Flyin' Planes

Airplanes are fun.  Airplanes are one of the ways people travel around the world.  The following are activities that explain how airplanes and lift work.  The science of airplanes and balloons is called aerodynamics. Below are the parts of an airplane.  Each of these parts has a role to play in an airplane.  The Cubs can discover how many of these parts work to lift an airplane off the ground, travel in the sky and safely bring it back down to earth.

AIRPLANE	An airplane is a vehicle heavier than air, powered by an engine, which travels through the air by the reaction of air passing over its wings.
FUSELAGE	The fuselage is the central body portion of an airplane which accommodates the crew and passengers or cargo.
COCKPIT	The cockpit is usually the space in the fuselage for the pilot and the passengers: in some aircrafts it is just the pilot's compartment.
LANDING GEAR	The landing gear, located underneath the airplane, supports it while on the ground.
WINGS	The wings are the parts of airplanes which provide lift and support the entire weight of the aircraft and its contents while in flight.
PROPELLER	A propeller is a rotating blade located on the front of the airplane. The engine turns the propeller which most often pulls the airplane through the air.  Many airplanes use jet engines.
FLAPS	The flaps are the movable sections of an airplane's wings closest to the fuselage. They are moved in the same direction (down) and enable the airplane to fly more slowly and help it take off (flaps up) and land (flaps down).
AILERONS	Ailerons are the outward movable sections of an airplane's wings which move in opposite directions (one up, one down). They are used in making left and right banking turns.
RUDDER	The rudder is the movable vertical section of the tail which controls lateral movement left and right.
HORIZONTAL	The horizontal stabilizer is the horizontal surface of the aft part of the fuselage used to balance the airplane.
ELEVATOR	The elevator is the movable horizontal section of the tail which causes the plane to move up and down.

 

Activity 1. Build and Fly an Airplane 
Give Cubs a sheet of unlined paper and instructions for construction of a paper airplane
Cubs should give their plane a name using the aviation alphabet. (Example N 831 FE represents November 831 Foxtrot Echo.
Have the Cubs build the plane, draw on them and have flight tests to try them out.  The Sixes can have competitions such as:
- Longest distance
- Most time in the air
- Most accurate when thrown through a hoop
- Flying highest
- Best design or coloration
Have the Cubs build a duplicate plane.  Cut slots on where the ailerons are and see what happens when the the ailerons up, down or opposite.  Build the  paper plane with a rudder and see what happens when these are moved to the left or right.  Cut off the ailerons (shown in red) and see how high the plane will fly opposite the duplicate.
Discuss the results from the flight tests.

ADDITIONAL QUESTION: "Why don't all planes have the biggest wing area possible? Why do some fighter jets have small wings?" (ANSWER: There are other factors that contribute to lift, such as velocity and shape of the wing)

 

Activity 2: Build and Fly a Hot Air Balloon

MATERIALS:
- Dry cleaner plastic film bags (select a bag with the thinnest possible plastic and have several on hand. You may have to experiment with bags of different thicknesses.)
- Several small paper clips
- Cellophane tape
- Heat source (Blow dryer, sterno, backpacker camp stove, etc.)
Matches
- Three feet of aluminum heat duct (if using open flame heat source)
 -Electric drill (to put holes in the heat duct)

PROCEDURE:
- Seal any openings and tears in the upperr end of the bag with a minimum of cellophane tape.
-  Attach several paper clips to the plastic around the lower opening. The number of paper clips to attach is determined by experimentation.
-  If using sterno or some other openn flame heat source, prepare the heat duct by drilling several holes around the base to allow air to flow in.
-  Turn on the blow dryer (or light tthe Sterno or stove and then set the heat duct over it) Spread the bag opening wide to capture the rising hot air while supporting the upper end with your hand. It is best to have assistance in keeping the bag open so that it does not melt.
 - When the bag is inflated with hot air, test its buoyancy by letting it go for a moment. If it rises quickly, stand back and let it fly otherwise continue heating it for a little while longer.
 -If the bag tips over and spills its hot air before it reaches the ceiling, add a few more paper clips to weigh down the bottom slightly. If the bag will not rise at all, remove a few clips. 

CAUTION: Be careful not to brush clothes or fingers into the flames or touch the metal heat duct. Keep a fire extinguisher handy if you use flames. If the bag starts to crumple and melt from the heat, set the blow dryer on a lower setting or hold the bag farther from the heat source.

DISCUSSION: Hot air is less dense than cold air. Heat accelerates the motion of the air molecules causing fewer molecules to occupy the same space as a much greater number of molecules do at a lower temperature. With fewer molecules, the hot air has less mass, and therefore is buoyant than an equal volume of colder air.

Placing the dry cleaner bag over the heat source captures the hot air and forces out the cooler air in the bag. The bag becomes a mass of low-density air which floats up-ward in the higher denser air surrounding it. The paper clips are placed at the bottom of the bag to keep the open end downward in flight to prevent it from prematurely spilling the hot air and terminating the flight. 

This material can be used to fulfill partial requirements for the Purple Star and the Individual Speciality Badge.

April 25, 2005