it. I've tried cutting aluminum of this thickness with snips, hacksaw, 4" mini-table saw, a dremel, and so on. Believe it or not, I found the cleanest and quickest approach is to cut it with a decent paper cutter. Aluminum sheers better than it cuts. This makes for a smooth, even, accurate edge, which is important for this design. Also cut out a large circle in the center of the square. I don't have a satisfactory way of doing this. I drilled a hole with a large drill bit and then used a nibbler tool and a Dremel tool to cut out the rest of circle. The circle doesn't have to be even or perfectly round because you won't see it, but the edges should be free of burrs and sharps. You will put a lot of wires through this large hole and you don't want them to get cut up.

Use a 7/32" drill bit to drill the hole pattern into each of the squares. There should be a pair of holes that match up with the hole pairs that you drilled into the arms. Only one of the holes of each pair is visible in my pictures because the other is covered up by the electronics. Make sure you make these as accurate as you can get them so that your holes line up and your arms are held square to the center frame. These holes align with the corners (points) rather than the sides of the square.

Also drill (4) slightly larger holes through which you'll put the threaded rod. These holes are placed midway along each side of the square. In the top center piece, also drill any holes you need to mount your electronics boards with nylon spacers. If you're going to use adhesive strip or some other method, you may be able to skip drilling these holes.

Now it's time to cut the perforated sheet. It's a 5 panel pattern. Think of it as a flattened cardboard box without a top. The approximate dimensions are as follows: There is a 4.25 square in the middle (the bottom). Each side of the square has a 4.25" x 1.25" panel attached to it, with a fold line in between. Dimensions are approximate because you need to think about the curve of your fold lines and the match up at the corners.

Cut (4) lengths of aluminum threaded rod to 4.5" each.

You you're ready to assemble:

If your using nylon standoffs to mount your boards, then put the nylon standoffs in place first, without the boards.

Bolt the center pieces together into a sandwich with the 1/2" standoffs in between (female end up, male end down). Thread the threaded rod and a nut above the top plate. Thread the 1-1/2" standoffs below the bottom plate (female up, male down). Repeat four times. The purpose of the threaded rod is so that when your unit flips, it protects the electronics and keeps the propellers off the ground so that they don't break as easily. It's a very basic design, but it's been very effective for me so far. You could also use steel threaded rod here, which is much stouter, but much heavier.

Mount the motors to the ends of your arms with the 3/4" machine screws and nuts. String your motor wires through the large hole on the underside of the tube toward the center of the quad. Of course, you'll need to solder on extender wire for it to reach. Leave yourself plenty of slack so that the wire can go down through the center hole and out the underside where you can grab it and insert the ESC wires. I soldered in gold bullet connectors for this purpose (and used heat shrink to cover the connectors). This allows you to swap in a new motor or ESC if one goes bad.

Now bolt the arm between the plates using two of the 3/4" machine screws and nuts. This is what holds your arms on. Repeat this procedure for each arm.

Now mount your electronics on the top piece. Fish your wires from your electronics down through your center hole, connect your ESCs, power distribution, etc., which should all hang underneath. Wrap it up with velcro so that it will fit in one half of your center piece square.

Now take the perforated pattern that you cut earlier and wrap it onto the underside of the lower center piece, mounting it on the male ends of the four 1-1/2" standoffs. Attach it to the standoffs with 4 nuts. The sides fold up vertically toward the lower center piece and stay in position on their own once they are folded upward.

Cut one of the sides in half to make yourself a battery access panel. You'll store your battery in one side of the undercarriage. The wires will be in a clump on the other side. In my quad, I have the battery charger and an arming switch plug sticking out where I can get to them easily in the field and/or on the workshop.

Please note that putting the battery into the undercarriage assumes you're using a 2200 mha battery, not something larger like a 4000, which won't fit in the compartment as shown. One other issue here is that if you flip the access panel up and down enough times, I suspect it will probably fatigue the metal and break off. At that point, I plan to use a simple velcro/adhesive hinge.

Comment by Bill Vickers on February 19, 2011 at 12:42pm

Are you still flying this?

Comment by Robert Beatty on February 19, 2011 at 12:52pm

Yes I am. It's been flying great. I've been using the ArduPiratesNG code. I installed a downward-facing Sonar and I've been using the altitude hold. It works well and I love it. It allows me to practice my yaw, roll, and pitch steering while not having to worry about crashing it into the ground. I've also installed a tiny EyeCam camera (made by DraganFlyer) for real-time video, which is kind of neat. I've also made other improvements as I go. Next I will be installing a GoPro so that I can record high-def video.

 

Comment by Bill Vickers on February 19, 2011 at 1:16pm

You have come a long way. Good to hear your still hanging in there. I have started flying fixed wing, will be adding fpv as I get more experience. I have been outta of R/C for years, but needed something to do since I've retired. I'm going to the desert next week and will be taking my plane, so hope to get in a lot of flying.

 

Thanks for keeping me updated.

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