flyrotary@lancaironline.net Mailing List Archive

Al,

I don’t recall - did you say you also have visible signs of smoking rivets? If not, no worries.

Exchanging the rivets for bolts, I agree. If doing this I would use the close tolerance MS bolts Vans requires for the spar - fuselage attach rather than standard AN-3. Other alternatives would include simply adding more rivets (if possible), or using some sort of adhesive with the rivets. I remember reading somewhere that for most riveted joints, Lear used Proseal on all joints in addition to riveting on the Learjet.

Mike

From: Al Gietzen

Sent: Sunday, March 21, 2010 8:53 AM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: Fwd: Question on RD2-C

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.

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.