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41-483: Aside from the placement of the driver and engine, the P48 was mechanically the same as the outgoing P25. It featured the same 2.5 litre straight-4 engine producing 275 horsepower. The P48 also featured a single brake disc at the rear mounted directly to the gearbox. The rear bodywork was cut off to aid cooling, which exposed the unlovingly nicknamed "bacon slicer" rear brake. During 1960 Tony Rudd designed his Mark II version of

82-413: A P48. Tony Rudd Anthony Cyril Rudd (8 March 1923 – 22 August 2003) was a British engineer involved in aero engine design and motor racing , with particular associations with BRM and Lotus . Rudd became involved with motor racing in the 1930s when he became an informal assistant to Prince Chula and Prince Bira 's White Mouse Racing team. This inspired him to take up engineering as

123-596: A career and family influence led him to take up an apprenticeship at Rolls-Royce . Rudd's engineering studies were interrupted by the Second World War during which he served in the Royal Air Force . Trained as a pilot, he flew Avro Lancasters on a tour of 30 operations. He became an expert in diagnosing failures in Merlin engines, but his main interest remained cars. Rudd resumed his engineering apprenticeship after

164-403: A continuous flow of electrolyte. Flow cells typically have the fuel dissolved in the electrolyte. Power-to-weight ratios for vehicles are usually calculated using curb weight (for cars) or wet weight (for motorcycles), that is, excluding weight of the driver and any cargo. This could be slightly misleading, especially with regard to motorcycles, where the driver might weigh 1/3 to 1/2 as much as

205-406: A cutoff voltage are typically specified for a battery by its manufacturer. The output voltage falls to the cutoff voltage when the battery becomes "discharged". The nominal output voltage is always less than the open-circuit voltage produced when the battery is "charged". The temperature of a battery can affect the power it can deliver, where lower temperatures reduce power. Total energy delivered from

246-467: A fluid, or storage in a pressure vessel . A variety of effects can be harnessed to produce thermoelectricity , thermionic emission , pyroelectricity and piezoelectricity . Electrical resistance and ferromagnetism of materials can be harnessed to generate thermoacoustic energy from an electric current. All electrochemical cell batteries deliver a changing voltage as their chemistry changes from "charged" to "discharged". A nominal output voltage and

287-563: A higher discharge current – and therefore higher power-to-weight ratio – but only with a lower energy capacity. Power-to-weight ratio for batteries is therefore less meaningful without reference to corresponding energy-to-weight ratio and cell temperature. This relationship is known as Peukert's law . Capacitors store electric charge onto two electrodes separated by an electric field semi-insulating ( dielectric ) medium. Electrostatic capacitors feature planar electrodes onto which electric charge accumulates. Electrolytic capacitors use

328-406: A liquid electrolyte as one of the electrodes and the electric double layer effect upon the surface of the dielectric-electrolyte boundary to increase the amount of charge stored per unit volume. Electric double-layer capacitors extend both electrodes with a nanoporous material such as activated carbon to significantly increase the surface area upon which electric charge can accumulate, reducing

369-507: A measurement of actual performance of any engine or power source. It is also used as a measurement of performance of a vehicle as a whole, with the engine's power output being divided by the weight (or mass ) of the vehicle, to give a metric that is independent of the vehicle's size. Power-to-weight is often quoted by manufacturers at the peak value, but the actual value may vary in use and variations will affect performance. The inverse of power-to-weight, weight-to-power ratio (power loading)

410-446: A misnomer, as it colloquially refers to mass. In a zero-gravity (weightless) environment, the power-to-weight ratio would not be considered infinite. A typical turbocharged V8 diesel engine might have an engine power of 250 kW (340 hp) and a mass of 380 kg (840 lb), giving it a power-to-weight ratio of 0.65 kW/kg (0.40 hp/lb). Examples of high power-to-weight ratios can often be found in turbines. This

451-401: A multi-volume history of BRM . Tony Rudd died in 2003 at the age of 80. He was married to Pamela and had three daughters. Power-to-weight ratio Power-to-weight ratio ( PWR , also called specific power , or power-to-mass ratio ) is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is

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492-647: A period of time is equal to the difference in its total energy over that period of time, so the rate at which work is done is equal to the rate of change of the kinetic energy (in the absence of potential energy changes). The work done from time t to time t + Δ t along the path C is defined as the line integral ∫ C F ⋅ d x = ∫ t t + Δ t F ⋅ v ( t ) d t {\displaystyle \int _{C}\mathbf {F} \cdot d\mathbf {x} =\int _{t}^{t+\Delta t}\mathbf {F} \cdot \mathbf {v} (t)dt} , so

533-628: A power-to-weight ratio of 153 kW/kg (93 hp/lb). In classical mechanics , instantaneous power is the limiting value of the average work done per unit time as the time interval Δ t approaches zero (i.e. the derivative with respect to time of the work done). The typically used metric unit of the power-to-weight ratio is W kg {\displaystyle {\tfrac {\text{W}}{\text{kg}}}\;} which equals m 2 s 3 {\displaystyle {\tfrac {{\text{m}}^{2}}{{\text{s}}^{3}}}\;} . This fact allows one to express

574-463: A single charge cycle is affected by both the battery temperature and the power it delivers. If the temperature lowers or the power demand increases, the total energy delivered at the point of "discharge" is also reduced. Battery discharge profiles are often described in terms of a factor of battery capacity . For example, a battery with a nominal capacity quoted in ampere-hours (Ah) at a C/10 rated discharge current (derived in amperes) may safely provide

615-401: A speed | v ( t ) | {\displaystyle |\mathbf {v} (t)|\;} and angle ϕ {\displaystyle \phi \;} with respect to the centre and radial of a gravitational field by an onboard powerplant , then the associated kinetic energy is where: The work–energy principle states that the work done to the object over

656-667: A train. As the coefficient of friction between steel wheels and rails seldom exceeds 0.25 in most cases, improving a locomotive's power-to-weight ratio is often counterproductive. However, the choice of power transmission system, such as variable-frequency drive versus direct-current drive , may support a higher power-to-weight ratio by better managing propulsion power. Most vehicles are designed to meet passenger comfort and cargo carrying requirements. Vehicle designs trade off power-to-weight ratio to increase comfort, cargo space, fuel economy , emissions control , energy security and endurance. Reduced drag and lower rolling resistance in

697-522: A vehicle design can facilitate increased cargo space without increase in the (zero cargo) power-to-weight ratio. This increases the role flexibility of the vehicle. Energy security considerations can trade off power (typically decreased) and weight (typically increased), and therefore power-to-weight ratio, for fuel flexibility or drive-train hybridisation . Some utility and practical vehicle variants such as hot hatches and sports-utility vehicles reconfigure power (typically increased) and weight to provide

738-413: Is a calculation commonly applied to aircraft, cars, and vehicles in general, to enable the comparison of one vehicle's performance to another. Power-to-weight ratio is equal to thrust per unit mass multiplied by the velocity of any vehicle. The power-to-weight ratio (specific power) is defined as the power generated by the engine(s) divided by the mass. In this context, the term "weight" can be considered

779-402: Is an important vehicle characteristic that affects the acceleration of sports vehicles. Propeller aircraft depend on high power-to-weight ratios to generate sufficient thrust to achieve sustained flight, and then for speed. Jet aircraft produce thrust directly . Power-to-weight ratio is important in cycling, since it determines acceleration and the speed during hill climbs . Since

820-520: Is because of their ability to operate at very high speeds. For example, the Space Shuttle 's main engines used turbopumps (machines consisting of a pump driven by a turbine engine) to feed the propellants (liquid oxygen and liquid hydrogen ) into the engine's combustion chamber. The original liquid hydrogen turbopump is similar in size to an automobile engine (weighing approximately 352 kilograms (775 lb)) and produces 72,000 hp (54 MW) for

861-417: Is conversely usually lower. Fuel cells and flow cells , although perhaps using similar chemistry to batteries, do not contain the energy storage medium or fuel . With a continuous flow of fuel and oxidant, available fuel cells and flow cells continue to convert the energy storage medium into electric energy and waste products. Fuel cells distinctly contain a fixed electrolyte whereas flow cells also require

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902-499: Is only delivered if the powerplant is in motion, and is transmitted to cause the body to be in motion. It is typically assumed here that mechanical transmission allows the powerplant to operate at peak output power. This assumption allows engine tuning to trade power band width and engine mass for transmission complexity and mass. Electric motors do not suffer from this tradeoff, instead trading their high torque for traction at low speed. The power advantage or power-to-weight ratio

943-405: Is then where: The useful power of an engine with shaft power output can be calculated using a dynamometer to measure torque and rotational speed , with maximum power reached when torque multiplied by rotational speed is a maximum. For jet engines the useful power is equal to the flight speed of the aircraft multiplied by the force, known as net thrust, required to make it go at that speed. It

984-455: Is used when calculating propulsive efficiency . Thermal energy is made up from molecular kinetic energy and latent phase energy. Heat engines are able to convert thermal energy in the form of a temperature gradient between a hot source and a cold sink into other desirable mechanical work . Heat pumps take mechanical work to regenerate thermal energy in a temperature gradient. Standard definitions should be used when interpreting how

1025-561: The Rubery-Owen takeover of the team. Peter Berthon and Raymond Mays were eventually sidelined after the drivers threatened to strike and Rudd assumed full technical control of the team in 1960. Rudd put in place proper engineering procedures within the team. Rudd drove a monocoque Killeen car at Folkingham and increased his interest in vehicle rigidity. His spaceframe and monocoque V8-engined designs took BRM to 1 constructors' and 1 drivers' World Championships. However, his H-16 engine for

1066-474: The fundamental theorem of calculus has that power is given by F ( t ) ⋅ v ( t ) = m a ( t ) ⋅ v ( t ) = τ ( t ) ⋅ ω ( t ) {\displaystyle \mathbf {F} (t)\cdot \mathbf {v} (t)=m\mathbf {a} (t)\cdot \mathbf {v} (t)=\mathbf {\tau } (t)\cdot \mathbf {\omega } (t)} . where: In propulsion , power

1107-534: The Chapman family (who retained ownership of Team Lotus ) asked Rudd to step in to head the racing team. He returned to racing for a year in 1989 until the team was sold on, then retired to become a freelance consulting engineer. In retirement, Rudd remained active in the Society of Automotive Engineers , wrote a widely acclaimed autobiography It Was Fun: My Fifty Years of High Performance and collaborated with Doug Nye on

1148-546: The War and built an Aston Martin -based 'special'. The much-delayed BRM V16 engine was fitted with Rolls-Royce superchargers and Rudd was seconded to BRM in 1951 to assist with their development. He never returned to Rolls-Royce, becoming part of the BRM team for almost two decades. Rudd was involved in the development of the V16 and four-cylinder P25 cars and started to assume more prominence after

1189-521: The car, with a conventional 2 disc rear brake layout, simple rear wishbone suspension and a much lower profile. This resulted in a much better handling car, and for the 1961 Formula One season BRM based their chassis designs on the Mark II. For 1960, BRM campaigned three P48s for Joakim Bonnier , Graham Hill , and Dan Gurney . The P48 debuted in the second race of the season, the Monaco Grand Prix . To

1230-425: The development of Lotus' own four-cylinder engine as well as improving production quality of their cars. Rudd also developed Lotus as an engineering consultancy working on high-technology projects for the rest of the automotive industry, creating another profit centre within the business. Team Lotus were struggling in the mid-1970s and Rudd led the research effort that produced ground effect Lotus 78 , which brought

1271-458: The dielectric medium to nanopores and a very thin high permittivity separator. While capacitors tend not to be as temperature sensitive as batteries, they are significantly capacity constrained and without the strength of chemical bonds suffer from self-discharge. Power-to-weight ratio of capacitors is usually higher than batteries because charge transport units within the cell are smaller (electrons rather than ions), however energy-to-weight ratio

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1312-457: The new three litre formula (based on two of the successful 1.5 litre V8s on top of each other) proved to be heavy and overcomplicated. The team struggled with the complex design and gradually lost momentum in the late Sixties. Rudd claims that the H-16 would have been successful had the drawings been followed accurately - as it was the engine had heavier castings than planned and its power-to-weight ratio

1353-442: The perception of sports car like performance or for other psychological benefit . Increased engine performance is a consideration, but also other features associated with luxury vehicles . Longitudinal engines are common. Bodies vary from hot hatches , sedans (saloons) , coupés , convertibles and roadsters . Mid-range dual-sport and cruiser motorcycles tend to have similar power-to-weight ratios. Power-to-weight ratio

1394-431: The power-to-weight ratio purely by SI base units . A vehicle's power-to-weight ratio equals its acceleration times its velocity; so at twice the velocity, it experiences half the acceleration, all else being equal. If the work to be done is rectilinear motion of a body with constant mass m {\displaystyle m\;} , whose center of mass is to be accelerated along a (possibly non-straight) line to

1435-701: The propulsive power of a jet or rocket engine is transferred to its vehicle. An electric motor uses electrical energy to provide mechanical work , usually through the interaction of a magnetic field and current-carrying conductors . By the interaction of mechanical work on an electrical conductor in a magnetic field, electrical energy can be generated . Fluids (liquid and gas) can be used to transmit and/or store energy using pressure and other fluid properties. Hydraulic (liquid) and pneumatic (gas) engines convert fluid pressure into other desirable mechanical or electrical work . Fluid pumps convert mechanical or electrical work into movement or pressure changes of

1476-643: The stands, killing one spectator and injuring several others. After the Zandvoort disaster, BRM scored just once more with Bonnier in the United States Grand Prix . BRM finished the season with a disappointing 8 points. The Mark II cars were raced in the 1961 Intercontinental Formula races. Dan Gurney won the 1961 Victorian Trophy at the Ballarat Air Strip circuit in Victoria , Australia driving

1517-556: The surprise of everyone, including the team, all three cars finished. Bonnier scored points for fifth. However, this proved to be a false hope, as each driver finished only once more. At the Dutch Grand Prix , Hill finished a respectable third behind the Coventry Climax engined Cooper and Lotus of Jack Brabham and Innes Ireland . Sadly, Gurney's rear brake failed on the entry to Zandvoort's first hairpin; his BRM rolled into

1558-435: The team back to the forefront of Grand Prix success. Rudd went back to the road-car side of the company to research active suspension , turbocharging, and lead consultancy work for other manufacturers. After Chapman's death in 1982 Rudd took on an increasingly significant role in the business but advanced engineering remained his forté. After the conviction of Fred Bushell for financial irregularities related to DeLorean ,

1599-508: The vehicle itself. In the sport of competitive cycling athlete's performance is increasingly being expressed in VAMs and thus as a power-to-weight ratio in W/kg. This can be measured through the use of a bicycle powermeter or calculated from measuring incline of a road climb and the rider's time to ascend it. A locomotive generally must be heavy in order to develop enough adhesion on the rails to start

1640-460: Was adamant that it could not be made raceworthy. Rudd and Wright were later to be reunited at Lotus on work that did lead to successful ground-effect racing cars. During a poor 1969 season and after management changes at BRM, Rudd left for Lotus Cars , gradually working up to the position of Engineering Director on the road-car side of the company - he was not directly involved in racing, which Colin Chapman looked after. Rudd's achievements included

1681-457: Was unfavourable; it also had breathing difficulties and only started to improve when it fired as a sixteen-cylinder engine rather than two eights. After abandoning the H-16, Rudd designed a compact V-12 that was to be the foundation of renewed success in the years after his departure from BRM. As a sideline to BRM's main development, Rudd and Peter Wright were also involved with the design of a ground effect car that never raced; driver John Surtees

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