22 January, 2018 at 10:03 #40759
For what your talking about, you’ll need one of the small electrolytic ones that are like 100-470uF and low-ESR. Maybe use something around 10 – 15 VDC as the servo input voltage is between 4-6 volts. Basicly your just using it as a frequency “shit-can” capacitor and voltage dump for spikes. Sometimes a smaller cap can work just as good or better than a large one, depending on the RC “resonance” of the circuit it’s applied to.
Note: The higher the capacitor uF, the greater the spike it can handle within it’s given voltage rating. However, any Capacitor or voltage rating higher than what i’ve suggested and the capacitor will become quite large relative to the servo cables it’s attached to. The uF of the capacitor relative to the resistance makes for a RC tank circuit, which has a frequency specific resonance. https://en.wikipedia.org/wiki/RC_circuit In those RC circuits, typically a ceramic capacitor is used for frequncy filtering. (think radios)3 February, 2018 at 11:56 #40867
Well the worked 😛 or I could mount them at least.
Gemfan 7042r clear propps, could be interesting to test out as soon the bf3.2 is ready
Attachments:8 February, 2018 at 22:00 #40906
Got some help today, Thx for the test Hex file on the BFF4.
Waiting on an 6v ubec for some more power to the servo and an tbs vtx before I rebuild my mini tri for the last time 🙂
Flashed the new hex on there today, remapped the motors so geting the servo and feedback left when the ubec arrives before I could do more “desktop” tests. But its an active project that moves in the right direction9 February, 2018 at 23:47 #40918
BFF4 up and running on BF3.2, all seems to work ok, after some change on the motors they spin fine, failsaife is working, but I can’t get the channel right for the servo tho. maps at ch7 but if ive read all right m3-m4 are locked on this board. so map should be as davids stock f3. m1 motor tail, m2 servo, m3 motor right, m4 motor left.
Bit of an stressful day but hope my little info so fare could give something.
//note, stock port rx6 don’t support ibus, had to put my rx on rx2 to get ibus working.12 February, 2018 at 17:06 #40951
Last evening I took the decision to rebuild my mini due to a probably broken BFF4 card.
Talked with the dealer today so a new card will come during the week but not an bff4, went over to a Hw F4 nano instead when that card got 6 pwm pins, thats a bit better for an tri, or more easy to set up.
But anyway I felt the need to fly so I put back the stock F3 card and put the new BF3.2 on that. 4S and 7″ gem fans. WOW OMG, not tuned but so smooth and quiet. Got the new TBS vtx today so ill build all together and maybe fpv maiden during the weekend 🙂22 February, 2018 at 18:43 #44932
Finally I got the time fore some more testing.
Full spec in video on youtube.
Running the basic setup I posted in the Betaflight 3.2 test thread.
Need more PID tuning I know but on my way 🙂
One thing that ive noticed is that Airmode is a bit low in RPM so I don’t have full control on min throttle as you’ll see in the video. Could be because of my 7″ but ill look into that. timing on the servo and motor is not 100% as well so some minor things but it looks good for the spring and summer22 February, 2018 at 19:35 #45059
One thing I’ve learned recently is that the Tail servo likes having lower Gyro and PID rates. If your seeing a lot of Wag this should help. Like your place, seams very nice for FPV.
The clear props make it harder to see the Copter in flight when not using FPV. They look cool otherwise. Maybe add an LED under them so they can refract the light and glow ?22 February, 2018 at 20:09 #45143
Where we live is perfect for testing 🙂 Ive found some small things out that ill test as soon im able to. Got some more changes to do before I tune the last things.
Airmode is one thing that buggs me, motors are spinning a bit to slow on min throttle and the timing on the servo is off for punch, but that could be because I run 7″ on those motors, they produce A LOT of torque.
Never go full så at the moment no problem. But a thing that will need to get fixed later on22 February, 2018 at 21:18 #45337
By the way Kevin, LOS is not a strong thing here 😛 so those clear props are not a problem when I run fpv 95% of the time. Only fly LOS for the absolute basic stuff when starting up a new build and for basic tune. Im to stupid to have control over any aircraft LOS, have goten better but I loos track of direction very easy so I flay mainly FPV23 February, 2018 at 00:22 #45864
What is your current draw while hovering? I ask because a 2200kv motor sounds a bit under powered for 7″ props. If your mini is anything like mine you should see between 7-9 amps to hover and that from everything combined. Much more then that and your looking at losses from rhe prop being too much. I have tried 7x4x3 and while it flies great, the extra current draw results in in noticably shorter flight times. (I am running 1900kv motors)
Props that are 6×4.5×3 should be ok but anything larger and your likely to be stressing the motors.
Keep in mind that David runs 1300-1500kv for an 8″ propeller.
Here is the link to Hobbywing’s website for your motors:https://www.hobbywingdirect.com/products/xrotor-2405-motor-blue?variant=35103758609
They recommend 6″ props.23 February, 2018 at 10:21 #47170
Sadly my Bff4 card got burned so as you see I run the stock f3fc now, I see the volt but nothing more. have not used blackbox or something.
But on 7″ I still get 7-8 min flight on 1500 4s so I cant say the motors work to hard. more like the setup gives more power than the servo could manage in speed. Well aware of HW specs thats why I chose the 2250 motors.
But I got 10 different 6″ at home so ill start testing them out after the next flight. Have made a change in the pids so need to fly one more pack on the 7″ before I switch.
Probably 6″ will be more suited for freestyle but get smother flight than with the 7″ is not possible, love the feel in those even with an tune thats not perfect23 February, 2018 at 10:41 #47222
Tested Gemfan 6042bi now, those did not go well at all with my tune. So need to retune all and start from stock bf again.
But the last change I did was for the better on 7″ so ill set up all 3 different profiles in Bf so I could switch between them.
I bumped up Yaw_d from .2 up to .3 that gave a much smother tail so its a bit more to the tune on a tri than the stock pid values that you see in the browser23 February, 2018 at 10:59 #47272
I’m going to try the Matek F405 CTR FC soon….
There’s a Triflight target for this so “if” this works better than the current FC i’m using on the Baby Tri, you could give it a try also for your Mini. It uses the old style IMU so it should be less sensitive to vibration.
I plan on pairing this up with Aikon 4-in-1 esc. I’ll have the FC mounted in it’s traditional position and the 4-IN-1 between the battery holder. Having the ESC between the carbon plates should keep the electronic interference away from the FC and allow the weight to be closer to the copters CG. (No esc’s attached to arms) This will save weight and allow me to use less wiring overall. The fewer connections means less crap to attach to the FC that can transmit vibrations. I’ll connect the two cards using the hole in the center of the carbon plate.23 February, 2018 at 16:48 #48192
Tested some more with the mini today, 6x4x3 and the 6042bi. Both with sad performance so I reflashed the fc and put in all as it was for the 7″. now I suddenly got tailwagg as hell, I recon that could be because -10c today and -2c when I tested in the last flight.
running hobby wing f4sd in my babytri with hw 40a esc. no hex for bf3.2 yet so have not tested that one more than get it in the air and see so all basic stuff is working. Going to play more with that as soon the hex for omnibus pro/sd is ready 🙂
For now I sadly think I need to wait for better weather, below 0 is not good to test in 😛23 February, 2018 at 18:57 #48528
Ive gotten rid of the tailwagg on the mini now, at least in LOS. first problem was some water from the snow 😛 then I found some tings in the setup that had poped wrong.
But the biggest change was to run the 7″ on a hi c 3s acc, if the power is there in lift I could probably run 1800-2200mah on 3s in my setup and get an amazing flight time.
After Ive tested both 3s and 4s on the same settings/setup I would say that the stock bluebird servo is to weak. on 4s I should theoretically pass 2kg lift/motor and thats on the same rpm as bi blades in 6″ with the stock emax setup. so my wild guess is that the servo is to small for the power/lift I get with the 7″, together with an timing/correction that should be a bit off.
But with 3s acc it all looked good, the little I could see in the dark 😛 no twist on yaw on punch so my pids are almost up for it. Ill check in daylight los and then go over to hd vid and see how it looks like.
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