Hi,I recently changed my esc, motor and prop combination in an attempt to get more efficiency. This has backfired and I don't know why. Any advice would be appreciated.The quad wants to yaw to the right excessively in a hover starts feeling underpowered after 2 / 3 minutes. (need 70% throttle to hover) even with 25 points yaw trim left it hold position the slowly yaws right again.My New setup is as follows:Weight with battery 1.9kgMotor: sunnysky 2213 980kvBattery; Haiyin 5000 3s 35cProp: 10x45 carbon finer.Absolutely no x and y vibrations. Y vibrations is between 1 and and 2 points on the graph.Is my quad just too heavy for 3s? And what logs can help analyse why it's yawning right. I have no clue where to start with diagnosing the problem. Any help will be appreciated.Arshish
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1.9kg for 3S and 10x45 is a bit on the low side. The TBS Discovery for example is around 1.6 - 2kg and that uses 4S with 9 or 10 props. WIth 9" props on 3S and 900kv motors, you won't be able to lift it.
Your problem may have to do with the way how one (or two?) motors are exactly aligned on the frame. If you have one motor that is slightly misaligned with the vertical, it already produces a yawing force that pulls the vehicle into a rotation. The vehicle attempts to compensate that by running the other motors at a higher rpm and the misaligned "pair" at lower rpm. The end result is a vehicle that has very poor yaw authority towards one side and extreme yaw authority towards the other. Efficiency is poor when you have such a configuration.
What I did to verify this:
- First discover in theory how you expect the misalignment to be.
- Put the vehicle on a really flat surface and then use a ruler to measure the tip of the prop above the surface on both ends of each motor, perpendicular to the axis of the arm.
- If the distance per motor is the same, this is not the issue. I expect however that one motor will have 0.5 or 1cm of difference.
- Fix the issue by inspecting the mount, see if the arm is slightly twisted or just put a very small piece of material on one end of the motor. In my case, I only had to use a piece of paper folded double covered by tape. So, the amount of material you need to fix it is really tiny.
Thank you for reading my post and replying Gerard. Regarding the power system I will try with 11x47 props. This will exceed the max watts at full throttle so I will set my end point to 80%. I would rather avoid investing in a ful set of 4S cells. Here is what ecalc shows with a 11x47
Another important point I forgot to mention is that the left top and bottom right motor are always hotter than the other two. Is this normal?
Will check the props distance from ground as you have suggested and report back. Is there anyway I could use Logs to identify what is happening?
Forgot to mention... also running arm LEDs, headlight LEDs, bosam hd19 cam and bosam 400 mw TX off the same battery using the balance port and filtered by a capacitor and torroid core.
Old setup was as follows:
1. No fpv gear
2. Lighter x frame 1.4kg. (Current is spider frame)
3. Smaller 4200 mah battery
4. Gemfan nylon 10x45 props
5. Avionics 850kv motor. Same size.
6. 4. Independent 20amp esc
Replies
1.9kg for 3S and 10x45 is a bit on the low side. The TBS Discovery for example is around 1.6 - 2kg and that uses 4S with 9 or 10 props. WIth 9" props on 3S and 900kv motors, you won't be able to lift it.
Your problem may have to do with the way how one (or two?) motors are exactly aligned on the frame. If you have one motor that is slightly misaligned with the vertical, it already produces a yawing force that pulls the vehicle into a rotation. The vehicle attempts to compensate that by running the other motors at a higher rpm and the misaligned "pair" at lower rpm. The end result is a vehicle that has very poor yaw authority towards one side and extreme yaw authority towards the other. Efficiency is poor when you have such a configuration.
What I did to verify this:
- First discover in theory how you expect the misalignment to be.
- Put the vehicle on a really flat surface and then use a ruler to measure the tip of the prop above the surface on both ends of each motor, perpendicular to the axis of the arm.
- If the distance per motor is the same, this is not the issue. I expect however that one motor will have 0.5 or 1cm of difference.
- Fix the issue by inspecting the mount, see if the arm is slightly twisted or just put a very small piece of material on one end of the motor. In my case, I only had to use a piece of paper folded double covered by tape. So, the amount of material you need to fix it is really tiny.
Thank you for reading my post and replying Gerard. Regarding the power system I will try with 11x47 props. This will exceed the max watts at full throttle so I will set my end point to 80%. I would rather avoid investing in a ful set of 4S cells. Here is what ecalc shows with a 11x47
Another important point I forgot to mention is that the left top and bottom right motor are always hotter than the other two. Is this normal?
Will check the props distance from ground as you have suggested and report back. Is there anyway I could use Logs to identify what is happening?
Thanks
Arshish
Old setup was as follows:
1. No fpv gear
2. Lighter x frame 1.4kg. (Current is spider frame)
3. Smaller 4200 mah battery
4. Gemfan nylon 10x45 props
5. Avionics 850kv motor. Same size.
6. 4. Independent 20amp esc