Germany's NSU motor company produced rotary engine cars over 30 years ago - a technology far in advance of the standard piston engine system.Oonagh Charleton has the details of this fascinating machine
What on earth do rotary engine cars have in common with knitting jumpers? And more importantly, what does one of the few remaining Irish-owned NSU Ro80s have in common with knitting in general?
Well, first things first. At the turn of the 19th century, the small factory town of Neckarsulm, in southern Germany, was the home of a company that made automatic knitting machines as well as a successful line of "safety" bicycles (bicycles with two small wheels and a chain drive, as opposed to the "penny-farthing" big-wheeled types). This company went by the name Neckarsulm Strickmaschinen Union (Neckarsulm Knitting-machine Union), which described their business accurately enough, but is quite a mouthful for the non-Germanic. Hence, they adopted the initials NSU.
Interestingly, an Irish NSU enthusiast, Jim O'Sullivan, a Dublin-based engineer, is part of a family-owned knitwear company, Ireland's Eye.
While the concept of knitting doesn't necessarily "click" well with the idea of a highly sophisticated and under-publicised engine, the two are definitively related.
NSU started life in 1873 and became a huge presence throughout the 1900s, moving from the humble bicycle to motorcycle production and finally to cars. With some of the most notable being the Sports Prinz and the Wankel Spider, Jim O'Sullivan is the proud owner of at least five NSU vehicles with the rotary engine Ro80 taking precedence on his busy front lawn. As an engineer, Jim O'Sullivan appreciates the Felix Wankel rotary engine like no other.
"To an engineer, the piston system in a standard engine makes no sense," says O'Sullivan. "The up down motion is inefficient. The rotary engine makes perfect sense and any engineer will appreciate that."
It is widely understood that a rotating engine is far superior to one in which pistons slide up and down, starting and stopping continuously.
This internal combustion engine, developed in the 1950s by Wankel, replaces the piston and cylinder with a three-cornered rotor that turns in a roughly oval chamber.
The idea is that the air and fuel mixture is drawn in to the intake port and trapped between one side of the turning rotor and the chamber wall. The rotating motion compresses the mixture, which is then ignited by a spark plug and exhaust gases are expelled through an exhaust port.
Its mechanical simplicity and lesser weight provided low manufacturing costs at that time, and its low centre of gravity made it a safer drive. Its main disadvantage lay in emissions and high fuel consumption. However, it can be run on unleaded petrol, as there are no valves to worry about.
Jim O'Sullivan disassembles and rebuilds rotary engines in his garage as a hobby, while at the same time maintaining and working on his other NSU projects. As well as the Ro80, he also has an NSU Prinz 1000 cc, a 1962 Sports Prinz Coupé, NSU VW K70, 1968 Sports Prinz and a 1960, twin-cylinder LHD Panard. And that collection is not complete without including the Rover 75 and NSU 250 motorbike.
Wandering around this extraordinary display of classics, he beams with pride before jumping into the Ro80 to bring his son, Cian, and myself for a quick spin around Howth.
Purchased about three years ago, it was fitted with a new engine and had some minor bodywork repairs including a rusty front wing. Gleaming in the sunshine, with not a square inch of chrome, just stainless steel, you would not believe that this car was built and designed over 30 years ago.
With an adamant philosophy about car modification and restoration, Jim O'Sullivan explains: "I would never modify a car, I always strive to put it back the way it was as a factory model. It has the same factory engine and who would want to modify that anyway?"
Sitting into the passenger seat, there is an instant sense of luxury and space with a high ceiling, roomy interior and minimal clutter. Seatbelts click into a central shared steel holder and there is an immediate sense of efficiency before Jim O'Sullivan rolls out onto the road.
"The worst way to drive this engine is like an ordinary car," he says. "When revs are at 3,000, the rotor is only at 1,000 rpm. So you should never drop below 2,000 rpm, always stay between 3,000 and 4,000. You have to drive the car with the rev counter, driving it like you would a bicycle, picking the speeds that suit the conditions."
As a semi-automatic with no clutch pedal, the "gear stick" is pulled back, let go, and the car takes off with a bit of throttle. Another wonderful feature is that the faster you go in a Ro80, the smoother and quieter it gets. "The main problem is keeping it slow," says Jim O'Sullivan, "as you honestly don't feel like you are travelling at 70 or 80 mph."
Front wheel drive, with independent suspension and McPherson struts, it also has all-round disc brakes. And happily, two completely independent brake-circuits, in case one fails. The engine is compact, lightweight and mostly aluminium, and the chassis immaculate.
This 1970 Ro80 has only been in his possession for three years, and yet he has given it as much attention as his other massive restoration projects. Easy enough to sell because they are unique and unusual, they can be priced in and around €4,000.
However, the only fully restored project he is willing to let go of at the moment is his Rover 75, and then it is only to create space for another beloved NSU in his garage.
With his first car being a 1962 Sports Prinz Coupé, which he still has, I am not surprised with his answer when I ask him what car he would choose if money was no object. "I would definitely go for the final fuel-injected version of the Ro80," he smiles.
This being one of the last models produced before NSU was eventually swallowed up by VW/Audi in 1969. With the Ro80 in production up to 1977 about 33,900 were produced in total. A three-rotor successor was in the works, but Volkswagen opted to extinguish any further rotary development.
Jim O'Sullivan also a co-founder of the Irish NSU club (set up in November 1999) and whose membership extends nationwide. With close to 40 members whose collection includes Prinz 1-3, Prinz 4, TT, Typ110, the Ro80 and the K70, the last NSU made by Volkswagen, meetings occur frequently throughout the year. One of the main objectives is to provide access to and supply of NSU parts for members, therefore making it easier to get projects on the road.
Why is it, then, that the rotary engine didn't successfully replace the piston engine after being hailed as 20 years ahead of its time? Well, it was released without the benefit of extended research and development, which may have phased out early teething problems that dogged its reputation. It also didn't benefit from significant advances in engineering and machine tools that exist today, and was generally driven by owners who didn't understand the engine. The piston engine had well over 100 years of trial and error while the rotary had a mere fraction of that.
So what place does it have in our current motoring times? Well it was rescued by the Japanese, who took the world by storm in 1978 with the RX-7, and then won Le Mans with a rotary engine Mazda in 1991. Now we can find it in the new RX-8, which holds a two rotor, water-cooled engine re-defined as the Renesis, the Rotary Engine's (RE) Genesis producing 250 bhp at 8,500 rpm.
So with the modern rotary engine having fewer parts, reducing stress levels on components compared to the piston, and high reliability, it is no wonder that it is under development for use in modern aircraft.
In the meantime, Jim O'Sullivan is more than happy to polish and maintain his Ro80 and focus on the restoration of his 1963 Sports Prinz Coupé. His only concern now being that he does not run out of space!
You can e-mail the Irish NSU club at nsuchairman@dol.ie