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Pumpkin drop event

MiG-3 with Violent Spinner Vibrations

#1
I bought a spinner off Amazon thinking that I would complete my MiG-3, but it's giving me problems. The spinner doesn't have any noticeable vibrations until the throttle hits 80-100%. I have not balanced my prop or my spinner- I was hoping the spinner would work straight out of the box since I don't have one of those balancing stands. Is this common? I've already tried a couple of nylon spinners and they all did this. Although they had no problems on my 1000 KV motor. Are spinners not meant for high KV motors (the 1400KV motor is new, so the shaft should be perfectly straight)? How well do the 3D printed spinners work (the ones that the flitetest team uses)?

Motor: Emax XA2212 1400KV
ESC: 30A
Battery: 1500mah 3S
Prop: APC 8x6E
Spinner: Great Planes 2.5" Nylon Spinner with Aluminum Backplate

 
Last edited:

Bricks

Well-known member
#2
You are using the backing plate with the correct spacer to fit shaft? You may need a threaded motor shaft to hold the assembly tight to the motor. Using the slip on prop holder is not keeping the spinner tight would be my guess..
 

rockyboy

Skill Collector
Mentor
#3
You can do a DIY balancing setup with a tube sized to fit through the shaft snugly and rest the ends on a couple razor blades held up in a DTFB frame. I got by with this type of setup for a good year before picking up a DuBro setup at a swap meet. If you have a 3D printer, making some cones to hold the prop / spinner onto whatever shaft you have handy would be a useful thing to have.

Balancing becomes even more important with 3D printed spinners as we've seen quite a few of them fly apart at high speeds, which would almost certainly influenced / exacerbated by being out of balance.
 
#4
I took your advice and bought myself a prop balancer. I balanced both the prop and the spinner. Everything looked promising, but vibrations still occurred. As I throttled up, the tip of the spinner was still, but as I got to 80%, it wobbled a lot. After cutting the throttle, I noticed that the spinner seemed off-centered because the tip appeared to oscillate even when I turned it by hand. I take off the spinner and notice the mini spinner nut wobbled a tiny bit at the tip when it spins. I have spares since my XA2212 was a 4 pack, but even the brand new slip-on prop holders had a little wobble. Has anyone else seen this before? If this slip-on prop configuration is not good for attaching spinners, what motor do you recommend (I want it to drive a 8" prop fast).
 

Hai-Lee

Old and Bold RC PILOT
#5
The things I would check is that my motor shaft is not slightly bent and that the vibrations have not damaged one of my bearings such that the motor shaft can move around whilst rotating and causing the wobble you are experiencing!

Have fun!
 
#6
I ordered a T-motor F80 1900KV this week and got to test it out today. No large vibrations. The motor has a threaded shaft (rather short, almost could not get the nut on with the backplate behind the prop) rather than the smooth shaft that requires an adapter.