Feathering shaft bearing ideas?

Jake2465

Newbie
Joined
Apr 27, 2016
Messages
46
Location
Huber Heights
Aircraft
project
Total Flight Time
65hrs
This fall I plan to get back on my project and I have not begun to build the rotor head yet. The bad news is that it's not built, lol. But the good news is that I have not advanced so far in one direction that the idea of going in another direction is too late.

I really like the Rotorway heads because they look so dang simple to me with a couple of parts on that build that I believe would prove to be a challenge. The first and obvious is that those feathering shaft elastomers would need to either be sourced from Rotorway, which I doubt they would be willing to just fork them over, and the other is the long drilled holes for the feathering shafts to go through the rotor hubs which I believe also need something like a 1.5 or 2-degree angle to provide a pre-cone for the blades.

The need for that pre-cone angle and those elastomers is whats stopping me right now. I have a fancy CNC mill that can certainly help me make some sick parts, but I don't have the headspace to stand a rotor head up on end to shoot angled holes like that. The other big issue is getting a hold of elastomers. Now, assuming that those bearings are nothing more than thin brass and neoprene sheets pressed together to provide enough feathering for, perhaps 20 degrees of movement, then it may be possible for me to make my own. I would need to first fabricate what would basically be a large washer punch contraption to cookie cut sheet after sheet of brass and neoprene.

I would imagine that the generated heat from the neoprene getting worked is basically a function of how many layers the bearing has and how many degrees of movement would be required of the bearing. So, my understanding is that if a bearing has 500 thin sheets of neoprene, then it would get to a certain temperature, and if the sheets are increased to something like 700 or whatever, then the temperature should be less. If the sheets are too few, then it may be possible that the neoprene boils out of the brass and locks up any hope of blade input along with bad vibrations and other stuff that is not so fun.

I don't know what the chance of success would be for making my own bearings like that. I have not found a whole lot of information about it online and I am not convinced that it's simply just slapping a whole lot of brass and neoprene together to make a bearing.

Some time ago I looked into using angular contact bearings for the feathering shafts but with the blades weighing some 30+ lbs apiece, those blades would love to brinell the angular contact bearings to oblivion. I would have to use stacked bearing that is precision ground and matched to each other so the loads are transferred evenly through the races. Because of that, I found it more or less impossible to get a hold of bearings like that. The only product I know of (besides helicopter) that would use those kinds of bearings would be injection molding extruder screws.

Does anyone have any suggestions for what to do here? If I recall, the Rotorway blades when up to operating RPM, something like 500, the forces across the rotor head are something like 15,000 lbs.
 

wolfy

Active Member
Joined
Dec 19, 2013
Messages
347
Location
western australia
I was a helicycle a owner a while back and up until recently I was receiving there message group messages, not so long ago they were talking about who was going to make the elastomeric bearings and other parts since the factory closed. The last I saw was that rotorway were going to manufacture for them with the new helicycle company owner doing the final machining. There was someone talking about making his own and supplying the group. I would suggest trying to get in contact with some helicycle owners and get the latest info, there seemed to be a lot of knowlage on the subject.

wolfy
 
Joined
May 11, 2005
Messages
149
Location
Burlington Wi
Hi All

The helicycle bearings are still made by the origional manufacturer Randolph Research. The same company who does bearings Rotorway. There was never any talk about Rotorway manufacturing bearings for them self or Helicycle.The supply problem was that they will not sell to anyone but Rotorway and helicycle. When the 2 companies went under (before the new owners took over) There was no supply. For Helicycle once the new ownership was established The supply of bearings to the new Helicycle company was resumed. I assume it was the same way for Rotorway.
I do Have a low hour pair of helicycle bearings removed from a parted out kit That are still fresh and good that I would sell $700.00

Doug
 
Joined
May 11, 2005
Messages
149
Location
Burlington Wi
Hi The bearing OD IS 1.975 od 1.050 id thickness is.565 What I was told by BJ Schramm is that there is more load on the Helicycle bearings than the Rotorway because of the increased RPM 615 the Rotorway and Helicycle bearings are made the same other than the ID and OD slightly different

Doug
 

Martin W.

Member
Joined
May 10, 2020
Messages
51
Location
Winnipeg
Jake2465 .... I have no advice for your project but to let you know Enstrom Helicopters uses the Lamiflex bearing .... and if my memory is correct the idea originated at Enstrom way back in the 50's or 60's .... one of the engineers I believe was Alb Ballauer came up with the idea.

(If I got the link right) .... here are some very good pictures of the bearing with advice on how to determine airworthiness condition
 

Attachments

Jake2465

Newbie
Joined
Apr 27, 2016
Messages
46
Location
Huber Heights
Aircraft
project
Total Flight Time
65hrs
Doug and Wolfy, thank you for the information about the bearings. As I approach my project continuation date, I will post videos on what I will be doing with the rotor head.
 
Top