Received-SPF: pass
 receiver=logan.com; client-ip=205.152.59.66; envelope-from=ceengland@bellsouth.net
Message-ID: <43CBFB67.9090007@bellsouth.net>
Date: Mon, 16 Jan 2006 14:00:39 -0600
From: Charlie England <ceengland@bellsouth.net>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax)
MIME-Version: 1.0
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: shake, rattle and hum
References: <list-928691@logan.com>
In-Reply-To: <list-928691@logan.com>
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Transfer-Encoding: 7bit

Russell Duffy wrote:

>but the talk
>of adding weight to the flywheel triggered memory of earlier talk of
>'rocking couple' on the 2 rotor engines, which if I read correctly, is
>the reason for the counterweights.
>
>All correct as I understand it.  When I mention adding weight to the flex
>plate, I'm very careful to keep the balance the same.  I went so far as to
>weight the groups of washers and bolts that I was adding, then mixed and
>matched them until I got 4 equally weighted sets.  The point of the test was
>to add mass, not change the balance.
>
>Is all of your counterweight on one end of the eshaft? If so, could the
>engine be rocking, causing the prop blades to not run true?
> 
>On a single rotor, the counterweights (one on each end of the shaft) have to
>be heavier than normal, and they have to both be opposite of the rotor to
>counterbalance the weight of the rotor.  
> 
>I'm pretty confident that there's nothing wrong with the balance of the
>rotating assembly.  I've run one test without the prop, which completely
>eliminated the prop oscillation.  That thing was steady as a rock sitting on
>the trailer :-)  I also got none of the 2500-3100 vibration, nor the drive
>rattle at 2000.  I'm going to test this one more time without a prop, then
>try the IVO prop (two blade, less weight) to see if it changes anything.  
> 
>I'm starting to believe that the dampener system on the RD-1C drive just
>isn't going to work for the single rotor.  Don't take this as a knock
>against the drive, because it works fine for what it was designed to do (2
>and 3 rotors).  Tracy was very up front about the fact that he had not
>considered anyone using it on a single, therefore no reason to believe that
>it would be suitable.   I knew full well that it might have these problems,
>but I figured that some lucky list member may just end up with a discount on
>an RD-1C and flex plate combo :-)
> 
>Does anyone know if Atkins ever got his single rotor belt drive built, and
>if it works?  Anyone got a suggestion for a ducted fan that might work for
>the Kolb (Bernie, Perry?)
> 
>Off to Panama City...
> 
>Rusty
>

You might go on to something with the Warpdrive prop issue. There were 
several cases of VW cranks being sheared off while running Warpdrives & 
the 'internet wisdom' was that the carbon blades were so stiff that the 
torque reversals from the VW (like a mini-Lyc) were killing the shaft 
because the prop wouldn't absorb the pulses. (The reality was probably 
that they had just the *wrong* resonant freq & were stronger than the 
crank.)

At any rate, Warps became verboten on direct drive VW's.