Two fried motors on my first flight

D

drone newbie

Member
Dear all,


As i am a newbie in the quadcopter world, i did my first flight ever yesterday, which resulted in two fried motors. After my research, i decided to buy the following parts for my first quadcopter. Those are

DJI F450 frame with its extension legs
DJI E310 tuned propulsion kit ( 2312 motor, 420S ESC, 9450 props)
APM 2.6 flight controller with gps module
Multistar 10000mah 4S 10C battery
TURNIGY 9XR radio with FRsky DJT transmitter and V8FRii receiver

The quadcopter should be in the 1,5-2kg range of takeoff weight.

So, I tried to do my first ever flights by slowly hovering over the ground for 10-15 seconds in order to see how the quadcopter responds. I had a couple of turnover to the side of the quadcopter during landing but without damages as the speeds were slow. However, in my last effort, the quadcopter landed and felt to the side with the 2 props attaching to ground. All The props didnt stop spinning and after 3-4 seconds i saw smokes coming out of 2 motors. In my panic i turned off the radio but it kept spinning a little faster and then i unplugged straight the battery cable.
After going back home, i tested all the ESCs with the DJI assistant software using a good motor and the result message was "motor parameters are OK".

1) does that mean that my ESCs are indeed ok and i can use them again?

After my cross checks i will need 2 new motors.
So, i need to find what caused these 2 fried motors.

2) in order to avoid cutting the long cable of the ESCs, i wrapped it around the quadcopter arm. Can this cause a fried motor?
3) is there a chance that with the prop attaching to ground and the quadcopter keep working, the fried motor was caused by the fact that the ESC kept sending signal but the motor/prop couldnt follow???
4)is there a chance that the motors started overheating/frying while the quadcopter was on air? Is that possible according to my specs? DJI says that the E310 kit is suitable both for 3S and 4S batteries and for weights up to 2,5kg.

Could you please help me find my answers?

Thank you very much
 
GJH105775

GJH105775

Off and on
Moderator
Are your motors 2312kv? With 9'' props then there is wonder they burnt around 1200 kv motors are suitable for 9'', 3212 would be more for 5''.


How fast were they trying to spin while in contact with the ground, it would burn the motor up if they were trying to spin but were stuck.
 
D

drone newbie

Member
The motors are the 2312 model which have 960KV and they are part of DJI E310 propulsion kit. I didnt made the choice for the motors,esc,props combination because all of them are sold as a kit from DJI saying that it is suitable for models up to 2,5kg and and for 3-4S batteries...

I dont know how fast they were spinning but definetily the spinning was not slow when they were attaching to the ground.. So as you say, most likely they got quickly overheated in 5seconds because the props were stuck...
Maybe i should also try using a 3S battery in order to be in a more safe margin regarding motor overheating.. True?

I also noticed that the throttle of my turnigy 9XR was ectremely sensitive..i used the althold mode of apm, and i was slowly and gradually increasing throttle.. Suddenly the quadcopter started going up quite fast... And then when gradually decreasing throttle it did the opposite.. Is this extreme sensitivity an issue of my turnigy 9xr or an issue of my apm flight controller??

Thank you
 
Jackson

Jackson

USA member at large
drone newbie said:
I also noticed that the throttle of my turnigy 9XR was ectremely sensitive.
Click to expand...
Try tweaking the throttle curve.

From this:
19-DSCN0137.JPG


To something like this:
maxresdefault.jpg


This vid explains what it does.
 
D

drone newbie

Member
Before playing with the curves of my throttle, I have some updates to my problems..

After replacing two faulty motors and setting up again my quadcopter, I tried again to make a flight in Stabilize mode in order to see how the quadcopter behaves.. In my video you can see the attempts I have made
In all the attempts I was just gradually increasing the throttle channel without touching the yaw, pitch, and roll channels at all. Therefore, I would expect my quadcopter to start lifting vertically in an acceptable way without moving in other directions...As you can see in my video, the time just before the quadcopter starts lifting, it sounds like it cannot lift and also like vibrating and when it starts to lift, it also moves in forward or another direction. I checked the arducopter wiki pages, and I tried to recalibrate the radio but nothing changed...
Could you suggest me what causes this behavior and how can I correct this ???
I haven't played with PID values and I'm using some default values. I also haven't done any autotrim procedure. Is this needed ???

Just for reminding my setup is:
DJI F450 frame with its extension legs
DJI E310 tuned propulsion kit ( 2312 motor, 420S ESC, 9450 props)
APM 2.6 flight controller with gps module
Multistar 10000mah 4S 10C battery
TURNIGY 9XR radio with FRsky DJT transmitter and V8FRii receiver
AUW is 1,6kg

Thank you very much for your help
 
H

HDtallrider

Well-Known Member
Wow! That's a big battery. Have you tried just popping it up quickly to get out of ground effect and then see if it hovers easily? It will still wander a bit unless you are in GPS mode. It should be easy to control manually though, even without GPS mode engaged. I would follow Jacksons advice and get everything trimmed up properly first. It also sounds a little like a prop out of balance as well. You may want to go around and make sure all the bolts and screws are tight. Did you use Loctite?
 
D

drone newbie

Member
Dear HDtallrider and Jackson,

probably I must throw my fear of crashing and start pushing the throttle more and more quickly. As far as I remember, in my earlier attempts I tried and lifted it up to 1,5m height and it was still shifting around, although not so much like my video shows. I will try again in an open flat area and I will post my new video to see if the behavior is acceptable . I will also try to fine tune my hovering using the video guide that Jackson posted.

All my motors and props are bolted tightly.
 
H

HDtallrider

Well-Known Member
Quadcopter102 said:
Looks interesting... Just been checking the DJI stuff.
Would this kit be OK on a 250 racing chassis - not looking to race as such, just thinking I would be bound to start building something sooner or later... just lacking technical knowledge of quads.
Been watching an eBay sale http://www.ebay.co.uk/itm/111748568061?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT its Mode 1 ??
Click to expand...
The DJI motor pack is way to large for a 250 class quad. If you have no desire to race and you like the idea of the DJI power system then go for a 350mm to 500mm kit. That will be more stable and easier to fly than a 250mm which can be a little twitchy. Check out the Hobby King website. They had that same Walkera for less than ebay, for example. Gearbest is another site. Mode 1 is throttle on the right of the Tx and mode 2 is throttle on the left.
 
H

HDtallrider

Well-Known Member
First. Do you have experience flying already? If not it would be wise to get an RTF quad to learn on. For ideas on building just google " quadcopter build guide" and start reading. The amount of info out there can be overwhelming.Take your time. Once you decide the type of quad you want to build , make a parts list and post it on the forum. There are a lot of smart guys here that will be happy to help you with your build. I personally think I like building and tinkering with quads more than I like flying. Blasphemy!! haha One more thought. Don't waste your money on the bottom end of product offerings. You'll just get frustrated and it will end up costing more in the long run. When a review on a motor or esc advises you to buy a couple extra to have on hand so you won't have to wait on shipping for the replacement you should look elsewhere. There is no more helpless feeling than watching all your hard work fall out of the sky because a cheap part failed. This is a fun hobby. Enjoy!
 
Jackson

Jackson

USA member at large
H

HDtallrider

Well-Known Member
Quadcopter102 said:
Thanks for the info. Is there any chart for showing motor size = framesize or similar help really green newbies like me to know more?
I did wonder about this bidding on eBay. What I could see the seller had very few sales or other items - for me I would have preferred to buy from a "name" store who will give after sales help. Buy luckily for the planet... not everybody is like me..
Fact is - having seen the FPV racing vids... it does give a buzz to get into it. I doubt I could think fast enough! But I do like to meddle with electronics and making up kits is also - ( I hope ) a way to get to understand more.
At the moment I am making lists of the different set ups I see online.
Click to expand...
Hey quadcopter102. Start a post in the "Newbie section" Use the title "Need help on new build". Folks will catch up with you there.
 
D

drone newbie

Member
Dear people,


here we go.. I tried to fly again and I discovered that mostly it was my fear that made me think that things are not good at all with my quad.. So, today I realised that I am actually in a pretty good path considering that I am a newbie.


Today , I tested my quad in two modes, the stabilize and the AltHold.



1. In stabilize mode I just needed to put some throttle to quickly go above ground effect and then it could fly. What I discovered in stabilize mode is that :

a) I couldnt make it hover steady in an acceptable degree. Initially I was flying with the default linear throttle curve and then I switched to a more gradual style curve. In both ways I couldnt find that magic point of the throttle stick where the quad would hover. Either it would go up or down.. Any reasons for this ???

b) It would also move to a horizontal direction as well. FOr this I wanted to try the Auto Trin/ Save trim features of APM but there was some wind and I didnt try it. Do you have to propose another solution as well ??? Is Auto trim going to fix this issue ??



2. In AltHold mode I just needed to put the throttle stick to 100% in order to make the quad go up.. The climbing speed I have set for my quad when in AltHold mode is 50cm/s which is the minimum possible. What I discovered in AltHold mode is that:

a) It could hover quite well when I had the throttle stick in the middle , but like in the stabilize mode, the quad would also move into a horizontal direction. Again, will this Auto/Save trim process will fix this ???



3. During my today flights I connected the battery to the APM three times. Obviously I disconnected the battery two times in order to check the voltage with a voltmeter. So my three sessions I guess created 3 dataflash log files that I am attaching..

During my second and third session while flying, I noticed that my quad was descending although I was putting more and more throttle. I noticed that as it was descending, it didnt descend vertically and it was also moving in a horizontal direction.. I guess this will be fixed with the Auto/Save trim process , as with the stabilize and AltHold mode.. Correct ?? So, these descendings made me suspect that the quad probably had switched to Land mode. And when I was back home I checked the log files and indeed you can see that during the second and third session the Land mode has been triggered.. But why did it switch to Land mode?? When I finished my session my battery was at 14.9V and my Battery failsafe trigger in APM is set to 14V ... Can you propose any reasons why it did switch to Land mode ??? Could it be that my battery by having 10C it cannot provide sufficient power instantly and therefore the APM switches to Land mode ???


4. Also, in the log files I compared the DAlt, Alt and BarAlt to check the behavior of my quad in Stabilize and AltHold modes... I saw that when the quad was in Stabilize mode, the DAlt curve is not perfectly following the Alt and BarAlt curves... What does this mean ?? What should I correct ??

However, when in AltHold mode, all three curves are quite similar.. By seeing my log files, is there something that you would like to mention. DO you see something wrong that I cant see yet as I am still a newbie ???


Many many thanks for your support..
 
H

HDtallrider

Well-Known Member
Regarding 1) and 2); You have to remember that you essentially have 4 nine inch "wings" formed by the spinning propellers. Any breeze will push the quad around. It is up to you as the pilot to control those movements. Part of the learning curve.Unlike stabilize and altitude hold, putting it in GPS mode will lock it solidly in place until you move the sticks to change altitude or direction. Putting it in manual mode will sharpen your flying skills because it gives you total control without any of the buffering that stabilize and altitude hold modes introduce. Now. Regarding 3) and 4), I haven't got a clue . You need someone with bigger brains to help you there.
 
GJH105775

GJH105775

Off and on
Moderator
For number 3 it sounds like you tested the battery while it was not under load, and your voltage tester was testing under load.

For a quad you pretty much don't get it to just hover, you have to mess with it real time, though throttle expo would help a lot.

As for the drifting check that you have it calibrated good, if it only drifts a little bit then it is the pilot's job to compensate for it.
 
D

drone newbie

Member
Hello,

as I keep progressing with my skills and my knowledge on the quadcopter world, I have a question.

At first I want to note that my quadcopter setup is:
DJI F450 frame
DJI E310 tuned propulsion kit ( 2312 motor, 420S ESC, 9450 props)
APM v2.8 flight controller with external gps/compass module
Installed power module
Multistar 10000mah 4S 10C battery
TURNIGY 9XR radio with FRsky DJT transmitter and V8FRii receiver

As you can see in my video, my Voltage indication fluctuates a lot between 14,2V and 16,5V. I have already calibrated the voltage reading of my power module and initially, (before arming the copter) my voltage indication is similar to the value that my multimeter shows.. In this video I am just having the quadcopter in ground without props and I was just giving a bit of throttle (about 25%) to see the behavior of voltage. Is this fluctuation normal ?? Shouldn't my voltage indication be more steady ???

APM 2.8 voltage indication (0 min 51 sec)


Thank you for your help,


UPDATE: I discovered that this fluctuation in Voltage happens when I connect Mission Planner with the APM using the telemetry radio (http://www.hobbyking.com/hobbyking/s...2_433Mhz_.html)
However, if I leave the telemetry radio module attached to the APM but I connect Mission Planner with the APM using the usb cable, the Voltage fluctuations that I see in the status are around 0.3V..

So why does this happen ??? Please help....
 
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