New Bearings average 13 dB quieter

[KenMc]

Solos have noisy motors. This noise is reduced by replacing the original bearings in the motors.
To document the improvement the sound from each motor was recorded before and after replacing the bearings.

The recording was done by placing a quality microphone within 1/4" of the motor (no propellor) and recording during the start-up period (about 9 seconds). The mic was connected to a mixer board and Audacity software.

Audacity plots the spectrum of the sound. The peak Hz dB was used to compare the sound.

Original Bearings New bearings
Motor 1 817 hz -16 dB 998 hz -33 dB
Motor 2 750 hz -21 dB 1016 hz -31 dB
Motor 3 796 hz -19 dB 1011 hz -31 dB
Motor 4 747 hz -17 dB 1012 hz -31 dB

The average reduction is 13 dB.

I was a little disappointed in the results - I had hoped for a much quieter result. The bearings I used were from McMaster Carr.

New Bearings:
57155K368
ABEC-5

3759T47
ABEC-7

What else about these motors is generating noise? I can post the spectrum graphs if anyone is interested.

 

[USMC86]

Hey Ken-
You just replaced the bearings? Was it pretty easy? I’ve seen a guy or two on the forum who switched out the motors-

 

[USMC86]

Search Bar- put in changing Solo motors- the second thread talks about installing 2216 t motors-

 

[RichWest]

Funny, I never thought to source bearings from McMaster for Solo...Nice find, always good stuff from MC, just a little pricey on some things. What brand are they?

If your interested, I have a motor balance thread that lead me to have a better understanding about bearings and preloading. Which does contribute to the sound you are hearing and in my case was a source of vibration.

fwiw, I did the T-Motor upgrade thereafter. Couldn't be happier...

 

[KenMc]

McCar refers to them by "trade numbers" R2-5-2Z ($13.35) and R2-Z2 ($5.22) - no indication of brand. Yes - pricey - you can get hobby replacement bearings for less (a lot). But, with McCar you know exactly what you're getting - I didn't want to put the effort into changing and testing without knowing I had the best possible bearings. One thing missing from their specs was details about lubrication - a couple sites make an issue about this. McCar just says "grease". Their spec says "Shaft mount type" is press fit - which these motors are definitely not. The housing is press fit - but it's obvious now that the shafts are a little less than 1/8" since the shaft slides in and out of the bearings with ease. I'm not sure what it would take to press fit bearings this small - probably the right tooling and heat/cool (although something this small would lose heat really fast, complicating things).

If I had thought it thru a little better I would have started with 'hobby' grade bearings first, tested, then replaced them with the the McCar bearings. That's because it's possible (likely) that the bearings are damaged when they are removed. I won't be replacing these bearings anytime soon.

I found your thread on balancing - I had scanned thru it before - but funny how really "doing" something drives things home. Now - bearing "preloading" takes on a whole new meaning. I'm going to study that thread.

I'm going to do 2 things from this point -

1. Source some nylon washers
2. Look into balancing the bell housing

I may try T-Motor upgrade in the future - first I want to see how far I can get with the stock motors.

Thanks for your reply.

 

[KenMc]

Hey Ken-
You just replaced the bearings? Was it pretty easy? I’ve seen a guy or two on the forum who switched out the motors-

I'm guessing you are a Marine - thanks for your service. 2/4 was my anniversary of joining the Navy - fortunate to serve, lucky I didn't go to Nam.

I'm going to post a more detail about bearing replacement - but here is the Cliff Notes version.

1. Buy M3 socket head replacement hardware, retaining clips, Loctite Blue and bearings. The new hardware is cheap and you don't have to clean off the existing loctite to reinstall.
2. Remove the motor pod
3. There are 3 plastic locator pins that hold the circuit board to the plastic motor mount - clip off their heads being careful to leave the pins. The motor pod can be reinstalled without gluing these back in place.
4. One last screw holds the motor to the motor mount.
5. Don't remove the set screws that hold the bell onto the shaft.
6. I'm not familiar with the 'circlips' used on these motors. I suspect they are junk. I got a tool to remove them, even then they came off deformed. One video suggests just ripping them off and throwing them away. The standard 1/8" retaining clip works. I rip them off and throw them away.
7. Knock the bearings out. I ground the point of a finishing nail so that it was contacting the outer race of the bearing. I tried to tap them out without damage - not sure if I did.
8. Press in the new bearings.
9. Reinstall in pods

KenMc

 

[USMC86]

Thanks Ken. Yup - 30 years in the Corps- Thank you for the info- going to give this a try!!

 

[divemasterphil]

RichWest, which T-Motor's and adapters did you settle on? Would you recommend the same or different kv's?

Funny, I never thought to source bearings from McMaster for Solo...Nice find, always good stuff from MC, just a little pricey on some things. What brand are they?

If your interested, I have a motor balance thread that lead me to have a better understanding about bearings and preloading. Which does contribute to the sound you are hearing and in my case was a source of vibration.

fwiw, I did the T-Motor upgrade thereafter. Couldn't be happier...

 

[RichWest]

I found your thread on balancing - I had scanned thru it before - but funny how really "doing" something drives things home. Now - bearing "preloading" takes on a whole new meaning. I'm going to study that thread.

Sure, doing produces more understanding than just reading. It's your rabbit hole now, when I saw the light I got out, but I learned a lot fumbling around. Look forward to reading of your adventures, let me know if you have any questions.

which T-Motor's and adapters did you settle on? Would you recommend the same or different kv's?

I was one of the original convert'ies. I went with 800kv and the PA029/030 that Roland recommended, ignorance is bliss. Less options today, but I'd be happy with the Luminier 900kv. Stock motors are noisy, was driving me crazy.

Further conversation, start another thread. Don't want to be rude to KenMc and his thread.

 

[KenMc]

A thread on replacement motors would be welcome - I appreciate the way you document.

One last Cliff Notes --- MARK the PODs with the motor number. I made hash marks on the PC board.

I will gather all the particulars and create a bearing replacement thread.

 

[RichWest]

A thread on replacement motors would be welcome - I appreciate the way you document.

Much of the info is here, but scattered between multiple threads. It would be a nice resource for the less able. I use the forum like a note book, if others benefit from the shared info then great. Otherwise I'm on to the next process or just flying....

 

[KenMc]

Your point is well taken. I'm messing with bearings because the winter weather doesn't cooperate with flying and it seemed like an important problem. It's 19 F this morning - it might climb into the low 30's -- if this was a business - I'd fly - but it's not fun in the cold.

 

[skyhax]

Solos .............................snip.....................
What else about these motors is generating noise? I can post the spectrum graphs if anyone is interested.

Great job with this and thanks for the part numbers.
I believe all the other noise is from the air traveling over the shell. On another brand of quad I upgraded to real sunny skies and still had a lot of "angry hornets" noise. Transplanting the entire quad to a flame wheel frame made it almost silent.

 

[Kamehameha1]

Funny, I never thought to source bearings from McMaster for Solo...Nice find, always good stuff from MC, just a little pricey on some things. What brand are they?

If your interested, I have a motor balance thread that lead me to have a better understanding about bearings and preloading. Which does contribute to the sound you are hearing and in my case was a source of vibration.

fwiw, I did the T-Motor upgrade thereafter. Couldn't be happier...

Where did you find the T-motors and the description or part ?

 

[RichWest]

Where did you find the T-motors and the description or part ?

MT2216-12 or now the Lumenier's FX2216-11, check GetFPV. Then here is the next sourcing problem, Prop adapter needed

 

[erikbuch]

I believe i read somewhere that these would fit the t-motor! TBS900 is supposedly a rebranded T-motor.
Team BlackSheep Online Store - 900kV2 Motor Self Tightening Prop Adapter (CCW)
Team BlackSheep Online Store - 900kV2 Motor Self Tightening Prop Adapter (CW)