iannetti@designideas.com wrote:
My opinion on the use of ceramic apex seals for aircraft applications was described in the letter I wrote to Paul after our meeting in Irvine, California during Seven Stock, circa October 2004. Now
regarding wear of internal engine components due to apex seals, I have the following comments:
Since the use of the ceramic version of the Iannetti Apex Seal in competition (>1993) we have never seen an issue with wear of components in contact with our product. Although this behavior is due
to the excellent tribological or compatability qualities between the various materials, it is also due to the finish achieved on the surfaces of the Iannetti Apex Seals, ceramic version.
A rough ceramic component will do considerably more damage to the rotor groove, apex seal springs and side housings than any metal seal regardless of how well its tribolgical or material
compatability qualities are with its surrounding components. In other words, the longevity or cutting efficiency of a rough ceramic file is better than that of a metal file.
Another very important factor that is obtained with the high surface polish on the surfaces of our ceramic apex seal is that it allows the component to achieve its theoretical strength limit. A
component made from a rougher or more scratched brittle material such as hardened tool steel, ceramic or glass will exhibit considerably lower strength than its polished counterpart. The rougher
part is, of course, a lot easier and thus cheaper it is to make.
There are many versions of ceramic materials which can be considered for an apex seal application. We have always inevested the resources to manufacture the Iannetti Apex Seals with the highest
strength and toughness materials available. The difference between the various ceramic products will be noticed mainly when things go wrong.
Francesco Iannetti
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