Ryan's Trex 800 AP

[Cirkus]

Originally Posted by R_Lefebvre

Wow, she's pretty big. You're staying with a flybar?

Yes, I fly FBL for 3D, flybar for precision hovering. Just my preference. It's difficult to explain, but I prefer the direct connection to the flybar over having software interpret my stick inputs and command the servos when it comes to hovering and small precision movements. I do prefer a V-bar for 3D though. It's weird, because you have to be two completely different pilot types.

[R_Lefebvre]

That's my feeling as well, and I know a few others. Seems that the flybar reacts faster than any gyro/servo system ever could.

[POWERFTK]

from Century Heli


A flybarless head with the DJI system is very stable. When flying in high winds in Manual mode and switching to ATT+GPS mode, it feels like the wind was suddenly turned off. However, when setting up the DJI system, a flybar head will be more tolerant to high wind than a flybarless head. This is due to the flybar acting as a mechanical gyro the entire time whereas an electronic system is trying to react to the helicopters movements caused by the wind. With this in mind the DJI system with a flybar will have the best of both worlds as you have mechanical stabilization and electronics with GPS holding.

[MattFL]

Originally Posted by R_Lefebvre

That's my feeling as well, and I know a few others. Seems that the flybar reacts faster than any gyro/servo system ever could.

This makes good sense. With FBL, the system cannot make corrections until a change has already occurred. So it is reacting to something that has already happened. With a flybar, physics makes the flybar want to stay in the same plane; the system does not have to wait for a change to react, the system naturally wants to stay.

[Cirkus]

I finished the electronics housing on the heli. One thing I did was to purchase a mico-to-mini USB adapter and ran it outside the box so I can program the DJI easier. Now the DJI and the Castle ESC can share the same cable. I also decided to use a Deans plug as a switch as I feel it is more failsafe than a mechanical switch and its easier than plugging and unplugging the battery. Also added a voltage display.

[Cirkus]

Gimbal electronics housing Version 3. Every time I think I'm done with it, either something new catches my eye or I get an idea that would be a better/cleaner installation. I'm thinking that this will be the final version.

A couple nice features in this version:

- Recessed switches, no accidental turning on or off.
- Charge jacks for each battery
- Picloc securely mounted
- All wiring hidden
- Voltage monitor for Picloc and Video Tx
- CNC files tweaked to cut perfect mounting holes with no gaps for flush install of components.

Version 1 (top)



Version 2



Version 3 (Current)









I'll try to get it mounted to the gimbal tomorrow and wire the servos up all nice and neat.



The heli got to get out in public at our Fun Fly today, even though it didn't fly. It drew lots of attention.

[MaSt0RaS]

it seems great.. N1..

Whats your total weight??

[Cirkus]

Originally Posted by MaSt0RaS

it seems great.. N1..

Whats your total weight??

Right now about 19-20 lbs ready to fly, but it's not quite actually ready to fly. I need to do minor things like solder battery connectors, and purchase a second Tx for the gimbal. All the annoying last minute items need to be done like double check all the screws for threadlock.

[Cirkus]

Looks like it will mount up just fine at the rear of the mount. I added a bubble level as well.










Off to tidy up some wiring...

[Twister773]

Beautiful heli Cirkus. Love the attention to detail and it is very refreshing to see someone willing to share there ideas with others. Keep up the great work, very impressed.

Tristan

[xfc3dcd]

Nice work. Due to the height and lateral rigidity of your landing gear, I am a little concerned you may suffer ground resonance. Hopefully not.

[Cirkus]

Originally Posted by xfc3dcd

Nice work. Due to the height and lateral rigidity of your landing gear, I am a little concerned you may suffer ground resonance. Hopefully not.

LOL, that will give me an excuse to build a Version 4 landing gear.

[xfc3dcd]

A few years ago I was hired by Northrop Grumman to troubleshoot a ground resonance problem with a very large UAV heli. Here is a brief summary of some things I learned:

- Blade lead-lag changes are the primary driving force. Once one side of the disc becomes the heavy spot, the forces can multiply with each revolution. If you were to lock both blades exactly 180 degees opposite, ground resonance would almost become an impossibility.
- Once the disc center of mass starts to wobble, the ground must feed back the forces generated back through the landing gear and frame. The stiffer these components are, the more reactive energy gets fed back into the system. Increasing the height of the helicopter also aggravates the issue.
- For any resonance condition, there are only two paths available to correct, either change the mass or damping or a combination of both.

For the large UAV, the final solution was to add elastomeric dampers between the lower frames and the landing gear along with making sure the blade grips were fairly tight and exactly evenly torqued.

Good luck!

[Cirkus]

Thanks, I'll be on the lookout for any funny business during the first few spool ups.

Test.

Evaluate.

Modify.

[cbergen]

Very nice work Cirkus.

[Cirkus]

Originally Posted by cbergen

Very nice work Cirkus.

Thanks Chris, it's getting there slowly but surely. Something about a day job that has a way of impeding progress.

[Azalin]

Unbelievable. I must say this is the most impressive build thread i ever see. Congratulations.

[Cirkus]

I made the decision about which camera is going on my gimbal. After weighing what I believe to be just about every pro and con of the current market in cameras, I have decided on the following combo: a NEX-5n with 16mm f2.8 prime and wide angle converter. I have seen the video from this setup as well as the stills and both are at the upper end of what I need. I was considering the GH2, T2i/T3i, D7000, and waiting for the NEX-7. For my needs, the NEX-5n had more of my check boxes ticked.

I wired and soldered the EC5 connectors and programed the ESC.

I filmed a great how-to video on soldering but forgot to switch from still to video mode on my GoPro, so I'll try that again later.

I finalized the electronics, and wired up the switches.

Going to try for a test hover before Sunday night.......crossing my fingers. Picture updates this weekend.

[floopy1]

Cirkus:

This help looks outstanding!

I am very interested in getting a CNC machine and cutting my own parts, too. I was wondering what CAD/CAM programs you use to design and G-code your ideas.

Also, can you tell me where you get your raw materials (i.e. your G10 sheets) and your hardware (boom clamps, threaded spacers, etc.)?

Thanks for any advice you can provide.

-Floop

[Cirkus]

Originally Posted by floopy1

Cirkus:

This help looks outstanding!

I am very interested in getting a CNC machine and cutting my own parts, too. I was wondering what CAD/CAM programs you use to design and G-code your ideas.

Also, can you tell me where you get your raw materials (i.e. your G10 sheets) and your hardware (boom clamps, threaded spacers, etc.)?

Thanks for any advice you can provide.

-Floop

Thanks.

Solidworks for CAD, Meshcam for CAM (hopefully upgrading this to SolidCam), Mach3 to run the Gcode

G10 from McMasterCarr, hardware too if I can't source it locally. Locally, I use Fastenal.