Paul are you saying that aluminum housings with hard anodized wear
surfaces have been
tried on a rotary?
If so who are these companies/people, and how did the housings fail?
What caused the housings to fail?
Royce
I am not sure who said what when. Could be Juergen Bax
in Germany, president of Wankel Gmbh whom I visited a few years
ago. Could be one of any number of other people I have spoken to
in the last five years. Perhaps Paul Ross at Alturdyne.
As I said the problem is probably related to temp. Aluminum starts
loosing
its strength rapidly as the temp rises. You could have a local hot spot
in the end housing around the combustion chamber and once the coating
is breached it does not take long. The bond between the very thin hard
anodize surface and the base aluminum probably breaks down due to
compression
fatigue. There is no thickness or plate bending strength in the very
thin anodize
coating to distribute the point loads from the end seals. All you
have to do is roll up one microscopic particle of hard anodize and
it will act like a cutting tool.
The bottom line is it is very very expensive to test any kind of
coating.
Flight test are out of the question. You are asking for a lot of
trouble
and a lot of time and expense. Go with something that is proven.
God knows how much Mazda spent on developing the coatings used in the
Lemans
engine with over 100 engineers on staff. Do you have the Mazda Lemans
SAE
paper?
The steel inserts in the rotor housings have been used on two million
rotaries.
You are not General Motors :)
Actually, you are like GM if you try to develop a wankel ignoring
Mazda's materials experience. GM tried to make the whole thing out of
cast iron with one spark plug per rotor and no oil cooler. Soon they
had twin plug aluminum housings with the nikasil type coating, then
they went to the Mazda style chrome plated housings.
Hans
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