Aeronavics / Droidworx Building a CX Titanium

dazzab

Member
After my sad maiden flight with a SkyJib Lite X4 coax Ti using APM 2.5 and Arducopter I decided to distract myself by building a CX. I wanted something small enough to travel overseas with and this may be perfect for that.

I have just finished the basic build and will be mounting the motors today. I am _very_ impressed with it. Quite a solid craft and very light. DW claim it will lift my Crane3 and a Sony NEX but we will see. I do have larger Tiger MN3510-25 motors for it and believe it or not 14" FC props!. It's going to be a mean little thing.

I'll post some photos later today.

Build photos now on my Flickr account.
 
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dazzab

Member
what esc did you use on your copter ? and 13" props carbon from tiger ?
thx marcell
I used 30amp Plush from Hobby King. Droidworx support suggested 13" or 14" props and I told them to send what was best for the intended payload. I ended up with Tiger 14".
I did a maiden yesterday and couldn't get it to fly. Thanks to Blurex, who was there with his incredibly stable DW X4 coax, we figured out that I hadn't balanced the ESCs correctly and that a 3S battery just wasn't going to cut it for these motors. So I've balanced the ESCs and I'm heading out for another test today with a 5S battery. Stay tuned, same bat channel, same bat time...
 

dazzab

Member
Quick update -
I discovered what many here probably already knew, the ESCs I used aren't rated for 5S batteries. I checked with DW staff and they recommended that I use 5S batteries so it looks like it's back to the work bench for me. Doh! This little units PDB is a real pain to solder up given the arrangement and tight space.
 

dazzab

Member
With new ESCs on board for the 5S batteries off I went for another maiden flight. It went well, but with no payload and those large motors with 14 inch props it was one mean little quad. I did a bit of tuning and it seems to be flying well. I even flew in Alt-Hold and Loiter modes which with the APM is a sure sign that it's working well. I tipped it over on landing which broke one of my sexy T-Motor FC props so after changing that I went for another test flight. I took it up to about 30 meters so I would have some room to recover from any problems, switched it to Loiter mode and the motors switched off. Of course gravity won and smashed the hell out of it. Two broken booms and broken landing gear.

I have no idea what happened. I've been flying the APM for about 9 months now and have a lot of experience with it. I could probably figure it out with some log analysis but I haven't had time for that yet. So now both DW copters are grounded waiting for parts. It's a real shame as I really like this copter. I can see it as becoming my all time favourite really. Small enough to travel around with yet very capable.

I won't be able to get back to this for at least a month now so no telling what will happen with it in the future.
 

SMP

Member
That sucks... Listen mate, DJI is the devil but I'm running two nazas and two wookongs without half the problems... Give in to the darkside till it gets a bit more dialed??
 

Droider

Drone Enthusiast
After starting on Gaui and then MK for the best part of 18 months when I moved VERY reluctantly to DJI it was because of the necessity to have a FC that worked without 12c errors that would just happen for no reason and the necessity to turn up in front of the client and get the job done. Yes there are reported issues but for me its a system that works and works with the minimum of effort. I will probably regret saying this but so far its been bomb proof. ALL 10 CAA approved craft we have are DJI flight controllers, Guess thats my case for DJI. There will be others but they will have a mountain to climb to convince me to move. Right now I can rock up, check out, preflight, fly, post flight go home. When you are doing the miles we are to push this concept thats is worth its weight in gold. AND we still have hair!

Dave
 

dazzab

Member
After starting on Gaui and then MK for the best part of 18 months when I moved VERY reluctantly to DJI it was because of the necessity to have a FC that worked without 12c errors that would just happen for no reason and the necessity to turn up in front of the client and get the job done. Yes there are reported issues but for me its a system that works and works with the minimum of effort. I will probably regret saying this but so far its been bomb proof. ALL 10 CAA approved craft we have are DJI flight controllers, Guess thats my case for DJI. There will be others but they will have a mountain to climb to convince me to move. Right now I can rock up, check out, preflight, fly, post flight go home. When you are doing the miles we are to push this concept thats is worth its weight in gold. AND we still have hair!
Dave

I hear you and totally agree. I'd like to thank you guys for all the great advice and info you post here. It's very helpful and it's great to have people to bounce all this off of. This has been a bit of process for me. I was bald to start off with so nothing to risk in that area.

I'm putting energy and time in to the APM largely for personal reasons. One of the developers is a friend of mine and just an incredible guy. Over the years he and his fellow software engineers have made very significant contributions to software such as rsync, samba and keeping MS at bay during a 10 year court battle where the big guys were trying to shut down all open source software use in Europe. He got me involved with the Canberra UAV group knowing that I was a commercial photographer in the past. That group went on to win the prestigious Outback UAV Challenge and continues to work on creating affordable professional systems for Search and Rescue use. As an ex Unix Sys Admin and the founder of an organisation that provides tech support to not-for-profit organisations I am very heavily committed to the Free and Open Source Software ethical stance. It's a very powerful model.

The APM development curve is extremely steep. What was there six months ago is significantly improved at this point. The advancements they are making are impressive and I am totally confident they will far surpass other flight controllers in the very near future. Then again, their goals are not based around 'plug and play' simplicity so the APM may or may not ever be as easy a platform to use as commercial based FCs. But I suspect that may happen naturally as the APM continues on it's very impressive path of improvement. I am more that willing to accept that the APM may not ever be suitable for the type of professional work being done by users here. I think that would be sad, but at the end of the day you need to get your work done.

At this point I'm going to put more time in to tuning my DW copters by putting them in a rig that restrains them. I will video that process for those interested. Apparently this method results in the best tuning parameters possible for a specific craft. I think it's best to make sure I've gone all the way in my testing of the APM before trying other FCs. That way I can say with confidence that I've done everything recommended and gave it my all to test it's suitability for my purpose. If I succeed it might result in a default configuration that will save others the issues I've dealt with and if it doesn't I'll just move on.

Cheers from down under.
 


nicwilke

Active Member

Hi DazzaB,
Dunno if you think I'm a ****head for the TBS Concordia comments etc, but like you, a droidworx junkie. I'm about to buy a CX4 titanium. What motors did you go for?
I want a quad first then maybe coax it later. My XM6 is really flying well, but something draws me to the CX4. I'm getting sent a new controller, the SuperX From Xaircraft. That's as good as zeroUAV and dji stuff. I guess I will see.
Should I opt for the extra long landing gear.
Hope you can enlighten me on the CX4.

Hope you can help,

Nic
 

dazzab

Member
Here's an unedited video of my first attempt to tune the SkyJib in a rig. It looks promising so I'll try and fly it again as soon as the weather clears up. The APM also has an auto tune function that I might try but that is done in air so you have to be tuned enough to at least fly.

I'm following a procedure from DIYDrones known as DaveC's Tuning Guide. It's all done in Acro (non-stabilized) mode.


Just realised I put this in the wrong thread. I'll leave it here and also put it in my SkyJib build thread as well.
 
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dazzab

Member
Dunno if you think I'm a ****head for the TBS Concordia comments etc, but like you, a droidworx junkie.
Not at all. It's all just discussions. You know, I think we have a mutual friend as I believe you know Bluerex as well?

I'm about to buy a CX4 titanium. What motors did you go for?
Should I opt for the extra long landing gear.
I let the staff at DW guide me on this. I told them that if the CX could handle a Crane3 gimbal and a Sony NEX I would be interested. They told me it would fly that fine with larger motors and props. So I choose the Tiger MN3510-25 (which they were out of and I had a hard time finding) motors and told them to include the best props for the application. They selected T-Motor 14" CF props.

To use a gimbal with the CX you need the extra long landing gear. When I ordered my spare parts this week after my crash I actually bought the standard landing gear as well. I didn't get much of a chance to fly it before the crash but I was _very_ impressed. With the larger motors, props and a 5S battery it's a mean little machine. Oh, and order an extra battery mount for the rear to balance the camera on the front. When flying without the camera you can put batteries on the landing gear.

When I build it I was really impressed with the quality and how it goes together. It's just a class act all the way round. It's small enough to travel with but I suspect still quite useable for serious work. I think it's going to end up being my favourite out of the two 3DR copters and 2 DW copters that I am luck enough to have now.
 



dazzab

Member
Given the issues I've had getting the APM FC to work on my SkyJib Lite, I've decided that when I rebuild my CX to use a DJI Naza with it. All the parts are on the way and when I return from holiday I'm looking forward to getting in the air again. Cheers.
 

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