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1st Electrohub build confusion

#1
Sorry to be a bother, two areas I am confused on Electrohub Spider build with RTFQ kits:
1. Was I supposed to solder two of the motor leads flipped to get the twp that spin in the opposite direction, or is it based on the port the ESC's connect to?
2. Someplace, I thought in the FT Build video I saw how to calibrate the ESC's with the transmitter but I can't find it again. When I search online I find only examples using a special firmware for the Flip 1.5 board. I'm sure the video I saw was pretty simple, but not sure.

I'm not very progressed, but have the motors soldered to the ESC's. Newbie to soldering too. Arms drilled, painted.
Thanks in advance!
Bill
 

TEAJR66

Flite is good
Mentor
#2
You will need to flip two wires on two of the ESC/Motor setups. Then test each, with no prop, then make a note of their rotation direction.

You can plug each esc separately into the throttle channel on your receiver. Turn on the transmitter and move the throttle to full. Power on the receiver, and wait for the beeps. Throttle down and wait for the beeps. Now moving the throttle should produce a motor response. Repeat for the remaining setups. That is just a very basic calibration for the ESC to the throttle range.

Once you have it assembled, read all the wiki's you can find for your FC Board.

When I built my electrohub with the RTFQ electronics and the flip 1.5, everything worked out of the box. No need to change any thing. I may have calibrated the ESC's individually first, I don't remember. The thing that needed adjustment was transmitter endpoints and that was laid out in the wiki's on the RTFQ web site. Once end points were set, everything worked. Then I connected the board to my PC just to assign the flight modes to a 3 position switch.

The elctrohub that I have fly's fine and there has been no tuning or adjusting other than TX End Points and Flight Mode Switch Assignment.

Good luck.
 
#3
Tommy, Thanks for your prompt response!

Bummer about the motors/wires - of course I just shrink wrapped the ESC's. Oh well, better now than after mounting everything. I had a feeling.

Thanks for the info on calibrating - I sort of remembered something like that, but could not track it down again. Also, I bought the RTFQ ESC Calibration cable - I think this allows cal of all 4 ESC's at once???

Thanks Again! Bill
 
#4
Making progress! Bound the Rcvr to my DX6i. Calibrated the ESC's. [Nothing blew up or smoked when I connect the battery, which was awesome!]Next question: for the props, I have one set marked "Multi Rotor Pushers" and one set just marked "Multi Rotor". Am I correct that the PUSHERS go on the Clockwise (from above) motors, and regular props go on the counter clockwise rotating motors?

Another issue, in trying to adjust the transmitter endpoints for my DX6i, I found the range more limited that what was shown in the Flip 1.5 for Dummies video. As well as the range printed on the controller package. For the Dx6i I could onlu adjust from 1000 - 2000 *in the MultiWiiConfig utility) and only +/- 125% in the transmitter. Am I missing something?
Thanks!
 
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#6
All set - I figured these out!
:applause:

I've had my Electro Hub for about a year now and still flying fantastic. I've recently enabled the Horizon level to a channel and the thing is 10x easier to fly. I'm glad I spent all this time learning in the initial acro(hard) mode. With the Horizon mode enabled I don't have any orientation issues and have much more time to react in any panic situation.

I did the same thing when I built mine the first time with the motor direction and soldered a few leads before checking. Had to cut and reattach but just power though it. I found I enjoy the construction time as much as I enjoy the flying.
 
#7
I agree with you Beeah! Had to learn to solder - love it now. Really enjoyed all the learning from FT and other videos. I just have to add the props now and find some time this weekend and go for the maiden flight.
Thanks!
 
#8
1st Electrohub confusion - ugh

OK, finally finished, all the MicroWiiConfig adjustments, calibrated the ESC's, transmitter endpoints, proper reverses for my DX6i, tested all the motor rotations. I have gone slowly so I think I was attentive to details. Put on the props in the proper orientation. Added battery.

Took it outside, calm day. connected battery, armed the controller. Throttle up, flipped over into a bush. Ok no harm done.

Took it more into the lawn, throttle up, took off, but wanted to bear to the right, strongly. it was a challenge to bring it back towards me, brought it down hard. Redo, same bearing strongly to the right. This time came down hard enough to break the ties on 2 landing legs.

Yes, I am new to flying, but does the strong bearing to the right mean I should be adjusting the roll trim, or something wrong with what I did in the MicroWiiConf adjustments.

Any guidance will be greatly appreciated!
Thanks!
 

NHS77

Senior Member
#9
Flipping over on take off is usually: one or more motors spining the wrong way and/or props on the wrong way. (The leading edge of the prop should always follow the spin direction of the motor... if the motor spins correctly of course).

If it just breaks out to one side: Check the trims on your radio (should be zero on any axis) and check sub trims on your readio while connected to the config software. Mid stick should read as close to 1500 as possible.

You can also check: Is the FC mounted the right way? Front of the FC is front of the craft? Is it the right side up?
Further casuses could be: Vibrations messing up the FC. These can come from unbalanced props and motors and possibly equipment on your fram that is not secured right and transmits vibrations to your FC. If you feel your props are sufficiently balanced (usuallly the prime source for vibes) you can try adding a layer or two of foam tape under your FC to dampen it.

If you have the baro and mag option on your FC disable it (via the arduino definitions in the sketch) for now. I had those on my first FLip 1.5 and they messed up everything.

See if any of thet helps. When in doubt erase the eeprom on your Flip and reflash with the newest firmware.

The deadcat config also introduces a number of problems, which can be dealt with the use of a custom motor mix. This however is easier on newer boards than run cleanflight and is something to look at once you get and stay in the air.

EDIT: And of course calibrate your gyro/acc again. Never a bad idea.
 
#10
Thanks NHS77!
I redid all the connections. FC mounted properly. NO baro or mag.
Verified motors rotating in the correct direction and that the props were properly placed. And I had carefully balanced the props previously using DuBro.
Replaced the Rcvr with a AR610, because I had one.
Recalibrated the ESC's.
Rechecked everything in MWC. This time adjusted the Sub Trims, plus calibrated the Acc after carefully leveling the FC/Quad. (did not do these first time).
Trims on Trans all at zero (in the middle correct?)
Angle mode.

Retested - a bit more stable, but now:
- Once i get it into the air it keeps on climbing. A small reduction in throttle brings it down fast, and it hops a lot. hits the ground, bounces back into the air, repeat, repeat. Breaks the ties on the legs. If I don't reduce the throttle, it just keeps on climbing, and quickly gets very high, like above my 3 story house.
- It also wants to wander, pitch forward and rolling right. Less extreme than previously, but still not in control.

I think better, but still out of control. Any other suggestions?

Thanks, Bill
 

makattack

Winter is coming
Moderator
Mentor
#11
That's great that you balanced the props, but how is the flight controller/flip1.5 mounted on your multirotor? Is it using double sided foam tape? How many pieces/what's the thickness?
 
#12
I used the 3M very high bond two sided tape that is referenced in the FT Build video. I used one piece, not sure the thickness. It's on there very tight and does not move at all. used the same for the rcvr.
Thanks, Bill
 

NHS77

Senior Member
#13
Well good, so far....

wandering: without gps you'll always have wandering to some degree if you just let it go. once your other issues are sorted out PID tuning can get rid off some of it. however, for now i'd check if your center of gravity is where your FC is mounted. sliding the battery back and forth goes a long way towards that end. the sideway wandering could also be that, but more likely PID or slight trimming issue... or wind frankly :)

Throttle response: have you adjusted your stick travel? throttle down should read close to 1000 in the config. If not, adjust it accordingly. (throttle all up = 2000). after that you can dial in your throttle curve, either in config or on the radio. This will dampen your stick input around the hovering point. It helps knowing at which throttle percentage your quad seems to hover. Usually around 50% or if overpowered lower than that.

Other than that it simply does take some practice to get your quad to hover. Starting out you'll always move the stick back and forth until you get a feel for it and do constant but minute throttle inputs to keep it where it is.
 

NHS77

Senior Member
#14
I used the 3M very high bond two sided tape that is referenced in the FT Build video. I used one piece, not sure the thickness. It's on there very tight and does not move at all. used the same for the rcvr.
Thanks, Bill
Try using 2 or 3 layers of foam tape... re-calibrate afterwards.
And make sure no wires are pulling or pushing the fc or are attached in such a way that they could transfer vibrations to it.
 
#15
Regarding the tape, why will 2-3 layers be better? Just asking because with the one I have used it will be difficult to remove the FC.

Regarding throttle, I did adjust stick travel to the 1000-2000 previously, sorry I forgot to mention it.

Let me check the battery position. While I measure the FC placement in the COG of the quad, I need to confirm the battery placement. I eyeballed it and thought it was close, but I'll go back and dbl check,

Regarding the wandering, other than the continuous climbing, it wanders a good 40-60 feet pretty quickly.

The continuous climbing is my main concern.
Thanks, Bill
 

NHS77

Senior Member
#16
OK, let's step back and look at your setup. What motors with what kv do have? Prop size and pitch? 3S or 4S battery? AND What's the all up weight of you quad?

Do you have a camera on it? This would tell us whether you are actually vibration free (wobble in the video).

2-3 Layers of foam tape will dampen vibrations reaching the FC and messing with it's sensors.

Regarding the wandering, I'm still not sure that this more or less normal, would have to see a video of it in the air. what you could check: Measure the distance from each motor to the center of the frame. If one boom was longer or shorter than the others that could introduce some issues. Do you have a spider/deadcat layout? (In choosing X-Layout during setup your fc thinks all booms are the exact same size and the layout is symmetrical, thus applying equally strong throttle commands to the ESC>Motor to maneuver the craft. If that is not the case though strange things happen... had this on my original Ehub spider. Can be fixed but we're off in the deep end for that...)
 
#17
Firstly, Thanks NHS77 & makatack for all your support and interest. Really appreciate your time, and this forum!

Here are the details of my quad:
- Flite Test Spider Electrohub kit plus camera platform
- ReadyToFly Quads kit for the above: Flite Test ElectroHub Electronic Kit
o Flight Controller: Flip 1.5 with CASE
o Firmware On fight controller: "Spider" MWC 2.3 Quad (as seen in video)
o Speed Controllers (ESCs): 4 pack of F-30A Fire Red series SimonK
o Motors: 4 pack of T2212-980KV RTF Motor
o Propellers: 2 pair 9x4.5 MM props Black
o Male XT60 Plus 12 Awg Wire
o Rx cables
o RTF Quad Receiver wire set
- Receiver: Spektrum AR610
- Transmitter: Spectrum DX6i
- Turnigy 2200mAh 3S 20C Lipo Pack
- All out weight including platform & LiPo, but without the camera: 871 grams (1.92 pounds)
- Camera, have not installed yet: Mobius with Lens C (would add 53 grams (~2 ounces)
Recap:
- FC at CoG, one piece of VHB Tape (I will triple this up before next test flight)
- Balanced props
- Motor rotation confirmed
- Calibrated ESC’s
- Calibrated Accelerometer (in MWC)
- Adjusted the transmitted endpoints 1000, 2000.
- Adjusted sub-trims
- Trims on Trans all at zero
- Channel 5 for Angle(0)/Acro(1) modes - have left this at Angle.


Thanks! I look forward to your guidance. Bill
 

NHS77

Senior Member
#18
OK, that all sounds good.
Your AUW is relatively light for the amount of thrust you can get from that combo but I had supected that you may use a 4S battery which would have really overpowered your craft, giving you a hover at 20-25% and thus explaining that your quad really just wants climb with little room for control left at the low end of the throttle stick.

But you're using a smaller 3S. This battery is relatively light, adding to my theory, but doesn't produce as much lift. Still, I'd have to research your prop / motor combo but I would guess you're easily getting 650g of thrust per motor at full throttle (maybe more). 4 x 650 = 2600g thrust. If your quad weighed 1.3kg you'd hover at 50% thrust. Since your's is over 400g lighter you're throttle point should be around 35% thrust. This gives you a smaller range of stick movement to manage your thrust, which is more challenging, especially for new pilots.

A quick thing to try is adding weight to it. Maybe 400g. Perhaps you can tape something small and heavy (AA batteries or something) symmetrically to all booms. Close towards the hub. Then see if you feel you have more control over it in terms of throttle management.

In the long run, with a camera, maybe a canopy and a beefier battery (3S 3700 35C) you'll easily add 300g or more and should end up at a good power/weight ratio. Also: FT's new Rail System for the Ehub is pretty neat. mounting options for cam and battery plus easy shifting of your CoG. Also ads 100g...

Other than that, as mentioned before, dial in a throttle curve. You can do this in the DX6i. Level out the curve between 30-40%. This will dampen your stick inputs around the assumed hover point, making it easier to manage thrust. You may have to experiment. You can also do this in multiwii config. If I remember correctly it's a blue graph. add a value of 0.50 and give it a try. I would do either or method and see where it gets you.

Hope any of this helps!
 
#19
Awesome detail NHS77! And I get it regarding the thrust estimate.

I have to take some small steps during the workweek, but here they are:
- The FC is now attached with three layers of the VHP tape.
- Carefully leveled the Quad, and re-calibrated the Acc.
- Confirmed all the transmitter endpoints held.
- Not sure about "dial in the throttle curve". In MWC, I see the blue line graph for the Throttle adjustment, but there is already a 0,50 in the Mid-box, and 0,00 for Expo. Does this suggest your recommendation is already in place, or is there still something I should do? Also I am not sure where to make this adjustment in the DX6i. Sounds like I only need to adjust in one place or the other?
- I have an E-Flite 3200mAh 3S 20C LiPo Pack (241 grams). So that is +50 grams. BTW - you mentioned 35C, what would that get me over the 20C?

Thanks!
 

NHS77

Senior Member
#20
The Expo value is what you want to dial in to flatten the curve in MWC at the hover value. Since our theory is that you hover below 40% move the midpoint to 0.4 or maybe lower and the choose an expo value. perhaps 30%, you'll have to try.

Your Spektrum radio will do the same to some extent: http://youtu.be/org2d6r6FRQ

And yes, do it either in MWC or on the radio. I've always used the software based options on the FC.

Battery: Well give it a try with the heavier battery. 50g is 50g. Why 35C? The higher the C rating the more amps the battery can deliver, which requires the packs to be more dense and thus heavier - which is what we were after. (which is curious because mostly you're trying to get rid of weight on a quad :)

Since we're talking C rating, it actually goes on: You've never driven your motors at max because it takes off at such low values. The motors you have will likely pull around 18 Amps at full load. So that's 72 Amps for all 4. Your 20C 2200mAh can only deliver 44 Amps (20C x 2.2A = 44). Usually they can double that value for short bursts, so up to 88 Amps. Now, once your copter is heavier, due to added dead weight to make it more flyable for you, or through extra equipment you're adding, anything above maybe 60% throttle would start straining that battery, shortening it's life as well as flight time and you won't get the performance needed.

With the 20C 3200mAh you have, you're already in better shape: 20 x 3.2 = 64 Amps. But there is always some inefficency in any setup as these calculations assume perfect conditions and the batteries rarely deliver what is written on them. Factor in 10% loss and we're back to 58 Amps or even lower. With 35C 3200 you're well above 100 Amps, giving you some overhead to what your quad will pull at the very most. Alternatively you can also increase the capacity: A 20C 5200 for instance will also get you 100+ Amps but longer flight times at that. (But these get fairly big and heavy... there is always a trade off :)