Subject: Redone rotor housings?
From: ACRE
Date: 3/19/2003, 12:11 AM


This is kind of long, Sorry.

Regarding rotary housings, they are what is commonly refered to as
"hard
chrome" plated. The composition includes an addition of tungsten
carbide
in the alloy for hardness.

My company is working on a deal with one of the manufacturers for the
housings, to refurbish existing ones with a new performance coating.
They have the only machine in the US that can microfinish the interior
of the housing like mazda does. The company has tested rotary engines
with a ceramic lined interior, and ceramic apex seals, and the results
are amazing. Over 20,000 hours before overhaul, and that is running
much
leaner than you could imagine. Mazda runs this coating on their LeMans
engines - 4 rotor, as well as their hydrogen buring engine.

If anyone is interested in getting a set of housings coated, for
performance or longivity, contact me. There is a possibility of
getting
a reduced rate during the development stage. If this works out, there
will be no need to ever replace rotor housings, unless they are
cracked.
Even damaged ones with a failed apex seal gouges can be brought back
to
as new. Cheaper than replacing them. Also, compression ratios can be
raised, by adding thickness to the rotor itself. possibility of
getting
rotors made from other alloys like stainless steel. Or if you have the
big bucks, some superlight alloy containing titanium.


The ceremic coating may be applied on regular apex seals as well,
hopefully cutting the cost of them, while dramatically adding
longivity,
and durability. One of the biggest issues in any pump is sealing, and
the gasoline engine is nothing more than a great big pump. Fix the
seal
and increase the  efficiancy, or in this case Horsepower. The weight
will still be a factor, so for ultra high revving engines, pure
ceramic
will still be recommended.

BTW, for those interested, the way the housings are finished is pretty
cool, the abrasive stays still, and the housing rotates around it in
an
eccentric orbit.


Cliff
93 CYM


Cliff Roberts
President
Metal Solutions Corp
p.o. Box 60002
San Angelo, Texas 76906<<<

This sounds like bullshit to me. You cannot plate the entire rotor and
increase the compression ratio. Only the pocket of the rotor is allowed to change.
As far as I know there is no tungsten in the Mazda Leman engine coatings.
According to Mazda SAE paper 920309 it was Carbide based cermet/Nickel Chrome 
detonation gun applied. The wear characteristic were only about 10%
better than soft nitrided cast iron of the stock housings.
I have heard of the 20,000 hour life for the ceramic apex seals however.
The ceramic seal are indeed tungsten carbide.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.