FULCRUM & HOVER-CRAFT MODELLING


Fulcrum : -

TOWER CRANE SPECIFICATIONS

The tower crane consists of 5 parts - Base Plot, Tower (Mast), Horizontal Arm (Jib), Elevating Mechanism and Trolley.
  • Base Plot
A wooden base with a pit of area of cross section 80 mm x 80 mm and depth of 60 mm will be provided by the organisers. The tower portion of the crane must fit into this pit.
  • Tower
  • The height of the tower must be a minimum of 450 mm above the wooden base and below the horizontal arm.
  • The cross section of the tower must be 80 mm x 80 mm at all times up to a height of 200 mm above the wooden base.
  • The tower height above the arm is not constrained.
3. Horizontal Arm
  • The length of the arm must be a minimum of 700 mm total (i.e. including the length of both the counter weight section and lifting section of the horizontal arm).The length of counter-weight section of the must not exceed 300 mm from the centre of the tower.
  • The cross section of the arm may not exceed 160 mm x 160 mm.
  • The arm can be supported by a maximum of 4 threads.
  • Participants are advised to make a flat structure in the counter-arm section for smooth loading and unloading of the counter-weights.
  • Elevating Mechanism
  • The lifting mechanism must be motorized.
  • Participants are allowed to use standard motors, gears, pulleys and readymade gear assemblies for this mechanism.
  • The rope to be attached to the block for lifting will be a thread of diameter not more than 5 mm. This will be not be provided by the organizers. The participants have to bring it with them. Participants are advised to pre-verify the thread' s strength to take the loads. If the thread breaks during testing, team will be disqualified.
  • The power supply for the elevating mechanism may be placed off the crane, on the platform provided.
  • The participant must ensure that any electric wiring of the mechanism does not interfere with lifting.
  • Participants must bring their own batteries and electric sources. No electricity will be provided by the organizers.
  • Trolley Mechanism
  • The trolley will be used to shift the lifted weight along the length of the arm. This is done by placing the elevating mechanism on the trolley.
  • The trolley mechanism may or may not be motorized.
  • Direct human contact with the trolley is not allowed. Manual pulling of strings is allowed.
  • The trolley can be connected with the counter-weight platform to allow for shift of counter-weights as the trolley shifts. Individual counter-weight shifting mechanisms can also be made.

Materials to be used:

1. Standard pop sickle sticks/ice-cream sticks of maximum 12 cm in length, maximum 1.5 cm in width and maximum 4 mm thick. Sticks made up of any other material are not allowed.
2. Only Adhesives like Fevicol, Fevistick, etc. can be used to build the structure. Adhesives such as M-Seal� are not allowed.
3. Threads of diameter 2mm. To verify this constraint each team must bring a 1 m long sample of the string used by them. (To verify the diameter of the string, it will be wound about a cylindrical object (like a pen). 10 turns will be wound about a cylindrical object. The length of the string will be measured along the axis of the cylinder. Thus the diameter of the string would be equal to the length of the string along the axis of the cylindrical object divided by number of turns wound about it).
4. Motor readymade gear assemblies, gears, pulleys, threads (2 mm diameter) and rubber bands (1 mm diameter) can be used only for making the elevating mechanism and trolley.

Building Rules

1. The structure of the crane (excluding the motor assembly, elevating mechanism, and trolley) must be made entirely of the pop-sickle sticks or ice-cream sticks and adhesives ONLY.
2. The pop-sickle sticks can be trimmed and used in smaller pieces.
3. Pop-sickle sticks can be stacked to make stronger elements.
4. Elevating mechanism and trolley can be made from other materials specified.
5. Threads cannot be used to reinforce any joints in the structure.
6. The structure may not be painted, sprayed or dipped in any coating material. All glue should be removed from surfaces that are not bonded together.
7. All motors and pulleys must be placed on the structure. Only the power source can be placed on the ground or the platform provided.
8. Participants are advised to keep a minimum of 10 cm width to place the counter-weights. Details of the weights would be provided on the spot.

Round 1

  • The weight of the structure consisting of pop-sickle sticks and threads will be considered (excluding the weight of the motor/elevating mechanism). The participant will be given time to integrate the elevating motor with the structure on-site.
  • Participants will be asked to place desired counter-weights on the counter-arm. Thereafter, the crane will be required to lift a standard load of 3kg with the help of elevating mechanism up to a height of 10 cm. After the elevating mechanism is actuated, participant is not allowed to alter the position of the counter weight.
  • Structures will be tested for weight, the downward deflection of the jib at a distance of 20 cm from the centre of the tower and the sideways deflection of the tower at a height of 20cm from the wooden base plot, while the crane is under the load of 3kg. These deflections will be taken with the help of dial-gauges. Once the block is lifted to a height of 10 cm then the stable dial-gauge reading will be considered for the purpose of judging.

Round 2

  • A wall of height of 20 cm will be introduced in this stage.
  • The crane is supposed to lift a block of unknown weight, the details of which will be provided on the spot, to a height of 20 cm or more. Thereafter with help of the trolley mechanism the block should be taken across the wall and safely placed on the other side.
  • The trolley mechanism may be driven manually or with the help of an external motor.

Definition of failure

A structure is said to have undergone failure if:
1. Structure fails to satisfy the above specified dimensional constraints.
2. Structure is broken at a joint i.e. it cannot take any load at that joint.

Scoring

The participants will be awarded points on basis of the following formula:
Score = (Weight of lightest structure in the competition/Weight of your structure)*20
The participants will be awarded points on basis of the following formula:
Score = (Least deflection of any structure in the competition/Deflection of your structure)*20
The participants will be awarded points on basis of the following formula:
Score = (Least deflection of any structure in the competition/Deflection of your structure)*10

IMAGES SHOWING WHAT IS TO BE DONE IN THE EVENT

  

  Example of a tower crane structure made of pop-sickle sticks:

HOVER-CRAFT MODELLING :-

ABOUT HOVER CRAFT:

A (air-cushion vehicle, ACV) is a craft capable of traveling over surfaces while supported by a cushion of slow moving, high-pressure air which is ejected against the surface below and contained within a "skirt".
It is one of the specialized means of transport. As they are supported by cushion of air they can travel on land (only on smooth surfaces) ,water and on ice as well. Small hovercrafts are used for sport or for passenger service whereas giant hovercrafts are used in military services.

PRINCIPLE:

Air fills the skirt, and the thin layer of air escaping the skirt creates a nearly frictionless layer between the craft and the ground. Another fan, much like an air boat, propels the craft forward.
1st round the hovercraft model is made to move in our arena comprising of smooth surface and water alternatively as shown in below diagram.

  • The time limit to reach the target will be fixed at the time of event depending on our arena length.
  • If the participant crosses the finish line, the time taken will be recorded else forward displacement will be recorded.
  • If any hover craft topples , it will be allowed to start from the same point of disturbance , meanwhile the stopwatch will be paused.
  • IInd round, in the same arenas , some targets will be placed , and the hovercraft has to pass through the targets and has to reach final extreme within time limit else the number of targets covers counts.

  •  If any hovercraft misses passing through any target, penalty time will be added depending on number of targets he missed.
  • Finally times taken in the first round and second round are added and the top three teams who took less time will be declared as winners.

TECHNICAL DETAILS OF HOVERCRAFT:

  • It can be an Radio Controlled or wired one (But it is convenient to use R.C ).
  • Its size i.e., length and breadth has to be within following limits:-35X25 cms
  • The important components are
    • Base material (if you use cardboard or thermocol make sure it is made water proof .)
    • Skirt material which forms air cushion at the bottom of hovercraft, is also a water proof one..
    • Two motors:-
One is driving motor , and other is lift motor
Fans on these motors have to be placed in such a way that lift motor fills air in the skirt (air bag ), drive motor drives the craft forward.
  • Propellers are to be used and are placed behind the drive motor fans, and these propellers are controlled with remote, so the direction of movement of craft is controlled by these propellers.
  • And power supply for entire setup.
  • Switches to control movement of motors.
  • The weight of entire setup has to be perfectly balanced, so the center of gravity lies at geometric centre approximately.

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