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88-471: The de Havilland Propellers Blue Streak was a British Intermediate-range ballistic missile (IRBM), and later the first stage of the Europa satellite launch vehicle . Blue Streak was cancelled without entering full production. The project was intended to maintain an independent British nuclear deterrent , replacing the V bomber fleet which would become obsolete by 1965. The operational requirement for

176-461: A fast Fourier transform of the TWF. The vibration spectrum provides important frequency information that can pinpoint the faulty component. The fundamentals of vibration analysis can be understood by studying the simple Mass-spring-damper model. Indeed, even a complex structure such as an automobile body can be modeled as a "summation" of simple mass–spring–damper models. The mass–spring–damper model

264-460: A "viscous" damper is added to the model this outputs a force that is proportional to the velocity of the mass. The damping is called viscous because it models the effects of a fluid within an object. The proportionality constant c is called the damping coefficient and has units of Force over velocity (lbf⋅s/in or N⋅s/m). Summing the forces on the mass results in the following ordinary differential equation: The solution to this equation depends on

352-430: A 1 Hz square wave . The Fourier transform of the square wave generates a frequency spectrum that presents the magnitude of the harmonics that make up the square wave (the phase is also generated, but is typically of less concern and therefore is often not plotted). The Fourier transform can also be used to analyze non- periodic functions such as transients (e.g. impulses) and random functions. The Fourier transform

440-763: A DUT (device under test) is attached to the "table" of a shaker. Vibration testing is performed to examine the response of a device under test (DUT) to a defined vibration environment. The measured response may be ability to function in the vibration environment, fatigue life, resonant frequencies or squeak and rattle sound output ( NVH ). Squeak and rattle testing is performed with a special type of quiet shaker that produces very low sound levels while under operation. For relatively low frequency forcing (typically less than 100 Hz), servohydraulic (electrohydraulic) shakers are used. For higher frequencies (typically 5 Hz to 2000 Hz), electrodynamic shakers are used. Generally, one or more "input" or "control" points located on

528-592: A German third stage was, for some time, sited on the edge of a gravel pit in Gloucestershire. Remains of Blue Streak F4 , launched on 24 May 1965, are on display at Woomera. Footage from the Blue Streak launch was briefly incorporated into The Prisoner ' s final episode, " Fall Out ". It was also used in the Doctor Who serial " The Tenth Planet ", treated within the story as the launch of

616-580: A brochure for a design using Blue Streak as the first stage of a two-stage to orbit rocket, with an American Centaur upper stage. The Centaur second stage would have either been built in the UK under licence or imported directly from the USA. Both the Centaur and Blue Streak had proved to be very reliable up to this point, and since they were both already designed development costs would have been low. Furthermore, it had

704-598: A civilian satellite launcher called Black Prince . As the cost was thought to be too great for the UK alone, international collaboration was sought. This led to the formation of the European Launcher Development Organisation (ELDO), with Blue Streak used as the first stage of a carrier rocket named Europa . Europa was tested at Woomera Test Range , Australia and later at Kourou in French Guiana. Following launch failures,

792-473: A collaboration with other European countries to build a three-stage launcher capable of placing a one-ton payload into low Earth orbit . The European Launcher Development Organisation consisted of Belgium, Britain, France, West Germany, Italy and the Netherlands, with Australia as an associate member. Preliminary work began in 1962 and ELDO was formally signed into existence in 1964. With Blue Streak,

880-403: A heat exchanger, the units reduced the temperature of compressor-bleed air by more than 300 °C. The use of epoxy resin/glass fibre-reinforced plastics for airscrew spinners, blade root fairings and other components were also developed extensively by de Havilland Propellers Ltd. at their Stevenage plant. Dr. Norman de Bruyne , FREng, FRS ( Aero Research Limited - ARL), successfully developed

968-738: A major world power . Britain was unable to purchase American weapons wholesale due to the restrictions of the Atomic Energy Act of 1946 . In April 1954 the Americans proposed a joint development programme for ballistic missiles. The United States would develop an intercontinental ballistic missile (ICBM) of 5,000 nautical miles (9,300 km) range ( SM-65 Atlas ), while the United Kingdom with United States support would develop an Intermediate-range ballistic missile (IRBM) of 2,000 nautical miles (3,700 km) range. The proposal

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1056-552: A payload of 870–920 kg to a geosynchronous orbit with, and 650–700 kg without the use of additional booster rockets. Following the cancellation of the Blue Streak project some of the remaining rockets were preserved at: A section of the propulsion bay, engines and equipment can be found at the Solway Aviation Museum , Carlisle Lake District Airport . Only a few miles from the Spadeadam testing site,

1144-483: A range of other proposals was made between 1959 and 1972 for a carrier rocket based on Blue Streak, but none of these were ever built in full and today only exist in design. In 1959 de Havilland suggested solving the problem of the Blue Streak/Black Knight geometry by compressing the 10 by 1 metre (30 by 3-foot) Black Knight into a 10-foot-diameter (3.0 m) sphere. Although this seemed logical,

1232-463: A rapid response to an attack. The missile was vulnerable to a pre-emptive nuclear strike , launched without warning or in the absence of any heightening of tension sufficient to warrant readying the missile. To negate this problem de Havilland created a stand-by feature. A missile could be held at 30 seconds' notice to launch for ten hours. As the missiles were to be deployed in pairs and it took ten hours for one missile to be prepared for stand-by, one of

1320-452: A real world environment, such as road inputs to a moving automobile. Most vibration testing is conducted in a 'single DUT axis' at a time, even though most real-world vibration occurs in various axes simultaneously. MIL-STD-810G, released in late 2008, Test Method 527, calls for multiple exciter testing. The vibration test fixture used to attach the DUT to the shaker table must be designed for

1408-423: A system behaves under forced vibration. The behavior of the spring mass damper model varies with the addition of a harmonic force. A force of this type could, for example, be generated by a rotating imbalance. Summing the forces on the mass results in the following ordinary differential equation: The steady state solution of this problem can be written as: The result states that the mass will oscillate at

1496-544: A year before the cancellation of the Blue Streak as a missile, the government requested that the RAE and Saunders-Roe design a carrier rocket based on Blue Streak and Black Knight. This design used Blue Streak as a first stage and a 54-inch (140-centimetre) second stage based on the Black Knight. Several different third stages would be available, depending on the required payload and orbit. The cost of developing Black Prince

1584-418: Is overdamped . The value that the damping coefficient must reach for critical damping in the mass-spring-damper model is: To characterize the amount of damping in a system a ratio called the damping ratio (also known as damping factor and % critical damping) is used. This damping ratio is just a ratio of the actual damping over the amount of damping required to reach critical damping. The formula for

1672-460: Is an example of a simple harmonic oscillator . The mathematics used to describe its behavior is identical to other simple harmonic oscillators such as the RLC circuit . Note: This article does not include the step-by-step mathematical derivations, but focuses on major vibration analysis equations and concepts. Please refer to the references at the end of the article for detailed derivations. To start

1760-414: Is called resonance (subsequently the natural frequency of a system is often referred to as the resonant frequency). In rotor bearing systems any rotational speed that excites a resonant frequency is referred to as a critical speed . If resonance occurs in a mechanical system it can be very harmful – leading to eventual failure of the system. Consequently, one of the major reasons for vibration analysis

1848-402: Is defined as: Note: angular frequency ω (ω=2 π f ) with the units of radians per second is often used in equations because it simplifies the equations, but is normally converted to ordinary frequency (units of Hz or equivalently cycles per second) when stating the frequency of a system. If the mass and stiffness of the system is known, the formula above can determine the frequency at which

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1936-428: Is defined by the following formula. [REDACTED] The plot of these functions, called "the frequency response of the system", presents one of the most important features in forced vibration. In a lightly damped system when the forcing frequency nears the natural frequency ( r ≈ 1 {\displaystyle r\approx 1} ) the amplitude of the vibration can get extremely high. This phenomenon

2024-420: Is less than the undamped natural frequency, but for many practical cases the damping ratio is relatively small and hence the difference is negligible. Therefore, the damped and undamped description are often dropped when stating the natural frequency (e.g. with 0.1 damping ratio, the damped natural frequency is only 1% less than the undamped). The plots to the side present how 0.1 and 0.3 damping ratios effect how

2112-414: Is now compressing the spring and in the process transferring the kinetic energy back to its potential. Thus oscillation of the spring amounts to the transferring back and forth of the kinetic energy into potential energy. In this simple model the mass continues to oscillate forever at the same magnitude—but in a real system, damping always dissipates the energy, eventually bringing the spring to rest. When

2200-410: Is often referred to as predictive maintenance (PdM). Most commonly VA is used to detect faults in rotating equipment (Fans, Motors, Pumps, and Gearboxes etc.) such as imbalance, misalignment, rolling element bearing faults and resonance conditions. VA can use the units of Displacement, Velocity and Acceleration displayed as a time waveform (TWF), but most commonly the spectrum is used, derived from

2288-463: Is the Fourier transform that takes a signal as a function of time ( time domain ) and breaks it down into its harmonic components as a function of frequency ( frequency domain ). For example, by applying a force to the mass–spring–damper model that repeats the following cycle – a force equal to 1  newton for 0.5 second and then no force for 0.5 second. This type of force has the shape of

2376-401: Is the minimum potential energy state) and in the process accelerates the mass. At the point where the spring has reached its un-stretched state all the potential energy that we supplied by stretching it has been transformed into kinetic energy ( 1 2 m v 2 {\displaystyle {\tfrac {1}{2}}mv^{2}} ). The mass then begins to decelerate because it

2464-421: Is to predict when this type of resonance may occur and then to determine what steps to take to prevent it from occurring. As the amplitude plot shows, adding damping can significantly reduce the magnitude of the vibration. Also, the magnitude can be reduced if the natural frequency can be shifted away from the forcing frequency by changing the stiffness or mass of the system. If the system cannot be changed, perhaps

2552-437: Is when a time-varying disturbance (load, displacement, velocity, or acceleration) is applied to a mechanical system. The disturbance can be a periodic and steady-state input, a transient input, or a random input. The periodic input can be a harmonic or a non-harmonic disturbance. Examples of these types of vibration include a washing machine shaking due to an imbalance, transportation vibration caused by an engine or uneven road, or

2640-601: The Polaris system from the Americans, carried in British-built submarines . After the cancellation as a military project, there was reluctance to cancel the project because of the huge cost incurred. Blue Streak would have become the first stage of a projected all British satellite launcher known as " Black Prince ": the second stage was derived from the Black Knight test vehicle, and the orbital injection stage

2728-639: The Treasury in early 1955, to £300 million in late 1959. Its detractors in the civil service claimed that the programme was crawling along when compared with the speed of development in the US and the Soviet Union . Estimates within the Civil Service for completion of the project ranged from a total spend of £550 million to £1.3 billion, as different ministers were set on either abandoning or continuing

Blue Streak (missile) - Misplaced Pages Continue

2816-637: The Zeus IV spacecraft. Images of the Blue Streak 1 are incorporated in the 1997 film Contact . De Havilland Propellers de Havilland Propellers was established in 1935, as a division of the de Havilland Aircraft company when that company acquired a licence from the Hamilton Standard company of America for the manufacture of variable-pitch propellers at a cost of about £20,000. Licence negotiations were completed in June 1934. At

2904-593: The rocket engine design from the Rocket Propulsion Establishment at Westcott . Operational Requirement 1139 demanded a rocket of at least 1,500 nautical miles (2,800 km) range and the initially proposed rocket would have just reached that threshold. The de Havilland Propellers company won the contract to build the missile, which was to be powered by an uprated liquid-fuelled Rocketdyne S-3D engine, developed by Rolls-Royce , called RZ.2 . Two variants of this engine were developed:

2992-652: The DUT-side of a vibration fixture is kept at a specified acceleration. Other "response" points may experience higher vibration levels (resonance) or lower vibration level (anti-resonance or damping) than the control point(s). It is often desirable to achieve anti-resonance to keep a system from becoming too noisy, or to reduce strain on certain parts due to vibration modes caused by specific vibration frequencies. The most common types of vibration testing services conducted by vibration test labs are sinusoidal and random. Sine (one-frequency-at-a-time) tests are performed to survey

3080-452: The ELDO project was cancelled in 1972 and Blue Streak with it. Post-war Britain 's nuclear weapons armament was initially based on free-fall bombs delivered by the V bomber force. It soon became clear that if Britain wanted to have a credible nuclear deterrent threat, a ballistic missile was essential. There was a political need for an independent deterrent, so that Britain could remain

3168-460: The U.K. plants of de Havilland Propellers: Hatfield was responsible for the design, research and development; Lostock manufactured a proportion of the weapon (the remainder being sub-contracted) and was also responsible for assembly and testing; Farnworth carried out manufacture and assembly of development rounds; and the factory at Walkden handled all production assembly. Woomera , Australia and Aberporth were used for test firing. The company

3256-628: The UK became the first stage of the European launch vehicle with France providing the Coralie second stage and Germany the third. Italy worked on the satellite project, the Netherlands and Belgium concentrated on tracking and telemetry systems and Australia supplied the launch site. The combined launcher was named Europa . After ten test launches, the Woomera launch site was not suitable for putting satellites into geosynchronous orbit, and in 1966 it

3344-753: The UK were constructed under the direction of the British Electrical and Allied Industries Research Association (more commonly known as the Electrical Research Association, or simply the ERA) during the 1950s and 1960s. de Havilland Propellers Ltd., erected during 1953 in St. Albans a 24 m diameter 2-bladed Enfield-Andreau type turbine. Other components produced at the company's Lostock works were de Havilland Comet undercarriages. Vibration Vibration can be desirable: for example,

3432-536: The United Kingdom has a collection of parts including start systems and combustion chambers amongst other things. He can often be seen displaying his collection at space days in the West Midlands. A part of the Blue Streak F1 rocket launched on 5 June 1964 from Woomera , Australia, found 50 km SE of Giles in 1980 (c.1000 km) is on display at Giles Weather Station . The titanium structure of

3520-401: The amount of damping. If the damping is small enough, the system still vibrates—but eventually, over time, stops vibrating. This case is called underdamping, which is important in vibration analysis. If damping is increased just to the point where the system no longer oscillates, the system has reached the point of critical damping . If the damping is increased past critical damping, the system

3608-399: The axis under test) permitted to be exhibited by the vibration test fixture. Devices specifically designed to trace or record vibrations are called vibroscopes . Vibration analysis (VA), applied in an industrial or maintenance environment aims to reduce maintenance costs and equipment downtime by detecting equipment faults. VA is a key component of a condition monitoring (CM) program, and

Blue Streak (missile) - Misplaced Pages Continue

3696-575: The cancellation of Blue Streak to be not only a blow to British military-industrial efforts, but also to Commonwealth ally Australia, which had its own vested interest in the project. The British military transferred its hopes for a strategic nuclear delivery system to the Anglo-American Skybolt missile , before the project's cancellation by the United States as its ICBM programme reached maturity. The British instead purchased

3784-631: The centre of design, development, and flight-testing , but with the main production plant still at Lostock in Lancashire. Work on missiles began in the late 1940s, early 1950s at the Hatfield plant in facilities which had been used during the war for the development and testing of aircraft propellers. By the early sixties, the company became Hawker Siddeley Dynamics which in turn became British Aerospace Dynamics, later BAE Systems (Guided Weapons Division). The Hatfield site closed in 1990. After

3872-426: The construction of many underground silos in the countryside carried enormous economic, social, and political costs. Development of the underground launchers presented a major technical challenge. 1/60- and 1/6-scale models based on a U-shaped design were constructed and tested at RPE Westcott. Three alternative designs were drawn up with one chosen as the prototype, designated K11. RAF Upavon would appear to have been

3960-400: The damping ratio ( ζ {\displaystyle \zeta } ) of the mass-spring-damper model is: For example, metal structures (e.g., airplane fuselages, engine crankshafts) have damping factors less than 0.05, while automotive suspensions are in the range of 0.2–0.3. The solution to the underdamped system for the mass-spring-damper model is the following: The value of X ,

4048-441: The damping ratio, the quicker it damps to zero. The cosine function is the oscillating portion of the solution, but the frequency of the oscillations is different from the undamped case. The frequency in this case is called the "damped natural frequency", f d , {\displaystyle f_{\text{d}},} and is related to the undamped natural frequency by the following formula: The damped natural frequency

4136-433: The designer can target a fixture design that is free of resonances in the test frequency range. This becomes more difficult as the DUT gets larger and as the test frequency increases. In these cases multi-point control strategies can mitigate some of the resonances that may be present in the future. Some vibration test methods limit the amount of crosstalk (movement of a response point in a mutually perpendicular direction to

4224-659: The development costs proved to be too high for the limited budget of the programme. Following its merger with Saunders Roe, Westland Helicopters developed the three-stage Black Arrow satellite carrier rocket, derived from the Black Knight test vehicle. The first stage of Black Arrow was given the same diameter as the French Coralie (the second stage of Europa) to make it compatible with Blue Streak. Using Blue Streak as an additional stage would have increased Black Arrow's payload capacity. To maintain this compatibility,

4312-475: The energy added by the force. At this point, the system has reached its maximum amplitude and will continue to vibrate at this level as long as the force applied stays the same. If no damping exists, there is nothing to dissipate the energy and, theoretically, the motion will continue to grow into infinity. In a previous section only a simple harmonic force was applied to the model, but this can be extended considerably using two powerful mathematical tools. The first

4400-405: The first provided a static thrust of 137,000 lbf (610 kN) and the second (intended for the three-stage satellite launch vehicle ) 150,000 lbf (670 kN). The engines could be vectored by seven degrees in flight and were used to guide the missile. This configuration, however, put considerable pressure on the autopilot which had to cope with the problem of a vehicle whose weight

4488-464: The first stage diameter was given in metres, although the rest of the rocket was defined in imperial units. Black Arrow carried out four test launches (without an additional Blue Streak stage) from Woomera between 1969 and 1971, with the final launch carrying the satellite Prospero X-3 into orbit. The United Kingdom remains the only country to have developed and then abandoned a satellite launch capability. In 1972, Hawker Siddeley Dynamics ltd produced

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4576-432: The force is always opposing the motion of the mass attached to it: The force generated by the mass is proportional to the acceleration of the mass as given by Newton's second law of motion : The sum of the forces on the mass then generates this ordinary differential equation :   m x ¨ + k x = 0. {\displaystyle \ m{\ddot {x}}+kx=0.} Assuming that

4664-423: The forcing frequency can be shifted (for example, changing the speed of the machine generating the force). The following are some other points in regards to the forced vibration shown in the frequency response plots. Resonance is simple to understand if the spring and mass are viewed as energy storage elements – with the mass storing kinetic energy and the spring storing potential energy. As discussed earlier, when

4752-407: The frequency range of the vibration test spectrum. It is difficult to design a vibration test fixture which duplicates the dynamic response (mechanical impedance) of the actual in-use mounting. For this reason, to ensure repeatability between vibration tests, vibration fixtures are designed to be resonance free within the test frequency range. Generally for smaller fixtures and lower frequency ranges,

4840-400: The initial magnitude, and ϕ , {\displaystyle \phi ,} the phase shift , are determined by the amount the spring is stretched. The formulas for these values can be found in the references. The major points to note from the solution are the exponential term and the cosine function. The exponential term defines how quickly the system “damps” down – the larger

4928-410: The initiation of vibration begins by stretching the spring by the distance of A and releasing, the solution to the above equation that describes the motion of mass is: This solution says that it will oscillate with simple harmonic motion that has an amplitude of A and a frequency of f n . The number f n is called the undamped natural frequency . For the simple mass–spring system, f n

5016-483: The investigation of the mass–spring–damper assume the damping is negligible and that there is no external force applied to the mass (i.e. free vibration). The force applied to the mass by the spring is proportional to the amount the spring is stretched "x" (assuming the spring is already compressed due to the weight of the mass). The proportionality constant, k, is the stiffness of the spring and has units of force/distance (e.g. lbf/in or N/m). The negative sign indicates that

5104-489: The manufacture of aircraft cold-air units, turbine-driven electric alternators, radar scanners, electronic equipment, plastic structures—even an experimental 80 ft windmill to derive electricity from the wind. In that year the company received a contract from the Ministry of Supply (MoS) for the development of a compact turbo-alternator to meet the electrical power requirements of missiles developed by other companies. In

5192-424: The mass and spring have no external force acting on them they transfer energy back and forth at a rate equal to the natural frequency. In other words, to efficiently pump energy into both mass and spring requires that the energy source feed the energy in at a rate equal to the natural frequency. Applying a force to the mass and spring is similar to pushing a child on swing, a push is needed at the correct moment to make

5280-416: The missile was issued in 1955 and the design was complete by 1957. During development, it became clear that the missile system was too expensive and too vulnerable to a surprise attack. The missile project was cancelled in 1960, with US-led Skybolt the preferred replacement. Partly to avoid political embarrassment from the cancellation, the UK government proposed that the rocket be used as the first stage of

5368-419: The motion of a tuning fork , the reed in a woodwind instrument or harmonica , a mobile phone , or the cone of a loudspeaker . In many cases, however, vibration is undesirable, wasting energy and creating unwanted sound . For example, the vibrational motions of engines , electric motors , or any mechanical device in operation are typically unwanted. Such vibrations could be caused by imbalances in

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5456-668: The museum carries many exhibits, photographs and models of the Blue Streak programme, having inherited the original Spadeadam collection that used to be displayed on site. RZ.2 engines are on display at National Space Centre – a pair on cradles alongside the Blue Streak rocket – and at the Armagh Planetarium in Northern Ireland and The Euro Space Center in Redu , Belgium. Blue Streak enthusiast Robin Joseph from

5544-427: The natural frequency of the system. Vibrational motion could be understood in terms of conservation of energy . In the above example the spring has been extended by a value of x and therefore some potential energy ( 1 2 k x 2 {\displaystyle {\tfrac {1}{2}}kx^{2}} ) is stored in the spring. Once released, the spring tends to return to its un-stretched state (which

5632-558: The preferred location for the prototype operational launcher with the former RNAS at Crail as the likely first operational site. In 1955–1956, the rocket motors were test-fired at High Down Rocket Test Site on the Isle of Wight . As no site in Britain provided enough space for test flights, a test site was established at Woomera, South Australia . Doubts arose as the cost escalated from the first tentative figure of £50 million submitted to

5720-455: The process of subtractive manufacturing . Free vibration or natural vibration occurs when a mechanical system is set in motion with an initial input and allowed to vibrate freely. Examples of this type of vibration are pulling a child back on a swing and letting it go, or hitting a tuning fork and letting it ring. The mechanical system vibrates at one or more of its natural frequencies and damps down to motionlessness. Forced vibration

5808-606: The project. The project was unexpectedly cancelled in April 1960. Whitehall opposition grew, and it was cancelled on the ostensible grounds that it would be too vulnerable to a first-strike attack. Admiral of the Fleet Lord Mountbatten had spent considerable effort arguing that the project should be cancelled at once in favour of the Navy being armed with nuclear weapons, capable of pre-emptive strike. Some considered

5896-607: The propellent system of Blue Streak, in which DHP were the prime contractors, engineers from de Havilland visited the Convair Division of the Dynamics Corporation in the United States to discuss problems associated with refuelling. A reciprocal technical information agreement existed between the two firms. Under licence from Hamilton Standard de Havilland Propellers produced cold-air units for most types of civil and military aircraft. Used in conjunction with

5984-499: The rotating parts, uneven friction , or the meshing of gear teeth. Careful designs usually minimize unwanted vibrations. The studies of sound and vibration are closely related (both fall under acoustics ). Sound, or pressure waves , are generated by vibrating structures (e.g. vocal cords ); these pressure waves can also induce the vibration of structures (e.g. ear drum ). Hence, attempts to reduce noise are often related to issues of vibration. Machining vibrations are common in

6072-419: The same frequency, f , of the applied force, but with a phase shift ϕ . {\displaystyle \phi .} The amplitude of the vibration “X” is defined by the following formula. Where “r” is defined as the ratio of the harmonic force frequency over the undamped natural frequency of the mass–spring–damper model. The phase shift, ϕ , {\displaystyle \phi ,}

6160-423: The same time an extensive new factory, claimed to be one of the largest in the world, was laid down at Lostock, Bolton , some distance away from de Havilland's main aircraft plant at Hatfield . This factory was built in only nine months as part of the government's emergency pre-war shadow-factory programme. de Havilland Propellers, Ltd., was incorporated on 27 April 1946, with the main headquarters at Hatfield as

6248-466: The same year a second contract was received for the development of an infra-red homing head. When these contracts had been completed the M.o.S. awarded the company a development contract for a complete weapon system for an air-to-air missile with infra-red homing guidance. Originally under the project designation Blue Jay , later to be Firestreak . Production of the Firestreak was shared between all

6336-428: The structural response of the device under test (DUT). During the early history of vibration testing, vibration machine controllers were limited only to controlling sine motion so only sine testing was performed. Later, more sophisticated analog and then digital controllers were able to provide random control (all frequencies at once). A random (all frequencies at once) test is generally considered to more closely replicate

6424-415: The swing get higher and higher. As in the case of the swing, the force applied need not be high to get large motions, but must just add energy to the system. The damper, instead of storing energy, dissipates energy. Since the damping force is proportional to the velocity, the more the motion, the more the damper dissipates the energy. Therefore, there is a point when the energy dissipated by the damper equals

6512-446: The system vibrates once set in motion by an initial disturbance. Every vibrating system has one or more natural frequencies that it vibrates at once disturbed. This simple relation can be used to understand in general what happens to a more complex system once we add mass or stiffness. For example, the above formula explains why, when a car or truck is fully loaded, the suspension feels "softer" than unloaded—the mass has increased, reducing

6600-417: The system “rings” down over time. What is often done in practice is to experimentally measure the free vibration after an impact (for example by a hammer) and then determine the natural frequency of the system by measuring the rate of oscillation, as well as the damping ratio by measuring the rate of decay. The natural frequency and damping ratio are not only important in free vibration, but also characterize how

6688-552: The two missiles could always be ready for rapid launch. To protect the missiles against a pre-emptive strike while being fuelled, the idea of sitting the missiles in underground launchers was developed. These would have been designed to withstand a one megaton blast at a distance of one-half mile (800 m) and were a British innovation, subsequently exported to the United States. Finding sites for these silos proved extremely difficult. RAF Spadeadam in Cumberland (now Cumbria)

6776-505: The use of reinforced phenol-formaldehyde resins in the manufacture of variable-pitch propellers for de Havilland. The attraction of this material was that, with a density of about one half that of aluminium alloy , centrifugal forces at the root were correspondingly reduced. Other products included the production of radar scanners and also the erection of a wind driven electricity generator for Enfield Cables Ltd. The first industrial-scale electricity-generating wind turbines to be built in

6864-437: The vibration of a building during an earthquake. For linear systems, the frequency of the steady-state vibration response resulting from the application of a periodic, harmonic input is equal to the frequency of the applied force or motion, with the response magnitude being dependent on the actual mechanical system. Damped vibration: When the energy of a vibrating system is gradually dissipated by friction and other resistances,

6952-400: The vibrations are said to be damped. The vibrations gradually reduce or change in frequency or intensity or cease and the system rests in its equilibrium position. An example of this type of vibration is the vehicular suspension dampened by the shock absorber . Vibration testing is accomplished by introducing a forcing function into a structure, usually with some type of shaker. Alternately,

7040-472: The war, the company diversified. The first departure from the production of airscrews took place in 1950, when small-scale manufacture of electronic vibration -measuring equipment was started for sale to the industry at large. These were the by-products of the vibration department, whose experience in electronics was, early in 1952, to provide the nucleus of a team which began the design of guided weapons: besides guided missiles, de Havilland Propellers undertook

7128-513: Was a small hydrogen peroxide/kerosene motor. Black Prince proved too expensive for the UK, and the European Launcher Development Organisation (ELDO) was set up. This used Blue Streak as the first stage, with French and German second and third stages. The Blue Streak first stage was successfully tested three times at the Woomera test range in Australia as part of the ELDO programme. In 1959,

7216-560: Was accepted as part of the Wilson-Sandys Agreement of August 1954, which provided for collaboration, exchange of information, and mutual planning of development programmes. The decision to develop was influenced by what could be learnt about missile design and development in the US. Initial requirements for the booster were made by the Royal Aircraft Establishment at Farnborough with input on

7304-545: Was also responsible for the Blue Streak rocket, Britain's own nuclear missile. Although cancelled in 1960 as a weapon, the technology went into providing Europe with an indigenous satellite launcher. Blue Streak as the first stage of the Europe rocket, performed flawlessly with every flight and bears the distinction of being the only rocket to have a 100% success rate in test firing. During preliminary investigations regarding

7392-773: Was decided to move to the French site of Kourou in South America . F11 was fired from here in November 1971, but the failure of the autopilot caused the vehicle to break up. The launch of F12 was postponed whilst a project review was carried out, which led to the decision to abandon the Europa design. ELDO was merged with the European Space Research Organisation to form the European Space Agency . Aside from Black Prince,

7480-503: Was designed by the Atomic Weapons Research Establishment at Aldermaston . The missiles used liquid oxygen and kerosene propellants . Whilst the vehicle could be left fully laden with over 20 tonnes of kerosene, the 60 tonnes of liquid oxygen had to be loaded immediately before launch or icing became a problem. Due to this, fuelling the rocket took 4.5 minutes, which would have made it useless as

7568-488: Was diminishing rapidly and that was steered by large engines whose thrust remained more or less constant. Vibration was also a problem, particularly at engine cut-off, and the later development of the autopilot for the satellite launcher was, in itself, a considerable achievement. Subcontractors included the Sperry Gyroscope Company who produced the missile guidance system whilst the nuclear warhead

7656-583: Was estimated to be £ 35 million. It was planned that Black Prince would be a Commonwealth project. As the government of John Diefenbaker in Canada was already spending more money than publicly acknowledged on Alouette and Australia was not interested in the project, these two countries were unwilling to contribute. South Africa was no longer a member of the Commonwealth. New Zealand was only likely to make "modest" contributions. The UK instead proposed

7744-544: Was the only site where construction was started on a full scale underground launcher, although test borings were undertaken at a number of other locations. The remains of this test silo, known as U1, were rediscovered by tree felling at Spadeadam. This was also the site where the RZ.2 rocket engines and also the complete Blue Streak missile were tested. The best sites for silo construction were the more stable rock strata in parts of southern and north-east England and eastern Scotland, but

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