23 February, 2018 at 23:25 #49710
The Servo torque is based off the avalible voltage. Too little voltage (less than 5 volts) and the Servo draws more current, can overheat and burn up. (will perform like crap too) Make sure you have at least 5 volts at all times but 6 volts is better if your FC can provide it. Bench test your Servo (props off) while the motors are spun up at least 30 to 50%. Check that the voltage stays at or above 5 volts while EVERYTHING is under load.
As for the LiPo’s the higher the voltage or number of cells the better the Copter efficiency. Hence a 1200mAh 6S LiPo is about the equivlent of an 1800mAh 4S with regard to flight duration. (weights about the same too) Furthermore, for the lift provided, the motors will draw less current and thus be less likely to overheat or create EMI noise. It’s really all about the wattage so with a higher voltage, less current is used to achive the same wattage.
4S (16.8v) @ 10 Amps = 168 watts, 16.8v x 2200kv motor = 36960 RPM @ full throttle
6S (25.2v) @ 6.66 Amps = 168 watts, 25.2v x 1800kv motor = 45360 @ full throttle
Keep in mind that its the voltage that spins the motors. Hence higher volts will result in higher RPM’s for the same throttle setting, while drawing less current to do so. This assumes that the same prop size and weight are applied to both the 4S and 6S Copters. I’d have to drop the kv rating to about 1500 to get the equivlent RPM’s as the 4S @ 2200kv. Big difference here is that the motors run better, use less current and provide way more torque.
I’d suggest running 1500 to 1800kv motors for those 7 inch props with at least a 4S battery. Sure 3S may feel smoother but thats cause everything is spinning much slower with those large props @ 3S. The 6 inch props like the 6x4x2 or 6x4x3 will work best with KV’s between 1800 to 2300 a 4S. LiPo’s under 4S are really not well suited for our copters as they just don’t provide enough voltage to induce the torque needed on a large / heavy airframe.24 February, 2018 at 17:03 #57134
3s was the solution for my mini and the setup im running. had image stabilisation on the hd cam so that have produced some strange gello in the video so im not able to pic up how the tune is. Bit of a bouns back on roll but more than that was hard to see.
full spec as usual on my tri in the youtube description, my tune is what it is and probably nothing that will work fore more than my setup.
Got audio timing problems in hd vid so thats the next thing to work on 😛24 February, 2018 at 22:06 #57137
cExplorer mini tri
f3fc from David
Aikon 32bit esc
Gemfan 7042 bi blades
Bluebird servo set to 250 instead of 300
TBS Unify Race Hv
Foxeer Monster V2
HD: Foxeer Legend3, 2.5k/50fps/4:3
RX/TX Turnigy Evolution, 1/2 board diversity rx
Skyzone V02 +03s with TBS Patch, Noname clover 8dbi
Tattu 3s 1550/75c
Running multi shot
Pids/BF 3.2 settings
air mode on
dynamic filters on
p_pitch = 58
i_pitch = 35
d_pitch = 28
p_roll = 54
i_roll = 33
d_roll = 46
p_yaw = 170
i_yaw = 45
d_yaw = 35
gyro_lowpass_type = PT1
gyro_lowpass_hz = 90
gyro_notch1_hz = 0
gyro_notch1_cutoff = 300
gyro_notch2_hz = 0
gyro_notch2_cutoff = 100
Anti gravity gain = 2.8
D set point =1.14
TPA o.1825 February, 2018 at 11:21 #57144
WOW, that p_yaw = 170 is really high, Thinking thats because your running 3S instead of 4S.
If you are using Dynamic filters you should be able to disable all of the Notch filtering provided that your motors dont over heat.
question: what is your D Term Lowpass Frequency [Hz] set to ? Thinking that 100-110 hz should be good for you.25 February, 2018 at 15:17 #57145
D_term_notch should be on together with the old F3fc, most of the f3 boards don’t like that of and there are a few f4 boards also that don’t like that off.
My d term lowpass is set to 110 at the moment.
p_yaw is what it is, works perfect on both 3 and 4s actually, but have run 3s for the moment to calm all down a bit and the 3s 1550 packs I got is new, my 4s packs are on their last charges so last evening I ordered some 4s 1800/95c packs for testing.
Got -10c here and a bit of wind so the flight today ended up with 2min lost video, the hd cam turned of after 2.5min so I lost almost half the flight. Hopefully we go towards warmer soon 🙂 not easy to test and tune in this weather1 March, 2018 at 18:39 #57184
Resigning my stock f3 board. It was damaged when I started the build with BF3.2
A cap for uart1 was gone so ive just been using uart2 for rx. But in the cold weather we have had and all testing ive started to get strange problems, won’t boot up as it should, going into “failsafe” directly when arming. Don’t think it is an software issue becuase its the same on the older .7beta
So redesigning everything in general. HobbyWing f4sd, new cage in 2mm carbon, underslung mount for extra things, ill cut down some V4 arms so I get 3/4 full instead of the stock 1/2 just because im in love with those 7″ 🙂 some extra3d parts. a v3 pdb or 6v reg, not decided but an easy thing when I get all the parts.
And some 4s 1800mha/90c that came in the mail today. Perfect fit and lots of power 😀
RcExplorer MiniXL Tricopter 😛2 March, 2018 at 16:49 #57189
If you are rebuilding, can i suggest the Matek F405-CTR?
I have it on my latest baby-tri and thus far its very good.2 March, 2018 at 16:54 #57190
I got the Hw f4sd as an spare thats why im going with that, got one fully operating in my baby so know the board a bit better.
Going to try and fix the rssi for feedback only, on my baby the feedback is on current so im out of that mesurment on the board sadly. If I switch board the matek is next in line just because I know you have made that to work 🙂2 March, 2018 at 18:50 #57191
So far I’ve been able to hook up everything that I’ve wanted to the Matek F405-CTR.
-FC is tripple isolated (soft mounting) from motor noise.
-Aikon BLheli-32 6S 4in1 ESC with 1000uf capacitor. Esc is isolated from the FC by soft-mounting it on the otherside of the carbon frame. I had previously used individual esc’s but realized that by having the 4in1 not only does it save weight, it keeps the esc’s mass close to the copters center of gravity. This only works if the copters arms are under 100mm in length. Otherwise signal attenuation becomes an issue.
-Matek VTX with 330uf capacitor on input vbat power. Upon Triflight upgrading to Betaflight 3.3, should be able to automaticly control the transmitter power. Allows the FC to lower the VTX power when not armed to prevent over its heating.
-Runcam Swift V2 with micro LC-filter between it and the VTX 5vdc power supply.
-Frsky R-XSR with telemetry. Unfortunately the range apears to be subpar from the Frsky XM.
-Modified BMS-385MAX Servo with feedback wire.2 March, 2018 at 19:50 #57192
The Hw f4 got the 6000 gyro so its going in hard. But have 3 ferrit cores for servo and signals so going to test some things out. Hopefully ill get the stock rssi working so ill get current values back in the osd. ikon 32 bit and 1000uf on all needed. but think ive might found the fault with my f3. when I plugged out the tbs unify all worked. so might switching back to my rush 1.1 just because I know that one works flawless4 March, 2018 at 18:38 #57199
Lets see if our chat and thoughts around the ferrit “filter” is something that will make an difference. +- is 5 loops around on the intake to the servo. Not pretty but if it works there always possible to make an nice 3d print for it after
Attachments:4 March, 2018 at 23:14 #57201
I’ve found that some open purchased Cores that are long, flat and narrow, allow you to just thread the Core once. This ends up being both a weight savings and makes things much easier to install. Don’t get me wrong, the bigger Cores do work but they add extra weight and complexity. In hindsight I’d suggest Cores only after other methods have been exhausted.
Here is some reading on the subject:
Be aware that ferrite cores are frequency specific. Hence just adding one on may not help as much if it’s working frequency is above or below your interference. That being said, if your problem is power specific then you’ll want a core with a lower filter point. Conversely your issue is from the VTX / telemetry then you’ll need a core specific to that, which in our case is 2.4ghz. One way to find out is to disable your VTX and outgoing telemetry and see if the Servo performance improves or not.
Side Note: Took a look at your JPG and I’d suggest not using hot glue. Reason being is that “if” you have to add or remove anything, getting rid of all that glue is a pain. Instead, thin (glueless) heat-shrink is more than suitable and could possibly end up saving you some weight too.
Beyond all that two thoughts…
1) Location and placement of Antennas and Current carrying cables is very important. Anything too close to your Servo can adversely affect its performance. It’s possible that a Core can help if your placement options are limited.
2) Keeping the power to the Servo as clean as possible will help more than anything else. (is much easier to do) On my Advanced Tri-Baby build, I’ve the 4in1-ESC card powering the servo so that the Flight Controller isn’t involved in powering the Servo. Only connections to the Flight Controler are the control and feedback wires. This separation / isolation has allowed me to achieve near zero tailwag on what’s a largely untuned copter. The way io have it wired, the FC’s BEC is supporting only the FC keeping the FC as clean and wire free as possible.
Yeah, I have yet to go out and fly it in the real world as I have been really sick over the last week. Furthermore the cold-snap has presented us with some shitty weather. I hope to fly later this week and make a video with full logs to take back and aid in tuning. (weather and wife permitting)
EDIT: I picked up a few of these and found them to be great for filtering. They’re extremely small such that i was able to solder one directly onto my Tri-Baby’s camera power supply. https://www.amazon.de/gp/product/B075V5M52V/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=17 March, 2018 at 21:45 #57215
I give up, first the stock fc (found the fault, an internal connection that has broke due to age and crashes before I started the build this time)
Hw f4sd, works on my baby but won’t work on mini, same goes for the Bff4, cant find the problem/bug in the system at all 🙁
Last test I soldered the stock f3 board up again, all works perfect up to the point of mounting all together, so nothing wrong with motors, esc, cables, its something with my boards.
just want all to work so bought a new f3 from David, at the moment I couldn’t care less about the things ill miss from the f4. Just want the MiniXl in the air at the moment.
Sadly, if an new stock board with all new parts fail im out… Built 30-40 (quads and 5 tri) units the last 2 years and never had this problems before so..17 March, 2018 at 19:18 #57277
Tuning needed, some wag from the tail. But damn I like my setup. 7min flight in -5c gave 14.92v an 13% on the acc.
So far I cant find much wrong in BF3.2, everything is working as it should. running 4k,4k and PT1 at the moment. bumped the d_yaw to 30 (stock20) thats almost all right now
Full description on youtube.23 March, 2018 at 18:04 #57318
After an “extreme” crash last weekend my minitriXL is in the air again.
The Hobbywing ferrit 5-6v core on the servo makes a lot of difference for the servo 🙂
Got a bit of tuning left now to get rid of the last nose/gitter.
For those amino 1800mha 4s acc I run now the new props came today.
Hq 7035x3V1s, first LOS flight felt perfect so looking forward to the tuning session during eastern
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