anyone recognize these part# e20-1400 or 4hbre20 elastomeric bearings?

skyguynca

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I am looking to purchase two of these bearings but I can not find a source.
Do any of you heliguys recognize them?

I believe they were used in the Lonestar rotorhead and also in the Rotorway rotor head?

Thanks for the help

David
 
If you contact Rotorway and tell them you are working on a Scorpion they will sell you parts without the $250 registration fee. But be warned, they are proud of their parts. Last I heard elastomerics were over $1000 a set and have a 5 year lifespan. The manufacturer will not sell them to anyone but Rotorway.

Their have been rumors of guys that are gonna build a better mousetrap but to my knowledge, none have succeeded.
 
The Rotorway head is a good design. the problem is its design is over 50 years old and uses proprietary elastomeric bearings that cost a fortune and can only be purchased from Rotorway. I would prefer a rotor head with a bearing stack over elastomerics.
When building a helicopter makes more sense to design and build your parts rather than use someone elses parts. They are not really that hard to make.

LD
 
Well so far I have head plans I have are the ones from the HRH which I can make all the parts but no parts list for the bearings and no source but Rotorway and they will not sell to me because I did not buy a helicopter kit from them.

The other head plans I have are for the Polynova Choppy, The Indian and AW95....which realistically are all the same head, no one flys these head very far off the ground, just hovering exercises.

I also have the Skytwister from Ben Showers. Talked with Ben many times, this is also a hovering exerciser.

I also have this set pictured below. I have not seen them anywhere being used. Designed for a two place so really to big for a single place but could be used but also heavy. Looks like this is my best bet though for a flyable reliable head.
 

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The head pictured is overkill for a single place helicopter. it just looks like some ones rendering. and not an actual workable rotor head and not very well designed. Believe it or not the mini 500 rotor head is a good design just copy it. very easy to build. just make sure that you know the spanwise cg of the blades to get the correct coning angle and undersling

LD
 
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Going to the elastomeric bearings was the biggest mistake Rotorway could have made. They had some problems with the bearing block design prior to the elastomeric. They used a flat thrust bearing that because of the design of the bearing block, the centrifical forces would pull the grease away from the bearing and sling it down the length of your main rotors.

About mid 80's, most of the european designs were going to the elastomeric bearings. But these were mostly the three and four bladed helicopters. Rotorway thought it would be a good marketing plan to change their design to follow suit. When they did that, they could truthfully say that they are the only american made helicopter that uses elastomeric bearings.

The issue with these bearings is first the cost. Currently, when you can get them, they cost $1500.00 a set. The second problem with these bearings is that time and temprature will deteriate the bearing. So basically, you can purchase a set of bearings from Rotorway and they might not be any good. You will only know when you install them and see how your rotor system behaves.

There was nothing wrong with their original design, besides the bearing block that housed them. If they would have simply reversed the end design, centrifical force would have kept the grease in the bearing and they would not have been running on dry bearings after a couple of minutes flying. Oh, and by the way, their tail rotor bearings are designed the same way. You have to drill a hole in the end of your tail rotor blades to let the grease have somewhere to go rather than building up and changing your static balance.

I am currently redesigning the bearing blocks to go back to a $25.00 thrust bearing, but reversing it so the forces keep the grease in the bearing for my Exec. I have a brand new set of elastomeric bearings, that are still in the plastic wrap from the factory, that has never been installed, and they are no good. Just because they sat on a shelf, in the heat for too long.

Now in my mind, if I pay $1500 for a set of bearings, even if it takes me 20 years to get around to mounting them, they should be just as good as when I first purchased them.

Rick
 
Oh, and even though Rotorway put out a mandatory directive to upgrade your main rotor mast and swash plate assembly to the 1.75" version, for us older Execs that still have the 1.5" version, we are ok.

I talked to a guy that used to work for Rotorway during the time that they went to the bigger shaft. The reason was because BJ wanted a larger shaft because it made the helicopter look larger. Totally marketing. So Rotorway hired an outside mechanical engineering firm to evaluate the 1.5" system prior to changing it. The employee from Rotorway told me that the consulting firm came back and said that the current design was perfect for what we were using it for.

But BJ insisted that the change be made, and the rest is history. So point being, if you currently have the 1.5" system, do just rush out and drop $12,000.00 on the new system. Yours is just fine.

Rick
 
Hey dunnr,
how does it look now, have you redesigned the bearing block with an axial thrust bearing or a tapered roller bearing? I'm really curious, you can also show a cross-section drawing. I think most people are technically ok enough to read and understand such drawings.
Bernd
 
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