Help... My tricopter keeps falling out of the sky!!

[JMundy]

I am getting a bit frustrated... my Tricopter keeps falling out of the sky for no apparent reason!

After I 1st built the tricopter... I had about 8-10 flights when this happen. I was flying 60-80 ft away in front of my house with my gopro and wifi on. All three motors stopped running and down it came landing in the snow.... this time wasn't as pretty, it hit concrete and busted all three arms. This time I was in a wide open area quite a ways from any house and the wifi was OFF, which I learned could have been the problem the 1st time.

Here is a my setup the 1st build:
Frame - David's Tricopter 2.5
Motors - DT750
ESC - RCTimer - NFS ESC 30A Multi-Rotor ESC SimonK Firmware (OPTO)
Props - Turnigy 10x4.5
Flight Controller - Readytoflyquads Flip 1.5
Battery - Turnigy 2200mAh 3S
Rceiver - Spektrum AR6100
UBEC - Hobby Wing 3A 5V (Powering thru Rx)

Here is latest build:
Frame - David's Tricopter 2.5
Motors - DT750
ESC - RCTimer - NFS ESC 30A Multi-Rotor ESC SimonK Firmware (OPTO)
Props - Turnigy 10x4.5
Flight Controller - KK2.1
Battery - Turnigy 2200mAh 3S
Receiver - Spektrum AR7610
UBEC - Hobby Wing 3A 5V (Powering thru port 1 & 5 on FC)

I checked the ESCs and motors as soon as it crashed, none were hot. It was about 57 degrees out and approx 15mph wind. I was getting some aerials so no hard flying...

I am starting to think it was the ESCs... I could sure use some help figuring this out!

Thanks in advance for any guidance you can provide!

 

[kah00na]

I would guess that you have a bad solder connection or bullet connection somewhere. Do you have any video of what it is doing. Maybe you could look at the video and see if you can tell if a single motor is failing or if all three at the same time. I got a new battery that came with a dean's connector which is what I use on my tricopter. I connected it and flew around a little and then it just toppled to the ground and I finally figured out that the dumb connector that came on the battery was ever-so-slightly larger than the ones I had on my tricopter. I replaced the connector and now it is fine.

 

[JMundy]

Here is a link to a youtube video from the 1st crash - https://www.youtube.com/watch?v=km1nL91ba3Y

It appeared to be the same issue... I guess I could rebuild the wire harness. A friend said that I should also try to power the servo directly instead of thru the FC

 

[xuzme720]

Here is a link to a youtube video from the 1st crash - https://www.youtube.com/watch?v=km1nL91ba3Y

It appeared to be the same issue... I guess I could rebuild the wire harness. A friend said that I should also try to power the servo directly instead of thru the FC

I doubt it's from powering the servo through the board, the KK2 has a separate buss on M2-M8 so it cant interfere with the board, which is powered by the other buss, left side inputs and M1, but I would certainly go over your harness very carefully to check for cold solder joints. That sounded like a power failure in the video...

 

[cranialrectosis]

I hear a low rattle in the video I don't want to hear in my copters. Motors hum but rattle is bad.

I have heard a similar rattle on my own Anycopter before it too fell out of the sky.

The culprit was a cold solder joint on a 3.5mm bullet connector.

 

[kah00na]

Here is a link to a youtube video from the 1st crash - https://www.youtube.com/watch?v=km1nL91ba3Y

That video is exactly what happened to me - except replace the snow with asphalt.

 

[FlyingMonkey]

I'd say that kah00na is on to something with the bad solder.

I'd be suspect of the power lead. If there's a bad connection there, it would shut down the whole thing.

Otherwise it sounds like what happened to me yesterday. I was a few hundred feet away, and it dropped. But that was because I let my transmitter battery get too low, and it lost signal.

 

[FlyingMonkey]

Ok, watched video, revising opinion...

First, cranialrectosis has hit on something important, you need to get rid of that vibration. I don't know if it's a bad bearing in a motor, a loose motor connection, or out of balance props. You need to get rid of that. I'm not sure how sensitive the Flip is to vibration, but it can damage the board's ability to adjust for level.

Also, it could vibrate a solder joint loose.

Another thing, in the video, did you kill power when it flipped over, or did it do that itself? You appear to have lost one or two motors, and the remaining one(s) flipped the tricopter over. That could be as simple as a bullet connector vibrating loose. I've had that happen before.

 

[CrashRecovery]

first you have a really badly balanced prop... you can see how the vibration makes it rock. What connectors do you use on your battery

 

[JMundy]

UPDATE - The DT750 motors are poor quailty.... i switched to Sunnysky x2212 980KV motors and haven't had a problem since. I tried for a while to work with the DT750s... I made sure to oil the bearings good and when I would hear a noise that didn't sound right I would break the motors down and re-oil the bearings. Those motors work fine on my son's quad, but I think the twisting motion of a tricopter puts too much pressure on the DT motor bearings.... that's just my $0.02.

I probably have over a 100 flights on the tricopter now.... I love it!! I recently set it up for FPV, but I think a tricopter is better suited for an experienced FPV'r, which I am not! I am now setup with a QAV400 that i just completed. I had purchased a MWC Pro EZ3.0 from readytoflyquads, but the FC has issues and after almost a week Paul still hasn't responded...so I used a Flip 1.5 FC that I had laying around..... I am thinking of giving up on getting a decent MWC w/ GPS and doing what i should of from the beginning and get a DJI Naza lite controller...

 

[cranialrectosis]

DTs are a pain. Sunnyskys are awesome. I have the 2300kvs on my String Theory and they are just frickin' awesome.

MW is also a pain in the butt. But the rewards are there if you are willing to work through the challenges.

I have the MW pro and it's just icky. I am flying the Naze 32 Acro and that is my favorite board. It is light, cheap, simple and can have all the toys MW can have. No arduino and you use Baseflight, a Google Chrome app, to control the board.

Of course, I like to flip my copters. Naza will fly the copter for you and I don't think you can flip a Naza. They do make good video platforms though.