When I designed these props I took a gamble that my reacher tech 65161 would have the tapered back end like the flipsky motors. I was wrong and now the props I had printed dont quite fit on the reachertech with the screw cap.
instead of butchering these with a dremel I thought i would offer them to you guys.
I will adjust my design and reprint instead.
A bit about these props. This prop is off my efoil with a know top speed of 44kph on a geared setup. I redesigned the hub and reduced the diameter a little bit. These props are 142mm diameter. I reduced the pitch a little to allow for higher rpm direct drive motors. My geared setup was only a theoretical 72KV after reduction. I estimate the pitch to be 200mm
I had these printed in PA12 HP Multi Jet Fusion, which on my geared efoil I cant break. In fact I can fully cavitate the prop if I give it full throttle. So plenty strong.
The design incorporates a 51101 thrust bearing. Ceramic is recommended for 0 maintenance. A wash port is designed into the hub. I will include a stainless thrust bearing, drive pins and a nyloc nut so its almost ready to go. Just need to find some M4 35mm countersunk machine screws.
I have two available. The first one was a bit of a poor print so the quality isnt the best. Its still perfectly functional and fits the motor. I think they removed it from the print block too early and hadnt cooled enough. So obviously this one wont be worth as much.
These cost 110 USD to print and Ive added most of the hardware needed to fit straight to the motor. Feel free to make an offer via PM. Can ship anywhere at cost.
This is the best one. Ceramic bearing not included. comes with a stainless bearing.
Im going to include a stainless thrust bearing. I dont think the Flipsky will have the same torque as a geared setup, which is why i reduced the pitch a little bit, but you never know. Maybe these motors will surprise us.
Edit: I see what you are saying now. The deep grove bearings they are using are designed to take axial loads when combined with radial loads. We have no radial loads in our application. Sure they will work for a while but if they are only taking axial loads the races will be damaged much sooner. I prefer the right bearings taking the right loads.
Test has be done : apparently a solas prop put out 72kg of thrust , I bought a FR motor for 1500€, do you think a Chinese motor at 400€ will stay waterproof all its life and has a thrust bearing inside that would hold this power ?
I would put a thrust bearing like this ( i did the same on my first setup and even didn’t bolt the gearbox on my second built …)
The NSK bearings in this motor are not bad bearings but,and it’s a big but, the axial load ratings for this bearing are about 160 kg for 1 million revolutions. That’s how they rate them. Obviously 1 million revolutions is not much in an electric motor.
General rule is to divide the rating by 12 for longevity.
So our 6901 bearing is good for about 13 kg of axial load each.
But we still don’t have any radial loads so our bearings are toast!
I’m with you, definitely going to use a thrust bearing.
Why should there be a radial load? Dont they behave better in case of some axial load if radial load is missing?
Often deep groove bearings are axially preloaded, especially in motors, to overcome the problem of missing radial load. Where did you get the number of 1 million revolutions? For which size of bearing is this used?
Deep grove ball bearings require radial loads to achieve the axial load ratings.
This is because without radial loads the balls do not run in the middle of the ball races where they are designed to. When you just apply axial loads the balls run wedged to one side of the race which they are not designed to do.
NSK have some good technical literature where its all explained quite well.
Any bearing carrying its full rated load will last 1 million revolutions. That is how they rate the bearings in the bearing industry.
Bearings are typically loaded with a fraction of there rated loading for acceptable service life. I have been told by a bearing guy who has been in the industry for years that the rating is usually divided by 12 to achieve acceptable service life.
See if you can find the specifications on the NSK 6901zz. Especially the axial load rating, divide it by twelve and see if it comes out below 30-40kg thrust we are trying to get.
And is the 360 CAD program for these two parts to share? (Propeller and bearing holder) for Flipsky motor. I’d like to print and try. thank you for answer
