Normally the ESC’s can handle being installed in tight places without much air. Are the motors hot?
5 lbs will need 960 kv and 9" props or better. Time to rethink the design and move out the props.
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You need to manually calibrate it, dont trust what you see online. I run x560mm quad with gimbal at 1800g and 650kv motor with 13inch prop. So here is examle of your weight/motor prop size and mine. Mine is hovering at 25% throttle so im pretty sure you are alot more. That motor/prop is draw too much current to just hover and is expected to heat up. Best way is to cut some weight down and try how’s that work.
Yes the motors are also very hot.
The thing is that I can not use bigger props due to the size of the drone (it is required this size 39x39cm square). And the weight is difficult to be reduced because of the equippment required.
Thank you for the info!
According to the logfiles of ardupilot I am hovering at 17-20% thrust. Of course I don’t know if that is the true.
I will try to reduce the weight at the maximum possible and test again.
Thank you for the help!!
Yes, that’s correct.
Let’s back up and look at reality. Antoni’s craft in a hover is as shown on the following graph. There is no lack of thrust, Ctun>Tho at hover is around 18% as he says. Average Rcoutput at hover is ~1400us. The thrust/weight on this craft is fine. He has a ESC cooling issue with the capacity of the ESC he has.
I going have to disagree, 6" props lifting 5 lbs is never going to work. Regardless. The proof is the heat. Just look at any VTOL inbedded in a enclosed frame the ESC’s work. I have seen hot ESC’s with a bad tune. Could be the tuning guide will help. Also I would check for long screws.
No heat and i’m using the same esc…
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I agree that he is hovering at 18%, but that setup is not efficent that is reasson for esc/motors heat up. Motors are just eat too much current because he has too much weight. I only see that he can cut the weight down or upgrate to lets say 65amps esc. But still he will heat up motors. I run my quad for 28 mins in hover and my motors are barely warm. For longer use and longer flights he will propably damage motors.
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If you can manage with less flight time using less batteries will reduce the power requirements enormously, the propeller efficiency goes off a cliff the more load you put on it, if you half your battery you will lose less than 25% of your flight time due to it being more efficient since It will weigh less.
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Hi guys,
First of all thanks everybody for the interest and for the help.
Well, our quadcopter is built with this configuration because we are very limited in size due to the application for which it is intended: indoor flights through small holes, very narrow passages, etc. The weight also is a problem because we need a good computer and a LiDAR scanner onboard. So when we do the calculations for motors, props and so on, we expect the results, in terms of current consumption, that we actually have with the drone. The eCalc also says more or less the same, that it is suposed that hovering we shouldn’t have any problem with the motors temperature (I’m not talking at 100% thrust, of course at that point we would have a lot of problems).
But in my newbie mind what I can not really understand is that, even hovering at 20% of thrust, the motors and ESC get this temperature. It is not supposed that any quadcopter should be hovering more or less at this percentage of thrust? Why mine is cooking the ESC and motors just at a 20-25% of its maximum power?
I will try to tune better the PIDs.
I will try also to reduce the weight as much as possible.
Do you think that maybe using props 6040 with 2 blades could be better? (according to ecalc the motors temp decrease a lot).
Thank you everybody again, I will keep you informed!!!
Hi geofrancis,
This is a thing in which I thought, I will keep it in mind, in case I can not achieve any better results, for me that should be the last resource, because for our missions we need at least 9-10min of flight time.
Do you think that maybe reducing the voltage of battery could be a good option? I mean reducing 6S to 5S? (it is supposed that should be worse because it will consume more current but I don’t know).
Decreasing pitch of propeller will reduce your amp draw for sure, but it will also produce less thrust. I dont have much experiance with 3 blade props but for sure 2 blade will produce less thrust and probably will consume less amps. As i can say your motor/prop combination is not efficent at that weight of craft, that is probably main reasson for your high temparatures, also good filtering and tune can help you a bit to lower temps. You did bad calculation from start with weight/size of your copter, now you can only try to cut some weight down by reduce battery size and maybe did some changes to frame itself.
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you could just get a 5v 30x30x10mm fan and place it on top of the esc so it has some airflow.
proppellers with a shallower pitch will help if your motors can spin fast enough, your only hovering so you dont need an aggressive pitch on the blade for speed. a 6x3x3 would be a better fit.
if you want to go further then I assume all this had to do is hover and slow flight so you could try a lighter battery type, something like a 10ah 21700 with 30A cells would take 300g off its weight.
get rid of all the bullet connectors on the motors, at 3g a pair, that almost 40g from some connectors,
titanium frame and motor bolts take a few grams off. also replacing all the steel nuts on the electronics stack with nylon will take a few off too.
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Okay, I will try then.
Thank you so much!!!
That could be very useful!!
We already use the Molicell 45B cells which are 70g each forming a 6S2P (9Ah) battery and with a total weight of 850g.
What I was thinking is to decrease the voltage of the battery maybe, doing a 4S or a 5S which would reduce the total weight and also the temperature of the motors. But maybe increasing the temperature of the ESC.
What do you think about that guys?
@geofrancis gives you good advice on prop size, i will go for 6S1P battery to cut down weight. Also follow his advice for connectors and other stuff to get even more weight reduction. I think when you drop to 1900-2000g your temps will drop alot.
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I bet this is the tune. I recently had the flight controller mounts shake a bit loose and this didn’t change the way the drone flew, but rather heated the motors up a lot. If they are spinning down and spinning up again at a very high frequency, the drone may look stable but actually is just oscillating at a very high frequency. Retuning (especially D term) and making sure your frame is stiff enough and your FC mounting is correct will likely allow your motors to run cooler, which puts much less load on your ESCs.
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Okey I’m on it right now. Finally I moved the ESC more under the airflow and reach a maximum of 90C, the motors are already hot, at more or less 100-110C (we used a thermal camera).
Do you know any trusted PID tuning tutorial for dummies?
Do you think it is possible to use the QuickTune in indoor small rooms (6x3m)?
Thank you!!!
For QuickTune you need to be in loiter mode so if u have some sensors for inside fly in loiter you can. Post a .bin file so we can see your current tuning.
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Hi Goran,
Here there is the .bin file of the last flight (I activate an ESC telemetry filter and a FFT filter, both with default tuning. I can not notice any improve).
I also leave the .params file in case you need.
Thanks for the help!!
Ok you have some Yaw imbalance as i can see, your Yaw tuning is not good also its all over place.
Disable FFT_ENABLE : 0 and install BDshot version for your Matek H743 board so we can enable BDSHOT to setup RPM Filters.
After you flash it with BDSHOT set INS_LOG_BAT_MASK : 1 and INS_LOG_BAT_OPT : 4 so we can setup Filters.
After we do that we will continiue to do setup.
Edit: Do a 30 sec hover in AltHold mode with gentle inputs so we can see how to setup filters. No need to fly full battery.