Indoor fun with a tiny ArduCopter quadcopter

Do you have an Ardupilot Mega and shield and want some fun for little money? check this tiny quad... my last drone in family...

Some specs:
- Size : 26.5cm (10.4 inches) from motor to motor
- Motors : 18-11 200kv 10 gram motors
- Props : 4x2.5 (standard CCW props)
- ESCs : Turnigy 6A
- Battery : 3S610 (or 3S800)
- Sonar : Maxbotics LV-EZ0 [optional]

The nice part about this frame is that it use standard kite parts, so it´s very easy to construct and it´s perfect for some radical tests.
Itried to find a bit different design that also make the quad less simmetrical (it´s very easy to loss the orientation with a quad) and I wanted to do as small as posible to flight indoors...
At this size and weight it´s very safe and robust also. The props use prop savers and this help a lot in crashes...
I am not very good writing... so I took a lot of photos during the build phase and I created a build log:

This code supports a sonar for altitude hold and also has a battery alarm (2 alarms).
Thisquad works with ArduCopter code, but because how main board is mounted, actual code doesn´t work. This is the code that I used with this quad :
(as zip format: )
note that this will be integrated on main Arducopter code. Now is temporarily in a branch.
ThePID gains are different than in standard ArduCopter, so you need to Initialize EEPROM on Configurator or put this ones manually:
-Stable mode: P : 4.8 ; I : 0.12 ; P_rate (D in configurator) : 0.4 ; Yaw : (4.5 ,0.15 ,2.8 )
-Acrobatic mode : P : 0.75 ; I : 0.1 ; D : 0 ; Yaw : (2.4 ,0.2 ,0 )

OK, but was all so perfect like in the video? I don´t believe that...
Yes, you are right, but fortunately this design is very crash resistance... and this part is also fun...

After all this battles I only needed a few drops of ciano in the crash with the lamppost :-)

What´s the real size?

On center, standard arducopter frame, on left, old ArduIMU quadcopter part III, on right-top this project.

And what about the automatic aerobatics on video?
I am starting to test a new function to do automatic aerobatics (Automatic Aerobatic Procedure). The idea is that you enable this function with a switch in the Tx to make an automatic predefined aerobatic and then automatically recover to a stable mode.
Thisis actually a proof of concept but works very nice. One limit here is the maximun rate of the gyros, in our case 500deg/s. If we exceed this, the IMU get confused...
An interesting point to note is that the IMU doesn´t loose the orientation in this hard movements...
Thestory is that I have never feel too much confidence doing flips manually with quads. Then I start thinking that with an automatic code we can get a precise timing and controled movement so maybe this could help to do better aerobatics. I started testing this function outdoor, on an open field but I was improving the code and got more tightly maneuvers, so tight, that I ended up doing flips with a quad inside my room!!!

Here is the code I was testing : (AAP function:
AAP.txt )
I implemented this functionality as a state machine where there are three kind of states:
- fixed commands for a limited period of time. (example : Apply a throttle command)
- fixed commands until we reach some IMU state (example : roll until we reach a certain angle)
- And a mix between this categories and a control (example : Throttle command + stable mode on roll, pitch, yaw)
There are many things to test and improve here but the basic concept works very nice...

If I can get a bit of help from a friend, I will probably made a carbon fuselage for this prototype...

Enjoy this “Science & Fun” mix...

Jose Julio.
Arducopter Team
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  • Developer

    Ralph, you can download latest ArducopterNG code from ArduCopter official wiki pages at


    From there you can always find official releases.

  • Hi Jose Julio,

    This is a great design - thank you for sharing. After a month of waiting now all parts have arrived and I will try to assemble it over the holidays.One question though: There have been some software updates like "" - which software would you recommend to use at this point in time?

    Thank you



  • Mmm i´ve already used that 4mm T, just trying, but i haven´t cut the T . I´ve bought the 8mm kit to use with leftover pieces from 6mm kit to make a second a second/bigger frame, but some pieces from 8mm kit are different.


  • Oscar, you don´t need the 8mm kit. The piece you are talking about cames with the 4mm kit ant it is like  a "T". Jose Julio cut the "T" so actually it looks like a small and simple 4mm inner diameter tube .

  • One Question Jose Julio, what´s the central part you used? i ´ve bought on decathlon 3 kits (4,6 and 8mm), and i can´t find what´s the part you used. I´ve one that seems similar (flexible) but´s it´s a lit bigger than the tube.


    Una preguntita, cuál es la pieza central que has usado? me he comprado los 3 pack en decathlon (4,6 y 8mm) pero no puedo encontrar cual es la pieza exacta que has usado, hay una parecida( es como un tubo flexible) pero el diametro del agujero es un poco más grande que el tubo de 4.


    Bye & Salu2

  • One thing that is sort of not clear is how the motors are mounted. Does the bottom-shaft portion of the motor just sit on the hole in the rubber mount in a tight fit? (Picture 12 in the document)

  • Developer

    @Theodor, you are right, thanks

    @Michael, I have tested this platform with 5x3 props and even 6x3 (with 2S batt)

    I don´t know if there is an optimun ratio but my experience is that if you use too much prop spacing (big arms) quads are more slow in response (and a lot less responsive in yaw!!). Short arms make quads more responsive and probably more fun for RC, but if your clearance between props is too low this could decrease performance.

    With respect to payload I have flight with 40grams without problems... I tested a 100gram payload and could fly but is not recommended.

  • I'm going to try these ones in couple of weeks:

    MY12ABEC Mystery 12A Brushless Speed Controller * 4
    T1811-1800 Turnigy 1811 Brushless Indoor Motor 1800kv  * 4

    and 6x3 props.

    Only near suitable from HK, some Sainta rush there, messy shipping.


  • Awesome work! I've been planning to build a small quad, but kept getting hung up on what props to use and stuff like that. Thanks to you, I have all I need to move forward. I am planning on making a few changes in my design though. I'll have to post something when I get that built.

    I do have a question for you. I notice that your quads all have a fairly proportional prop-size/prop-spacing ratio. How important is that? Several of the quads I've built flew a much tighter configuration (one was 10" props with only 1" clearance between the blades.) most of mine are spaced out a little more than that. Is there some ideal there? I guess, asking the question another way, if you were to build the same tiny quad with larger props mounted closer together (so the outer dimensions of the craft stayed the same) how do you think that would affect flight performance?

    Oh yeah, one more thing, how much can your tiny quad payload? Thanks!! You're my hero!
  • This is so awesome! well done Jose..
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