How about large alum. rivits with very large shaft diam. for more shaft contact with both plts., would have to be large machine/press set in place. Just a thought. David R. Cook RV6A Rotary. (snowless in MI finaly)
Subject: [FlyRotary] Rotating Disc Vibration nodes was [FlyRotary] Re: Adaptor plate rivets
Have not gone out and checked my rivets on my R1C, will do that this weekend. However, there is one possibility for the cause of the smoking rivets that I have not heard addressed and that is vibration nodes of a rotating disc. There is the possibility that if the disc were in some oscillatory mode that the smoking rivets might be caused by with the rivets being at the nodes of certain modes (like that?) of vibration which could be causing the holes in the discs to be sliding up and down the shaft of rivet.
In the end, it may be important to know what is causing this. The 20Bs should be smoother than the 13Bs, on the other hand, they do have a different firing frequency. For the same RPM the number of firing pulses from the 20B are 1/3 higher than the 13B over the same time period. That could possibly induce vibration nodes in the disc that the 13B (which has longer duration between firings pulses). The long time between firings in the 13B might permit the mass/structure of the assembly to dampen the amplitude of any such induced vibration between firings pulses – where not so for the more frequent pulses of the 20B. The higher the frequency of the input, the stiffer structure that can be caused to vibrate. A vast over simplification, but thought I would throw it out just incase somebody had a finite analysis package sitting on their computer. Just a WAG.
Here is an URL that provides a drawing of how such nodes might form on a disc
http://demonstrations.wolfram.com/NormalOscillatoryModesOfRotatingOrthotropicDisks/
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Thursday, March 25, 2010 2:25 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Adaptor plate rivets
Al,
I had a bunch of AN-6A bolts, so I used them with two thick washers, one under the head and one under the nut. I mainly wanted to ensure that the shank went all the way through both pieces. You might be able to use AN-5.5A or even AN-5A bolts if you use only one thin washer under the nut.
On Thu, Mar 25, 2010 at 11:22 AM, Al Gietzen <ALVentures@cox.net> wrote:
To answer your question about the washers, I used thick washers on both sides. But I'll have to remove them all in order to replace the AN-6A bolts with AN173-6A's. I'm hoping the bolts arrive by this weekend so I can start putting everything back together.
Normally washers are needed only under the side that you’re turning to apply the force; unless needed to provide shimming or a more uniform or larger surface. The -6A length has a 3/8” grip length, and I assumed the plate was 1/8” and the flange ¼”. If the thickness is less I may have to get some more, or thicker, washers.
Al