The Norton Classic is a rotary-engined

motorcycle A motorcycle (motorbike, bike; uni (if one-wheeled); trike (if three-wheeled); quad (if four-wheeled)) is a lightweight private 1-to-2 passenger personal motor vehicle Steering, steered by a Motorcycle handlebar, handlebar from a saddle-style ...

built in 1987 by Norton as a

special edition The terms special edition, limited edition, and variants such as deluxe edition, collector's edition or expanded edition are used as a marketing incentive for various kinds of products, originally published products related to the arts, such as b ...

of just 100 machines.

Engine development

The Classic used an

air-cooled Air-cooled engines rely on the circulation of air directly over heat dissipation fins or hot areas of the engine to cool them in order to keep the engine within operating temperatures. Air-cooled designs are far simpler than their liquid-cooled ...

twin-rotor

Wankel engine The Wankel engine (, ) is a type of internal combustion engine using an eccentric (mechanism), eccentric Pistonless rotary engine, rotary design to convert pressure into rotating motion. The concept was proven by German engineer Felix Wankel, f ...

that had been developed by David Garside at BSA's Umberslade Hall research facility. Garside, who had been impressed by the

single-rotor

Fichtel & Sachs ZF Sachs AG, also known as Fichtel & Sachs, was founded in Schweinfurt in 1895 and was a well-known German family business. At its last point as an independent company, the company name was Fichtel & Sachs AG. In 1997, the automotive supplier w ...

engine in the Hercules motorcycle, installed a bought-in F&S engine into a BSA B25 'Starfire' frame as a "proof of concept". This proved reliable and smooth, but under-powered. Having obtained a

licence A license (American English) or licence (Commonwealth English) is an official permission or permit to do, use, or own something (as well as the document of that permission or permit). A license is granted by a party (licensor) to another part ...

from Felix Wankel in 1972, Garside then created a prototype twin-rotor engine (with F&S rotors) which doubled the capacity of the earlier test "mule". This twin-rotor engine was installed in a BSA A65 frame. Wankel engines run very hot, so in addition to its very deep cooling fins Garside gave this air-cooled motor interior air-cooling. Air was drawn through a forward-facing filter situated to provide a ram air effect. This air passed through the interior of the rotors and then into a large pressed-steel plenum before entering the combustion chambers ''via'' twin carburettors. The plenum (which doubled as the bike's

semi-monocoque The term semi-monocoque or semimonocoque refers to a stressed shell structure that is similar to a true monocoque, but which derives at least some of its strength from conventional reinforcement. Semi-monocoque construction is used for, among o ...

frame) enabled the transfer of much of the heat to the surrounding atmosphere. The carburation process further reduced temperatures ''via'' the

process A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management * Business process, activities that produce a specific s ...

of evaporation. Even so, at 50 °C the fuel-air mixture was still hotter than ideal, and the engine's

volumetric efficiency Volumetric efficiency (VE) in internal combustion engine engineering is defined as the ratio of the equivalent volume of the fresh air drawn into the cylinder during the intake stroke (if the gases were at the reference condition for density) to th ...

remained somewhat impaired. The eccentric shaft's main bearings and the inlet manifolds were fed by oil-injection lubrication, and the fuel-air mix also carried residual mist of oil from the interior of the rotors, which helped to lubricate the rotor tips. DKW Wankel 2000

Engine geometry

Source: * Generating radius ''R = 71 mm'' * Eccentricity ''e = 11.6 mm'' * Equidistance ''a = 0.5 mm'' * Rotor housing width ''B = 68.2 mm'' * Chamber displacement ''V_k = 294 cm³'' *

Compression ratio The compression ratio is the ratio between the maximum and minimum volume during the compression stage of the power cycle in a piston or Wankel engine. A fundamental specification for such engines, it can be measured in two different ways. Th ...

''ε = 9.2:1''

The Classic motorcycle

While its engine was revolutionary, in other respects, such as appearance, suspension and brakes, the Norton Classic was a conventional twin-shock roadster. The fork stanchions were protected by rubber gaiters; and a full enclosure protected the final-drive chain. The air-cooled Classic was lighter and more powerful than its only Wankel competitor in production, the over-complicated single-rotor Suzuki RE-5 motorcycle (which had

liquid-cooled Liquid cooling refers to cooling by means of the convection or circulation of a liquid. Examples of liquid cooling technologies include: * Cooling by convection or circulation of coolant, including water cooling * Liquid cooling and ventilatio ...

jackets and an oil-cooled rotor). The Classic was discontinued after a limited production run of only 100 motorcycles,Salvadori, Clement
"Retrospective: Norton Classic, 588cc Rotary Engine: 1988"
''Rider Magazine'', 22 November 2007. Retrieved: 2 August 2012. and was succeeded by the

Norton Commander Norton Commander (NC) is a discontinued prototypical orthodox file manager (OFM), written by John Socha and released by Peter Norton Computing (later acquired in 1990 by the NortonLifeLock, Symantec corporation). NC provides a text-based user i ...

. .

Wankel engines in motorcycles and aircraft

Compared to pistons, the rotors of a Wankel engine are massive and need time to warm up; yet, as NSU found to their cost with their Ro80 car, neither bikers nor car drivers have proved patient enough to give the engines time to reach operating temperature, and this impatience adversely affected reliability. The Wankel's virtues of smoothness, compactness and lightness should be particularly suitable for aircraft, especially since the start-up procedure and the taxi to the runway gives ample time for warm-up. However, although wankels have been fitted into gliders and light aircraft such as the

ARV Super2 The ARV Super2 (''Air Recreational Vehicle'') is a British two-seat light aircraft with Strut, strut-braced shoulder wings and tricycle landing gear. Designed by Bruce Giddings, the Super2 was available either factory-built or as a kit. It ...

, such engines are still uncommon in aviation. Perhaps inevitably, the Norton Classic's Wankel engine was further developed at Staverton into the

MidWest The Midwestern United States (also referred to as the Midwest, the Heartland or the American Midwest) is one of the four census regions defined by the United States Census Bureau. It occupies the northern central part of the United States. It ...

aero-engine. The Midwest engine's output increased from BSA's 85 bhp to nearly 110 bhp by improving volumetric efficiency as follows: cooling air was pumped under pressure by a belt-driven centrifugal fan through the interior of the rotors, but then dumped overboard. Filtered induction air at ambient pressure was then drawn into the combustion chambers.Midwest AE110R operator's Handbook

References

Bibliography

Development of the Norton Rotary Motorcycle Engine', D W Garside, SAE paper 821068 {{Norton motorcycles

Classic A classic is an outstanding example of a particular style; something of Masterpiece, lasting worth or with a timeless quality; of the first or Literary merit, highest quality, class, or rank – something that Exemplification, exemplifies its ...

Motorcycles powered by Wankel engines Motorcycles introduced in 1987