In a message dated 5/21/2006 7:49:18 A.M. Eastern Daylight Time,
ARGOLDMAN@aol.com writes:
In a different forum, not related specifically to engines, the following
was stated,
"...Rotary is different issue. Their unusual combustion chamber requires
them
to mix 2 cycle oil with each tank. If they don't their compression
seals
die prematurely. Just like your boat motor mix, I don't see it as a
big
deal.
It is true that the rotary uses a microscopic amount of its own
sump oil to lubricate its apex seals. There is a tiny pump mounted on the engine
that performs this function. Some people choose to remove this pump and mix oil
with the fuel, but the stock pump system works perfectly, and a change is not
required.
In
addition, if they use aviation fuel, they develop power drop on
departure
and have to replace all their plugs before next flight. This
happens every
20 hours. They don't have solution for this."
It is true that lead fouling of automotive style spark plugs is
a problem. It can appear in as little as 50 hours. The plugs are inexpensive,
and the brighter folks clean or change to new plugs before there is a problem. A
high energy ignition system on the leading would extend the operating hours, but
even 30 hours is a lot of flying and changing plugs is so
easy.
The problem involves only aviation fuel, and the advantage is
that you don't need aviation fuel. Any pump gas, even very low octane fuel is
just fine for a non-turbo rotary engine.
What is the experience that you are having? Is there any truth to
this. If not true, where might this info have come from??
The number of rotary powered aircraft is increasing, so a large
number of people are changing their minds about the engines.
In the 60s the number of people who would ever in their lives
check the oil level on a street car was growing at about the time the Mazda
powered cars were first imported. So after 4 years of hauling the young ladies
back and forth to college the engine in the second hand RX-3 (or whatever) would
go soft, and the car would be sold.
The oil level would be so low that the rotor bearings and
rotor cooling would be compromised.
Often, just filling the sump with oil would get another few
years out of the car, but many failures also occurred. The popularity of quick
oil change joints actually had an affect on rotary reliability. When the oil
gets changed, even occasionally, the engine has a life span similar to a piston
car engine. Like Chrysler built cars rusting out quickly, the legend lives
on.
It is even less of a problem in aircraft, where it is common to
check the oil before each flight.
Oil consumption is less than a piston aircraft
engine.
thanks,
Rich
Lynn E. Hanover