[TowerTalk] PST61 Rotor Reliability?

Jim Thomson jim.thom at telus.net
Mon Dec 11 19:37:34 EST 2017


Date: Mon, 11 Dec 2017 00:46:45 -0700
From: David Gilbert <xdavid at cis-broadband.com>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] PST61 Rotor Reliability?

<I don't think you read my post.?? A paddle isn't applicable here at 
<all.? In fact, it would make things worse by adding cross sectional area 
<to the system.

<Dave  AB7E

###  Are your pair of optibeam yagis even Torque balanced to begin with,
probably not, since I dont see any form of tq comp used on any commercially made yagi.   
If not,your swirling winds will make  your situation even worse.   
That paddle the fellow was talking about is actually called a torque compensator.  
If you dont have an equal amount of boom on either side of the mast, it will not be 
tq balanced.    If you have more boom on one side of the mast than the other side,
it has been mounted at the center of gravity.   If you do that, you require a small tq comp plate
down at the shorter end of the boom. 

## method 2 is to mount the boom to mast... dead center in the middle of the boom. Then
use a small counter weight at the light end of the boom.  Ditto with both yagis.

##  with 2 yagis on a mast, they need to be mounted on opposite sides of the mast. 

##  do all of the above, and most of your issues will be alleviated. 

##  I thought that prosistel made bigger rotors like the 71  and the  110 / 115 ??  

##  My SMALL k7nv PP is good for 1250 ft lbs of tq, thats 15,000  inch lbs of rotating tq.  
Its lighter than my M2  OR-2800.   OR-2800 only has  233 ft lbs of tq  = 2800 inch lbs. 

###  on a PP, the final big gear is meshed,and driven by 3 smaller gears, every 120 degs. 
PP also come in the medium and large size.  

##  are u saying your swirling winds are essentially blowing in 2 directions at once, like N at
one end of boom, and S at other end of boom ??   With the boom oriented  E-W.   If that’s the
case, you have a real serious problem.  And any TQ imbalance will make it even worse, a lot worse. 

Jim   VE7RF



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