a collection of learning experiences on rocketry€¦ · some of these variables will be present in...

ELEMENTARY SCIENCE PROGRAM MATH, SCIENCE & TECHNOLOGY EDUCATION

A Collection of Learning Experiences on

ROCKETRY

Rocketry Student Activity Book

Name__________________________________________________________ This learning experience activity book is yours to keep. Please put your name on it now. This activity book should contain your observations of and results from your experiments. When performing experiments, ask your teacher for any additional materials you may need.

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TABLE OF CONTENTS Activity Sheet for L.E. #1 - The Solid Propellant Model Rocket Engine ..................2 Activity Sheet for L.E. #2 - Major Parts of a Model Rocket .....................................3-4 Activity Sheet for L.E. #4 - Stability .........................................................................5-6 Activity Sheet for L.E. #5 - Rocket Stability............................................................7-8 Activity Sheet for L.E. #7 - Tall Things ....................................................................9 Activity Sheet for L.E. #8 - One Station Tracking/Two Station Tracking/Finding Altitude....................................................................................................................10-14 Activity Sheet for L.E. #9 - The Electric Launch System.........................................15-16 Activity Sheet for L.E. #10 - Model Rocketry Safety Code ......................................17-20 Rocketry Student Assessment ................................................................................21-24 Glossary..................................................................................................................25-28

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Activity Sheet for Learning Experience #1 Name______________________

THE SOLID PROPELLANT MODEL ROCKET ENGINE

Label the parts of the solid propellant model rocket engine. Use the information below to help you. 1. The clay nozzle is located at the bottom of the rocket engine. The narrow

opening of the nozzle is designed to increase the velocity (speed) of the hot gases leaving the engine. The downward force overcomes gravity and provides the thrust needed for lift-off and acceleration of the rocket.

2. The cardboard casing is the outside wall that holds the contents of the rocket

engine. 3. The thrust charge, when ignited, gives off hot gases that are forced through

the clay nozzle at great speed. The upward force of this charge develops the propulsion needed for lift-off and acceleration of the rocket.

4. The delay charge provides a visible white smoke to help the observer track

the rocket. This charge lasts approximately three seconds. 5. The ejection charge pressurizes the body tube forcing the nose cone and

recovery system out of the body tube. This allows the recovery system (parachute or streamer) to deploy and bring the rocket safely to the ground.

6. The clay retainer cap keeps the three charges in place.

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MAJOR PARTS OF A MODEL ROCKET

Label the parts of the solid propellant model rocket engine. Use the information below and on the next page to help you. 1. The nose cone is the front end of a rocket. It is usually shaped so that the

wind resistance will be reduced during the rocket’s upward flight. 2. The shock cord prevents the nose cone and recovery system from being torn

free from the rocket during the ejection phase of the flight. It is made of elastic material (usually rubber) which absorbs much of the ejection force by stretching.

3. The recovery system (parachute or streamer) slows the rocket’s descent and

return it to each undamaged.

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Activity Sheet for Learning Experience #2 Page 2 4. The body tube is the basic frame of the rocket. All other rocket parts are bulb

on or attached to it. It must be sturdy enough to withstand the pressure of the ejection charge.

5. The launch lug is a piece of straw paper two or three centimeters long that is

glued to the body tube. The launch lug fits over the launch rod and is designed to guide the rocket during lift off. (Make sure the launch lug has several coats of glue to prevent it from coming loose during lift off.)

6. The stabilizing fins are designed to keep the rocket traveling in a straight

path. As pressure is exerted on the nose cone during flight, the rocket tends to be pushed off center. By placing the fins as far back on the rocket as possible, the forces exerted on the side of the fins will overcome the forces on the nose cone and the rocket will follow a stable, upward path.

7. The solid propellant engine serves three major purposes:

a. The first charge provides the trust to propel the model rocket skyward from the launcher.

b. The second is the delay charge which allows the rocket to slow down so the recovery system can be activated without being torn apart. This charge also provides a white puff of smoke to help the tracker find the rocket’s altitude.

c. The third purpose is to deploy the recovery system. The ejection charge pressurizes the body tube and “pops” the nose cone and deploys the recovery system.

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STABILITY

A model rocket will not fly properly unless it is aerodynamically stable. Being aerodynamically stable means that a rocket will fly straight without wobbling throughout its upward flight. Variables that can make a model rocket turns its nose away from the intended direction of flight can result from: engines mounted incorrectly, air drag on launch lugs, crooked fins, excessive glue or paint, etc. Some of these variables will be present in most rockets. Therefore, a rocket must be designed and built to eliminate as many of these variables as possible. The following learning experience will help you understand how a rocket can overcome variables that make a rocket unstable. 1. Tie a piece of fishing line around the dowel so the dowel “balances” or is

perpendicular to the fishing line as shown below. The fishing line should be tied to the dowel’s center of gravity or center of mass. Now put a piece of masking tape on the dowel so it covers the fishing line. The tape will prevent the fishing line from slipping.

2. Now that you have found the center of gravity, swing the suspended dowel in

a circular motion. Be careful! Make sure you are not too close to anyone. How does the dowel look as it moves in a circular motion? Draw what you see in the space below.

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Activity Sheet for Learning Experience #4 Page 2 3. Make fins from the oaktag. Tape your fins to the dowel so that one end of the

dowel points in the direction of swing as it moves in a circular motion. 4. Draw a picture to show what you did to make the dowel point in the direction

forward of the circular path

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ROCKET STABILITY

If the model rock is not stable it will not follow the intended flight path. As a result, the model rocket might injure people on the ground. As a rocket is propelled upward, its nose should always point in the intended direction of flight. One way to insure proper stability is to place the fins as far back on the rocket as possible. The further the fins are behind the center of gravity on the rocket, the more stable it will be in flight. Generally, this means the rear edge of the fin will meet the rear edge of the rocket body and the fins will be swept back. Never place fins forward of the center of gravity on a rocket because this fin placement will make the rocket unstable. All rockets should be tested for stability before launching. The easiest method for checking stability requires only string and tape. The following learning experience can help you find out if your rocket is stable. 1. Place an A8-3 engine in the rocket’s engine holder. Attach a piece of string

around the rocket’s body using a loop as shown below. Slide the loop to the position where the rocket balances or hangs perpendicular to the string. Tape the loop to the rocket to hold it in place.

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Activity Sheet for Learning Experience #5 Page 2 2. Swing the suspended rocket overhead in a circular path. CAUTION! Do not

hit yourself or someone else during this learning experience. If the rocket is stable, it will point forward into the wind created by its own motion. Sometimes the rocket will not point itself into the wind unless it is pointing directly forward at the time the circular motion is started. This is accomplished by holding the rocket in one hand, arm extended, and turning your entire body as the rocket is started in a circular path. If it is necessary to hold the rocket to start it, another test should be made to see if it is stable enough to fly. Move the loop back on the tube until the angle of the tube is 10 degrees below the horizontal.

If the model keeps its nose pointed forward when swung in a circular motion, it should be stable enough to launch. If the rocket does not pass the stability test, it can be made stable by: Moving the center of pressure rearward. This is accomplished by making larger fins or moving the existing fins farther back on the body tube.

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TALL THINGS

Use the diagram below to help you understand how to find the height of a flagpole. 1. Mark off a 100 foot baseline with the measuring wheel. The baseline is the

distance from the base of the flagpole to the observer with the clinometer. 2. The observer sights the clinometer on the tope of the flagpole. 3. Another student should read and record the angle from the clinometer. 4. Use the following equation for right triangles and the Tangent Table to find the

height of the flagpole.

opposite h ------------- = tangent of angle ---------- = tangent of 24 degrees adjacent 100 ft. h h ------------ = tangent of angle ----------=.45 baseline 100 ft. Suppose we found the angle to be 24 degrees. H = .45 x 100 ft.

H = 45 feet Go outside and find the height of three “tall things.” Write the name of each “tall thing” on the line provided. Use the space provided under each “tall thing” for your calculations. 1.__________________ 2. __________________ 3. __________________

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ONE STATION TRACKING

How high did the rocket go? To answer this question, a rocketeer must know two things: 1. The length of the baseline. 2. The angle measurement found by the tracker using a clinometer. The baseline is the distance from the launcher to the tracking station. The angle of inclination is somewhat difficult to obtain due to the speed of the rocket. For this reason, we usually sight the clinometer on the highest point of the rocket’s smoke trail, as shown below. Use the following equation for right triangles to find the maximum altitude a rocket reaches. opposite ------------= tangent of angle adjacent h -----------= tangent of angle (h = maximum altitude of the rocket) baseline h = tangent of angle multiplied by the baseline to help result error, the baseline should be as long as possible. ROUND ALL MAXIUMUM ALTITUDES TO THE NEAREST TEN FEET.

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Activity Sheet for Learning Experience #8 Page 2 EXAMPLE: Support a baseline of 100 feet was used and your measured angle was 68 degrees. Use the Tangent Table. h ----------=tangent of angle 100 ft. h = tangent of angle x baseline h = tangent of 68 degrees x 100 feet h = 2.48 x 100 feet h = 248 feet (maximum altitude of rocket) h = 250 feet (rounded to the nearest 10 feet) Find the following maximum altitudes using data collected from a single station altitude tracking system. ROUND ALL MAXIMUUM ALTITUDES TO THE NEAREST 10 FEET. 1. Angle = 49 degrees 2. Angle = 73 degrees 3. Angle = 64 degrees 4. Angle = 58 degrees 5. If the maximum altitude of a rocket was 180 feet,

what was the angle recorded at the tracking station.

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Activity Sheet for Learning Experience #8 Page 3

TWO STATION TRACKING

The same method for two station tracking is used as in one station tracking except that the average (mean) of the sum of the angles from station #1 and station #2 is used, as shown below. Use the Tangent Table. EXAMPLE 1 Baselines for both stations are 100 feet. ROUND MAXIMUM ALTITUDES TO THE NEAREST TEN FEET. h (69 + 71) ------ tan --------------- 100 ft 2 h =tan 140 ------ --------------- 100 ft. 2 h =tan 70 ------ 100 ft. h =.275 ------ 100 ft. h = 2.75 x 100 ft. h = 275 ft. (max. altitude of rocket) EXAMPLE 2 Baseline for both station are 100 feet. ROUND MAXIMUM ALTITUDES TO THE NEAREST TEN FEET. h (70 + 63) ------ =tan -------------- 100 ft. 2 h 133 ------ =tan -------------- 100 ft. 2 h ----- =tan 66.5 degrees 100 ft. h ----- = 2.305 100 ft. h = 2.305 x 100 ft. h = 230.5 ft. (max. altitude of rocket)

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Activity Sheet for Learning Experience #8 Page 4 Find the maximum altitudes using data collected from a two station altitude tracking system. All baselines are 100 feet. ROUND ALL MAXIMUM ALTITUDES TO THE NEAREST TEN FEET. Use the Tangent Table. Show all work! 1. Angle #1 = 59 degrees 2. Angle #1 = 67 degrees 3. Angle #1 = 63 degrees

Angle #2 = 63 degrees Angle #2 = 71 degrees Angle #2 = 66 degrees 4. Angle #1 = 78 degrees 5. If the maximum altitude of a rocket was 290 feet Angle #2 = 73 degrees and the angle found at tracking station #1 was 68 degrees, what was the angle found at tracking station #2.

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FINDING ALTITUDE Find the following maximum altitude using data collected form a single station altitude tracking system. ROUND ALL MAXIMUM ALTITUDES TO THE NEAREST TEN FEET. Use the Tangent Table. Show all work! 1. Baseline = 600 feet 2. Baseline = 900 feet Angle = 36 degrees Angle = 21 degrees 3. If the maximum altitude of a rocket was 321 feet and the baseline was 300

feet, what was the angle recorded at the tracking station? Finding the maximum altitudes using data collected from a two station altitude tracking system. RECORD ALL MAXIMUM ALTITUDES TO THE NEAREST TEN FEET. Use the Tangent Table. Show all work! 4. Baselines are both 400 feet. 5. Baselines are both 500 feet Station #1 angle = 51 degrees Station #1 angle = 60 degrees Station #2 angle = 57 degrees Station #2 angle = 57 degrees 6. If the maximum altitude of a rocket was 141 feet, the angle found at tracking station #1 was 23 degrees, and both baselines were 300 feet, what was the angle found at tracking station #2?

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THE ELECTRIC LAUNCH SYSTEM

The launch controller is a hand-held device containing the safety key, arming light, and ignition button. It is activated by inserting the safety key into the hole labeled “KEY” on the launch controller after the launcher has been set up as shown above. The safety key is a safety mechanism on the launch controller used to activate the electric launch system. It acts as a switch to insure that an accident will not occur. If the safety key is not in the hole labeled “KEY”, the launcher will not operate. When the arming light is on, the launcher is ready for ignition. The ignition button, located on the launch controller, will launch the rocket when it is depressed if the electric launch system is properly set up. The string attaches the key to the launch controller. The launch cable is at least 10 feet long and completes the electrical circuit which makes the launch possible. The battery clips are two large alligator type clips used to attach the launch cable to the positive and negative terminals of the battery. The 6 or 12 volt battery is the power source used in the electric launch system. The microclips are two small alligator type clips used to attach the electric launch system to the ignitor wire that has been inserted into the nozzle of the engine.

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Activity Sheet for Learning Experience #9 Page 2 The launch rod holds the model rocket on the launcher before firing and guides the rocket as it leaves the launcher after ignition. (The launch lug on the model rocket slides over the launch rod holding the rocket in place.) The blase deflector plate is a metal plate that slides over the launch rod used to prevent the ignited engine propellant from burning or scorching the launcher or the vegetation beneath it. The swivel mount assembly allows the launch rod and blast deflector plate to be turned and angled toward the wind. The three legs form a tripod to support the launcher.

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Activity Sheet for Learning Experience #10 Name_____________________

MODEL ROCKETRY SAFETY CODE 1. Construction Construct model rockets from lightweight materials such as paper, wood, plastic, and rubber without any metal as structural parts. 2. Engines Use only preloaded factory made solid propellant model rocket engines in the manner recommended by the manufacturer. Do not change in any way or attempt to reload these engines. 3. Recovery Always use a recovery system that will return the model rocket safely to the ground so it can be flown again. 4. Weight Limits Model rockets will weigh no more than 16 oz. (453 grams) at lift-off, and the engines will contain no more than 4 oz. (113 grams) of solid propellant. 5. Stability Check the stability of each model rocket before its first flight, except when launching a model of proven stability. 6. Launching System The system used to launch model rockets must be remotely controlled and electrically operated, and will contain a switch that will return to “off” when released. Stay at least 10 feet (3 meters) away from any rocket that is being launched.

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Activity Sheet for Learning Experience #10 Page 2 7. Launch Safety No one will approach a model rocket on a launcher until either the safety interlock key has been removed or the assembly has been disconnected from the launcher. 8. Flying Conditions Do not launch any model rocket in high winds, near buildings, power lines, tall trees, low flying aircraft, or under any conditions which might be dangerous to people or property. Surface winds at the launch sight should be less than 15 miles per hour (24 kilometers per hour). 9. Launch Area Model rockets will always be launched from a cleared area, free of any easy to burn materials, and will only use nonflammable recovery wadding. 10. Jet Deflector Each launcher will have a jet deflector device to prevent the engine exhaust from hitting the ground directly.

Share the sky with everyone

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Activity Sheet for Learning Experience #10 Page 3 11. Launch Rod Always place the launcher so the end of the rod is

above eye level or cover the end of the rod with a safety cap or hand when approaching it to prevent accidental eye injury. Never place your head or body over the launching rod. When the launcher is not in use, always store it so the launch rod is not in an upright position.

12. Power Lines Never attempt to recover a rocket from power lines or other dangerous places. 13. Launch Targets Do not launch rockets so their flight path will

And Angles carry them toward targets on the ground, and never use an explosive warhead or a payload that is intended to be flammable. The launching device will always be pointed within 300 of vertical.

Never recover rockets from electrical lines

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14. Pre-launch Test Use pre-launch tests when conducting research

activities with unproven designs to determine their stability. Conduct launchings of unproven designs in complete isolation from persons not participating in the actual launching.

Never tilt a rock more than 30 degrees from vertical.

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GLOSSARY Acceleration: the increase of speed or velocity of an object. Airfoil: a part of an aircraft with a flat or curved surface such as a wing or fin. It is designed to keep an aircraft up or control the aircraft’s movements by reacting with the air through which it moves. Altitude: the height of an object above ground level; elevation above sea level. Apogee: the highest point of a model rocket’s flight. Blast deflector plate: a metal plate that slides over the launch rod used to prevent the ignited engine propellant from burning

or scorching the launcher or the vegetation beneath it. Center of gravity: that point in a body around which its weight is evenly distributed. The balance point. Center of mass: same as center of gravity; the point on an object

about which the object’s mass is centered. Center of pressure: the point on a model rocket where an air current will no longer cause either end of the rocket to point into the wind. If the center of pressure is behind the center of gravity on the model, the air pressure will exert the greatest pressure against the fins forcing

the model to fly straight. The point about which an object’s surface area is centered.

Clinometer: an instrument used to measure angles of slope or inclination. Delay charge: the second of three charges in a model rocket engine. This charge (1) allows the rocket to slow down and (2) provides a visible smoke trail for tracking the rocket. Drag: the resisting forces of air acting on a model rocket during its upward flight. Ejection charge: the third of three charges in a model rocket engine. It is designed to pressurize the body tube and eject the recovery system.

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Fillet: a glue filler applied to the launch lug joint or a fin joint strengthening the bond between the fin or launch lug and the model rocket body. Fin: a part (airfoil) of a model rocket whose chief function is to provide stability in flight. Gravity: force that tends to draw all bodies in Earth’s sphere toward the center of the earth. Igniter: a device that ignites a rocket’s engine. An igniter must be inserted into the nozzle of a rocket so that its coating touches the solid propellant before connecting the microclips to the launch system. Launch: to send off a self-propelled object (rocket). Launch area: the football field, playground, park, or large open area used as a place to launch model rockets. The larger the unobstructed launch area the better. Launch controller: a device that transfers electrical energy to ignite the coating on the igniter wire. Launch lug: a section of soda straw mounted parallel to the sides of the body tube to hold the model rocket on the launcher before and during lift-off. Launch rod: a rod used to hold the model rocket on the launcher before firing and to guide the rocket as it leaves the launcher after ignition. Microclips: clips used to attach the power source to the igniter. Model rocket engine: the solid propellant power system of a model rocket designed to perform all power functions during launch, acceleration, and activation of the recovery system. Nichrome wire: high resistance wire made from nickel and chromium. It is the wire used to make igniter wires. Nose cone: the front part of the rocket designed to cut down drag (wind resistance) as the rocket is propelled through the air.

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Nozzle: the small opening at the lower end of a model rocket engine through which hot gases escape at a high velocity.

Parachute: an umbrella-shaped sheet made of plastic or lightweight material used to slow the descent of the model rocket as it moves earthward after reaching its maximum altitude. Pre-launch test: activities used to see if the rocket is stable enough to fly safely. Rocket: any device, usually cylindrical, containing a solid propellant which, when ignited, produces gases that escape through a nozzle at the rear, driving the container (rocket) forward by the principle of action- reaction. Shock cord: an elastic band usually attached to the nose cone and glued to the inside of the model rocket body tube by a shock cord mount. It is designed to absorb the shock when the ejection charge blows the nose cone off the body tube. Shroud lines: the strings that connect the rocket to the parachute or streamer. Solid propellant: a mixture of rocket fuel and oxidizer in solid form that burns to produce thrust. Stability: all rotating forces of a model rocket are counteracted or overcome enabling a steady, stable flight. Streamer: a strip of lightweight plastic used as a recovery

system when the launch area is relatively small or the wind velocity might carry the rocket too far away from the launch site.

Tangent: in trigonometry, the ratio between the side opposite a given acute angle to the adjacent side in a right triangle. Thrust : the forward force produced in reaction to the gases escaping through the nozzle of a model rocket engine.

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Thrust charge: the initial or first stage of a model rocket engine designed to provide lift-off and acceleration.

Thrust ring: a cardboard ring glued inside the body tube

directly in front of the engine of model rockets that do not have an engine mount tube and engine holder. It prevents the engine from pushing through the body tube during lift-off and acceleration.

Track : to observe the moving path of a rocket. Tracking station: a station used to track the path of a rocket or other missile and record certain types of data related to that spacecraft. Trajectory: the curved path a model rocket takes from the time it leaves the launch pad to the time the recovery mechanism is ejected. Velocity: speed Wadding: Flame-resistant tissue paper packed between the

engine and the streamer or parachute to protect the recovery system from the heat of the ejection charge.

a collection of learning experiences on rocketry€¦ · some of these variables will be present in...

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