Tuesday, July 10, 2007

A Jet Plane Made of Plastic and Fabric!

Boeing unveiled its new 787 Dreamliner on 7/8/07. At first glance, it looks like other airplanes, only sleeker. The Dreamliner is truly different, both inside and out.

The 787 is set apart from other passenger jets because it is built from composite materials. According to the Boeing website, the 787 is half composite, which is much more than any passenger jet ever made!

What are composites?

Composites are materials that are made of two or more things that have different physical properties. Bricks, made of mud and straw, are an example of composites used long ago by the ancient Egyptians.

Why are composites important?

Let us imagine what would happen if we built a home using only straw or only mud.

A home built of straw alone would probably blow away (remember the story of the Three Little Pigs?).

A home built from dried mud would not last very long because the bricks would eventually fall apart.

When both straw and mud are mixed together, they work together. Straw provides a matrix, or a support structure, that mud can hold on to so it does not fall apart. The mud makes the straw stronger by filling in the empty spaces around the straw fibers. Buildings made from composite bricks by the Egyptians were strong and lasted a very long time.

Although modern composites are much more advanced, they work by the same principle: two different materials mixed together to make a much stronger final product.

The composites used in the Dreamliner, called Carbon Fiber Reinforced Plastics (CFRP for short), are among the most advanced composites used today.

What is CFRP?

Carbon fiber is a long thin thread of a carbon polymer that is bundled together in small ropes. Each individual thread is very strong, and when it is bundled, it is even stronger!

I think of carbon fiber as the straw in the brick example above.

The carbon fiber ropes are then weaved together to make a fabric.

Here is what carbon fiber fabric looks like:

The fabric is then coated in a special plastic and molded into the desired shape. Depending on how the threads are weaved and the type of plastic used, CFRP of different strengths can be made.

CFRP is very strong and very lightweight; it has been used to make bike frames, boat hulls, race cars bodies, kayaks, laptop computer cases, musical instruments, plane parts, and skateboards!

Composites like CFRP have been use to manufacture passenger airplane parts for over a decade. Smaller private planes like the Diamond Star (the kind I fly) has a body that is made almost entirely of composites.

Here is a picture of a Diamond Star:

The 787 Dreamliner is the first large passenger jet to have its body made mostly of composites. This will help to keep the airplane’s weight low so it can carry more passengers and fuel, allowing it to fly very far.

Here is a picture of the piece of the 787 composite body.

There is a small company called Scaled Composites that has been using composite materials to makeinteresting planes for a long time. Scaled Composites was responsible for designing and making the Voyager, Global Flyer, and (my favorite) White Knight and Space Ship One.

This a picture of White Knight carrying Space Ship One.

From skateboards to the 787 Dreamliner, composites have found multiple uses in our daily lives. All of this is made possible by science.

Dr. Dave

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