Blade 400 Flybarless Conversion with CopterX CX-3X1000 -- Success!

[Harbormaster]

The maiden flight of my flybarless conversion to a CopterX CX-3X1000 went flawlessly. A guy I know on another forum had told me that his CopterX conversion had been plug and play, and mine went the same way.

Here's a short, low quality, not-very-exciting video. (There is a piro at the 52 seconds--pretty agro for a maiden flight. )
http://vimeo.com/39996657

Bill of materials:

• CopterX Flybarless 3 Axis Gyro System (CX-3X1000) -- $40 from eHirobo.com
• CopterX USB programming cable (CX-PB002) -- $5 from eHirobo.com
• Tarot 450 FBL head (TL45110-01) -- $34 from CNChelicopter.com
• 2 Align T-Rex 450 swashplate balls (larger diameter balls for swash driver "porkchops" screw right in to the stock B400 swash) (AGNH45048)
• FBL Gyro programming software at http://fbl.net.nz/ -- Donation-based payment (Send the programmer who created this nice piece of software some love from PayPal!)
• (Optional) 2 Align 1.3mm x 32mm linkage rods (Align linkage rod "D") They were a better fit for me than the Tarot turnbuckles)
• Earlier mods (relevant but not required): Spektrum H3000 digital cyclic servos ($33 each), JR DS3500G digital tail servo ($75). Castle ICE 50 ESC, which has a BEC that feeds the cyclics a solid six volts, which helps. ($75)

Total cost of the flybarless conversion (not including the earlier servo and ESC upgrades): about $85 (including a $5 donation for the programmer in New Zealand. )

I don't want to oversell how easy this was--there is always a lot of fussing with a project like this--but overall it was pretty inexpensive and not as difficult as I had feared; with the exception of filing the main shaft a little (a two minute task) it was all readily available, bolt-on stuff. This was my fourth flybarless conversion project, and the experience gained on earlier projects definitely helped. (Props to master modder luvmyhelis for all of his ideas and info.)

In a nutshell, to make the conversion you:

• Mount the controller with the supplied foam tape (Mine is shifted a little to the starboard side so I can plug in the programming plug. You can see the shift in the photo.)
• Screw two new T-Rex 450 balls into the swash for the swash drivers to mate with (they need bigger balls than the stock B400 ones)
• Change the head (requires filing about 1 mm or less off the top of the stock B400 main shaft for it to fit in the new head. If you drilled out the head a tiny bit you wouldn't have to do any more filing at main shaft replacements.)
• "Set transmitter gyro tail gains to 28% and 71%" says the CopterX manual. Unlike setting up a VBar, in which these settings just flip between banks of settings, on the CopterX these really are tail gain settings, just like on any single-axis gyro. At 71% my B400 would occasionally break into a nasty oscillations. Reducing it 10% to 61% works, so I'm reducing the Rate 10% by setting it to 38% (since Rate min to max goes from 50 to 100--upside down).
• Plug CopterX into AR6100 radio: 1 empty (bind), 2 ESC, 3 Aileron, 4 Elevator, 5 Rudder, 6 Tail Gain, 7 Collective Pitch
• Plug servos into CopterX: Ch 1: Bottom, Ch 2: Top, Ch 3: Front, Ch 4: Tail
• Plug the USB dongle into the computer and the CopterX and do the setup with the software, which walks you through the process in a nice, fairly clear manner.
• Fly!

(The wiring in the photo is definitely just a test-flight lashup. I'll pretty it up later, but it flew fine even with servo wiring wrapped all over the place.)

[-kenny-]

Cool. I had a blade 400 once, wich i had traded for an mcpx. I would be curious to see how this flies as opposed to stock. Don't think the stock servo's are up for the job though, so that would add to the cost

[Harbormaster]

Originally Posted by -kenny-

Cool. I had a blade 400 once, wich i had traded for an mcpx. I would be curious to see how this flies as opposed to stock. Don't think the stock servo's are up for the job though, so that would add to the cost

The mCP X is a great little heli.

Replacing the stock servos is a given on a B400--the first thing most people do (or maybe I should say "did" now that the B400 is 2 models behind current production). Same goes for the gyro. This bird flew much better with the FBL unit than before on the very first flight. I had too many degrees of cyclic pitch on the maiden, so I've backed off on that. With a few more tweaks, it should be rockin'! (And I'm encouraged that the CX-3X1000, while simple to set up, has lots of adjustments you can make; in the Advanced menu you can actually get in and directly adjust the PID controller settings, which is powerful.)

[berserkk]

Great job! any other mods to the heli that would effect the conversion?
Eg esc, tail servo..
When are you going to flip it

[-kenny-]

I think at least all servo's need upgrading. They're not the best out there

[Harbormaster]

Originally Posted by berserkk

Great job! any other mods to the heli that would effect the conversion?
Eg esc, tail servo..
When are you going to flip it

Thanks! Lots of other people have done the conversion before me, of course, but I always had a hard time figuring out the specifics, so I thought I'd write them all down for the record...

The servo upgrades are listed in the original post. They're good ones.

The ESC is a Castle ICE 50. I love the logging and governor,but of course it's not really relevant to the conversion. Actually, it has a good 6V BEC, and running the servos at the full six volts with adequate current on peaks makes a big difference in performance, so I guess it does count.

I could have flipped it on the maiden but for the small space, basketball players, and asphalt. (I did some serious damage to another bird on test flight there once--pavement isn't the best substrate to fly over with unproven gear ). The bird was a little too responsive with too much cyclic and not enough expo, but it was very flyable--very precise and predictable, which is what I love about flybarless. I plan on some upside-down time and loopy stuff as soon as I can get it out to a bigger field. Looking forward to it!

[dbennettya]

Good Job!

Let us know what collective and cyclic pitch you end up running after doing some flips, rolls and loops.

Thanks, Don

[Harbormaster]

Originally Posted by dbennettya

Let us know what collective and cyclic pitch you end up running after doing some flips, rolls and loops.

I did test flight two this morning before work with eight degrees of cyclic pitch and twelve degrees of collective pitch. After tweaking the tail rotor neutral pitch and increasing the expo, the bird was flying fine (within the limits of flying it around a tree-lined basketball court).

Now that warts are gone, I can start the beautification program, gradually fine tuning everything until it's exactly how I want it. The CX-3X1000 is very configurable, with tons of adjustable settings if you like fussing with that kind of stuff (which I do ), but it's flying great with just the settings that were automatically applied by clicking the "F3C" button in the software. (It's actually more agile than I would have expected for that conservative-sounding setting.)

So far I am very impressed with the CopterX (but I haven't been able to push it very hard at the basketball court here in the neighborhood, and I'm no 3D flyer, so it may have shortcomings that I'll never be good enough to discover). It will be interesting to see how the bird flies at the big field next weekend.

[Harbormaster]

For test flight #3 this morning I turned the Castle ICE 50's governor back on at 2500 and 2700 RPM. Everything still worked fine. With high head speed and flybarless the B400 is both very nimble and very controllable; it's a big improvement over its earlier flybarred incarnation.

I'm going to reduce the collective pitch from 12 degrees back to 10. I just don't need that much pitch response, which makes her very "hoppy."

[CousinLarry]

Good stuff! I think I will go this route. Thanks for the peer pressure! haha

[jabu32]

just placed my order. hell ya.

[Harbormaster]

Test flight #4 this morning (10 stolen minutes while driving to work):

Just had to try flipping it this morning, which is a little scary flying over a small basketball court ringed by 100'-tall trees. No problem! She went over very cleanly, just like a FBL heli should.

The motor bogs when I give it the full 12 degrees of collective pitch, so I'm definitely going back to 10 degrees. [EDIT: When I went to reset the pitch last night, it was at *15 degrees,* not 12! No wonder the motor was bogging. Back to 10 for now.]

[cdrsteve]

Wow. Nice work. Thanks for the excellent write-up on your mod. Damn, adding yet another project to my list . Was wondering what to do with the old 400 - now I know.

[Harbormaster]

I finally got to the big field today for test flight #5. Below is the video of my first couple of (really badly executed) flips followed by a little inverted hovering, just to show that it can be done with this setup, I guess. Don't blame the hardware for the crappy flips--I was still getting used to this setup, and I'm no 3D wizard.

Here's my CopterX B400 in action this afternoon:
https://vimeo.com/40424727

This was with the default "F3C" settings in the Flybarless Gyro Configuration Software.

It was interesting flying my T-Rex 450 with VBar right after the Blade 400 with CopterX. Although the CopterX B400 flies fine, the VBar bird feels much more "locked in." From my time messing with the CopterControl board on the OpenPilot project (which uses all PID controller terminology so you get to know it--OpenPilot is an interesting project, by the way, but their heli implementation still has a long way to go), I think I know what I need to do, and that is to increase the "P gain" on the roll and pitch axes.

EDIT: I had left the "I" gain set at 80, not 120, which is the setting used when you click the "Hard 3D" button. With the I gain (which sets longer term stability) at just 66% of the level I thought it was as, no wonder it was a little more "wobbley"--that's what it was set for.

When P gain is too low, the bird feels kind of loose and sloppy (because the system can't give enough correction); when P gain is just right, the bird feels locked in; when P gain is too high, you start to get oscillations.

The "Advanced" section of the CopterX manual says that you can increase the P gain if you have fast servos, and I do, so I'll try increasing the gain 10 or 15% to see if that helps. (Actually, I'll keep increasing the P gain until I get oscillations, then back it off.)

The manual also says, "With fast cyclic servos integral gain ("I gain," the "I" in "PID") can be increased after the first flights in order to get more flight stability," so I think more I gain is definitely in my future. Looks like I'm going to be taking a laptop or the CX-PB001 programming box to the field next time. (It's not only a field programmer; it tests batteries and servos as well, which is pretty handy.)

"PID controllers" (which is what we're dealing with in flybarless controllers) can take a little time to figure out, but they can be understood intuitively without doing a lot of math, at least at the level we're operating at. The following OpenPilot video has a good discussion of them with lots of dynamic graphing and stuff. Just skip to the last third of the video. https://vimeo.com/25839978

It will probably be a couple of weeks until I get to play with this setup again, but I'll post what I learn about increasing the P and I gains as soon as I have anything.

[InFocus]

I've also done a lot of research on PID controllers as part of my copter-x FBL converstion.

I've played with the general gains, P, I, D gains, etc.. After a bit of tweaking, flying, tweaking, flying etc, I've found these settings work best for me:

https://www.helifreak.com/showthread...=375742&page=3 (see my post #29).

[Harbormaster]

Originally Posted by InFocus

I've also done a lot of research on PID controllers as part of my copter-x FBL converstion.

I've played with the general gains, P, I, D gains, etc.. After a bit of tweaking, flying, tweaking, flying etc, I've found these settings work best for me:

https://www.helifreak.com/showthread...=375742&page=3 (see my post #29).

Excellent! Thanks so much for posting that link! (The title is "Post Your Tarot ZYX Heli Setup Here," and the CopterX is the same board as the ZYX, so the settings should be completely compatible).

[tonyblademad]

Hi I have a cx 1000 and the blade 400 but can't get me srevo moving right how did you connect yours and what's your setting in your dx6i eg swash mix ect
Many thanks
Tony

[tonyblademad]

Hi I have a cx 1000 and the blade 400 but can't get me srevo moving right how did you connect yours and what's your setting in your dx6i eg swash mix ect
Many thanks
Tony

[Harbormaster]

Originally Posted by tonyblademad

Hi I have a cx 1000 and the blade 400 but can't get me srevo moving right how did you connect yours and what's your setting in your dx6i eg swash mix ect
Many thanks
Tony

Here's the info from post #1:
Plug CopterX into AR6100 radio: 1 empty (bind), 2 ESC, 3 Aileron, 4 Elevator, 5 Rudder, 6 Tail Gain, 7 Collective Pitch
Plug servos into CopterX: Ch 1: Bottom, Ch 2: Top, Ch 3: Front, Ch 4: Tail
The swash mix settings and that sort of info are all in the manual. (Basically, you disable everything in the TX to start except gyro gains.)

[InFocus]

Another description of PID settings, and how they relate to heli actions.

I actually found this to be more helpful, and its a bit shorter and easier to read as well.

http://rc.runryder.com/helicopter/t683512p1/