bye bye rotary engine...

I had the RX-2 coupe and a RX-3 station wagon. Both were a gas to drive. The wagon was a goofy lime green with an automatic. The small station wagon concept was pretty practical and it was kind of on the fast side. Yay!

Sad, but the RX-8 is neither sports car nor practical, so it's demise wasn't hard to predict. That and I bet a rotary is more difficult to get through emissions.

nate

If you had sticks, i bet you wanted to run that little beast up to the redline before you shifted? ;)

bob

I have never owned, or driven a vehicle with a rotory engine, I guess I wont miss that. Yep, it is sad, no more rotary engines.Maybe someday they will return better than ever.I Hope so. cuhulin

My understanding is that the surface area of the combustion chamber is large and rapidly expands during the power stroke and retaining the heat of combustion is difficult. The result is unburnt gases. My Mazdas had a heavy cast iron chamber at the exhaust ports which allowed the unburnt gases some additional time at an elevated temperature. I think you are right that emissions were a problem. The seals also needed some lubricating which was done on my cars by pumping engine oil into the big carb. My guess is that probably didn't help much with the emissions either.

The RX-2 had a 4 speed, the wagon had an automatic. The rotary worked great with either setup. I was a conservative driver so I shifted pretty early. My sister-in-law who had a hot Camaro and kind of a hot foot, drove the car and told me that the car kept buzzing when she accelerated. Of course that was the warning alarm that these cars had to keep folks mindful of the redline. The torque didn't drop off the same way it does on a piston engine so the buzzer was needed.

bob urz wrote in news:j6pp94$9qf$ snipped-for-privacy@speranza.aioe.org:

Every time! They really were as smooth as the advertising said they were. And they were quick for their day.

I had a '74 RX-4, which was the first one with the "big" 13B.

Nate Nagel wrote in news: snipped-for-privacy@news1.newsguy.com:

Rotaries have long, rectangular, square-cornered combustion chambers. My understanding is that the primary problems with rotary emissions are those corners, plus the trailing edge of the combustion chamber. Lots of HCs lurking there, and that second spark-plug only helps somewhat.

Keep in mind that piston engine designers must now grapple with the emissions effects of the microscopic gap between the top of the piston and the upper ring. Imagine what rotary designers have to contend with.

If you want a little bitty Wankel engine to play with, I think some of those stores that sell model Airplane engines also sell some Wankel rotary engines. I have no idea what they cost. cuhulin

The 80s were the heyday of the rotaries. One could always tell when a rotary went down the street at high RPMs. Without a muffler, the engines were loud and ear-piercing. They were loud because they used big holes on the exhaust stroke instead of valves. Ear-piercing because of the high RPMS they were capable of. Painful music to the ears.

dsi1 wrote in news:j6qvhc$9uv$1@dont- email.me:

That's arguable. By then, the rotary was installed only in the RX-7. I think the heyday was the early-'70s, prior to the gas crisis.

During the early '70s, Mazda was putting them in just about every model they made, including station wagons and pickup trucks. The rotary was considered to have such promise and future that GM, Mercedes and Citroen all took out licenses to develp their own rotaries. Even AMC dipped their toe in the water: the Pacer was originally intended to have a rotary.

The gas crisis, plus the crisis that arose from the early rotaries' propensity for sudden self-destruction, killed that engine as a mass-market proposition.

Except that the big holes acted like valves in that they were covered and uncovered gradually. I don't remember my unmuffled 13B being any louder than an unmuffled V8.

But they were HOT, which was great for the heater on winter days. My RX-4 had an exhaust-temperature warning lamp on the dashboard. One day it lit-up on me. It turned out the exhaust pipe had cracked in half above the rear axle, and the rubber trunk mat had /melted/.

hachiroku wrote in news:4e91f5ab$0$56655$c3e8da3$ snipped-for-privacy@news.astraweb.com:

I remember those. There was a probe that was inserted into the cat body.

But the pre-'81 rotaries had no cat except in CA. What they did have for exhaust emissions was a "thermal reactor", basically a specially-shaped open chamber that was meant to operate at super-high temperatures to cook- off HCs.

The problem with the reactor was that it required a rich mixture to keep the fire going inside of it, which really cut into gas mileage. I never saw more than 19mpg. Plus, the reactor also required a separate air-pump and air jacket to help control its temperature. The exhaust for that air jacket was the second, smaller tailpipe next to the usual one. Reactors were notorious for cracking because of heat-cycling. I think BMWs around that period also used reactors.

The exhaust ran so hot on rotaries on account of the thermal-reactor system that Mazda had to install the warning-lamp system. The sensor was in the trunk, above the rear axle. Right where my exhaust broke....

I had one of the early ones in the US - the RX2? Soured me on rotaries for good. Backfires kept blowing holes in the muffler, horrible gas mileage, and worst of all, it wouldn't start in the winter in Chicago. And the factory admitted it - I called about this, and they told me, "yeah, they don't really start when it gets below 30 degrees". Maybe they shouldn't have sold them in cold climates, then. And Chicago ain't exactly the north pole.

It handled pretty well, though.

A New Rotary Engine Design? (Video)

Another type of rotary engine were the old rotary Airplane engines.The crankshaft didn't spin around, but the rest of the engine did. cuhulin

Bill Vanek wrote in news: snipped-for-privacy@4ax.com:

I had almost exactly that happen once. The backfire split the muffler along the roll-seam, opening a big hole in the middle.

Rotaries were powerful, but you paid for that power!

My RX-4 had no trouble starting in winter, and I live in Canada.

You're right that the crank was bolted to the bulkhead. The prop was fixed to the engine housing. My guess is that moving the cylinders around like that promoted pretty good cooling. The gyroscopic effects of such a setup must have made turns a bit tricky. One thing you don't want is a fighter plane that doesn't want to change directions. :-)

The worst thing one could do would be to blip the throttle right before shutting the engine off. That would cause a backfire of dramatic proportions. In my case, once was enough to ensure that it didn't happen again.

Light backfiring was perfectly normal when the engine was decelerated. I de-linked the servo on the carb which kept the trottle open during rapid deceleration so I tended to get that a lot. A little backfiring when downshifting is a happy sound to my ears.

Explaining that a little backfiring is normal to a guy not familiar with the rotary was met with a skeptical look. That's the breaks.

dsi1 wrote in news:j703pn$3en$1@dont- email.me:

That's exactly what I had done when my muffler split! The bang sounded like a gunshot.

Oh, yeah. That pop-pop-pop-POP-pop-pop-POP-pop-pop-pop...

Happened during decel, downshifting, and going downhill.

Ha ha, I was young and kinda stupid back in those days.