Build a Pizza Box Glider

The main material is the stiff cardboard used in the construction of pizza boxes, although any stiff corrugated cardboard will work equally well.

Built and balanced carefully this small glider flies extremely well.

Teacher's Notes

Things to Emphasize

1. For any object to be aerodynamically stable when moving through any fluid, its centre of mass must be ahead of the object's centre of pressure.
2. A object's centre of mass can be moved by adding or removing mass from the object or by redistributing the mass within the object.
3. An object's centre of pressure can be moved by adding or removing fins to the object.
4. In general, centre of mass depends upon the composition and structure of an object, whereas, centre of pressure depends only on the shape of the object.

Materials

1. large pizza box (lid or bottom)
2. metre stick or metric ruler
3. craft knife (Xacto knife)
4. Plasticine or modeling clay
5. glue

Glider Plans Transparency Master	The diagram to the left shows the scale plans for a simple glider. The grid is a one centimetre square. ( i.e. each square is 1cm x 1cm). The dimensions are suitable for layout on a large pizza box lid. The fuselage and vertical stabilizer should be cut out as single piece. A small slot is cut in the tail of the glider to accommodate the horizontal stabilizer.

Top View (assembled) Transparency Master	The diagram to the left shows the assembled glider as seen from above (top view). The pieces are held together using ordinary white multipurpose glue. Allow the glue to harden overnight before handling and balancing the assembled glider.

Assembly

top view	The materials needed are shown in the figure to the left. Note: safety glasses should be worn when cutting heavy materials such as cardboard with a craft knife. The sharp tips of such knives are prone to snapping off under excessive pressure and may become dangerous projectiles. Transfer the glider plan to the top lid of the pizza box using the dimensions shown on the plan. All dimensions are in centimetres.
side view	Once the plans are drawn on the top of the box, each piece should be carefully cut out. Two large books can be used to hold the fuselage upright while the wing and the horizontal stabilizer are glued in place. (Be careful not to get glue on either the books or the table top.)
front view	Obtain a printed copy of the top view of the glider [Click here]. Using this drawing, determine (by calculation) the line which divides the forward and rear sections of the planes' top view into two exactly equal areas. Mark the tips of the wings along this line and insert a small pin into each wing tip so that the glider can be balanced between two books (or other suitable supports.) Using Plasticine or window putty, add mass to the nose of the glider so that it balances almost exactly. It should be very slightly tail heavy. (see the photo to the left).

1. Make sure that the edges are free from ragged cuts and rough surfaces.

2. Add the mass (Plasticine) to the lower edge of the fuselage at the nose of the glider. By adding it to the lower side the glider's centre of mass lowered as much as possible (below the centre of lift) increasing the glider's roll stability. (Note: that the glider in photo has not done this, as a result it did not fly as well as it could have).

Your glider will have to be flight tested.

Based on the glider's initial performance it may (or may not, if you have been careful) have to be trimmed by adjusting the centre of mass.

If several gliders have been built, a very useful exercise is to compare the construction of those that have good initial flight characteristics with those that have less desirable flight characteristics.

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