@Flying_Rodeo Are you doing another run of props for the 65161? I’d love to get my hands on a half dozen.
Hi.
Yes, but in my defense🤣…The term thrust bearing is often used generically to specify the bearing that supports the thrust forces. That is the only bearing that supports the thrust loads, thus it is, generically speaking, the thrust bearing.
The amount of thrust these motors produce is well within the limits of a good quality NSK deep groove type ball bearing. Look as skateboards. These bearings can handle hundreds of pounds of side force. However, they do not handle moisture very well, and they must be lubricated.
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I think this thread helped me the most so far, planing my project and deciding if I want to go ahead with building a foil or not.
So thank you first of all.
Have you seen that maytech is now selling the 65152 motor instead of 65150 or 65151 that is talked about here. Flipsky is still selling the 65151.
First thing that sticks out is that the motor is not available anymore in the 120kv version. Only 100 and 190 kv. But both motors are available sensored and not sensored. They claim for our purposes to use a sensorless motor, which makes sense to me.
Has anyone talked to maytech yet about what is the difference or better what is the improvement?
Otherwise I can offer to try and get in touch with them. But I thought maybe one of you who has been active here for longer than me might allready have a connection to
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I am also curious what is inside maytech motor!
I understand deep grove bearings quite well after researching NSK specification and application lititurature.
The axial load ratings for deep groove bearing only apply as a proportion of radial loads. Radial loads must be applied to the bearing to achieve any axial rating.
Like on a skate board which has a radial load applied.
Our motor bearings have no radial loads applied so therefore no axial rating. FYI, the NSK 6901 is rated for about 16N axial load. So that is 160kg for 1 million revolutions.
Engineers divide this number by 12 to achieve acceptable service life. These bearings are good for about 13kg of axial load when enough radial load is also applied. Again we have 0 radial load so not even this 13kg applies.
The whole time these bearings are running with only axial loads, the balls are running on a part of the race it was not designed to run. These bearings will fail prematurely in this application.
But they are cheap so I guess you can just replace them every 20hrs.
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This thread started with ReacherTech as RT65150 in Feb 2019 and the motors very quickly became 65160, 65 being the motor diameter and 161 or 162 being the length.
- 65162 as Maytech motor reference since its launch in August 2019 (wide shaft end cone),
- 65161 as Reacher Tech (squared shaft end) and Flipsky (narrow shaft end cone probably made by Reacher Tech). Reacher Tech is now selling a new “D65L161-2” motor with a narrow shaft end cone, a motor they were so far manufacturing only for Flipsky.
I don’t know what improvement you mean but the latest we saw with Maytech and Flipsky is the bearing and ceramic sealing shown at the bottom of the page here also showing the winding
Why upgrade from oil sealed to water/ceramic sealed)?
Adding a ceramic ring in the middle, reduces the direct contact between the sealing ring and the bearing, extends the life of the bearing; improves the waterproof performance
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@Flightjunkie when the oil drained was it full of bubbles? What about water, dust, or emulsion of any type?
I’ve tried this in the past. The problems I had were the oil starts clear, and becomes paste. Air gets mixed in, it all becomes opaque. And any dust, flecks, sand, crud gets mixed into soup.
And when water gets in, it doesn’t sit, it mixes, and then forms dendrites on ANY exposed wiring. Once they get long enough they zap, clear themselves, but it makes carbon crud.
Keen to know how Lift/FR avoid these issue. Or is there an oil chamber? i.e. is the oil kept from the spinning parts.
When the motor was first released it was named the 65150.
Then it changed to either the 65161/65162 depending on which reseller was selling it.
All versions are made by one manufacturer. The different companies are just different resellers. You can get any variation from any reseller upon request.
For the different versions, they mostly differ in the following areas: case shape, shaft, seal type and KV.
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No chamber , oil clear
Just high quality parts in a well sealed can
There are at least 2 different companies manufacturing those motors.
Minimum.
As a mechanical engineer, I did the math with a standard SKF bearing.
Deep Grove bearings can actually handle quite a lot of thrust (axial forces).
With standard SKF 6001-2RSH bearings (almost the same as the NSK one), with 3000RPM, 350N Axial force and 5N radial (weight of the rotor + propeller), it gives a L10 of 883.32, which is 4907h.
Even using your “rule”, this means 409 hours.
This L10 value means that after 883 x 10^6 revolutions, 90% of the bearings will be working properly.
No need to open your motor every 20h. Mine has more than 50hours already and is running smoothly.
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Thanks for reporting back.
One problem with mineral oil is that it expands and contracts with temperature. That means that it will suck in air/water through the seals. So to help you need a ‘pocket’ of something compressible like air. With air, you get a bubble emulsion which would be opaque, unless you use a bulb which can expand and contract.
I think there is a bit more engineering concealed here. Credit to Lift/FR for making the oil can work in mass production. I didn’t think it was practical. Perhaps its a specialist fluid that is ultra low viscosity? I’ve only tried this with clear mineral oil; liquid paraffin, which is what you use in static liquid cooling like power transformers.
Any more insights you have would be great to know. Brent.
Does the problem with mineral oil apply to corrosionx as well?
When I initially opened the FR motor I didn’t see much oil/liquid at all. Just really enough to coat the internals in case of water ingress. Basically it looked like something had been poured in and left for a bit, then poured out leaving a coating for protection.
I have done the same with CorrossionX in my 65161. The idea is not to lubricate but to coat the inside just in case of water ingress. From an engineering perspective the bearings should be fine for a long time without lubrication…
Dont misquote me. I never said it was a rule. It was information given to me by an engineer.
A real engineer wouldnt be using a different specification to the NSK bearing in question.
Care to back that up somehow?
There is one formula that is used by all to calculate bearings life using dynamic rated load C and static rated load C0.
This formula is, however for “perfect condition”. This is why all bearing manufacturers are using their own to make sure their products will last the desired time.
SKF for instance, is using Pu": fatigue load limit. The life calculated is then lower but not 12 times.
I don’t doubt n engineer told you this rule and I am sure it is a legit rule, but saying here that those NSK bearings will last 20 hours is just wrong.
The most likely to fail are the Vrings. If salt water ingress inside the motor, the winding itself will survive for a long time. Not the bearing if it is made of steel, and not stainless.
20 hours wasnt calculated. I was just alluding to a reduced service life, whatever the time frame might be.
The problem I saw with the lip seals on my reachertech was the condition of them. They were a very hard compound, or aged seals. I replaced mine with fresh NBR seals. Its a grease filled double seal setup which shouldnt leak. A similar setup has over a hundred hours on my geared drive without problems.
I recommend replacing the shit factory seals.
Would you have a link ?
Interesting. Do you have a link for such seals ?