Eachine Racer 250 - How Does Openpilot Compare to APM/Pixhawk

I saw a good deal on Banggood.com for a small ARF (Almost Ready to Fly) Quad called the Eachine Racer 250 and went ahead and purchased it.  It is a 250 sized unit with the FPV built in, includes a battery, and charger, and cost around $125.  I added a spare Orange DSMX receiver and a Spectrum DX4e transmitter and was up and running!  It sends video to my 5.8 GHz integrated receiver-monitor and works like a charm.  Build quality is good for the price, packaging was good, and it is designed well.  As usual, there are NO INSTRUCTIONS from the Chinese manufacturer in the box and you have to hunt around on the web to find out how to set it up.  I found a few good Youtube videos and they guided me through setup without a problem.

The only thing that was challenging was my lack of knowledge of the flight controller, the CC3D, an open source flight controller that is somewhat different from the APM or Pixhawk.  I again queried the web and found the ground controller for Openpilot, which supports CC3D hardware.  I downloaded the software, installed it, connected USB to the quad, and followed the instructions in the video.

The quad flew, but was very sensitive to control inputs, too much for my flying skill.  I again went to the web, found some tutorials, and tried to fix the settings.  The tutorials were out of date so I went to the wiki, which seems to be permanently down.  I then posted a question on RCgroups.com and got some information.

Unfortunately, there seems to be a schism in the Openpilot community and it has split into three factions: Taulabs, Librepilot, and Openpilot.  While Openpilot works, it does not seem to have as much support as it used to.  The other 2 options seem to be works in progress.  APM and Pixhawk/PX4 are definitely better options if you have a choice.

But I did figure out how to desensitize the quad using the current Openpilot and it flew well in a couple of outdoor test flights.  Stay tuned for more info.

New Quadcopter Build: SK450 Dead Cat

Now that we are back from Florida and parts have arrived, it is time to start the new build.  I salvaged whatever I could from the Flying Flowerpot (may it rest in peace).  Two motors, the four speed controls, battery, flight control, receiver, and camera were all salvageable.  However, I decided to replace some of these parts and to change the configuration of the quadcopter to "Dead Cat" - a non-square quad setup with more room for cameras.  See the picture below for the basic setup, not fully assembled.

The other changes that I plan to make are:

• New flight control system (Pixhawk) with more accurate GPS (LEA-6H).  I bought the genuine 3DR versions instead of the Chinese clones to ensure quality.  My old APM 2.6 system was a Chinese clone and had limitations and unknown quality.
• New receiver (Spektrum AR610).  This receiver is highly regarded compared to the Orange R615X, which has rumors of range issues.  New Spektrum DX6i transmitter.
• Use of a PCB as a frame to distribute battery power, bought from Hobbyking.
• Dead Cat configuration using a conversion kit from Hobbyking.  I made a mistake and assumed that all I needed was the previously mentioned SK450 Dead Cat PCB, but it turns out that you need this plus the Dead Cat conversion kit.
• Full monitoring of power by the control system.  This was included with the Pixhawk.
• A proper cover instead of a flower pot, sourced from Quadrysteria.com.
• Receiver power from the Pixhawk or separate UBEC, not from the ESC's.  This should be higher quality power with less interference.
• Use of loctite on all screws to reduce the chance of loosening with vibration.
• Carbon fiber props.

The new control and radio system are shown below.

Review: Hero RC Sky Matrix H1306

This small low cost toy-grade quadcopter is an ideal trainer due to its design, low cost, and resilience.

The Hero RC Sky Matrix H1306 is a small indoor unit available from Amazon and others for about $35 to $45 US.  This includes the copter, transmitter (mode 2), extra battery, USB charger, and extra props.  All you need to add are AA batteries for the transmitter.

Design

The unit incorporates an all around plastic and metal cage, ostensibly for rolling up and down walls.  You can certainly do that but the main advantage is that you can hit the floor, ceiling, or almost any other obstruction without damaging the quadcopter.  See my previous post for video of Matrix bashing into all manner of things with no damage.  Other than that, it is a pretty standard 4 channel quadcopter with 6 axis gyro stabilization.

Documentation is terrible - a google translation from Chinese with some made-up words thrown in.  Read it to get some basic ideas and a good laugh.

Flying

Relatively easy to fly, but very sensitive to throttle input, you will spend a lot of energy jockeying the throttle stick to maintain altitude.  The LEDs are bright inside and will help you with the orientation of the copter.  Flight time is about 5 mins on one battery and it takes about 1 to 2 hours to recharge.  The inevitable crashes do not seem to mar walls or ceilings, in case your wife or mother is wondering.

This can be flown outdoors if it is really calm, but be careful as it will be harder to control than in controlled indoor environment.

Accessories

There are no accessories and you cannot add any due to the small size of the unit.  There is no easy way to attach a camera and it would have to be really small and light, and you would see the plastic cage when using the camera anyway.

FREE Quadcopter Manual Editing

To all Chinese Quadcopter Manufacturers,

Your English manuals are awful.  It looks like they are a bad mix of Google Translate and Spellchecker, with some made-up words thrown in (see below).

I will happily edit your manual in English to make it understandable in return for a free sample of your product.  I will take the product sample and a draft of your manual and return a readable manual within 1 week in Word format for your use.  I am serious about this - I get free quadcopters, you get readable manuals which can help sell your products.

Think about it.