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3D Robotics

MAV wing differential

From BotJunkie:

"Part of the appeal of flapping wing micro air vehicles is that (unlike helicopters) they offer some resilience against crashing into obstacles. Crashing is still bad, though, and (with some exceptions) significant damage to things that fly generally keeps those things from continuing to be useful. To mitigate this, Harvard University has developed an itty bitty differential to keep a pair of wings (say, on arobot bee or robot fly) generating the same amount of torque, even if one of those wings is damaged. The beauty of the PARITy differential (Passive Aeromechanical Regulation of Imbalanced Torques) is that it’s completely mechanical, and simply due to its design it will (for example) increase the flapping speed of a damaged wing to match the torque output of a paired, undamaged wing. Basically, it’s the same kind of thing that you have controlling the power to the wheels in your car, except about a million times smaller."
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Another Quad

I'm starting to build my own quadcopter. I'm a newbie in UAV world so I'm trying to understand all the concepts behind with this project.

I started from scratch building my own IMU and all the control (I don't have a RC system yet).

Here are my specs for now:

Control Board:
  • Arduino Mega
  • 3 LY530AL gyros
  • 1 ADXL330 accelerometer
  • 1 XBee Pro module
Mechanical parts:
  • 4 AX 2308n 1100kv rotor
  • 4 Flying 20A ESC with BEC
  • 4 8x3.8 SF Regular props (well... I cannot found pusher props here so I will use the Jose Julio's idea to turn some degrees in front and rear rotors)
  • 3000mAh 3S mystery battery
I'm sure I have miscalculated something but for now, if it hover with some stability and control I'll be happy.

Nothing is working for now, but I did some tests with rotors and ESCs (breaking one rotor in the process).

Here are some pics of the frame and mounting:



All the photos are posted on my profile and as soon as I get the other photos with my brother I'll upload than.

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ArmQuad v. 016 outdoor




I am continuing the ArmQuad software development.
I believe that soon I will release for FREE a ACRO software version with current (or improved ) performance that can be seen in these 2 videos.

Un saluto agli Italiani presenti in questa community.



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3D Robotics

The HoverFly folks got in touch to tell me about their new quadcopter control board, the HoverFly Pro, which will be hitting the market in October for $360. It's got twin Parallax Propeller chips (that's also the chip used by AttoPilot), and has the standard quad controller features with the addition of built-in OSD. That seems like a pretty good price for a plug-and-play (closed source) system. It's not a full autopilot, since there's no navigation ability, but the site lists a forthcoming GPS version, so maybe that's coming (or maybe that's just for position hold--the closed source autopilots have serious regulatory restrictions, which normally limits their waypoint abilities, but we'll just have to wait and see in this case.)

From their site:

Feature List:

- Plug-N-Fly - just hookup to your quad and fly. No calibration software and no tweaking needed.

- All boards come fully assembled. The HoverflyPro is precision
manufactured. Sensors are the smallest on the market and the entire
board is assembled by pick-and-place robots.

- Features 2 Parallax Propeller MCUs that provide a total of 16 microprocessors running in parallel for the fastest data collection and
control of your Electronic Speed Controllers (ESCs).

- MCUs operate at 80Mhz for a total of over a GHz of processing power.

- Operates with Brushed or Brushless motors.

- Support for standard PWM Speed Controllers (I2C is not required).

- On-board voltage conversion switches automatically for 5.0V or 6.0V ESCs.

- UltraPWM technology means better stability. The PWM signal is compressed to achieve a faster update rate without using I2C ESCs.

- Scalable Control - Use any size motor or frame. HoverflyPro is capable of running very large motors.

- Not limited to tiny cameras. You pick the motors, battery and frame for the payload you want to carry.

- On-board voltage regulation. Input power range 6V-15V.

- Direct USB programming. No need to connect flight battery for
programming. Use the Windows update client and any mini-USB cable to
connect to the HoverflyPro. Programming clip no longer needed.

- Position holding gyros on all axes.

- FREE software upgrades. Windows update client notifies you of software updates. A simple USB connection provides quick and easy
software updates.

- You choose the configuration. Quad, Hex, or Octo. In Quad configuration you can pick "+" or "X" orientation.

- Altitude hold via barometer / accelerometer

- Auto leveling

- Automatic Pitch,Roll compensation for video and still cameras.

- Built in control for pan/tilt when in altitude hold mode

- Simple to use. Comprehensive instructions to ensure your success.

- Use any receiver and transmitter. HoverflyPro automatically senses and uses any PWM input.

- Basic and Aerobatic mode. Basic uses accelerometer to keep the quad level when the sticks are centered. It limits the maximum bank
angle achievable. Aerobatic allows the user to rely on the gyros only
for stable, but more extreme performance.



Detailed Specifications

- 2.75" x 2.75" (70mm x 70mm)

- Board height - < 0.5" (12.7mm)

- Programming power - USB or flight battery

- Flight battery - Input power range 6V-15V. Power connection is symmetric (no wrong way to connect power).

- 8x Receiver inputs

- 8x ESC outputs

- Camera Pan/Tilt outputs for camera mount stabilization

- 2x Future outputs (3-pin)

- On-Screen Display (OSD) input and output (3-pin).

- Buzzer

- RGB LED

- XYZ Digital Gyroscope

- XYZ Digital Accelerometer

- Pressure/Barometric Sensor

- Expansion Interface (12-pin)

- ESC voltage conversion output module

- Flight Battery voltage level sensor (for OSD and emergency modes)

- Programming switch (2-position). Base program and advanced feature programs required during update.

- Manual Gain adjustment (potentiometer)

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These camera's are $299, full widescreen HD, 2 hours of battery life. They come with a waterproof casing and are very resistant to shock. Combined with a 16Gb SD card, you can shoot about 4 hours of video. My brother works in LA and he just bought a few of these for a documentary he is going on oyster farming. He has some pretty impressive vids of dredging for the oyster bags under water. I think this would be a perfect addition to arduCopter.
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QuadRotor Project

3689369260?profile=original

I have started my quadrotor project.

Im using the mikrokopter frame with some additional center plates and a few modifications.
E-flite motors, with E-flite ESC. An arduino MEGA board. A Vectornav VN-100 which includes magnetometers, accelerometers, gyros, and an onboard kalman filter. Xbee PRO modules. Laptop with Labview.

Right now Im testing and tunning my own PID controller. Here are some pics of my quad and a small clip showing the actual behaviour of the controller, which I have to improve.




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3D Robotics

Arduino 19 Out Now

You can download it here.

Mostly minor changes, although APM folks who use the Serial Monitor will appreciate the increased control there.

  • SPI library.
  • The Ethernet library has been refactored to use the new SPI library. Existing sketches will need: #include <SPI.h> added to the top of their code. Just select SPI from the Sketch > Import Library menu.
  • String class
  • A0, A1, etc. aliases for the analog input pins
  • shiftIn() function
  • Added Arduino Pro 5V and Arduino Fio to the boards menu
  • Added control over automatic scrolling and outgoing line endings in the serial monitor
Full release notes are here.
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3D Robotics

T3-Round 8 Deadline Extended to Monday

Well, I did it again: scheduled the T3 contest to end on a 3-day weekend in the US and forgot about the holiday. This is Labor Day in the US, and most people have Monday off, so I'm extending the deadline by 24 hours to 12:00 midnight PST on Monday.


BTW, we now have two successful entries. Brakar's very creative double-egg drop mechanism is above. They didn't break!


Get out there and drop some eggs! As always, entries in the comments here.


And remember the egg-drop command is now in the stock ArduPilot code. Couldn't be easier...just uncomment this routine in the Events tab and assign a waypoint to your target location:


{

/*

float temp = (float)(current_loc.alt - home.alt) * .01;

egg_dist = sqrt(temp / 4.903) * (float)ground_speed *.01;


if(wp_index == 3){

wp_radius = 10;

if(wp_distance < egg_dist){

servo_out[CH_RUDDER] = PAYLOAD_OPEN;

}

}else{

wp_radius = 20;

servo_out[CH_RUDDER] = PAYLOAD_CLOSED;

}

*/

}

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1 YEAR AGO

was our trip to NASA.



The thing that disappointed us was how banal the aircraft were. Our focus was always making the hopelessly unstable stable through software & here our government was flying tried & true, statically stable gliders, pushers, & R-maxes. It was hardly the crazy stunt that Ares-1 was.



Sadly, we were depressed about the Air Force. Last year seemed to be a dead cat bounce driven by hope, but the most basic thing never happened with the Air Force & now we're winding down again.

We're not completely dead yet, but we conceded flying UAV's on the golf course is never going to be the happy escape that it was. That was really our #1 weapon against the reality of getting old, forsaking love & all the other stuff in the pursuit of feminism. There was but 1 way our hobby could fail & it failed as hard as it could. Thought it would come back for a year but it wasn't possible.

Nothing we did that year in place of flying actually comes across as enjoyable, just because it was a year in which progress came & went.

Indeed, the most trouble we ever got into was trying to forsake love by spending all our time flying UAV's on a golf course.


HELIX ANTENNA CONTINUES



Open drain hack to get the uBlox to work. It needs configuration commands every time it starts.





Ublox strapped in. Haven't seen any difference between this & the patch antenna on the bench.





Rebuilt yet again.



1 day later. PID calibration required for manual attitude control. The human takes it to levels the autopilot never did. This time, we're shooting to make attitude control permanent.



NOW WE HAVE CAMERA #4.



1080p finally got cheap enough to upgrade from the $100 Canon A's we were crashing to a $190 Sanyo, our very 1st 1080p camera.

The fixed lens & electronic image stabilization shouldn't break in a crash like the telescoping lenses & mechanical image stabilization did. Unfortunately this camera has a rolling shutter. Still photos suck. It gives up a lot of the picture fidelity of the $100 cameras in the name of HD video. Video is recorded at 13Mbps which is not enough for water.

The stock battery dies after only 40 minutes. Buy several aftermarket batteries.



Wasted no time in building a battery eliminator, but this circuit ended up heavier than a stock battery.

Continuous shooting mode requires reducing the compression quality, but haven't noticed any difference between compression qualities.

The battery charger blew up immediately due to a stray solder ball. Be sure to open it up if it rattles. Fortunately, managed to salvage it.

Now some ground footage in case you're in the market.












Looks like Dean successfully blocked Hobbyking from selling clones of its connectors. Ended up using those for all our gadgets & now the price is back to income tax levels.

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SMi’s Unmanned Aircraft Systems 2010 will explore a complete overview of UAS in military, commercial and civilian sectors. Attend and enjoy this unique networking opportunity with key industry leaders and decision makers from the field of UAS. Assess the latest national strategies and industry technology and ensure your organization is strategically placed to benefit from the dynamic growth sector in the global aviation industry.


17th to 18th November 2010, Millennium Gloucester Hotel, London, United Kingdom.







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Aileron modification

3689367790?profile=originalFitting ailerons is not exactly new to the EasyStar so here is my rendition.
Using 1" masking tape I laid out a strip across the entire straight part of the wing









3689367902?profile=originalMarked 10cm from edge of surface (the first part that can be seen when assembled not the hidden section).
Marked 40cm from that mark along.
Cut along both marks
Cut along the side of the masking tape.









3689367826?profile=originalMeasured 5mm back from cut edge (depth of wing in cut)
Cut a diagonal section from the wing (to allow aileron movement)









Using masking tape to template the servo and its throw area (about 1cm longer than just the servo).
Used masking tape to make straight line from box section cut out.
Stuck servo template below masking tape line.
Using scapel I cut out the servo hole and a groove along the masking tape line.








The servo has two tabs so with the servo partially in I marked the foam and cut out little sections for the tabs. It goes in really snug now.









.
To hide the wire I cut a 5mm groove along the box section insert.
With the servo extension cable attached I positioned the connector part on the box section insert and pushed to mark it.
I then cut out that area with a scapel
Cut another groove where the wing meets the chassis for the cable to exit (and attach to the chassis







All closed up and pushed together.
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Wing magnets

Having heard the EasyStar puzzle fit wings come loose (but not fall out or anything wierd) being the cause for magnet help I figured getting it done now would be easier. The same technique for the chassis was used to fit the magnets in each wing.
10mm drill bit pushed into foam
Scapel cut along marked line
Poke out foam inside line
CA glue magnet in place
NOTE.. CA glue is fast drying so make sure you get your magnets the right way round before glueing otherwise you will be stuffed.


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Here is documentation that I made for the ArduCopter Beta Frame as well as thoughts and a short flight test video. All of the pictures can be clicked on for full-resolution and the videos are in 1080p.




Assembly:


Open Bag #1 and take out 1 of the Main Frame boards. You'll also need 4 of the M3 x 25mm Male-Female Nylon Spacers and 4 of the M3 x 6mm Nylon screws that are in Bag #9. The main frame is supposed to
support both '+' and 'X' configurations. Take each of the spacers and put them over the hole closest to the
center of the three holes near the outside edge of the Main Frame board with the female side down. Secure each one with a screw from the bottom of the board. The spacers should NOT be installed over where the aluminum arms will be which depends on if you have a '+' or 'X' configuration. Now, take 4 - M3 x 20mm steel screws out of Bag #9 and place them through the innermost hole. These will end up going through your aluminum arms, so place them accordingly. In anticipation of installing the Power Distribution Board and to make it easier for ourselves when we do, it is best to install the spacers right now. Open Bag #3 and take out the 4 - M3 x 12mm Male-Female Nylon spacers and the 4 - M3 Nylon Nuts. Place the spacers through the innermost holes with the female side up that are not being used by the steel screws. These spacers should line up with the longer spacers already installed. Secure them from the bottom side of the board with a nut.







Now, remove the second Main Frame board and line it up with the first one. These two boards will sandwich the aluminum arms. Take out the 8 - M3 x 20mm Nylon Screws and 8 - M3 Nylon Nuts from Bag #9. Two of the nylon screws will be on either side of an aluminum arm and the steel screw will pass through the arm. Place the nylon screws through both Main Frame boards in the outermost holes of where your arms will be. Place a nut just barely on the other end; we will tighten it later.







Now, choose the size of aluminum arm you want to use. If you look at it, you should an elongated hole on both ends. Find the side where the hole is furthest from the end of the arm. This is the side that should face up and the end that your motor will mount to. The motor mount parts are located in Bag #7 and #8. The upper part of the motor mount is the larger piece. Take a M3 x 25mm Steel screw and place a steel washer followed by a nylon washer on it. Push it through the lower motor mount, the aluminum arm, and the upper motor mount. Take your 16/19 mm spacing motor and line it up with the holes on the end of the upper motor mount and the steel screw you just put it. Tighten the steel screw and use the mounting screws that came with your motor for the remaining three holes. Find 2 - M3 x 25mm plastic screws and nuts and place them through the remaining holes of the motor mount. These should press the motor mount pieces tightly to the aluminum arm and brace both sides of the arm. Do this for all four of the arms.






Slide each aluminum arm between the nylon screws of the Main Frame boards and pass the steel screw through them. Secure the steel screws on the bottom with the 4 - M3 x 10mm Female-Female Nylon Spacers found in Bag #4 and tighten the nylon screws so that the Main Frame boards are snug with the aluminum arms.





Take out the Battery Mounting Plate and the 4 - M3 x 6mm Nylon Screws from Bag #4 along with the velcro battery strap from Bag #9. Thread the velcro strap through the batter mounting plate ensuring that you have the correct side of the strap so that it will stick to itself. Make sure the recessed screw holes are also on that side.






Line the screw holes up with the nylon spacers on the bottom of the Main Frame board taking note of which direction you'll want the battery to be. In my 'X' configuration, I want the length of the battery to be facing straight forward and aft. Secure it with the 4 nylon screws.






Now, look at the Power Distribution PCB found in Bag #3. I didn't bother with using the PCB to route the signal cables of the ESCs because my cables are long enough to reach the APM directly. Notice there are 3 distinct trace areas on the PCB. The largest one in the middle is the positive and the two others are negative. Since the negative areas are not connected, we will bridge them together in two places with the 18 AWG cable included in Bag #3. Pass those through the bottom side of the PCB. The positive and negative cables from each ESC and from the battery need to be soldered on. Also place an additional solder layer of about 0.8 mm thickness on the traces. In my case, since this is a prototype, I want to be able to easily swap out parts like motors and ESCs. So, instead of soldering my ESCs directly to the PCB, I have EC3 connectors soldered on and I am not mounting the cabling inside of the arms.




Place the PCB into the 12mm nylon spacers and secure it with 4 - M3 x 6mm Nylon Screws from Bag #3.





Now, take out a carrier board from Bag #1. I used some nylon screws from the extra parts bag to mount my ArduPilot Mega board. Normally, you should mount the board so that the edges are parallel with the side of the carrier board, but mine is mounted at a 45 degree angle. I'll explain later in my thoughts section. Keep in mind when attaching your board that the edge opposite the right-angle headers must be the front of the Arducopter.





Place the IMU shield on top of the APM.



Take the second carrier board and attach the magnetometer (if you have one) as well as the receiver from your transmitter. If you take a look at the magnetometer, there are two arrows labeled 'x' and 'y'. The coordinate frame for aircraft designates the x-axis out the nose and the y-axis out the right wing. So, in the Arducopter, the x-axis should be pointing to the front and the y-axis to the right.



A velcro sticker is supplied in Bag #9 for mounting the receiver, but you may not be able to use it. I later found out the velcro adds too much thickness to the point where the protective dome doesn't fit, so I have mine secured instead with zip ties.


Place the carrier board that has the APM and IMU on top of the 25 mm Nylon spacers already on your frame. Take the other 4 - M3 x 25mm Male-Female Nylon spacers out of Bag #9 and screw them on top of those. Place the second carrier board with your magnetometer and receiver on top of those spacers and secure with a M3 nylon nut.





All of the parts for the protective dome and landing gear are in bags #5 and #6. The upper and lower dome center have elongated slots in them that the protective dome arches slide into. Secure with 2 - M3 x 20mm
Plastic screws and two M3 plastic nuts. The top carrier plate will have more room if you hold the dome centers with the nuts being placed on top and the screw head on the bottom. Two extra nuts are included for both sides of the dome center, but I don't think they are necessary as the dome arches are supporting it.





If you look at the end of the arches, notice that there is material removed from one side of it between the 3 screw holes. This is the side that is against the aluminum arm.



The Landing Gear Fins also have material removed on one side and they attach with 3 - M3 x 20mm Plastic Screws and Nuts. Keep the nuts loose until all of the landing fins are on so that you can center the entire Protective Dome on the Arducopter. Once it is centered, tighten the nuts. (Some people may find it
easier to attach the Protective Dome Arches and Landing Fins to the aluminum arms and then snap the Dome Centers in place)





The GPS is placed in the top dome and is secured with a zip tie.












Thoughts:


When I initially received the box containing the ArduCopter Beta Frame via EMS Express from Jani, I was surprised how small it was. Upon opening it, everything was neatly packed. There was an 8 1/2" by 11" piece of paper with a parts list and letter on it along with individual bags containing parts and two sets of aluminum arms (21.5 cm or 28 cm) wrapped in padded foam. I set about putting it together even though there were no instructions available. It definitely helped that the bags were grouped together into ones such as 'Battery Mount'. That way, I at least knew which sizes of screws and spacers belonged to each component. Like my Power Distribution PCB video, I filmed myself putting it together; although it wasn't always correct or in the optimal order as I would discover later. I might post that video later.


I'm using 12 x 3.8 APC props and decided to go with the longer of the two sets of included arms at 28 cm. All of the holes were drilled precisely and I didn't have any problems with alignment. However, I had a fair number of quality problems with the plastic nuts. I don't know if it was because the threads were crooked or what, but quite a few of the nuts wouldn't go onto the screws farther than the initial bit. Flipping around the nut didn't help. Thankfully, Jani included a 'Beta Spares' packet that provided enough spares to cover the ones that didn't work.


One of the problems I had was with Bag #8. As you can see in the diagram below, the parts list didn't match the parts I received and the parts received weren't all the parts I needed to mount the motors. The innermost screw on each motor is a steel screw that goes through both motor mounts, the aluminum arm, and into the motor. Only one of these screws was included for the entire frame. None were included in the Beta Spares bag, so I went and bought some at a local hardware store. The motor mounts themselves are a fantastic design. I love not having to use the 'plus' motor mounts and the spot for an LED to slide into is a nice touch. I thought there was supposed to be a cover for the LEDs that keep them pressed in their slot. If there is, some longer plastic screws will be needed to pass through the extra thickness.



Another problem I had was with '+' versus 'X' configuration. It is supposed to allow for both, but I don't see how to mount the carrier boards for the 'X' configuration and maintain the same structural support and ease of mounting the APM+IMU. Ideally, an edge of the carrier boards faces the direction of flight so that there are no spacers in the way of mounting the APM+IMU and so there is nothing blocking the I/O ports of the APM. With the '+' configuration, it works, but with the 'X', you're either faced with mounting the point of the carrier board
facing the direction of flight like I've done on mine, or mount it the other way. The problem with the other way is that the Aluminum arms are there. I could increase the distance between the main carrier boards to allow a screw head to fit between the top carrier board and the aluminum arm, but then it doesn't benefit structurally
from having the main frame board being pressed against both sides of the aluminum arm. Another option would be to drill an extra hole all the way through the aluminum arm. With the corner facing my direction of flight, I have everything mounted, but it is not perfect and some of the I/O ports are blocked. Another thing is accessing the APM+IMU. It is difficult to access things like SW1 for data logging.


A velcro sticker was included for mounting the receiver (I have the one that comes with the Turnigy 9x) to the top carrier board, but the velcro added too much thickness so that the receiver couldn't fit underneath the dome center. I just used cable ties because they didn't add as much thickness although they are still pressing
against the dome center. The dome arches were a little hard to snap into the dome
centers. Maybe increasing the notch that faces upwards would provide a better lock. There really isn't a reason the top one has to be flush with the upper dome center. The bottom one is nice being flush so that it doesn't restrict mounting on the top carrier board. I would definitely like to see some longer landing fins and maybe an optional protective dome that protects all of the electronics instead of just protective arches. With my 4900 mAH battery, there is only about an inch of ground clearance for the battery. Combine that margin with a soft lawn and the small surface area of the landing fins, the fins slip into the ground and the battery may take a hit on the landing. So, I'd like to see options for longer landing fins and some to permit a camera to be mounted beneath the frame. I imaged the battery mount is perfect for about a 2200 mAH battery, but my 4900 mAH might be about the limit of what it can
mount.


Could traces be added on the bottom side of the Power Distribution PCB to connect the negative sides? That way, two of the wires wouldn't be needed to jumper them. My view of this frame is to be bundled together with the electronics, motors, etc, to make a complete kit and make it easy for people to know what to buy and put together. Every little bit of wire and soldering that can be avoided would make it easier for people. I didn't even solder the connectors for the signals of the ESCs because my cables are long enough to reach the APM. Is there a benefit to routing them to the PCB and then adding an extra cable to the APM? It just seems like more complications and wire to me. Also, could some holes be added for the (+) and (-) of the ESC to connect to instead of just mounting them flat across the top trace?


A foldable frame would make it easy for transportation. I think this was designed for it and I see how removing one of the nylon screws bracing an aluminum arm on the Main Frame would allow for the arm to pivot around the steel screw, but wouldn't the Protective Dome also have to be removed to make it fold? Maybe we can find a way that would make it a quick process, but still be structurally sound in flight.


I just mounted my ESCs on the outside of the arms since this is a prototype anyways. I have Turnigy Plush 30A and I would need an extension to be able to mount the ESC on the main frame and get the cables through the arms because the cables on the ESCs aren't long enough.




These thoughts were all intended as constructive criticism. I am impressed by the design, weight, and especially the motor mounts. Great job on the frame Jani! I'd like to continue working with you guys to improve ArduCopter!


My whole flying setup weighs 2.85 lb = 1.293 kg. This is with Turnigy 2217 motors, Turnigy Plush 30A ESCs, and a 4900 mAH LiPo Battery






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