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The actual amount of lift depends on how much weight the craft is carrying. A fan of a given power will create a certain amount of pressure under the craft.

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Presentation on theme: "The actual amount of lift depends on how much weight the craft is carrying. A fan of a given power will create a certain amount of pressure under the craft."— Presentation transcript:

1 The actual amount of lift depends on how much weight the craft is carrying. A fan of a given power will create a certain amount of pressure under the craft. Now since: pressure = force / area it follows that a bigger hovercraft (one with a bigger overall area) can carry more weight than a smaller hovercraft with a fan the same size.

2 Special Features 1. Propellers 2. Air 3. Fan 4. Flexible Skirt Note: the air vents moving through the hovercraft creates the air cushion below the craft for movement.

3 BagsegmentJupe Costlowhighlow Drag (smooth water/rough water Same/highSame/lowSame/very high Stabilitygoodpoorexcellent Roll ability for turningslightexcellentnone Hump performancemoderategoodPoor moderate High speedgoodmoderate Bouncepoorgood Durabilitygoodpoormoderate Lifegoodmoderategood

4 BAG SKIRT Consists of a tube that encircles the perimeter of the craft. The bag is inflated which serves to lift the craft off the ground and more importantly, to contain the air cushion. There are two methods of inflating the bag skirt, the first being serial feed and the second being parallel feed. The serial feed method requires that air be directed from the lift fan _through_ the skirt and then out into the cushion. The parallel feed method requires that a certain amount of air be split off of the lift fan into the skirt (about 10%) and the rest into the cushion.

5 THE SEGMENTED SKIRT Called a 'finger' skirt because it consists of several separate nylon segments that, when inflated, press together to form a shape that looks like fingers of a hand that are pressed tightly together Offers much less resistance to obstacles and much more ease of repair when damaged since you only need to replace one or two damaged fingers instead of an entire skirt. Less stable and more complex to manufacture than bag skirted craft

6 JUPED SKIRT Consists of several cells that look like cones with their tops cut off and have their bases attached to the bottom of the craft. When inflated, these cones readily support the weight of the craft upon a stable cushion. Very stable but will experience difficulty when attempting to inflate the jupes on a rough terrain such a tall grass or deep gravel. Tend to scoop water in rough conditions and drag on grass.

7 Hovercrafts uses Police and Fire Department use Ice and water transportation Oil spill clean up Wildlife conservation and rescue

8 Without lift, hovercrafts would be useless. Propellers shoot air down at the surface of the water or the ground to lift the hovercraft a few inches. Hovercrafts use something called a skirt to hold air inside the area underneath the vehicle. The skirt must be the perfect length and weight otherwise air would escape from under the vehicle, and the hovercraft could hit the ground. Too mush airflow directed under the craft will cause it to hover too high above the ground, resulting in the hovercraft to tip Not enough lift will cause the craft to remain on the ground.

9 Recreational Use Small homebuilt and kit-built hovercraft are increasingly being used for recreational and racing purposes. mainly on inland lakes and rivers but also in marshy areas. Hovercraft Club of Great Britain regularly organizes inland and coastal cruising hovercraft races in various venues across the United Kingdom. Similar events are also held in the U.S.

10 Hovercraft Video Clips


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