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Date: Sun, 21 Mar 2010 13:07:49 -0500
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Fwd: Question on RD2-C
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Is there room to add separate bolt holes & still maintain required edge 
distances/spacing? If so, you could drill undersize & ream to fit 
standard bolts.

Another thought would be to look at availability of stronger aluminum 
rivets; there are multiple alloys of rivets in various strengths.

Charlie

On 3/21/2010 11:30 AM, Mark Steitle wrote:
> Al,
>
> Bolts were AN3-6A, but not of the close tolerance variety... not a bad 
> idea though.  Does Van's sell those?
>
> Mark S.
>
> On Sun, Mar 21, 2010 at 10:53 AM, Al Gietzen <ALVentures@cox.net 
> <mailto:ALVentures@cox.net>> wrote:
>
>     The rivets are aluminum.
>
>     I find this surprising, as well as disappointing.
>
>     I checked the rivets on my RD2-C damper assembly and was able to
>     confirm that they were in fact beginning to loosen as evidenced by
>     the radial streaks on the damper plate.  I picked four rivets at
>     random, approx. 90 degrees apart, and grabbed the shop heads with
>     vice grips and tried to spin them.  All four would spin with
>     little effort, thus confirming that they were beginning to loosen.
>      After a phone call to Tracy, we decided to replace the ring of
>     rivets with AN3 bolts, which I've now done.
>
>     One advantage to rivets is that they fill the holes to zero
>     tolerance.  The bolts will be MUCH stronger, but I’m wondering
>     about the potential for some very small amount of ‘play’ to begin
>     with, which would not be a good thing.  I don’t know much about
>     steel rivets, but maybe that’s the way to go.
>
>     Mark; what nominal length and grip length on the bolts? Are you
>     using standard AN bolts or are there ‘true’ diameter or ‘close
>     tolerance’ bolts available.
>
>     Al
>
>     Hum-m-m; I just decided I could change schedules in order to fly
>     to the Jean, NV gathering next week. Now I’m wondering whether to
>     fly anywhere before changing out the rivets. I’m thinking that
>     since I see no movement between flange and plate after 180 hours,
>     it should be good for at least a few more hours.
>
>