Central Cross Repair

Hand picked how-to's for your AR.Drone
Post Reply
Ruyton
Made it over nextdoor
Posts: 292
Joined: 06 Jun 2013, 16:39
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Central Cross Repair

Post by Ruyton » 24 Sep 2013, 08:00

This is a repeat of my post in the AR Drone 2.0 section, but is probably better in the 'fixes' section.

A crash resulted in a broken central cross leg, rather than the central bracket. I've fitted a new central cross, but I though that I'd have a go at fixing the old one - nothing to loose. The break is in an awkward position so I scratched my head a bit as to how to fix it, but I have a plan. I wanted to 'tack' the parts together with superglue so that I could add some steel rod on the outside and bind it with strong thread before applying epoxy. Unfortunately, my superglue had gone hard, so on to plan 'B'.

I cut 2 one inch lengths of the steel rod - left over from an RC project - and inserted them inside the cross leg. There's just enough room for them to fit snugly. I had to pull the wiring harness through the leg a bit to give me enough room to get the pins in. As the pins could move with vibration, I applied a bit of JB Weld over the wires and pins and pushed the broken parts together. I THINK that I've pulled the wiring harness back to where it should be so that I've got long enough leads to connect to the motor and main board.

I still intend to add some rod externally and bind and epoxy it if this fix holds enough for me to do this. Of course, this is going to add a bit of weight to one side of the drone, so I may have to add a bit of weight to the opposite leg to balance it out. I'm probably only going to fly this cross if I break the new one that I've just fitted, but an interesting experiment none the less.

Update: The JB Weld has set overnight and the leg is self supporting, but almost certainly not strong enough to fly, but strong enough to allow me to add more reinforcement.
DSCN1627.jpg
DSCN1629.jpg
DSCN1630.jpg
You do not have the required permissions to view the files attached to this post.
Gary - Shrewsbury UK

Shaft
Charged up again
Posts: 1186
Joined: 21 Dec 2012, 16:09
Drone Type: Jumping Sumo
Location: Perth, Western Australia
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by Shaft » 24 Sep 2013, 12:12

I like your thinking so hope it works... Will be interested to see you try it on the AR.

ControlFreak
Ready for take off
Posts: 24
Joined: 08 Jan 2014, 17:59
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by ControlFreak » 08 Jan 2014, 18:46

Hi Guys,
This is my first posting here.

I got an AR Drone 2.0 for Christmas. After a few indoor flights, I was obviously a bit overconfident. I took it outside and wanted to get it above the treeline so I could look at the landscape. I ended up with it hung up in the top of a pretty large tree. "Fortunately" I was able to tell it to launch and get itself out of the tree, but it tumbled down to the ground. In that crash, one of the carbon fiber legs was snapped off right at the central cross.

The purpose for my post here is to say that I have been successful with repairing the broken leg using the fast-curing JB Weld and reinforcing the joint with some small fiberglass rods (something like 1/16" diameter) that I had laying around. I think the rods were salvaged out of some junk that we were tossing out. I wish I remembered what they came out of, because it sure would be handy to be able to get some more!

I now have about 5 flights on it since the repair and it seems to be good as new. I regret that I didn't take any pics of the repair. Some time if I have the need to take the bottom sticker off, I'll get some pics and post them here.

So my main point here is that it is possible to do this repair. With the fiberglass rod reinforcement, I think that the resulting joint is stronger than the original, but I won't know for sure until I have another major crash. Obviously, there's a bit of additional added weight, but it flies just fine as far as I can tell with my level of experience. I now have a total of about 10 flights under my belt.

Fly safe,
Dan

PS: I posted some pics of this repair in this other thread that was addressing the same type of repair. http://www.ardrone-flyers.com/forum/vie ... 423#p75423
Last edited by ControlFreak on 26 Jan 2014, 20:59, edited 1 time in total.

Carl190_1
Just flips over
Posts: 73
Joined: 07 Apr 2013, 20:51
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by Carl190_1 » 18 Jan 2014, 23:21

I snapped a leg off in a crash very near motor PCB used JB Weld and has held so far.
I did consider using some type of reinforcement.

Sherm6178
Ready for take off
Posts: 31
Joined: 20 Jun 2013, 03:26
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by Sherm6178 » 19 Jan 2014, 00:12

I have actually had a bit of luck swapping legs and or feet from separate broken crosses that I still fly today.

Sent from my Nexus 7 using Tapatalk

slayaz
Newcomer
Posts: 4
Joined: 05 Feb 2014, 14:37
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by slayaz » 07 Feb 2014, 12:30

i've been buzzing it around the courtyard at work and was having a great time until i hit a wall.

I have slightly bent a shaft (have a spare) but the front arm feels slightly loose. It doesn't appear to effect flight, and as the main cross is a big job i was wondering whether i need to repair or what it might be.

The arm is still attached but a little wobbly.

Any advice appreciated.

Many thanks

ControlFreak
Ready for take off
Posts: 24
Joined: 08 Jan 2014, 17:59
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by ControlFreak » 07 Feb 2014, 12:54

You'll need to get that fixed pretty quick. Sounds like you have fractured the leg, but it may not be completely severed. You can repair it, but you're right, you'll have to completely remove the central cross. It's much easier if it's just a fracture since it would still be held in alignment by the remaining fibers. You can see my link in an above post where a complete break has been repaired. I have now flown about 50 flights with this repair (including a few minor crashes), and its still holding.

slayaz
Newcomer
Posts: 4
Joined: 05 Feb 2014, 14:37
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by slayaz » 10 Feb 2014, 11:25

Parts ordered!

Thanks for your help.

msota84
Newcomer
Posts: 3
Joined: 21 Feb 2014, 16:05
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by msota84 » 26 Feb 2014, 14:07

Sherm6178 wrote:I have actually had a bit of luck swapping legs and or feet from separate broken crosses that I still fly today.

Sent from my Nexus 7 using Tapatalk
PLEASE, how did you get the legs off? Thats what Im up against now

ControlFreak
Ready for take off
Posts: 24
Joined: 08 Jan 2014, 17:59
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by ControlFreak » 26 Feb 2014, 16:38

Those legs looks very securely glued into the central member, looks like with cyano adhesive. It will be interesting to find out how this was done. Perhaps a cyano debonding agent?

Jayson Hanes
Spying is fun
Posts: 666
Joined: 23 May 2013, 14:42
Drone Type: AR.Drone 2
Location: Tampa, FL USA
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by Jayson Hanes » 26 Feb 2014, 17:11

I saw a youtube video of a guy showing this being done with an open flame.. I was never successful and have just thrown out 5 broken crosses this past weekend.. perhaps it is possible but I tried to remove 4 feet.. and destroyed them all, lol

ControlFreak
Ready for take off
Posts: 24
Joined: 08 Jan 2014, 17:59
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by ControlFreak » 26 Feb 2014, 22:47

Jayson,

Why not use JB Quick and put it back together that way? I have 50+ flights with my repaired cross. I have posted pics of the repair on this forum, here:
http://www.ardrone-flyers.com/forum/vie ... 423#p75423

Dan

MontanaMac
Ready for take off
Posts: 12
Joined: 13 Apr 2014, 13:55
Drone Type: AR.Drone 2
Has thanked: 0
Been thanked: 0

Re: Central Cross Repair

Post by MontanaMac » 14 Apr 2014, 22:27

Yes, heat is the answer to remove the arms from the cross and the motor mounts, but I wouldn't do it with fire. Check out this video for cross disassembly:

Direct link: http://www.youtube.com/v/xZjG_Ok0SQo

I am also using this to teach myself Final Cut Pro, so please excuse the cheesy/amateurish video.

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests