Posted tagged ‘working model’

Working model of Hovercraft

September 29, 2011

The idea of making a Hovercraft dates back to 1716 when Emmanual Swedenborg recorded a design, but it was short lived.  In 1870, Sir John Thornycroft filled patents involving air lubricated hulls. And it was in 1959 a hovercraft was built, by Christopher Sydney Cockerell  by discovering the Momentum Curtain theory. Hover craft also called Air cushion vehicle (ACV) travels on any kind of flat surface. It is supported by a cushion of pressurized air.

Design

  • Can be powered by one or more engines
  • Small crafts have a single engine with the drive split through a gear box
  • Usually one engine drives the fan responsible for lifting the vehicle
  • The other forces air from

hovercraft

Working

Two main principles:

1)      Lift

2)      Propulsion

  • A skirt is required to quarantine airflow
  • No contact with ground hence friction is eliminated
  • The shape of the body affects stability
  • All parts are essential for proper working

Parts

1)      Lifting fan: Usually a centrifugal fan is preferred. When rotated air is sucked into the center hole, it is coupled via a gearbox and connected to the engine

2)      Thrust propellers: An aircraft type propeller with variable type pitch blades. Diameter ranges from nine feet to nineteen feet. In bigger crafts the propellers are rotated while in smaller ones, rudders are used.

3)      Skirt: Flexible strip which is fitted below the bottom edges of the plenum chamber. Skirt design is the most sensitive design parameter as it protects the craft and helps to lift it even higher.

hovercraft diagram

In theory hover crafts are simple machines but a plethora of problems exist to make a functioning hovercraft. The plans as well as the design must be flawless. To build a hovercraft one must be well aware of the demands of construction. Only then can one design a hovercraft.

Magnetic Levitation Train

September 29, 2011

Love to turn a 45 minute car ride to an 8 minute blur?

China was the first to country to have an up and running Maglev you could buy tickets to. Back in 1979 the Germans developed the 1st Magnetic levitation (Maglev) train.  The first to overcome the limitation of wheel and rail, because the rail moves entirely without contact!

This is a wonderful topic for your mechanical engineering seminar as well as project if you dare to make a working model.

The functions of the wheel and rail on a normal rail road including support guidance propulsion and braking are accomplished through an electro magnetic levitation and propulsion system. The mechanics have been replaced by electronics. Support Magnets draw the vehicle towards the guide way from below. While, guidance magnets hold’s the vehicle laterally on track. These support and guidance magnets are mounted on both sides of the vehicle along its entire length. An electronic control system ensures that it levitates at a constant height above the guide way. The Maglev train is propelled and braked by a synchronous long stator linear motor. This motor is not located in the vehicle itself but rather in the guide way. It functions on the same principle as a traditional rotating electrical motor, whose stator has been cut open, unrolled and stretched length wise along both sides of the guide way. But, instead of a rotating magnetic field a traveling magnetic field is generated in the windings, one that pulls the vehicle along the guide way without contact.

The guide way can be elevated where it makes ecological sense. in this way it won’t divide the landscape or developed areas and the area beneath the guide way can continue to be used as before. The guide way can be built at ground level to allow easier co location with existing transportation systems. Therefore, the guide way can be adapted to the landscape instead of being the other way round.

Maglev Train

The operation control system controls and safe guards the vehicle’s switches, guide ways and stations along the maglev route. The vehicle communicates with the control system by means of directional radio data transmission. The vehicle’s location is monitored by means of a location reference system integrated into the guide way. The only motor section in operation along the guide way, is the one in which the vehicle is currently traveling. When the vehicle passes from one section to the next, the new motor section is automatically switched on. More power is supplied on gradients and acceleration segments along the route than on flat segments this way the propulsion power is distributed very economically. It is always available exactly where it is needed.

The technology’s success in India could ultimately hinge on a combination public funding and private investments.

 

References:

Prototype Advantages and Disadvantages

September 25, 2011

Rapid prototype is a process wherein a working model or prototype is developed for the purpose of testing the various product features like design, ideas, features, functionality, performance and output. This process of development of working model is quite quick. The user can give an early feedback regarding the prototype. Rapid prototyping is, generally, a significant and essential part of the system designing process and it is believed to decrease the project cost and risk.

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The Rapid prototype that is developed by the process of rapid prototyping is based on the performance of earlier designs. Hence, it is possible to correct the defects or problems in the design by taking corrective measures. The product can be produced if the prototype meets the requirements of all designing objectives after sufficient refinement. There are many advantages of rapid prototyping.

ADVANTAGES:

  • Rapid Prototyping can provide with concept proof that would be required for attracting funds.

  • The Prototype gives the user a fair idea about the final look of the product.

  • Rapid prototyping can enhance the early visibility.

  • It is easier to find the design flaws in the early developmental stages.

  • Active participation among the users and producer is encouraged by rapid prototyping.

  • As the development costs are reduced, Rapid prototyping proves to be cost effective.

  • The user can get a higher output.

  • The deficiencies in the earlier prototypes can be detected and rectified in time.
  • The speed of system development is increased. It is possible to get immediate feedback from the user.

  • There is better communication between the user and designer as the requirements and expectations are expressed in the beginning itself.

  • High quality product is easily delivered by way of Rapid prototyping.

  • Rapid prototyping enables development time and costs.

  • There are many innovative ways in which Rapid prototyping can be used.

DISADVANTAGES:

  • Some people are of the opinion that rapid prototyping is not effective because, in actual, it fails in replication of the real product or system.

  • It could so happen that some important developmental steps could be omitted to get a quick and cheap working model. This can be one of the greatest disadvantages of rapid prototyping.

  • Another disadvantage of rapid prototyping is one in which many problems are overlooked resulting in endless rectifications and revisions.

  • One more disadvantage of rapid prototyping is that it may not be suitable for large sized applications.

  • The user may have very high expectations about the prototype’s performance and the designer is unable to deliver these.

  • The system could be left unfinished due to various reasons or the system may be implemented before it is completely ready.

  • The producer may produce an inadequate system that is unable to meet the overall demands of the organization.

  • Too much involvement of the user might hamper the optimization of the program.

  • The producer may be too attached to the program of rapid prototyping, thus it may lead to legal involvement.

  • The cost reduction benefit of rapid prototyping also seems to be debatable, as sufficient details regarding the calculation basis and assumptions are not substantial.

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Rapid prototyping

September 25, 2011

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It’s time for your Prototype! The Development phase is exciting, but nothing compares to the feeling of holding a working model of your product idea in your hands. Prototyping is a key phase of product design where the 3D CAD file(s) is converted to an accurate solid part that will be used for fit, function, testing, and marketing.

I have experience, and enjoy working with all types of technologies that will quickly make your product a reality. Some of these include SLA, SLS, FDM, Urethane, Cast, and CNC machining. Use of Stereo Lithography (SLA) and Selective Laser Sintering (SLS) is very common. These processes allow parts to be built exactly as designed in a matter of hours.

There are various methods of making models, and other processes available that can bring your Invention to life. Whether you’ve created a basic concept or a fully detailed model, you have given actuality to your product. Improvements may be made now by using focus groups, brainstorming, and testing, to assure that your product is marketable to investors and valuable to consumers. Through the pages below, you can discover which process best meets your needs, or fits into your product definition.

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