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My drone only climbs and does not hover

#1
I want to apologize in advance if I am posting to the wrong subforum.

I just built a new drone. The specs are later on in the post. My main problem is that it only climbs and never hovers. This is even an issue at low throttle. Here is a video of what is going on https://www.youtube.com/watch?v=gFsT9RCtNNw. I honestly have no idea what is going on as I have calibrated the compasses and radio through qgroundcontrol and recalibrated the ESCs a bunch of times through this method
. When I spin them using mission planner, they all spin at the same consistent rate.
I included a picture of the throttle position at which it climbs like that.

It uses a raspberry pi with an emlid navio2 hat.
https://emlid.com/navio/

I use a taranis qx7 as the transmitter
https://www.frsky-rc.com/product/taranis-q-x7-2/

My motors are racerstar
https://m.racerstar.com/Racerstar-R...CCW-for-220-250-RC-Drone-FPV-Racing-p-33.html

My propellers are 8045s
https://www.amazon.com/dp/B00L59WZZS/?tag=lstir-20

My Escs is a 4 in 1
https://www.banggood.com/Racerstar-...er-p-1068210.html?rmmds=buy&cur_warehouse=USA
 

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#4
If you look at the picture that I included, you can see that the throttle that causes it to shoot up like that is very low. Even if I lower it slowly, which I do, it crashes because the throttle is now too low. The problem is that it is too sensitive. I tried modifying the weight and expo for the throttle channel on my Taranis qx7, but that doesn't do anything. Here is a better video of what I speak of
 

ElectriSean

Eternal Student
Mentor
#5
You should be able to fix it with expo, but you will probably have to add an offset so the expo is at the bottom of the stick, rather than the default which is center stick. You should be able to see the actual curve on the screen.
 
#6
I already tried messing with the expo but the extreme sensitivity remained an issue. Here is ONE of the MANY settings I used. I will try modifying the offset now, but I dont think that I can really test it until monday because I broke one of the propellers and I dont have the proper replacement on me now
 

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#8
Thanks I looked at it. It seems like nothing I could do could fix the problem. I tried other configs like the following. However, the problem is that it is either not doing anything or climbing too fast. Like it goes from 0 to 100 too quickly. It seems like there is a particular threshold that causes the motors to start spinning at a much faster right. Like a Heaviside function
 

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ElectriSean

Eternal Student
Mentor
#10
Thanks I looked at it. It seems like nothing I could do could fix the problem. I tried other configs like the following. However, the problem is that it is either not doing anything or climbing too fast. Like it goes from 0 to 100 too quickly. It seems like there is a particular threshold that causes the motors to start spinning at a much faster right. Like a Heaviside function
Could be PIDs, I'm not familiar at all with the firmware you're running. One thing I noticed is that the motors you chose are way too small and fast for 8" props, those are made for 5" or maybe 6" on 3S. They won't live long running 8".
 

Merv

Well-known member
#13
No, the props are not the cause of your “can’t hover” issue @ElectriSean is saying the props are making your motors work too hard and will burn them out far too soon. Smaller props may help the can’t hover issue, there is another cause we haven’t stumbled across yet.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#14
You are spinning your props too fast generating WAY too much thrust for your copter at the low end of the throttle.

2205s should be paired with 5" props on 4S or 6" props on 3S and are too small for your copter. Use 2205s on a 250 size quad.

You should be running 8" - 10" props on your copter. To spin an 8" prop on 3S run a 1400kv motor. For 10" props on 3S you should be running around 1000kv motor.

Your motors are going to fry trying to spring your copter up so hard. 6" props aren't going to fly that copter well.

Longer props on lower kv motors generate more efficient power and are used for larger quads for longer flight times.

Use short props and high kv motors for fast thrust and rapid moves such as racing a small 250 or smaller copter. :)
 
#15
You are spinning your props too fast generating WAY too much thrust for your copter at the low end of the throttle.

2205s should be paired with 5" props on 4S or 6" props on 3S and are too small for your copter. Use 2205s on a 250 size quad.

You should be running 8" - 10" props on your copter. To spin an 8" prop on 3S run a 1400kv motor. For 10" props on 3S you should be running around 1000kv motor.

Your motors are going to fry trying to spring your copter up so hard. 6" props aren't going to fly that copter well.

Longer props on lower kv motors generate more efficient power and are used for larger quads for longer flight times.

Use short props and high kv motors for fast thrust and rapid moves such as racing a small 250 or smaller copter. :)
Would changing motors and ESCs help? Would this 1400kv motor be good? https://hobbyking.com/en_us/d2826-10-1400kv-brushless-motor.html
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#17
You have motors, props and ESCs for a 250mm racing quad running 5045s on 4S or 6045s on 3S. You have a frame for something much larger and more docile that can carry a larger payload.

I'm not sure what you really want to do.

@FDS has a good point depending on your lipo and all up weight and the flight times you are looking for, 1100 or 1000 kv may be a better solution for you if your frame can handle them and you want the power 10" props will give you.

The question here is profound for such a build, so we need to start at the start. :)

Other than just fly (yeah, been there ;)), what do you want this machine to be able to do?

How large is this frame (measure in millimeters diagonally from motor 1 shaft to the motor 3 shaft)?

Are you trying to lift a payload such as a camera and gimbal?

What lipo(s) do you already have?

Right now you have half performance and half utility like a Porsche motor in a Mack truck.