A bicycle is a two wheeled vehicle driven by the riders feet pushing on cranks or pedals. A common misconception is that the earliest form of bicycle was the dandy-horse, which was pushed along by the rider's feet. However, while both the dandy-horse and the later bicycle are both velocipedes, the dandy-horse is not propelled by cranks.
The first bicycle was introduced to England from France in 1868, and comprised two solid wheels of equal size fitted to a frame, much like a modern bicycle in appearance, with a saddle fitted in the centre and propelled by cranks attached to the front wheel. This vehicle provided such a bumpy ride to the rider that it became popularly known as 'the bone-shaker'. Later came the Penny-Farthing with pedals fixed to the large front wheel which was made large to achieve high speeds. Later still, around 1895, came the safety bicycle with pedals driving the rear wheel by way of a chain, and the rider sitting upon a saddle set back from the front wheel so as to reduce the chances of falling forwards over the handlebars, from this developed the Raleigh bicycle design of 1900 which forms the basis of the modern bicycle. In 1888 the two-person tandem bicycle was invented.
In 1906 it was reported that speeds of 50 mph were attained on a bicycle. Around the same time, slightly earlier, the motorised bicycle (motorcycle or motorbike) was invented.
A typical bicycle is comprised of several parts. The principal and essential being: the frame, front forks, wheels, pedals, saddle, handlebars, chain and brakes. The largest part of the bicycle is the frame, and these vary in design depending upon the specialised intention of the bicycle.
A frame for a BMX bicycle being small, heavily braced and made of aluminium. The frame for BMX xyxling needs to be strong so as to endure the stresses of the bumpy ride, and the saddle low as competitors never sit down during a competition and as such they need space to sprint and jump with ease.
Cross-Country cycle frames are generally made of aluminium and carbon-fibre so as to be light weight. They are relatively small frames to allow quick and easy mounting and dismounting off road, and strong to endure off-road bumpy conditions. The smaller frames are often compensated for by having a longer seat post to allow a normal height saddle position.
The cycle speedway bicycle frame is designed primarily for strength, and as such is typically made from steel or aluminium.
Road racing bicycle frames are designed to be light and stiff. Traditionally they ewre made of steel, but by the start of the 21st century carbon fibre was being used for the more expensive models as this offered the same stiffness at reduced weight. The design of the tubes also developed over time, tubes becoming of a larger diameter, but thinner walls, to allow the same stiffness with reduced weight.
Bicycles are fitted with various types of brake, the most popular being the calliper, cantilever, hydraulic or disc and the V brake. The most common form of brake found on leisure bicycles, is that form used also on road racing bicycles. The calliper brake. Calliper brakes are a very efficient means of rim braking and basically comprise two blocks of rubber or plastic which are squeezed onto the wheel rim when the brake lever is squeezed by the ride.
Cantilever brakes operate on the same principal as calliper brakes, but are of a slightly different design at the wheel end, offering increased clearance between the tyre and the brakepads and as such are frequently employed for cyclo-cross bicycles and mountain bikes.
The most efficient form of rim brake is the V brake. The V brake also offers the most clearance of any rim braking system, and is most often found on mountain bikes.
Hydraulic or disc brakes are the most efficient and powerful form of bicycle brake. They use the wheel hub to brake, rather than the rim. Disc brakes offer the most clearance, and as such are used on mountain bikes, but are also expensive to fit and maintain.
Bicycle wheels are generally of one of three types. The most common and traitional bicycle wheel is the spoked wheel, comprising a rim connected to the central bub by a series of thin metal rods known as spokes. Spoked wheels are light in weight. Less common than spoked wheels, but offering greater strength and durability at the expense of weight are mag wheels which comprise a rim attached to the hub by a few, thick solid plastic bars. Solid wheels, also known as disc wheels, are made from composite material or carbon fibre are very strong, stiff, aerodynamic and very expensive. They are rarely used except as rear wheels in time-trialing and track racing. Research Bicycle More pictures of Bicycle
A sociable was an open, private, four-wheeled carriage with two seats set facing each other. A sociable was a kind of tricycle for two riders, in which they sat side-by-side, thus distinguishing it from a tandem in which one ride sits behind the other. Research Sociable
A tandem is a bicycle with two seats one behind the other. Other multi-person bicycles include the triplet, with three seats, the quadrupet with four and the quintet with five. Research Tandem
The autonomic nervous system is responsible for the self-controlling aspects of the body's nervous network, and is under the control of the cerebral cortex, the hypothalmus, and the medulla oblongata. Working in tandem with the central nervous system, the autonomic nervous system features two subsystems which regulate body functions such as involuntary smooth muscle movement and heart rate. These two subsystems are called the sympathetic and parasympathetic nervous system, and their functions operate in opposition to one another, delicately balancing the bodily functions which they control. The sympathetic nervous causes fight or flight responses in moments of stress or stimulus, such as increased heart rate, saliva flow, and perspiration. The parasympathetic system counterbalances these effects by slowing the heart rate, dilating blood vessels, and relaxing involuntary smooth muscle fibres. Viewed individually, the sympathetic nervous system, also referred to as the thoracolumbar system, features a series of nerves which branch out of the spinal cord between the first thoracic vertebra and the second lumbar vertebra. These nerve fibres join into a long trunk of fibres, called the sympathetic trunk, on each side of the spinal cord. Along the sympathetic trunk are enlarged clusters of nerve fibres, called ganglia.
From these ganglia, a number of nerve fibres extend throughout the body's tissues. Many of these nerves create additional ganglia, such as the celiac ganglia and the mesenteric ganglia. The sympathetic nerves are responsible for contracting involuntary smooth muscle fibres, viscera, and blood vessels, speeding up the heart rate, and dilating the bronchial tubes in moments of stress. The parasympathetic nervous system, also referred to as the craniosacral system, features ganglia in the midbrain, in the medulla oblongata, and in the sacral region. The first two, the cranial ganglia of the parasympathetic system, give pass impulses to the facial, oculomotor, glossopharyngeal, and vagus nerves. The sacral group of parasympathetic nerves originate at the second, third, and fourth vertebrae and extend nerves to the bladder, the distalcolon, the rectum, and the genitals. The nerves of the parasympathetic nervous system are responsible for conserving and restoring energy in the body following a sympathetic response to stress. Research Autonomic Nervous System
The Ataka is a Soviet anti-tank guided missile with a maximum range of 8 kilometres and a target hit probability of better than 0.96 at ranges from three to six kilometres. The missile has a shaped charge warhead with a tandem charge for penetration of 950 to 1000 mm thick homogeneous armour and also multilayer and explosive armour. Research Ataka
MR Trigat is a British medium range infantry laser guided anti-tank weapon. It has an effective range of 2000 metres and fires a tandem high-explosive hollow charge missile designed to defeat reactive armour. Research MR Trigat
The RAAM (rifle-launched anti-armour munition) is an American anti-tank rocket-boosted bullet-trap riflegrenade, designed during the 1990s and equipped with a tandem, shaped charge warhead capable of being fired from any M16A2 rifle by means of a disposable plastic adapter which is slipped over the rifle's muzzle. On impact, the RAAM's two shaped charges fire in rapid succession; the first charge designed to remove reactive armour leaving the second charge to penetrate the then exposed standard armour. The RAAM has a maximum range of 250 metres and can penetratearmour more than 400 mm thick. Research RAAM
The Curtiss Model 60 Shrike (A-12) was an American attack aircraft of the Second World War in service from 1933 to 1942. The A-12 was manned by a crew of two comprising a pilot and a gunner seated in tandem, and was powered by a Wright R-1820-37 radial piston engine rated at 690 hp giving a top speed of 177 mph and a typical range of 838 km. The A-12 was armed with four 7.62 mm Browning fixed forward-firing machine-guns in the landing gear fairings, and one 7.62 mm Browning trainable machine-gun in the dorsal position. Up to 221 kg of disposable stores could also be carried on two hard points under the wings and generally comprised four 122 lb or four 100 lb bombs or ten 25 lb or 30 lb bombs. Research A-12
The AB-1 was a Brazilian two-seat tandem training sailplane first flown in 1965 at the Nova Iguacu Aero Club in Rio de Janeiro. The AB-1 was a braced high-wing monoplane of mixed wood and metal construction. Research AB-1
The Aeritalia G91 is an Italian single-seat light attack, close support and reconnaissance fighter developed to NATO operational requirements issued in early 1954, and first flown in 1956 (as the Fiat G.91). The Aeritalia G91 is a low-wing cantilever monoplane of metal construction powered by a Bristol Siddeley Orpheus 803 turbojet engine providing a top speed of about 1045 kmh depending upon model. The Italian version is armed with four 0.5 inch Colt-Browning M3 machine-guns, the Portuguese version with two 30 mm DEFA 552 cannon, both gun arrangements located in the sides of the forward fuselage. Up to 1500 kg of disposable stores can be carried on four hard points two under each wing.
A photographic-reconnaissance version of the G91 is produced as the G91R, and a tandem two-seater trainer version as the G91T. Research Aeritalia G91
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Bicycle
