Bebop 2 wobbles after crash

[costas]

Hi everybody,

I have an old/used Bebop 2, having a great time with it usually (only one month of ownership).
Today I have just turned it on, GPS was alright, took off, tried to fly it a bit in front but suddenly it didn't respond to my commands; took my hand off the phone screen but it kept going and rotating and went right into a tree then fell in the grass.
I expected it to be broken but it didn't look like it. I have checked the motors/blades and they didn't seem broken either (they rotate smoothly/coherently but I can't bet on them) - the frame also looks good, a single mark one one of the arms.
Powering it up again, it took of but started to wobble quite annoying. I can fly with it, but it does not feel good. I tried resetting it, recalibrating, but it is still does the same.
Any idea what might be broken? (to me it looks like some gyroscope issue, any idea how to check that?).

Thanks,
Costa

[AR.Tommy]

Hello and welcome,

could be a bent motor cage or broken cross (the frame). Did you already try spinning the motors with your hand? Do they look fine?

[waterlanding]

Bent Prop?

[dries_w]

. . . . .
Today I have just turned it on, GPS was alright, took off, tried to fly it a bit in front but suddenly it didn't respond to my commands; took my hand off the phone screen but it kept going and rotating and went right into a tree then fell in the grass . . . . . . .

The 'wobling' and roting could be caused by a BB2 thats not had a Flat Trim and was not calibrated before the flight. On the other hand the 'didnt respont to commando' would indicate a WiFi disconnection with the phone. Did you set your phone in Airplane mode so you cant get a disconect by receiving a message from your phone?
Did you calibrate/flat trim before take off and had you WiFi connection ?
If the motor case and the props are allright as Tommy suggested and Calibrated/Flat Trim doesnt help you could try to Reset the BB2 by pushing the power button for 10-15 seconds and wait for a restart. Succes.

[costas]

Hi,

Thank you all,
I didn't expect so much replies.
I have uploaded a video of bebop's flight, so you can have a better view of what I'm talking about (I hope the link works).

https://photos.app.goo.gl/AejS8XujTc25TxR1A

So, I have checked the motors, tried to spin them manually and they looked fine. The frame also looks fine. (there could be some electric coil broken though and I cannot check that).
Also the propellers look fine, but I will try to change them tomorrow, just in case.

By the way, I did a flat trim and recalibrated bebop. Was there supposed to be an "OK" message or something when I do the flat trim, because I have tried several times and had no feedback when pushing the button in the "Flat Trim" window and had to just go back to the previous screen (if there is not, it should).
I have also did a hard reset of the board (mentioned that before), nothing's changed.

What is strange or maybe relevant, is that it only wobbles on one axis, so I am having this idea that a gyroscope on y axis is broken. Is there a way to see the values of the gyroscope settings? I know how to telnet the board but I am not sure how to get the gyroscope values, they might be useful to see if they're not behaving OK.

Thanks again,
Costa

[asmith61]

Hi
Just watched your video to me it looks like you have a slightly bent prop, the same happened to me a few weeks ago, it was only very slightly bent but it done the same as yours so I would check that first

[costas]

Hi,

I have just tried a different set of propellers and it still wobbles. I still don't see anything unusual with the propeller/frame, but how can I rule that out?

Thanks,
Costa

[asmith61]

Hi
Oh that’s a shame I thought that would have solved your problem, you say it only does it on one axis ? I wonder if it has bent the motor spindle ? You could try a new motor they don’t seem that expensive, hope you soon get this sorted

[costas]

Ok,

The motors look expensive around 120 dollars with shipping.
There's some motor repair kit at around 30 dollars, I think I'll try that first.
It may be that what I see as one axis wobbling is the mainboard compensating for a broken motor.
I'll also try to film the wobbling at 120 fps, maybe I can see better which one is the culprit. But only in two days or so...

Best Regards,
Costa

[waterlanding]

Look very, very closely at the crossframe. Flex the arms just a little. A small crack anywhere on the assembly (usually where the arms meet the body) can cause this kind of wobble.

[costas]

Look very, very closely at the crossframe. Flex the arms just a little. A small crack anywhere on the assembly (usually where the arms meet the body) can cause this kind of wobble.

Hey, that did it, indeed, I could see a crack in the frame by flexing one of the arms, check out the link.
Should I be able to glue it somehow (I have some special plastic adhesive I have never tried) or is it better to replace it?

https://photos.app.goo.gl/Rj9Q8EBJBcPWjWG27

Thanks,
Costa

[waterlanding]

Look very, very closely at the crossframe. Flex the arms just a little. A small crack anywhere on the assembly (usually where the arms meet the body) can cause this kind of wobble.

Hey, that did it, indeed, I could see a crack in the frame by flexing one of the arms, check out the link.
Should I be able to glue it somehow (I have some special plastic adhesive I have never tried) or is it better to replace it?

https://photos.app.goo.gl/Rj9Q8EBJBcPWjWG27

Yup, you found it! That will definitely cause a wobble, and it could break anytime.

Gluing: That's Carbon Fiber, not plastic. Nothing sticks to it. You can build up a layer of epoxy all around the crack for a temporary fix, but that's just putting a collar over the break. No glues will make a true bond with CF. Sooner or later it'll fail - sometimes catastrophically.

New crossframes are inexpensive, and (relatively) easy to replace. You'll just need a crossframe and the Parrot tool kit (or equivalent) for the little screws.

[costas]

I have tried the temporary fix with the glue I had. It seemed to stick really well - it looks like something acrylic, but much stronger than the usual superglue - I'm not sure what exactly that is though, I bought it on some occasion with no logos an only short instructions (it's made of two components, one for cleaning and one for bonding). From what I know, acrylic glue should do well with carbon fiber.
The wobble is gone for now, but I'll keep that under observation and order order a frame anyway.
So, thanks for the help, much appreciated!

Best Regards,
Costa

[asmith61]

Hi

Glad you have managed to find the problem

Also well done on the tempary fix but keep a close on it but happy flying

[IronSpear]

Look very, very closely at the crossframe. Flex the arms just a little. A small crack anywhere on the assembly (usually where the arms meet the body) can cause this kind of wobble.

Hey, that did it, indeed, I could see a crack in the frame by flexing one of the arms, check out the link.
Should I be able to glue it somehow (I have some special plastic adhesive I have never tried) or is it better to replace it?

https://photos.app.goo.gl/Rj9Q8EBJBcPWjWG27

Thanks,
Costa

Hiya!
It's pretty easy to change the cross frame.
There are great videos on YT on how to do it.
I think I got the cross frame from Parrot for about AU$50.
Good luck.