ProjectIn

AdvancedPhysics

Submitted by:Walter Tabuso

IV-Marconi

Submitted to:Mrs. Eloisa Aquino

“COMPACT DISC HOVERCRAFT”What is a hovercraft?

A hovercraft is an amphibious vehicle that is supported by a cushion of slightly pressurized air. Although often seen as a mysterious, even bizarre mode of transportation, it is conceptually quite simple. To understand how hovercraft work, it is necessary to realize that the dynamics are more closely related to aircraft than to boats or automobiles. As a member of the family of air cushion vehicles (ACVs) or ground effect machines, which includes wing-in-ground-effect or ram wings, surface effect ships, sidewall hovercraft, and surface skimmers, hovercraft, are the amphibious member of the air cushion vehicle family. They are the most novel among vehicles that are supported by pressurized air. Refer to the illustration below as you read about how hovercraft actually function.

Hovercraft float on a cushion of air that has been forced under the craft by a fan. This causes the craft to rise or lift. The amount of lift can range from 6" to 108" (152mm to 2,743mm) depending on the size of the craft. The amount of total weight that a hovercraft can raise is equal to cushion pressure multiplied by the area of the hovercraft. To make the craft function more efficiently, it is essential to limit the cushion air from escaping, so the air is contained by the use of what is called a skirt. Fashioned from fabric, which allows a deep cushion or clearance of obstacles, hovercraft skirts vary in style ranging from bags to cells (jupes) to separate fingered sections called segments. Most Neoteric hovercraft utilize the segmented skirt system because each segment can deflect individually when passing over bumps so that very little lift air is lost on uneven terrain.

Once "lifted" or "on cushion", thrust must be created to move the hovercraft forward. With many craft, this is generated by a separate engine from the one used to create the lift, but with some, the same engine is used for both. As the diagram above indicates, the fan-generated air stream is split so that part of the air is directed under the hull for lift, while most of it is used for thrust.

Materials:

Balloon

Cartridge of a Ballpen

Cover of the Ballpoint of a Ballpen

Compact Disc

Rubber Bands

Glue Stick

Match

Candle

Pin

Styrofoam/Rubber Disc/Gatorade Cap

Procedure:

1. Prepare all the materials needed in making the toy.

2. Cut a styrofoam in a circled shape or we can just use the cap of the Gatorade bottle or a rubber disc.

3. Create a hole in the center so that there would be a path for the air

that will come out from the balloon.

5. Insert the cover of the ballpoint of the pen on the middle of the

styrofoam.

4. By using the pin that was heated with the help of the candle, create a hole in the cover of the ballpoint of

the pen.

6. By using a gluestick, combine the Compact Disc and the styrofoam with

the ballpoint cover.

7. Using rubber bands, connect the cartridge and the balloon and be sure that there will be no leak of air.

8. Combine the cover of the ballpoint and the cartridge by simply putting it down.

9. But, inflate the balloon first and you’re ready to go. Be sure to only use this on smooth surface.

Concepts of Physics involved:

1. Air Pressure-

A simple hovercraft is powered by a leaf blower. Using the leaf blower, it would inflate the shower curtain (on the other side) and cause the molecules to expand. But, we don't want there to be a lot of air pressure as the shower curtain can rip open. To solve this problem, we will have to cut some small holes in the shower curtain so that the excess air would be able to move out of the hovercraft. The holes shouldn't be too big and let all the air escape. The air pressure needs to rise until there is a point where gravity has less force than the air pressure molecules which would cause the hovercraft to inflate and start gliding.

2. Friction-

Friction is defined as "surface resistance to relative motion, as of a body sliding or rolling." To make hovercraft's ride as smooth and as effective as possible, the leaf blower should inflate the shower curtain and blow a layer of air between the ground and craft and can be pushed. But there should be little friction for the ride to be as safe, lessen potential damage, and make the iniatial force as effecient as possible. This hovercraft should be able to move on surfaces on a consistent manner due to the lack of friction. We can compare the hovercraft to an ice skating rink. The ice causes a person to glide               because of the lack of friction and the hovercraft should do the same.

3. Momentum-

Momentum can be described as "mass in motion". When this hovercraft is at motion, it has a great momentum as its mass and velocity are reasonably high. But when an external force (also an "unbalanced" force according to Newton) is applied, the momentum shifts. A hovercraft should have less friction, so the momentum would be very constant. In regular objects such as a basketball, when this ball is rolled, friction will be acted upon it causing it to slow down- The momentum changes. But with a hovercraft, friction is very little, so the momentum should stay constant for a good period of time.

4. Newton’s First Law of Motion

Using Newton's First Law, an object in motion will stay at motion unless acted upon by an unbalanced force. The hovercraft is supposed to glide on any surface, and in our case, friction is the unbalanced force. When friction is taken out of the equation, the hovercraft is going to glide on the surface until acted upon by an opposite force (such as air resistance). The ride will be as smooth as possible because there will be little friction between the shower curtain and the ground. According to Newton's first law, when Friction (unbalanced force) is removed, the object will stay at motion until acted upon by an unbalanced force.

5. Newton’s Third Law of Motion

As air blows out of the back of the hovercraft, the vehicle moves forward.

How does it work?My Compact Disc Hovercraft works by inflating with the help blowing the

cartridge where the balloon is connected. After inflating the balloon, cover the hole where you had blown the cartridge then immediately connect it with the ballpoint cover. We will notice that the air from the balloon will slowly go out towards the hole of the ballpoint cover. We can control if we like to let the hovercraft glide or move faster by widening the hole from the ballpoint pen. We can let the hovercraft to any direction we want by pushing it.

Possible lessons in Physics where you can use the toy: Aerodynamics

Friction

Momentum

Newton’s First Law of Motion

Air Pressure

Newton’s Third Law of Motion