Misplaced Pages

#319680

99-417: Velomobiles are a class of faired cycles. One "speed" class of velomobiles emphasizes fairing aerodynamics for high speed. Most velomobiles in this class use three wheels, and so it is instructive to compare the four-wheel Quatrevelo against three-wheel designs. "Speed" velomobiles (compared to "cargo" velomobiles) are limited mainly by aerodynamics and rolling drag. Thus, "low aerodynamic drag" has long been

198-424: A differential . A double freewheel , preferably using no-backlash roller clutches, is considered superior. Trikes with a differential often use an internally geared hub as a gearbox in a 'mid drive' system. A jackshaft drive permits either single or two-wheel drive. Tadpoles generally use a bicycle's rear wheel drive and for that reason are usually lighter, cheaper and easier to replace and repair. Some trikes use

297-438: A vacuum bag can be used. A fiberglass, carbon fiber, or aluminum mold is polished and waxed, and has a release agent applied before the fabric and resin are applied, and the vacuum is pulled and set aside to allow the piece to cure (harden). There are three ways to apply the resin to the fabric in a vacuum mold. The first method is manual and called a wet layup, where the two-part resin is mixed and applied before being laid in

396-401: A 2/2 weave. The process by which most CFRPs are made varies, depending on the piece being created, the finish (outside gloss) required, and how many of the piece will be produced. In addition, the choice of matrix can have a profound effect on the properties of the finished composite. Many CFRP parts are created with a single layer of carbon fabric that is backed with fiberglass. A tool called

495-735: A 4-wheel velomobile, which he called the Quattro Kingsbury finished just in time to ship it to the USA to participate in ROAM, a group of several dozen velomobile riders riding from coast to coast. Several ROAM riders were impressed that Kingsbury in his Quattro had good cornering stability; was able to keep pace with riders with "aerodynamic"-class velomobiles; and had much larger storage volume—an issue of practical value for velomobiles used for everyday transportation. This led several velomobile designers to re-consider 4 wheels for aerodynamic velomobiles—despite

594-437: A central wing-box made of CFRP; it is the first to have a smoothly contoured wing cross-section instead of the wings being partitioned span-wise into sections. This flowing, continuous cross section optimises aerodynamic efficiency. Moreover, the trailing edge, along with the rear bulkhead, empennage , and un-pressurised fuselage are made of CFRP. However, many delays have pushed order delivery dates back because of problems with

693-447: A chopper gun is used to quickly create these composite parts. Once a thin shell is created out of carbon fiber, the chopper gun cuts rolls of fiberglass into short lengths and sprays resin at the same time, so that the fiberglass and resin are mixed on the spot. The resin is either external mix, wherein the hardener and resin are sprayed separately, or internal mixed, which requires cleaning after every use. Manufacturing methods may include

792-405: A complete tricycle. Conversion sets can also supplied ready to be brazed onto a lightweight, steel bicycle frame to form a complete trike. Some trike conversion sets can also be used with recumbent bicycles to form recumbent trikes. Adults may find upright tricycles difficult to ride because of familiarity with the counter-steering required to balance a bicycle. The variation in the camber of

891-462: A core. Applications for CFRPs include the following: The Airbus A350 XWB is built of 53% CFRP including wing spars and fuselage components, overtaking the Boeing 787 Dreamliner , for the aircraft with the highest weight ratio for CFRP, which is 50%. This was one of the first commercial aircraft to have wing spars made from composites. The Airbus A380 was one of the first commercial airliners to have

990-411: A criterium (massed start racing) series. A delta tricycle has one front wheel and two rear wheels. A tadpole tricycle has two front wheels and one rear wheel. Rear wheel steering is sometimes used, although this increases the turning circle and can affect handling (the geometry is similar to a regular tricycle operating in reverse, but with a steering damper added). Some early pedal tricycles from

1089-425: A delta trike can be quite close to the weight of a tadpole trike if they are both of a similar quality and similar materials are used. The Hase Kettwiesel Allround delta trike has an aluminium frame and weighs 39.4 lbs (17.9 kg). The Catrike Road tadpole trike has an aluminium frame and weighs 37.5 lbs (17 kg). The recumbent tadpole or reverse trike is a recumbent design with two steered wheels at

SECTION 10

#1732876392320

1188-493: A focus for such designs. Three-wheel designs tend to have better aerodynamics than four-wheel designs: Beyond aerodynamics, three wheels instead of four has other advantages: Three wheels have at least three significant disadvantages compared to four: For the above reasons, most "aerodynamic"-class velomobiles have used a tadpole tricycle configuration, while most four-wheel velomobiles have been used for "transportation"- and "cargo"-class velomobiles. In 2009, Miles Kingsbury

1287-527: A geometry (also called center point steering) with the kingpin axis intersecting the ground directly ahead of the tire contact point, producing a normal amount of trail. This arrangement, elsewhere called "zero scrub radius" is used to mitigate the effects of one-sided braking on steering. While zero scrub can reduce steering feel and increase wandering it can also protect novices from spinning out and/or flipping. Tadpole trikes tend also to use Ackermann steering geometry, perhaps with both front brakes operated by

1386-505: A mold, with epoxy either pre-impregnated into the fibers (also known as pre-preg ) or "painted" over it. High-performance parts using single molds are often vacuum-bagged and/or autoclave -cured, because even small air bubbles in the material will reduce strength. An alternative to the autoclave method is to use internal pressure via inflatable air bladders or EPS foam inside the non-cured laid-up carbon fiber. For simple pieces of which relatively few copies are needed (one or two per day),

1485-432: A number of field applications strengthening concrete, masonry, steel, cast iron, and timber structures. Their use in industry can be either for retrofitting to strengthen an existing structure or as an alternative reinforcing (or prestressing) material instead of steel from the outset of a project. Retrofitting has become the increasingly dominant use of the material in civil engineering, and applications include increasing

1584-452: A parking brake when stopped on a hill. Recumbent trikes often brake one wheel with each hand, allowing the rider to brake one side alone to pull the trike in that direction. On 1 July 2005, Sudhakar Yadav from India rode a tricycle in Hyderabad with a height of 12.67 metres (41.6 ft), a wheel diameter of 5.18 metres (17.0 ft) and length of 11.37 metres (37.3 ft). This tricycle

1683-422: A quick and easy conversion. The advantages of a trike conversion set include lower cost compared with new hand built tricycles and the freedom to choose almost any donor bicycle frame. Tricycle conversion sets tend to be heavier than a high quality, hand built, sports, touring or racing tricycle. Conversion sets can give the would-be serious tricyclist a taste of triking before making the final decision to purchase

1782-422: A refinery in a one-step process. Capture and reuse of the carbon and monomers is then possible. CFRPs can also be milled or shredded at low temperature to reclaim the carbon fiber; however, this process shortens the fibers dramatically. Just as with downcycled paper, the shortened fibers cause the recycled material to be weaker than the original material. There are still many industrial applications that do not need

1881-720: A single carbon fiber with diameter of 5–7 μm is sealed in a glass capillary. At the tip the capillary is either sealed with epoxy and polished to make carbon-fiber disk microelectrode or the fiber is cut to a length of 75–150 μm to make carbon-fiber cylinder electrode. Carbon-fiber microelectrodes are used either in amperometry or fast-scan cyclic voltammetry for detection of biochemical signalling. CFRPs are now widely used in sports equipment such as in squash, tennis, and badminton racquets, sport kite spars, high-quality arrow shafts, hockey sticks, fishing rods, surfboards , high end swim fins, and rowing shells . Amputee athletes such as Jonnie Peacock use carbon fiber blades for running. It

1980-417: A single rear wheel typically has two small compartments, one on either side of the rear wheel. A quadracycle can have one large stowage area between the rear wheels. A single large storage area is often more useful, as it can hold cargo which cannot be easily divided among several small compartments. A humorous competition demonstrated that a Quatrevelo can hold 26 six-packs of beer in glass bottles Although

2079-405: A spinal cord injury. Tricycles have been constructed that tilt in the direction of a turn, as a bicycle does, to avoid rolling over without a wide axle track. Examples have included upright, recumbent, delta, and tadpole configurations. Tricycle conversion sets or kits convert a bicycle to an upright tricycle. Tricycle kit can remove the front wheel and mounts two wheels under the handlebars for

SECTION 20

#1732876392320

2178-473: A vehicle that was powered by hand cranks. In 1789, two French inventors developed a three-wheeled vehicle, powered by pedals; they called it the tricycle. In 1818, British inventor Denis Johnson patented his approach to designing tricycles. In 1876, James Starley developed the Coventry Lever Tricycle, which used two small wheels on the right side and a large drive wheel on the left side; power

2277-481: A wide front and narrow rear offer superior aerodynamics to a delta trike configuration. Hand-crank trikes use a hand-operated crank, either as a sole source of power or a double drive with footpower from pedals and hand-power from the hand crank. The hand-power only trikes can be used by individuals who do not have the use of their legs due to a disability or an injury. They are made by companies including Greenspeed, Invacare, Quickie and Druzin. In case of paralysis of

2376-462: Is (2024/04) nearing 400 units, however the volume of independent tests is still limited. Several riders have both a Quatrevelo and another "aerodynamic"-class velomobile; and report in public forums Quatrevelo speed is nearly as fast as several "best in class" three-wheel velomobiles such as the DF and Milan. Another comparison is cargo capacity. One practical use is commuting and/or shopping. A tricycle with

2475-494: Is a human-powered (or gasoline or electric motor powered or assisted, or gravity powered) three-wheeled vehicle . Some tricycles, such as cycle rickshaws (for passenger transport) and freight trikes, are used for commercial purposes, especially in the developing world, particularly Africa and Asia. In the West, adult-sized tricycles are used primarily for recreation , shopping , and exercise . Tricycles are favoured by children,

2574-560: Is a recumbent cycle rickshaw that is used in central London and operated by Eco Chariots. The trike pictured is called the SUV (Sensible Utility Vehicle) and is produced by the company Organic Engines, which operates in Florida in the United States. It is a front wheel drive tricycle, articulated behind the driver seat, and has hydraulic double disc brakes and internal hub gears . The passenger

2673-406: Is a longer and/or wider three-wheel velomobile. A wider profile hurts aerodynamics, but smoother air-flow can compensate to a degree. At the same time, CFRP is stiff and strong enough that the weight penalty for "larger three-wheeler" is comparable to the added weight for a "smaller four-wheeler". As of 2017/05, a main example of a good-aerodynamics three-wheel velomobile with large cargo capacity

2772-409: Is dependent on the fiber orientation and machining condition of the cutting process. To reduce tool wear various types of coated tools are used in machining CFRP and CFRP-metal stack. The primary element of CFRPs is a carbon filament ; this is produced from a precursor polymer such as polyacrylonitrile (PAN), rayon , or petroleum pitch . For synthetic polymers such as PAN or rayon, the precursor

2871-466: Is electric golf cart-style vehicles, freight trikes are human-powered, so they do not have the maintenance required to keep batteries on golf carts charged up. Common uses include: A tricycle is a typical toy for children between the ages of eighteen months and five years before a balance bike . Compared to adult models, children's trikes are simpler, without brakes or gears, and often with crude front-drive. Child trikes can be unstable, particularly if

2970-993: Is exhibited at the Sudha Cars Museum and has been verified as the largest tricycle by the Guinness World Records . Carbon fiber reinforced polymer Carbon fiber-reinforced polymers ( American English ), carbon-fibre-reinforced polymers ( Commonwealth English ), carbon-fiber-reinforced plastics , carbon-fiber reinforced-thermoplastic ( CFRP , CRP , CFRTP ), also known as carbon fiber , carbon composite , or just carbon , are extremely strong and light fiber-reinforced plastics that contain carbon fibers . CFRPs can be expensive to produce, but are commonly used wherever high strength-to-weight ratio and stiffness (rigidity) are required, such as aerospace, superstructures of ships, automotive, civil engineering, sports equipment, and an increasing number of consumer and technical applications. The binding polymer

3069-438: Is first spun into filament yarns, using chemical and mechanical processes to initially align the polymer chains in a way to enhance the final physical properties of the completed carbon fiber. Precursor compositions and mechanical processes used during spinning filament yarns may vary among manufacturers. After drawing or spinning, the polymer filament yarns are then heated to drive off non-carbon atoms ( carbonization ), producing

Quatrevelo - Misplaced Pages Continue

3168-518: Is mitigated by the material's unsurpassed strength-to-weight ratio, and low weight is essential for high-performance automobile racing. Race-car manufacturers have also developed methods to give carbon fiber pieces strength in a certain direction, making it strong in a load-bearing direction, but weak in directions where little or no load would be placed on the member. Conversely, manufacturers developed omnidirectional carbon fiber weaves that apply strength in all directions. This type of carbon fiber assembly

3267-613: Is most widely used in the "safety cell" monocoque chassis assembly of high-performance race-cars. The first carbon fiber monocoque chassis was introduced in Formula One by McLaren in the 1981 season. It was designed by John Barnard and was widely copied in the following seasons by other F1 teams due to the extra rigidity provided to the chassis of the cars. Many supercars over the past few decades have incorporated CFRPs extensively in their manufacture, using it for their monocoque chassis as well as other components. As far back as 1971,

3366-413: Is much more difficult to process and more expensive. Despite their high initial strength-to-weight ratios, a design limitation of CFRPs are their lack of a definable fatigue limit . This means, theoretically, that stress cycle failure cannot be ruled out. While steel and many other structural metals and alloys do have estimable fatigue or endurance limits, the complex failure modes of composites mean that

3465-409: Is often a thermoset resin such as epoxy , but other thermoset or thermoplastic polymers, such as polyester , vinyl ester , or nylon, are sometimes used. The properties of the final CFRP product can be affected by the type of additives introduced to the binding matrix (resin). The most common additive is silica , but other additives such as rubber and carbon nanotubes can be used. Carbon fiber

3564-413: Is protected from rain and sun with a canopy. Urban delivery trikes are designed and constructed for transporting large loads. These trikes include a cargo area consisting of a steel tube carrier, an open or enclosed box, a flat platform, or a large, heavy-duty wire basket. These are usually mounted over one or both wheels, low behind the front wheel, or between parallel wheels at either the front or rear of

3663-519: Is quite high compared to recumbent trikes. Because of this, non-tilting trikes are more prone to tipping over in corners and on uneven or sloping terrain. Conversely, the rider enjoys better visibility than on a recumbent because their head is higher. Recumbent trikes' advantages (over conventional trikes) include stability (through low centre of gravity ) and low aerodynamic drag . Disadvantages (compared to bicycles) include greater cost, weight, and width. The very low seat may make entry difficult, and on

3762-646: Is significantly improved if a thin layer of carbon fibers is moulded near the surface because a dense, compact layer of carbon fibers efficiently reflects heat. CFRPs are being used in an increasing number of high-end products that require stiffness and low weight, these include: CFRPs have a long service lifetime when protected from the sun. When it is time to decommission CFRPs, they cannot be melted down in air like many metals. When free of vinyl (PVC or polyvinyl chloride ) and other halogenated polymers, CFRPs can be thermally decomposed via thermal depolymerization in an oxygen-free environment. This can be accomplished in

3861-442: Is sometimes referred to as graphite-reinforced polymer or graphite fiber-reinforced polymer ( GFRP is less common, as it clashes with glass-(fiber)-reinforced polymer ). CFRP are composite materials . In this case the composite consists of two parts: a matrix and a reinforcement. In CFRP the reinforcement is carbon fiber, which provides its strength. The matrix is usually a thermosetting plastic, such as polyester resin, to bind

3960-453: Is that many tricycles put about 1/3 of total weight on the drive wheel, while many quads put about 1/2 weight on the two drive wheels. Further, the Quatrevelo uses two ratchets, one to drive each rear wheel; thus, if one drive wheel loses traction, the other one continues to drive. Note this is different than driving via a simple differential , in which the loss of traction on one wheel causes

4059-470: Is the Milan 4.2 ("for two"). The Milan 4.2 is not directly comparable to the Quatrevelo, as the 4.2 has enough stowage for an adult passenger (though no passenger drivetrain). The weight and aerodynamics of the Milan 4.2 are thus broadly similar to the Quatrevelo; and stability depends significantly on cargo loading and weight distribution. Tricycle#Tadpole A tricycle , sometimes abbreviated to trike ,

Quatrevelo - Misplaced Pages Continue

4158-401: Is the total composite modulus, V m {\displaystyle V_{m}} and V f {\displaystyle V_{f}} are the volume fractions of the matrix and fiber respectively in the composite, and E m {\displaystyle E_{m}} and E f {\displaystyle E_{f}} are the elastic moduli of

4257-436: Is typical). As a consequence, only small cross-sectional areas of the material are used. Small areas of very high strength but moderate stiffness material will significantly increase strength, but not stiffness. CFRPs can also be used to enhance shear strength of reinforced concrete by wrapping fabrics or fibers around the section to be strengthened. Wrapping around sections (such as bridge or building columns) can also enhance

4356-412: Is used as a shank plate in some basketball sneakers to keep the foot stable, usually running the length of the shoe just above the sole and left exposed in some areas, usually in the arch. Controversially, in 2006, cricket bats with a thin carbon-fiber layer on the back were introduced and used in competitive matches by high-profile players including Ricky Ponting and Michael Hussey . The carbon fiber

4455-633: The Citroën SM offered optional lightweight carbon fiber wheels. Use of the material has been more readily adopted by low-volume manufacturers who used it primarily for creating body-panels for some of their high-end cars due to its increased strength and decreased weight compared with the glass-reinforced polymer they used for the majority of their products. CFRPs have become a notable material in structural engineering applications. Studied in an academic context as to their potential benefits in construction, CFRPs have also proved themselves cost-effective in

4554-580: The brittle nature of CFRPs, in contrast to the ductility of steel. Though design codes have been drawn up by institutions such as the American Concrete Institute , there remains some hesitation among the engineering community about implementing these alternative materials. In part, this is due to a lack of standardization and the proprietary nature of the fiber and resin combinations on the market. Carbon fibers are used for fabrication of carbon-fiber microelectrodes . In this application typically

4653-474: The ductility of the section, greatly increasing the resistance to collapse under dynamic loading. Such 'seismic retrofit' is the major application in earthquake-prone areas, since it is much more economic than alternative methods. If a column is circular (or nearly so) an increase in axial capacity is also achieved by wrapping. In this application, the confinement of the CFRP wrap enhances the compressive strength of

4752-512: The wheelbase or track are insufficient. Some trikes have a push bar so adults can control the trike. Child trikes have frames made of metal, plastic, or wood. Children's trikes can have pedals directly driving the front wheels, allowing braking with the pedals, or they can use chain drive the rear wheels, often without a differential, so one rear wheel spins free. Children's trikes do not always have pneumatic tires , having instead wheels of solid rubber or hollow plastic. While this may add to

4851-460: The Quatrevelo is of special interest because (as of 2017/05) tens of units are in the hands of private owners and so can be used for independent testing. The Quatrevelo may be compared against other "aerodynamic"-class velomobiles. As of 2024, some of the fastest tadpole velomobiles are the Tuna, Milan, Bülk and Snoek. The Snoek is made by Velomobiel.nl, but the others are not. Production of the Quatrevelo

4950-426: The brittle fracture mechanics presents unique challenges to engineers in failure detection since failure occurs catastrophically. As such, recent efforts to toughen CFRPs include modifying the existing epoxy material and finding alternative polymer matrix. One such material with high promise is PEEK , which exhibits an order of magnitude greater toughness with similar elastic modulus and tensile strength. However, PEEK

5049-468: The competition was humorous, it demonstrates the practical stowage capacity of the Quatrevelo is both much larger than most "speed" velos, and also large enough for many daily uses. Another use is carrying a passenger. The Quatrevelo is offered standard with a second seat for a small (non-pedaling) rider. Most 3-wheel velomobiles drive (power) the single rear wheel, and a four-wheel velomobile with two driven wheels may have better drive traction. One reason

SECTION 50

#1732876392320

5148-407: The concrete. However, although large increases are achieved in the ultimate collapse load, the concrete will crack at only slightly enhanced load, meaning that this application is only occasionally used. Specialist ultra-high modulus CFRP (with tensile modulus of 420 GPa or more) is one of the few practical methods of strengthening cast iron beams. In typical use, it is bonded to the tensile flange of

5247-409: The desired component. The benefit is the speed of the entire process. Some car manufacturers, such as BMW, claimed to be able to cycle a new part every 80 seconds. However, this technique has a very high initial cost since the molds require CNC machining of very high precision. For difficult or convoluted shapes, a filament winder can be used to make CFRP parts by winding filaments around a mandrel or

5346-442: The disabled, and senior adults for their apparent stability versus a bicycle ; however a conventional trike may exhibit poor dynamic lateral stability, and the rider should exercise appropriate operating caution when cornering (e.g., with regard to speed, rate of turn, slope of surface) and operating technique (e.g., leaning the body 'into' the turn) to avoid tipping the trike over. Designs such as recumbents or others which place

5445-550: The fatigue failure properties of CFRPs are difficult to predict and design against; however emerging research has shed light on the effects of low velocity impacts on composites. Low velocity impacts can make carbon fibre polymers susceptible to damage. As a result, when using CFRPs for critical cyclic-loading applications, engineers may need to design in considerable strength safety margins to provide suitable component reliability over its service life. Environmental effects such as temperature and humidity can have profound effects on

5544-401: The final carbon fiber. The carbon fibers filament yarns may be further treated to improve handling qualities, then wound onto bobbins . From these fibers, a unidirectional sheet is created. These sheets are layered onto each other in a quasi-isotropic layup, e.g. 0°, +60°, or −60° relative to each other. From the elementary fiber, a bidirectional woven sheet can be created, i.e. a twill with

5643-495: The following: One method of producing CFRP parts is by layering sheets of carbon fiber cloth into a mold in the shape of the final product. The alignment and weave of the cloth fibers is chosen to optimize the strength and stiffness properties of the resulting material. The mold is then filled with epoxy and is heated or air-cured. The resulting part is very corrosion-resistant, stiff, and strong for its weight. Parts used in less critical areas are manufactured by draping cloth over

5742-415: The form of hydrogen embrittlement has been blamed for the gradual deterioration of the prestressing wires in many PCCP lines. Over the past decade, CFRPs have been used to internally line PCCP, resulting in a fully structural strengthening system. Inside a PCCP line, the CFRP liner acts as a barrier that controls the level of strain experienced by the steel cylinder in the host pipe. The composite liner enables

5841-415: The frames can be broken down into pieces for easier transport. Manufacturers of recumbent trikes include Greenspeed, WhizWheelz and Inspired Cycle Engineering. Most cycle rickshaws , used for carrying passengers for hire, are tricycles with one steering wheel in the front and two wheels in the back supporting a seating area for one or two passengers. Cycle rickshaws often have a parasol or canopy to protect

5940-434: The front (called tadpole ). The rider straddles the frame in both delta and tadpole configurations. Steering is through a handlebar directly connected to the front wheel via a conventional bicycle fork in delta, or via a form of Ackermann steering geometry in the case of the upright tadpole. All non-tilting trikes have stability issues and great care must be used when riding a non-tilting upright trike. The center of gravity

6039-434: The front and one driven wheel at the back, though one model has the front wheels driven while the rear wheel steers. Steering is either through a single handlebar linked with tie rods to the front wheels' stub axle assemblies (indirect) or with two handlebars (rather, two half-handlebars) each bolted to a steerer tube, usually through a bicycle-type headset and connected to a stub axle assembly (direct). A single tie rod connects

SECTION 60

#1732876392320

6138-456: The front wheel with a large handlebar (over seat steering). Some delta trikes can be stored upright by lifting the front wheel and resting the top of the seat on the ground. Delta trikes generally have higher seats and a tighter turning radius than tadpole trikes. The tight turning radius is useful if riding on trails with offset barriers, or navigating around closely placed obstacles. The higher seat makes mounting and dismounting easier. Even with

6237-415: The higher seat a delta trike can be quite stable provided most of the weight (including the rider) is shifted back towards the rear wheels. Many delta trikes place the seat too far forward and that takes weight off the two rear wheels and puts more weight onto the front wheel making the trike more unstable. The Hase Kettwiesel delta trike has an 18 in (460 mm) high seat that is placed to put most of

6336-510: The inherent drag losses of 4 wheels compared to three. Velomobiles.nl claims for a given width, four wheels offer 40% higher cornering stability than a tadpole tricycle of similar width and center of gravity. Or, a tricycle would need to be 40% wider to get the same stability; but since air drag is directly related to frontal area, making the tricycle wide would directly hurt aerodynamics. As of 2017/05 there are several projects by various makers to introduce "aerodynamic"-class 4-wheel velomobiels;

6435-404: The late 19th century used two wheels in tandem on one side and a larger driving wheel on the other. An in-line three-wheeled vehicle has two steered wheels, one at the front and the other in the middle or at the rear. Upright trikes resemble a two-wheeled bicycle, traditionally diamond frame , or open frame, but with either two widely spaced wheels at the back (called delta ) or two wheels at

6534-400: The left and right axle assemblies. The tadpole trike is often used by middle-aged or retiree-age former bicyclists who are tired of the associated pains from normal upright bikes. With its extremely low center of gravity, aerodynamic layout and light weight (for trikes), tadpoles are considered the highest performance trikes. Most velomobiles are built in a tadpole trike configuration since

6633-514: The legs, more speed and range of distance can be obtained by adding functional electrical stimulation to the legs. The large leg muscles are activated by electrical impulses synchronized with the hand cranking movement. Recumbent tandem trikes allow two people to ride in a recumbent position with an extra-strong backbone frame to hold the extra weight. Some allow the "captain" (the rider who steers) and "stoker" (the rider who only pedals) to pedal at different speeds. They are often made with couplers so

6732-440: The load capacity of old structures (such as bridges, beams, ceilings, columns and walls) that were designed to tolerate far lower service loads than they are experiencing today, seismic retrofitting, and repair of damaged structures. Retrofitting is popular in many instances as the cost of replacing the deficient structure can greatly exceed the cost of strengthening using CFRP. Applied to reinforced concrete structures for flexure,

6831-419: The manufacture of these parts. Many aircraft that use CFRPs have experienced delays with delivery dates due to the relatively new processes used to make CFRP components, whereas metallic structures have been studied and used on airframes for decades, and the processes are relatively well understood. A recurrent problem is the monitoring of structural ageing, for which new methods are constantly investigated, due to

6930-568: The matrix and fibers respectively. The other extreme case of the elastic modulus of the composite with the fibers oriented transverse to the applied load can be found using the equation: The fracture toughness of carbon fiber reinforced plastics is governed by the mechanisms: 1) debonding between the carbon fiber and polymer matrix, 2) fiber pull-out, and 3) delamination between the CFRP sheets. Typical epoxy-based CFRPs exhibit virtually no plasticity, with less than 0.5% strain to failure. Although CFRPs with epoxy have high strength and elastic modulus,

7029-619: The matrix in CFRPs such as compressive, interlaminar shear, and impact properties. The epoxy matrix used for engine fan blades is designed to be impervious against jet fuel, lubrication, and rain water, and external paint on the composites parts is applied to minimize damage from ultraviolet light. Carbon fibers can cause galvanic corrosion when CRP parts are attached to aluminum or mild steel but not to stainless steel or titanium. Carbon Fiber Reinforced Plastics are very hard to machine, and cause significant tool wear. The tool wear in CFRP machining

7128-433: The mold and placed in the bag. The other one is done by infusion, where the dry fabric and mold are placed inside the bag while the vacuum pulls the resin through a small tube into the bag, then through a tube with holes or something similar to evenly spread the resin throughout the fabric. Wire loom works perfectly for a tube that requires holes inside the bag. Both of these methods of applying resin require hand work to spread

7227-647: The need to re-true a wheel and the reduced mass reduces the moment of inertia of the wheel. CFRP spokes are rare and most carbon wheelsets retain traditional stainless steel spokes. CFRPs also appear increasingly in other components such as derailleur parts, brake and shifter levers and bodies, cassette sprocket carriers, suspension linkages, disc brake rotors, pedals, shoe soles, and saddle rails. Although strong and light, impact, over-torquing, or improper installation of CFRP components has resulted in cracking and failures, which may be difficult or impossible to repair. The fire resistance of polymers and thermo-set composites

7326-412: The other wheel to stop driving. Several Quatrevelo riders are also riders of 3-wheel velomobiles and report online the Quatrevelo has much better traction and climbing on loose or slippery surfaces. There are two- and even three-wheel drive tricycles; so improved traction is not unique to the Quatrevelo, but it may be unique among "speed"-class production velomobiles. An alternative to "more/four wheels"

7425-571: The passengers from sun and rain. These vehicles are widely used in South Asia and Southeast Asia, where rickshaw driving provides essential employment for recent immigrants from rural areas, generally impoverished men. In the 1990s and first decade of the 21st century, rickshaws became increasingly popular in big cities in Britain, Europe and the United States, where they provide urban transportation, novelty rides, and serve as advertising media. Spidertrike

7524-494: The polymer-based composites, including most CFRPs. While CFRPs demonstrate excellent corrosion resistance, the effect of moisture at wide ranges of temperatures can lead to degradation of the mechanical properties of CFRPs, particularly at the matrix-fiber interface. While the carbon fibers themselves are not affected by the moisture diffusing into the material, the moisture plasticizes the polymer matrix. This leads to significant changes in properties that are dominantly influenced by

7623-436: The proportion of the carbon fibers relative to the polymer. The two different equations governing the net elastic modulus of composite materials using the properties of the carbon fibers and the polymer matrix can also be applied to carbon fiber reinforced plastics. The equation: is valid for composite materials with the fibers oriented in the direction of the applied load. E c {\displaystyle E_{c}}

7722-414: The reinforcements together. Because CFRPs consist of two distinct elements, the material properties depend on these two elements. Reinforcement gives CFRPs their strength and rigidity, measured by stress and elastic modulus respectively. Unlike isotropic materials like steel and aluminum, CFRPs have directional strength properties. The properties of a CFRP depend on the layouts of the carbon fiber and

7821-649: The resin evenly for a glossy finish with very small pin-holes. A third method of constructing composite materials is known as a dry layup. Here, the carbon fiber material is already impregnated with resin (pre-preg) and is applied to the mold in a similar fashion to adhesive film. The assembly is then placed in a vacuum to cure. The dry layup method has the least amount of resin waste and can achieve lighter constructions than wet layup. Also, because larger amounts of resin are more difficult to bleed out with wet layup methods, pre-preg parts generally have fewer pinholes. Pinhole elimination with minimal resin amounts generally require

7920-471: The rider lower relative to the wheel axles have a lower centre of gravity , and/or designs with canted wheels (tilted at the top towards the centerline) may be more resistant to lifting inner wheels or tipping during fast sharp turns, but still require operator awareness and technique. A three-wheeled wheelchair was built in 1655 or 1680 by a disabled German man, Stephan Farffler , who wanted to be able to maintain his mobility. A watch-maker, Farffler created

8019-401: The rider makes a pair of front wheels change directions by shifting the center of weight and moves forward by rotating the rear wheel. The hand and foot trike can be also converted into a manual tricycle designed to be driven with both hands and both feet. There are also new hybrids between a handcycle, a recumbent bike and a tricycle, these bikes make it even possible to cycle with legs despite

8118-443: The road is the principal difficulty to be overcome once basic tricycle handling is mastered. Recumbent trikes are less affected by camber and, depending on track width and riding position, capable of very fast cornering. Some trikes are tilting three-wheelers, which lean into corners much as bicycles do. In the case of delta tricycles, the drive is often to just one of the rear wheels, though in some cases both wheels are driven through

8217-433: The road they may be less visible to other traffic. A recumbent delta is similar to an upright, with two wheels at the back and one at the front, but has a recumbent layout in which the rider is seated in a chair-like seat. One or both rear wheels can be driven, while the front is used for steering (the usual layout). Steering is either through a linkage, with the handlebars under the seat (under seat steering) or directly to

8316-490: The section, both increasing the stiffness of the section and lowering the neutral axis , thus greatly reducing the maximum tensile stress in the cast iron. In the United States, prestressed concrete cylinder pipes (PCCP) account for a vast majority of water transmission mains. Due to their large diameters, failures of PCCP are usually catastrophic and affect large populations. Approximately 19,000 miles (31,000 km) of PCCP were installed between 1940 and 2006. Corrosion in

8415-709: The steel cylinder to perform within its elastic range, to ensure the pipeline's long-term performance is maintained. CFRP liner designs are based on strain compatibility between the liner and host pipe. CFRPs are more costly materials than commonly used their counterparts in the construction industry, glass fiber-reinforced polymers (GFRPs) and aramid fiber-reinforced polymers (AFRPs), though CFRPs are, in general, regarded as having superior properties. Much research continues to be done on using CFRPs both for retrofitting and as an alternative to steel as reinforcing or prestressing materials. Cost remains an issue and long-term durability questions still remain. Some are concerned about

8514-429: The strength of full-length carbon fiber reinforcement. For example, chopped reclaimed carbon fiber can be used in consumer electronics, such as laptops. It provides excellent reinforcement of the polymers used even if it lacks the strength-to-weight ratio of an aerospace component. In 2009, Zyvex Technologies introduced carbon nanotube-reinforced epoxy and carbon pre-pregs . Carbon nanotube reinforced polymer (CNRP)

8613-482: The stronger hand. While the KMX Kart stunt trike with this setup allows the rear brake to be operated separately, letting the rider do "bootlegger turns", the standard setup for most trikes has the front brake for each side operated by each hand. The center-of-mass of most tadpole trikes is close to the front wheels, making the rear brake less useful. The rear brake may instead be connected to a latching brake lever for use as

8712-447: The tadpole configuration, with the cargo box (platform, etc.) mounted between the front wheels. India and China are significant strongholds of the rear-loading "delta" carrier trike. Freight trikes are also designed for indoor use in large warehouses or industrial plants. The advantage of using freight trikes rather than a motor vehicle is that there is no exhaust, which means that the trike can be used inside warehouses. While another option

8811-516: The twenty-four hours' unpaced Tricycle record. At 100 miles Payne was inside his schedule time, but shortly afterwards had to desist at Wisbech , having encountered five hours of incessant rain. In the UK, upright tricycles are sometimes referred to as "barrows". Many trike enthusiasts in the UK belong to the Tricycle Association, formed in 1929. They participate in day rides, tours, time trials, and

8910-702: The unusual multi-material and anisotropic nature of CFRPs. In 1968 a Hyfil carbon-fiber fan assembly was in service on the Rolls-Royce Conways of the Vickers VC10s operated by BOAC . Specialist aircraft designers and manufacturers Scaled Composites have made extensive use of CFRPs throughout their design range, including the first private crewed spacecraft Spaceship One . CFRPs are widely used in micro air vehicles (MAVs) because of their high strength-to-weight ratio. CFRPs are extensively used in high-end automobile racing. The high cost of carbon fiber

9009-407: The use of autoclave pressures to purge the residual gases out. A quicker method uses a compression mold , also commonly known as carbon fiber forging. This is a two (male and female), or multi-piece mold, usually made out of aluminum or steel and more recently 3D printed plastic. The mold components are pressed together with the fabric and resin loaded into the inner cavity that ultimately becomes

9108-422: The use of CFRPs typically has a large impact on strength (doubling or more the strength of the section is not uncommon), but only moderately increases stiffness (as little as 10%). This is because the material used in such applications is typically very strong (e.g., 3 GPa ultimate tensile strength , more than 10 times mild steel) but not particularly stiff (150 to 250 GPa elastic modulus, a little less than steel,

9207-446: The vehicle, to keep the center of gravity low. The frame and drivetrain must be constructed to handle loads several times that of an ordinary bicycle; as such, extra low gears may be added. Other specific design considerations include operator visibility and load suspension. Many, but not all, cycles used for the purpose of vending goods such as ice cream cart trikes or hot dog vending trikes are cargo bicycles. Many freight trikes are of

9306-503: The weight of the tricycle and reduces the shock-absorbing qualities, it eliminates the possibility of punctures. Pull brakes are rarely fitted to front-drive trikes, but the child can slow the trike down by resisting the forward motion through the pedals. Drift trikes are a variety of tricycle with slick rear wheels, enabling them to drift , being countersteered round corners. They are commonly used for gravity-powered descents of paved roads with steep gradients. With hand and foot trikes,

9405-582: The weight onto the cambered rear wheels making it more stable. Delta trikes are suitable to be used as manual scooters for mobility, rehabilitation and/or exercise. The Hase Lepus Comfort is an example of a rehabilitation delta trike designed mainly for comfort and ease of use. It has a lowered front boom and the seat can be adjusted to a height of 20 to 28 in (510 to 710 mm), which aids in mounting and dismounting. It also has rear wheel suspension for comfort. The 56 lb (25 kg) Lepus can be folded for easier storage and transportation. The weight of

9504-955: Was claimed to merely increase the durability of the bats, but it was banned from all first-class matches by the ICC in 2007. A CFRP bicycle frame weighs less than one of steel, aluminum, or titanium having the same strength. The type and orientation of the carbon-fiber weave can be designed to maximize stiffness in required directions. Frames can be tuned to address different riding styles: sprint events require stiffer frames while endurance events may require more flexible frames for rider comfort over longer periods. The variety of shapes it can be built into has further increased stiffness and also allowed aerodynamic tube sections. CFRP forks including suspension fork crowns and steerers, handlebars , seatposts , and crank arms are becoming more common on medium as well as higher-priced bicycles. CFRP rims remain expensive but their stability compared to aluminium reduces

9603-436: Was manufactured in 1881 by The Leicester Safety Tricycle Company of Leicester, England, which was brought to the market in 1882 costing £18. They also developed a folding tricycle at the same time. Tricycles were used by riders who did not feel comfortable on the high wheelers, such as women who wore long, flowing dresses (see rational dress ). In September, 1903 Edmund Payne , the popular comedian, started an attempt to beat

9702-443: Was racing a tadpole tricycle velomobile, and often lost to a competitor riding a streamliner (which Kingsbury had designed and built). Kingsbury concluded one reason he lost to the streamliner was limited cornering stability of his tricycle. He calculated that it was plausible to build a 4-wheel velomobile which would both have the needed stability and also have good enough aerodynamics to be competitive. He then designed and built

9801-551: Was supplied by hand levers. In 1877, Starley developed a new vehicle he called the Coventry Rotary, which was "one of the first rotary chain drive tricycles." Starley's inventions started a tricycling craze in Britain; by 1879, there were "twenty types of tricycles and multi-wheel cycles ... produced in Coventry, England, and by 1884, there were over 120 different models produced by 20 manufacturers." The first front steering tricycle

#319680