Rotard Heaven

by Dave Coleman

If you find yourself in Germany with a day to kill, you could do worse than Googling "rotary musem Germany." I did just that, and stumbed into the Museum Autovision in Altussheim, about a one-hour autobahn blast south of Frankfurt. For a rotary nerd like me, this place is a mecca of obscure little triangles. It's a fascinating look at that forgotten decade when the rotary engine was the future. Too bad I couldn't read most of the signs...

The rotary hall is just one small room in a museum mostly intended for sowing the seeds of engineerdism in students. It's a dense room full of historcal gems, though.


nsu ro80 autovision rotary museum

The NSU RO80 was the first attempt at a real, mainstream rotary-powered car. It was a technologically impressive machine with lots of features that seemed like a good idea at the time, like front-wheel drive, inboard disk brakes and, well, a rotary engine... Visually, it could easily have been mistaken for a mid '80s Audi, even though it was built 20 years earlier. This is the cutaway auto-show special used at the car's debut at the Frankfurt motor show. The elaborate hydraulic system that opens the hood and drops the side is still functional.


rotary collection at museum autovision in germanyAutovision's  collection of rotary engines you've never seen before is surprising. 


first NSU rotary autovision museumOn the left is the first NSU rotary prototype. This is actually the first rotary engine ever where the rotor housing itself didn't rotate. Felix Wankel hated the idea, and right behind these engines is a blown up copy of the nastygram Wankel sent to NSU telling them they fucked up his brilliant engine design. Of course, his original design was so unreliable it made an NSU Spyder seem as reliable as a Volvo 240.

The engine on the right is the second prototype engine, in its 27th iteration. Each iteration had the spark plug location moved half a millimeter. #27 was the best location.

 trabant rotary museum autovision germany

All rotary engines are built under a license agreement with NSU. Except the ones developed behind the iron curtain. This tiny 1-rotor engine is actually an East-German prototype developed for the Trabant. Because all East-German cars were 2-strokes anyway, gas stations only pumped pre-mix. With oil already mixed in the gas, this engine had no need for an oil injection system. Such are the engineering benefits of communisim.


nsu ro80 3-ROTOR PROTOTYPE ENGINEThis one-of-a-kind prototype 3-rotor was designed for a high-output version of the RO-80 that never saw production.

3-rotor eccentric shaft

Much of the early excitement around rotaries was the ability to endlessly stack up rotors to make engines as big and powerful as necessary. These muti-piece eccentric shafts were an early attempt at making the engines modular. I'm guessing they're NSU, but I don't really know.


NSU Hyrdrogen rotary engine museum autovision germanyMazda is big on hydrogen rotaries these days, but they're not the first to that party. This is an NSU-built hydrogen rotary prototype. You can just see the unique combustion pocket (in red, on the rotor face) designed to help mix the hydrogen and air before ignition.

Also, if you're a student of rotary evolution, you'll notice the coolant passages suggest this one is pretty well evolved. Early rotaries from both NSU and Mazda had self-contained water passages around each trochoid, with coolant entering the combustion side and flowing around the housing to exit on the intake side. The multiple o-ring-grooved holes around this housing suggest coolant flowed front to back through the engine like modern Mazdas. Also, notice there is no o-ring on the top right, which is the intake region, where no heat is generated, and thus no coolant is necessary. Mazda handles this by just restricting the coolant flow in this area.










NSU Spyder engine bay museum autovision germany

The rear-engine, single-rotor NSU Spyder was the first production rotary-powered car. In this pristine example, you can see the radiator hoses entering and exiting the top of the rotor housing, indicating the early-style coolant flow.

NSU Spyder, 81000 kmThe 81,000 km on this NSU Spyder's odometer suggest it's on its 4th engine...


sachs rotary powered chainsaw museum autovision germanyIf rotary engines sound like chainsaws, what does a rotary chainsaw sound like?


rotary lawnmower museum autovision germanyWhat about a rotary lawnmower?


rotary waterski machine museum autovision germanyOr what about a rotary-powered waterski machine? What's a waterski machine?


THIS is a waterski machine. For the waterski enthusiast without any friends...


Hercules rotary motorcycle museum autovision germany
hercules rotary motorcycle posterThis thing is so awesome I don't even need to write a caption.


Van Veen rotary motorcycle museum autovision germany
This Dutch motorcycle promised to be monstrously powerful, packing a 1,000cc 1-rotor engine (no telling how big it really was, as there was quite a bit of debate over how to define rotary displacement in the engine's early years). The engine was lifted from the small Citroen car (the silver one in the middle, below) and used a Porsche-designed gearbox. The bike, apparently, did not live up to its monstrous promise, and the company went bankrupt.
museum autovision germany

 If you get a chance to visit Museum Autovision yourself, be warned, they seem to be open only Thursday through Sunday. Do yourself a favor and bring someone who can read German. Or be lucky, like me, and get a long guided tour from museum owner Horst Schultz. To pull off the latter, I suggest wearing a Mazda jacket and travelling with with a handful of Mazda engineers. I'm guessing that improves your odds of a personal tour.


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Saturday, April 10, 2010 1:28 PM
"The 81,000 km on this NSU Spyder's odometer suggest its on its 4th engine..."

LMAO, it's funny cuz it's true. Thanks for the virtual guided tour, it made for an interesting read.
Saturday, April 10, 2010 1:45 PM
mhm good for a sunday education trip :) thanks too the unrestricted german autobahn its only 2hours away *g*
Jeff Naeyaert
Jeff Naeyaertlink
Saturday, April 10, 2010 2:54 PM
The tail letters on that airplane seem pretty appropriate for rotary powered aircraft--just missing a "y" at the end ;)
Saturday, April 10, 2010 7:46 PM
I could spend a nerdish couple of hours in that museum for sure. Rotaries are cool in their own little way. Now where is the Diesel engine museum?
Sunday, April 11, 2010 3:44 PM
When I first saw the guy on the rotor bike, I thought it was a toy. The guy looks like an action figure with his protractor straight arms and legs. The only thing missing on this nazi poster boy would be if his right arm came up in a stiff Sieg Heil!
Monday, April 12, 2010 6:58 AM
Whoa! I want to go there! I just finished reading a book on rotary history and it's so cool to see so many things the book talks about in one museum!
The book, however, ignored the waterski machine for waterski enthusiasts without friends.

I want to see one of those original Wankels up close, the pre-NSU screw up/where they made it better ones with the inner and outer moving rotors.

I wonder if anybody has tried putting a 12A or 13B in a RO80... front wheel drive would be tricky, but at least it would last more than 10K per engine. Not forever, but, ya know, it would be better...
Dave Coleman
Dave Colemanlink
Monday, April 12, 2010 8:11 AM

What book did you read?

Oh, and lots of people have put Mazda engines in RO-80s. Anybody with a running RO-80 has done it. This is the first one I've ever seen with an NSU engine!
Monday, April 12, 2010 8:39 AM
The book is called "The Wankel Rotary Engine. a History" by John B Hege. Blue cover, picture of Wankel with a DKM125 prototype. I think it's one of the first books to pop up on amazon if you type in "Wankel Rotary" or something like that. The book has some history stuff, different companies and what they did with rotaries, and quite a bit of engine problems that surfaced during development, along with how they problems were adressed. There's even some talk of Wankel's rotary valves, and mention of the rotary valve-V8 powered torpedo! I think it's an interesting read, but I'm a rotary noob.

Are there any books you would suggest? I've been trying to find some rotary tech articles online but since jstor.org doesn't contain engineering journals, i've only found old stuff (which i'm still gonna read) mostly from math journals, and one from some journal of medicine (still confused as to why a car article is in there).
Wednesday, April 14, 2010 4:47 AM
@ Paul: If there's a local college or university close by that could be one way to get your hands on some journal articles. Lots of schools just allow a basic login without id and password in their computer labs and the computer itself will usually have permission to access various journals via their library.

I see people come in and use our computers at my school all the time who clearly don't attend. Granted they're probably not looking up journal articles concerning rotaries but they could if they wanted to :)
Wednesday, April 14, 2010 6:50 AM
Yeah thats a great idea but this is the only university in this city. I am moving out to Boston this summer, though, so I'll have quite a few schools to look through. I did scan through google patents and google scholar which is a cool place to look, too.
Thursday, April 15, 2010 12:41 PM
Not even close to a Rotard myself, but a cool place.
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