The MiniQuad

There are something very special about multirotor platforms. I can’t really put my finger on it but maybe it has something to do with how good they fly or how little noise they make. Anyhow I decided to build a small Quad just for the fun of it.

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This is what I’m going to use for the frame. 3mm square carbon tubes and a unpopulated KK board I had laying around. The motors I’m planning on using are the 1404N 2290Kv 9.2g motors from Hobbyking. The prop in the picture is a 4*2.5” prop which says something about the scale.

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Time to make some motor-mounts. I used the edges of the KK board, which is 0.8mm glass fiber.

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I had to drill a hole in the center for the motor axel.

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Glued straight on the arms.

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Glued the arms together.

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Glued the arms to the blank KK board.

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The size of the frame ended up to be 22cm motor to motor and 31.5cm across.

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Since the carbon arms were hollow I though it a shame not to use it to my advantage.

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Internal wiring look so much nicer. I used coated copper wire I had laying around from rewinding motors.

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Scrape the coating from the ends and solder the motor. Easy as pie

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After some testing I noticed that the 1404N 2290Kv 9.2g motors did not work well at all. Something had to be off on them because they did not spin true. Not a single one of the four so I decided to ditch them and get some HexTronic 5g 2000kV motors instead. They much better and run perfectly smooth. Much better mounting plate as well.

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Soldered on.

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Heatshrink on.

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Glued in place. I decided to go with glue as it saves weight and break away in a crash.

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All four motors in place.

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I used Turnigy Plush 6A ESC’s

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Speedcontroller soldered and mounted using double sided foam tape.

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Looks pretty neat so far.

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We need a receiver on there as well but I can’t stand having something so bulky and heavy on this little thing so… Receiver! Activate!

mq20
Removed the pins and other unnecessary stuff.

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The stock “boda” antenna was way to big an bulky so I made a simple whip instead. I’m not planning on flying that far with this little thing either way.

mq22
Soldered the signal wires straight board to board. The Optima receivers have a really neat function and that is built in voltage telemetry. That way I always know when it’s time to land without having to have anything extra on the model. Love it!

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Started soldering the battery connector and power distribution to the ESCs

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Done!

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Just needs some foam for the board and it’s ready to fly.

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Ready!

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It’s pretty small

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Needed a lot of tape on the 4*2.5 props to make them balance properly

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It flies!

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Outside in the cold

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It flies outside as well.

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Size comparison to some regular sized moose droppings, which is a standard unit here in Sweden, like a dollar coin in the US.

Here is the video!

I’m quite happy with the way it flies. It’s soooo cute! It so stable as well. I expected it to be very jittery, wobbly and all over the place but it feels so locked in. Love it!

After flying the MiniQuad for a while I decided to increase the prop size. But then I ran into some trouble, the carbon tubes twisted under heavy load. To fix this and also make it more impact resistant I added a carbon square frame.
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A little bit of extra carbon made all the difference.

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The frame is now super stiff and the MiniQuad flies even better in fast forward now.

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As a battery I used an old 2s800mAh 15C liPo I had laying around. Flight time is about 15 minutes.

mq43
Simply cut the corners at 45° angles and glued them to the motor mounts.

Specifications:
Motors: HexTronic 5g 2000kV
ESC’s: Turnigy Plush 6A
Battery: 2s800mAh 15C
Props: First 4*2.5 GWS then 5*3 GWS
Arm length: Motor to center 16cm (Radius). Motor to motor 22cm
All up weight: 89 grams without battery, with extra carbon rectangle.

7 thoughts on “The MiniQuad

  1. Great job, once again David!

    The 6A ESC will work fine with a 2A motor. 6 amps is just the maximum recommended working current for the ESC. I purchased the Hobby King 2S, 6A UBEC (P/N: 261000001) and flashed it with SimonK BS V2012-09-30 firmware and the motor seems quieter + smoother running = happier with that than the OEM firmware. Have yet to build my quad though.

  2. Seeing that the motor can generate about 70 grams of force with a 5×3 prop and a 2S pack, maximum lift force would be about 280 grams. Subtract the weight of the quad ready to fly form that…

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