[TowerTalk] Thrust Bearing for Use with Prop Pitch Rotor

[Kurt Andress]

VXB Bearings sells a 2 1/16" dia bore flanged bearing....it's the only 
one at that size I have found so far.....should work with a 2" 
galvanized mast.
One might need to file down some high spots of the galvanized coating, 
because when the masts are pulled out of the tank the end that is down 
collects more material...
We have had to do that many times......it's not a big deal......a flat 
file & vernier calipers gets the thing right to fit thru a bearing.

https://www.vxb.com/2-1-16-Inch-HCF211-33-Flanged-Eccentric-Collar-p/hcf211-33.htm

Regarding the K4GMH prop pitch situation......he cannot put any vertical 
load on his prop pitch because he does not have the top plate & bearing 
that support the bevel gear/mast connection, or whatever he has 
imagineered....which could handle the axial load (around 1000 lbs). He 
has other issues to deal with, like how to seal the top end of the unit 
to keep water out of it. That is what ruins most of the prop pitch units 
put in service by amateurs!

73, Kurt, K7NV
P.S. We are still here doing what We do....something like starting to 
build our 330-335th ones....., but it is hard to stay up with my 
assistant, Marco, because I have some much larger fish to fry......

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of
Patrick
Sent: Sunday, March 10, 2019 12:20 PM
To:towertalk at contesting.com
Subject: Re: [TowerTalk] Thrust Bearing for Use with Prop Pitch Rotor

I'd double check the need for a down thrust bearing to relieve the
weight from the PP unit. Kurt Andress the preeminent PP re-purpose guru
advised me against it.

Patrick        NJ5G


On 3/10/2019 10:16 AM, Mike wrote:

> Hello,
>
> What have others used to take the weight off of a tower mounted prop pitch
> rotor?
>
> Presently, in the final stage of modifying a rescued prop pitch and,
> unfortunately,  it didn't have the triangle bearing plate.  Plan to use a
> couple of Rohn TB3 thrust bearings, one at top of the tower and the other
> approx. 2 ft below the top, but wanted to find out what others

successfully

> have used to keep the weight off prop pitch rotors.
>
> The load will consist of a 2" dia. X 1/4" wall X 21 ft chrome molly mast
> plus a homemade 40 m Moxon (approx. 70 lbs) and a 4 el SteppIR (approx. 50
> lbs).
>
> I've review the TT archive for thrust bearings for possible application
> with a prop pitch rotor without any consensus on what to use other than

the

> available thrust bearings are not reliable in the long run.
>
>     73,
>     Mike, K4GMH
> _______________________________________________