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First Multirotor Problems, I'm New at This

#1
kk2.1 board
e-flite Park 300 1380kv motors
Turnigy Multistar 15amp ESCs
Spektrum dx6i transmitter and AR600 receiver
Anyrotor kit from the fabulous Flite Test guys


# Tricopter
-TGY375DMG Metal gear digital servo
-Props mounted using built in prop savers on motors and o rings
-Flips every time when launching. I've checked all settings, calibrated ESCs, calibrated kk2.1 board, balanced props and check correct rotation direction, and everything else imaginable.
-One motor seemed to speed up more than others but I believe I have the ECSs calibrated better.
-Last couple attempts I was able to launch copter but it oscillates badly
-Digital servo has now stopped working. Possibly after crash?

# Quadcopter
-Same setup just four motors and no servo of course
-Will launch into air but then oscillates badly to the point of flipping sometimes
-Mounted motors upside down and used prop mounts this time

1) Are the Multistar ESCs even able to be calibrated?

2) What are some good kk2.1 beginner settings?

3) Should I be using a plane profile or copter profile on my dx6i?

4) Prop saver vs solid prop mount?

5) I have DT750 motors and Turnigy Plush ESCs available, should I try these instead?

Thank you so much in advance for any advice. I am so excited to build these machines. The Flite Test guys are amazing and want to support them as much as possible.

I'm out here in Arizona with plenty or clear skies and warm flying weather!!
 
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FinalGlideAus

terrorizing squirrels
#2
Just some quick answers from me as I'm at work. I'm sure others can fill in the blanks.

You should be able to calibrate the multistars no worries. You will benefit from using an esc flashed with SimonK firmware for much smoother a crisper response. Search YouTube for SimonK and how flash ESC's with it. The multistars are really not much chop even though HK and FT flog them off as being a Multirotor esc.

The default firmware is crap on the kk2.1 which may be half yor problem. You would be icing from flashing it with. Steveis firmware version 1.12s1. The stock settings in that version generally fly pretty well. Buying a USBasp tool will do this and flash ESC's. They can be bought cheaply on eBay. Check the Multirotor top tips sticky for a video on flashing a kk2 board.

Plane or heli profile doesn't really matter. If you are familiar with a plane profile then use that. Nearly everyone does.

I would personally not use the prop saver. You need a solid mount to get the many changes in rpm to go straight into the prop not the rubber mount that will flex.

Although they are working hard, I would continue to use the park 300's. Bang them up while learning and then go to the bigger motor. That's what I did.

Haa. So much for the quick reply.
 
#3
Thanks FinalGlideAus!! This is a great starting point for me. I've heard a lot about the SimonK firmware and will be looking into it.

Thanks again!
 
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#4
Not to sound like such a rookie, but what could be considered a bigger motor in the future? I'm still trying to wrap my head around kV, amperage, and thrust with motors. I went with the Park 300s per the FT recommendations.
 
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FinalGlideAus

terrorizing squirrels
#6
When I was reffering to bigger motors I was talking about your DT750's. Bigger motors mean more thrust to deal with and a heavier craft that doesn't take impacts as good as the light version.
 
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jhitesma

Some guy in the desert
Mentor
#7
Actually the Multistars can't be calibrated. The instructions that come with them seem to indicate they can be...but it just doesn't work. It's one of the reasons I'm not a fan at all of them and have 4 of the 10a ones sitting here gathering dust. I did quite a bit of searching on-line and never found anyone who was able to get a multistar ESC to calibrate.
 

cranialrectosis

Faster than a speeding face plant!
Mentor
#9
Lower KV uses longer rotors and the motors are heavier the lower KV you go and are 'larger'. Faster motors with higher KV ratings tend to be smaller and lighter and run shorter rotors, hence are 'smaller' motors.

Fast motors with short rotors tend to not cause the same levels of vibration as larger motors with longer rotors. Therefore smaller rotors are simpler for a beginner to handle as you don't need the same level of expertise to balance the rotors/motors.

Definitely lose the rubber bands. Rotors on a copter are the flight control surfaces not just propulsion. Imagine having your wings flop around while you are flying a plane due to a loose rubber band. That is what it is like for your copter when you use rubber bands to secure a rotor.

I concur with jhitesma. The Multistar ESCs are toxic by reputation. I believe you will be hampered so long as you deploy them as they are outdated tech. You want Simon K. Ask for it by name. Slow ESCs that are not calibrated can cause wobble particularly on a heavy > 1kg copter.

How is your FCB mounted to the frame?
What does your copter weight with/without a battery?

I recommend the following:
1. Re-trace your ESC servo cables from the motors to the board. Ensure that motor 1 ESC is connected to M1 on the KK2, motor 2 ESC to M2 on the KK2 and so on. I doubt this is the issue but it needs to be ruled out.

2. Ensure your subtrims are zero'd out. Set your transmitter trims to 0.
3. Ensure your sticks are calibrated so that when you push left rudder on your stick the board shows left rudder in the receiver test. Do this for all stick movements.
4. Ensure your KK2 cannot move during flight.
5. Flash the KK to something newer and more stable.
6. Reset PI to the defaults.

Maiden with autolevel turned off. Autolevel makes wobble worse in most cases. Do this over soft ground as flying in acro mode is HARD for new pilots.

Capture test flights on video and post to this thread so we can see the issue and provide better help.

If the wobble still persists with autolevel off and new firmware set to the defaults, we will start asking weight questions and looking for motors tilted or loosely attached to the copter or vibration issues hitting your FCB.

Welcome to FliteTest!
 
#10
Such great responses thank you so much guys! I ordered the USBasp and will be reprogramming the kk2.1 and ESC's to start.

My kk2.1 is mounted to the foam lid it came in as I have seen this done by the FT guys but maybe I need to solid mount it with a vibration damper?

I'm learning that the Multistars may not be the best option for multi rotors and have some Turnigy Plush one's to try in the future.

Working on a picture and videos to upload for further troubleshooting.

Thanks again so much!

I have verified all leads to my servo and I think I may have fried it somehow. Already have a spare on the way and will update ASAP.
 

cranialrectosis

Faster than a speeding face plant!
Mentor
#11
I too use the foam lid for the KK2. I secure it to the copter with zip ties as detailed in my current build log http://forum.flitetest.com/showthre...ium-Engineering-Super-Simple-Spider-Hex-build.

Personally, I would start with the quad. It is mechanically more simple than a tri-copter.

If you are flipping on lift off, chances are you have a reversed channel, a subtrim WAAAAYYYY out of whack or the ESC servo wire for motor 1 connected to M2 on the KK2 and visa versa or a similar mismatch connecting ESCs to the KK2. I have made this mistake more times than I can count.
 
#12
Video Upload

Ok finally have some video to load. No programming done on kk2.1 boards or ESCs yet though:



1) Testing prop start up and rotation on flat table. Motor #4 seems to cut out or not respond at times. I have tripple-checked all settings and connections. Tried calibrating ESCs multiple times. Factory reset everything and started from scratch. Maybe due to non level surface, ESC stock firmware cutting out the motor, or maybe even problem with ESC or motor...?




2) Testing directional input from transmitter. It's really hard to see but when I move the right joystick the copter responds in the correct direction (forward, backward, left, right, etc)




3) Launching with auto level off. Copter appears to want to flip one direction.




4) Launching with auto level on. Copter rises but oscillates badly.




I am making progress and so excited to keep learning more!
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#13
Progress!!!!

What you're describing with the motors randomly quitting sounds like the ESCs are stalling -- sounds pretty typical for reports on the multistars. If you've got the Plush ESCs on hand without ripping too many airframes apart, it might be best to give them a go.

Check out HK's F-20A or F-30 ESCs -- they're not bad with the stock ROM, but they're *really* easy to reflash, and are nice/cheap ESCs (instead of crappy/cheap).

for the oscillations, it sounds like the gains are too high, but you need to sort out the stalling motors first.


Oh, and before Xuzme can get to it . . . a short PSA:
 

Balu

Lurker
Staff member
Admin
Moderator
#15
Love these short videos. It helps a lot to see what problems I might encounter when I start my build :)
 

cranialrectosis

Faster than a speeding face plant!
Mentor
#17
After seeing the video, I concur with Dan. Suspect the Multistars.

To trouble shoot I would:
First remove the rotors. I cannot stress this enough.

I would then swap motor 4 with another motor on the copter. Does the problem move with the motor or stay with the ESC.

If the issue moves with the motor, check the motor berings and the wiring at the base of the motor. Does the motor take more torque to twist with your fingers or make a squeak or whine or pinging noise when you spin it? If you gently tap it, do metal shavings or does sand fall out?

If the issue sticks with the ESC, swap that ESC for another on the copter. Does the problem move or does it stay?

If it moves the problem is likely the ESC. Calibrate it distinctly with the transmitter using the calibration process for a fixed wing craft for that ESC. If you do this for one, you may need to do this for all four.

If the problem stays with boom 4, swap the servo leads at the KK2. Disconnect motor 4 ESC from M4 on the KK2 and plug it into M3 on the KK2 and plug the motor 3 ESC servo wire into M4 on the KK2. Does the problem move or does it stay with boom 4?

If the problem never moves from boom 4, check your wiring harness. Tug on the bullet connectors. Wiggle the solder joints. Movement in the joint or crunching sounds are bad. Resolder the joint.

If the problem moves to motor 3, check the solder on the M4 pin on the KK2. This results in a MUCH longer post that I will spare everyone if I can.


I think you will fix the issue with a calibration of the ESC, or the flashing of them to Simon K or the equivalent for a Multistar (if Multistars won't take Simon K).


That PSA always cracks me up. :)
 
#19
What a difference flashing makes! Programmed both the kk2.1 board and multistar ESC's.

What setting should I adjust so the throttle is less responsive? Being new I'm still learning how to control everything and am constantly over adjusting the throttle.

Don't laugh:

 

FinalGlideAus

terrorizing squirrels
#20
We'll done mate! Having the right gear helps doesn't it.

I wouldn't say you're over controlling the throttle much at all. It's just a matter of getting the feeling for it.