Using a DJI 450 FlameWheel Quadcopter with the APM

Hi, I previously set up a KKX525 with the APM2, but when one of my ESC's started fading, I thought I'd try something a little more upscale.

I have now put together a DJI 450F Flamewheel ARF including DJI motors, Opto ESCs and props from "RC-Drones" at a reasonable $180.00 and am quite happy with it at this point in it's evolution.

If you try this there are a few things you need to know, but no real problems.

Generally follow the downloadable instructions I have provided on the Arducopter Wiki for assembling and setting up and testing a quad copter and in addition see below.

1. If you get the ARF kit, it will come without instructions, but the manual can be downloaded from the DJI website under their FlameWheel support section. It is some help.

2. When you assemble the copter assemble the top board so that the narrow slots are in the front and the back and the wide slots are on each side.

3. Use blue or purple thread lock sparingly on all screws and try to keep it off the plastic. 

4. One of the nifty features of this quad is that the bottom board is also the power distribution board, heat the connection pads adequately to get a good wet bond with the ESC and Battery Wires.

5. You can cover the solder joints with liquid electrical tape or "Glyptol" if you can find it.

6. I tie wrapped each ESC under each arm with 2 tie-wraps front to back through the arm webbing.

7. You will need to add an external switching BEC, the DJI 30 amp Opto ESCs are great optically isolated ESC's but they do not include a built in BEC. I used a Castle 10 amp switcher for about $20.00 you can get cheaper ones from HobbyKing but you should use a switcher, they are much much more efficient. You do not need to cut or remove the ESCs power wire, it doesn't do anything.

8. You do not need to balance or tune the ESCs as shown on the Wiki (in fact you can't they are not programmable).

9. I recommend O-ring suspension mounting of the APM board between 4 standoffs secured at the ends of the long thin slots at the front and back of the top DJI board (assuming you put it in as I described in (2.) above.) Put a machine screw in the top of each standoff and suspend the APM board between them by putting a thin O-ring through each APM corner hole and passing the 2 loops over the top of the screw in each standoff. Size the O-rings so there is little or no APM board movement, they will still provide good vibration isolation. Too much free movement and they will cause handling lag. If you prefer you can mount a fiberglass or plastic board to the standoffs instead and Velcro or double side foam tape the APM board to it. I like the suspension method best though.

10. DJI supplies 2 sets of props, I recommend that for a 3 cell battery you use the longer 10" ones, Only DJI props will fit the self locking oval shaft of the motor unless you do what I did below. The shorter 8" props are for 4 cell use.

11. I didn't like the DJI props although they worked OK. They are light, flexible, noisy and would break easily. So I bored out some very nice GemFan 11" x 4.5 props that I was previously using on my KK to fit the outer diameter of the oval part of the motor shaft (about .31") and because of a thinner hub section I also had to add a washer under each prop. This is a very highly recommended modification, they are quieter, more efficient and will not break at the first unpleasant encounter. These are not the expensive carbon fiber Gemfans but the $2.50 carbon filled ones and they are still great, however looking at Innov8tive's web site I see they now have a 10" x 4.5 version of this prop already hubbed correctly for the DJI motors, buy these, they are a no brainer. My guess is if you use the stock ones you'll need new props soon anyway.

12. When starting the Flamewheel, it arms as per normal (throttle down and to the right) but if you do not spin the props within 10 seconds or so, the DJI Opto ESCs will shut down and you need to disarm (down and to the left) and then rearm again. Anytime you are on the ground longer than 10 seconds without turning the props you will need to rearm. This is not a big deal. You will quickly get used to it and given the capability of these things to shred flesh you will probably come to appreciate it as a worthwhile safety measure.

13. When you are setting up your board with only the USB connected, the ESCs beep continuously, ignore them.

14. When you turn your transmitter on and plug in the FlameWheel's battery, the ESCs should emit a short musical series and be quiet. You are then ready to arm and fly.

I have only covered substantial differences to the normal quadcopter setup procedure, but I highly recommend the Flamewheel 450, it flies quite well with standard PIDs but I will publish PID info later as I tweak it. (See Below).

Although the current stock PID's fly quite adequately, I have found the following changes decreased "twitchiness" and increased stability:

As of 12 / 8 / 2012

Reduce the Angular Rate PIDs P value from .175 stock to .145

Increase the Angular Rate PIDs I value from .010 stock to .030

Reduce the Stabilize PIDs P value from 4.5 stock to 4.0

The above will be revised as I continue to tweak.

Loiter will probably want some tweaking too and I will publish that after I have more extensive experience.

Roll and Pitch inputs are very sensitive so you need a light finger on the control sticks, but once you learn control with them I think you will be happy with them, If not you can probably detune them with the same PID's I am changing above.

I have a friend who has also successfully set up the Flamewheel F550 Hexacopter with larger motors and Graupner props following these procedures with such adaptations as are necessary with a Hex and he is using stock Hex PIDs.

Hope this helps, please feel free to ask questions I will respond as best I can.

Views: 12516

Tags: 450, 450F, APM, APM2, Construction, DJI, FlameWheel, Multicopter, Quad, Quadcopter, More…Setup

Comment by Michael Johnston on December 8, 2012 at 3:39pm

Hi Gary,

Great post - should be of assistance to many.

I've fitted my APM2 up onto a Shamewheel clone frame, but ended up mounting it onto some polycarbonate - as I couldn't get holes in the top plate to line up.  The build took place late at night though so probably should revist this in the light of your comments. It is a bit painful to replace broken arms now with the 'protective case' fitted. Will be watching for your PIDs although different powertrain will presumably mean that it won't be a perfect fit for me.

I'm running NTM 'Juz' motors http://www.hobbyking...32-882B16ECE279 that have performed well even when filled with red 'pindan' dust. and 8 inch Gaui props. Been tempted to look at bigger props but I have a heaps of these 8's to get through yet.

High heels from Iris Aerial.

Found these arms last night -  http://www.wildpilots.com/colorizedarms/

Might bling up my machine when the current supply of arms are broken (won't be long!).

I also noticed these Wild Pilots fellas suggested another handy tip to reduce leads being ripped from motors - see http://www.wildpilots.com/dji-arms-save-motors/

By happy accident I have always been mounting motors this way.

MJ

Comment by Peter Meister on December 8, 2012 at 4:49pm

Gary thanks for posting this, I am in the process of assembling the same one. I really appreciate it, my wife bought me the flame 450 arf for an early holiday present :) When your ready to post pids I look forward to trying them :) Cheers!

Comment by Gary McCray on December 8, 2012 at 6:09pm

Hi, Response to Michael and Peter above:

Michael, looks great. If your running 4 cell the 8" Gaui props are probably fine especially on your 1200 KV motors, but at 3 cell the 10" x 4.5 GemFans will work better and they are a LOT tougher. I haven't broken one yet. I have a friend with a Gaui and he has switched.

The current arms on the Flamewheel are incredibly tough, but if I need replacements I will definitely check out your source. I am not sure that the bullet connectors would ever pull out in time from the standard OPTO ESC's I have to use needle nose pliers to put them in or remove them they are so tight. But I thread them through the spot on the frame nearest the motor anyway and that is where they seem to break, so should be OK anyway.

I will probably get a set of the "High Heels" myself, even though I am planning on a FlameGear XP camera mount. I would like something higher than the stock Flamewheel for non camera use and I am planning on making the entire FlameGear landing gear / camera system easily removable with 3M Dual Lock (super Velcro).

Peter, I found the current stock PID's work very well for my setup although the control stick's are very much on the sensitive side and I have made a few initial adjustments that seem to help in Stabilize mode. I will publish them in the original BLOG. The FlameWheel flies very well with the APM2 and is very stable in a hover.


3D Robotics
Comment by Chris Anderson on December 9, 2012 at 2:55pm

Gary, can you please add pictures to your post?

Comment by Gary McCray on December 9, 2012 at 6:59pm

Done

Comment by Gary McCray on December 9, 2012 at 7:31pm

Installing SONAR now, I have already found that the Max SONAR board power supply filter recommended on the Arducopter Wiki is very worthwhile.

Other than that trying to locate it sufficiently away from ESC interference is proving tricky.

Previously on my KK X525 I put aluminum tape around the 2 most adjacent ESC's which solved the problem and I may do that again.

I will publish my final solution.

Comment by Marty LaBelle on December 9, 2012 at 9:32pm

Gary, I built this nearly identical to you but I find the throttle a little frustrating. In stabilize mode, there doesn't seem to be much room between climbing to fast, and falling like a stone. I'm still new and having trouble deciding what PID to manipulate.

I've considered manipulating the throttle curve on the TX, but that hardly is the point. I want to understand how to do it with the more powerful PID concept.


Developer
Comment by Randy on December 10, 2012 at 12:54am

I also use a copy of the firewheel for my testing.  The thing I really like about that frame is that it's very easy to put together and my copy at least is extremely cheap so I don't mind crashing it.

The problem is the arms are a bit flexible and as you say, the props are very flexible so perhaps not good for aerobatics but I don't do that anyway.

I see you'e extended the legs .. I really dislike how short the stock legs are.

Comment by Gary McCray on December 11, 2012 at 11:00am

Hi Marty, The throttle is quite sensitive, but I find that on mine at least with the PIDs I have listed it is very controllable with (subtle) stick inputs. I am using a 3 cell battery and the GemFan 11" props I mention in the text. A 4 cell battery generally is even faster in throttle response and needs smaller diameter props.

And Randy, the actual FlameWheel frame is still very inexpensive and generally has stiffer and stronger frame arms (really heavy duty plastic) than the clones. As for the props, I detest the stock props and strongly recommend the GemFan 10" ones that are expressly made for the FlameWheel motors (if that is what you are using) on a 3 cell battery anyway. I am using bored out 11" GemFans because I did not know about the special ones for the FlameWheel at the time, but these are fantastic low priced props; at least 5 times stiffer and stronger than the DJI props. The legs aren't on mine, but I am working on another design for an extended landing  gear (skid type) which will extend from the motor support ends of the frame arms. This works on the FlameWheel because the arms are so strong and do not permanently bend unlike other multicopters..

Comment by Isaac Sloan on December 19, 2012 at 11:13pm

Have you have you got the PIDs figured out for loiter, altitude hold, and auto pilot? I've gotten stabilize working well but I'm having a hard time holding altitude in stabilize... It seems like I'm either going up or down. When I put my throttle at 50% it gains altitude pretty fast. I've turned my throttle gains way down and it still does that. How would I balance it out so that 50% throttle is hover. On my naza it just didn't that automatically.

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