In article <aChmi.13458$Cz2.11986@newsfe12.lga>,
"Proctologically Violated(C)(R)" <entropic3.14decay@optonline2.718.net>
wrote:

Nobody else wanted it due to the practical problems it had in the early
days. On paper, it was *GREAT*. In practice, the early versions outright
SUCKED.

Main drawback used to be the apex seals wearing/burning quickly, but
from what I've heard, that's been improved immensely with improved
oiling systems. (You do realize that a rotary deliberately burns oil,
right?) Another problem was the occasional "start it up, back it out of
the garage, shut it down, get whatever it was blocking out of the
garage, try to start it to put it back in the garage, and it won't start
no matte what you try" syndrome. Basically, "never run it for less than
10-15 minutes if you want to be able to get it started again".  But like
the apex seals (which MAY have been a contributing factor for this
problem), I've heard that this has been pretty much ironed out in the
modern versions.

A rotary WANTS to run high RPMs - Gear it right, and it can. And when it
does, it'll go like the proverbial raped ape. Those two rotors are
roughly equivalent to six cylinders.  

That's the improved oiling system. A rotary *HAS TO* burn at least a
little oil. If it doesn't, the seals - especially the apex seals - go to
hell in no time flat. In the early days of rotaries, what came out the
tailpipe was real similar to the exhaust from, for instance, a chain-saw
or weed-eater - lots of oil being burned. Nowdays, the oiling system has
been tweaked so that oil consumption is minimal, while still keeping the
seals from burning up/wearing out at a ridiculous rate.  

They must've tried to gear it wrong. The key with Wankels is to get 'em
to high revs and keep 'em there. And the key to doing that is picking
the right gear ratios to put between it and the tires. Seems to me I
recall reading that early 1.6 (or was it 1.8?) liter RXs *IDLED* in the
2500-ish range, with the sweet spot being up around 6-7K, and redline
being something like 12K. Meaning it's gotta be geared a lot lower than
a similar-powered (but significantly lower RPM) "boinger" engine to get
reasonable shift points.

By comparison, my 2 liter Mazda 626 "boinger" from '82 is specced to
idle at 950, with the shift point at just a hair under 2500, and a 6K
redline. According to the book, 2476 RPM is the sweet spot, and the
beast is geared accordingly - Using the gear ratios the book says are in
the tranny and rear end, assuming stock tires, and using a solid 2500
RPM on the tach to simplify the math (at least a little...), 1st gear is
14.76 MPH, 2nd is 26.03, 3rd is 36.44, 4th is 47.37, and 5th gear is
55.09 MPH. All of which match well with what a friendly neighbor (not
neighborhood, neighbor) cop's radar gun reads.

(In theory, taking it to redline in 5th would have me doing 132.23 MPH,
but I ain't ready to try it and see if that theory holds up in the real
world! Come on... This poor beast is old enough to go out and buy itself
a beer! I expect trying to get it to redline in 5th would scatter pieces
of the engine all along the road...)

They were one of the companies that originally licensed it from
NSU/Wankel for development in the early '60s. Actually, Mazda hit upon a
workable engine before NSU, much to NSU's embarrassment. As I recall,
Mazda was asked to delay introduction of the Cosmo until NSU could debut
the Prinz, so NSU could say it was the first to release a rotary to the
public.

By the time the gas crisis hit, some dozen companies, including GM,
Mercedes Benz and Citroen bought licenses to make the engines. Mazda was
the only one that carried the thing through all the way.

Lots of things were developed in Germany. NSU had some daring people,
more so than the big guys, and they were willing to take the plunge. I
think Felix Wankel was an NSU engineer.

Unfortunately, the costs of development (of the engine and of the Ro80
car), plus the warranty costs of fixing failed engines, eventually
brought NSU down by about 1968, and it was absorbed by Volkswagen/Audi.

Everybody was. It was the "wave of the future".

It was the engine that went "hummmm" instead of "boing boing boing".
Anybody remember those ads?

Not any more, besides less-than-great gas mileage. And they really,
really ARE that smooth. Smoother than a V8.

I got 19mpg out of my '74 RX-4.

They had apex seal problems. I had an RX-4 (the first 13B) which
suffered from that exact issue.

The biggest gotcha was that when the rotary failed, it didn't go bad
over months and miles, it failed RIGHT NOW. That stranded drivers and
also pissed them off. Sales tanked. Mazda almost got into financial
trouble themselves. The GLC saved them.

I think they kept on building rotaries all the way up to the RX-7 in
1979, updating the RX-4 chassis over the years.

I think Norton put a rotary in a bike at one point, too.

Mazda's parent company (Toyo Kogyo sp?)is a machine tool manufacturer.

On Jul 14, 11:43 pm, "Proctologically Violated??"
<entropic3.14de...@optonline2.718.net> wrote:

Felix Wankel invented the engine.  Licenses were issued to many
companies, including Curtiss-Wright in US.  NSU and Mazda were the
only two companies who brought it to production in an automobile.

There were both emissions and efficiency problems due to same cause-
the surface area to chamber volume is higher than in piston/cylinder
configuration.  The added chilling of charge increases emissions and
reduces efficiency somewhat.

Additionally, seal wear has been a problem.  Supposedly Mazda has
solved that problem.  However, with the problems it has had, there is
no strong driver to use the engine.  It is most appropriate where
specific power is a big driver, since its power to weight is very
good.  So it is best for high performance cars and aircraft.

While it has fewer parts, fancier machining has made it no cheaper to
produce than piston/cylinder engine.

Actually, GM did a lot more work on it than any of the German companies,
IIRC. Then they abandoned it and only Mazda carried the torch. Another
bit of trivia- the AMC Pacer was designed with the intent of using a
GM-built Wankel engine, and when GM pulled the plug on that engine AMC
had to substitute their own straight-six at the last minute.

A few:

Oil consumption (oil is deliberately sacrificed, albeit slowly, to
lubricate the rotor tip seals). That adds to emissions, too- really
jacks up the unburned hydrocarbon percentage.

Rotor tip seal wear (largely contolled by materials selection and
sacrificing oil, see above :-)

Fuel distribution sucks because the "intake" area of the engine always
stays much colder than the "combustion" area. Remember that the
"combustion chamber" loaded with fuel/air mix sweeps around the engine
as it runs, unlike a piston engine, so it has to move past "cold" parts
of the rotor chamber before getting to the spark plugs and hot
"combustion" area. Fuel injection helped that a lot, but its still an
issue that both reduces fuel efficiency and increases emissions.

Because at the time, the Japanese were more willing to take a jump into
an unproven technology than anyone else.  Mazda was part of a big heavy
machinery and machine tool combine that wanted to get into the car business
and wanted something different.  The Wankel sure was different.

Poorer gas mileage and lots of emission problems from burned oil.  The
_problem_ is that Mazda was introducing these cars into the US market
in the seventies, just as gas prices were climbing and emissions controls
were coming into place.

The Wankel has to burn some amount of oil in order to keep the seals working
properly.  This means it's always going to have higher emission issues than
a comparable 4-cycle engine.

The thing about the Wankel is that it produces huge amounts of power and
is very efficient at full throttle, but it is a comparatively poorer
performer at lower throttle settings.  This would make it a better choice
for applications like aircraft and marine engines which are normally run
at or near full throttle most of the time.

I would LOVE to see stationary generator packs made with small 2-rotor
Wankel engines.  Quieter generators make the world a better place,
they run mostly near full throttle, and the emissions are less of an issue.
--scott

On Jul 15, 12:43 am, "Proctologically Violated??"
<entropic3.14de...@optonline2.718.net> wrote:

Probably because the big german automobile companies were very
successful with piston based powerplants and they saw no real benefit
from having to create a whole new production line for a motor that
would in all likelihood be just a sideshow.

Well, the drawback really ends up being whether it can offer any
improvement over existing piston engine technology.  After bankrupting
itself with a premature conversion to the rotary in the 1970's Mazda
has spent the last 30 years bringing it up to snuff with piston
engines.

In a sense it is an oddball like the two cycle engine. Both designs
squeeze a lot of power from a compact engine.  But for differing
reasons neither design really offers an improvement over more
traditional powerplants.

On Jul 15, 12:43 am, "Proctologically Violated??"
<entropic3.14de...@optonline2.718.net> wrote:

Friend of mine back in the 60s had a Wankel NSU car.

NSU was the first company to market cars with Wankel engines. NSU was
eventually absorbed into VW, but they long ago gave up on Wankels.
Mazda is the only company that has had any success at selling them.
The poor fuel economy associated with Wankels pretty much limits them
to niche markets these days. Before the first fuel crisis of the 70's
GM was well on the way to marketing Wankel powered cars.

Ed