Get Ready for Rocket Day!

Janet & Charles HoultAssured Space Access Technologies, Inc. (ASAT)

2008 AIAA Passport to the Future Teacher Workshop21-22 July 2008

Hartford, CT

So, What’s a Rocket Day?

• Objective is to encourage students to consider a career in science, technology, engineering or mathematics

• A Rocket Day is a school-sponsored coming together of rocket enthusiasts to fly their model rockets

• Rocket Days sometimes include competitive events– Team America Rocketry Challenge– Coming closest to predicted apogee altitude

• Type of rocket flown depends on student grade level– Grades 3-5 fly water rockets…compressed air drives water from soft

drink bottles converted to rockets– Grades 6-9 fly small solid rockets– Grades 10-12 fly larger solid rockets

• Rocket Day includes many activities– Classroom instruction on rocketry & space exploration– Workshop for each student to build his own model rocket from a kit

• Can be done on a weekend to encourage parental participation…It can be a great picnic opportunity

Workshop Outline

• Introduction to Rocket Day will focus on three topics

1. How rockets work

2. Rocket assembly workshop

3. Rocket Day activities

• Overview of supplemental material

• Wrap up

How Do We Get Started?

• The best way to begin model rocketry is with an Estes flying model rocket Starter Set or Launch Set. You can either start with a Ready To Fly Starter Set or Launch Set that has a fully constructed model rocket or an E2X® Starter Set or Launch Set with a rocket that requires assembly prior to launching.

• Both types of sets come complete with an electrical launch controller, adjustable launch pad and an information booklet to get you out and flying in no time.

• Starter Sets include engines, Launch Sets let you choose your own engines (not included). Buy motors at your local hobby store. You’ll need four ‘AA’ alkaline batteries and perhaps glue, depending on which set you select.

How Easy & How Much Time Does It Take to Build My Rockets?

Estes model rocket kits range from ready to fly in just minutes to those that provide many enjoyable hours of building fun. Estes kits are classified into five categories.READY TO FLY (RTF): No paint, glue or modeling skills required. Rocket comes assembled and is ready for liftoff in just minutes.E2X® ROCKET KITS: No paint or special tools needed. E2X® kits contain parts that are colored and easy to assemble. Simply glue the parts together as per the instructions, apply the self-adhesive decals, attach the recovery system and you are ready to blast off! Assembly takes 1 hour or less.SKILL LEVEL 1 ROCKET KITS: Requires some painting, gluing and sanding. Features laser cut balsa fins, slotted body tubes, plastic nose cones and self-adhesive decals. Step by step instructions make building very easy. Assembly takes at least an afternoon.SKILL LEVEL 2 ROCKET KITS: First tier of more advanced kits. Requires beginner skills in model rocket construction and finishing. Features laser cut balsa or plastic fins, plastic nose cones and unfinished body tubes. Assembly may take a complete day.SKILL LEVEL 3 ROCKET KITS: Second tier of more advanced kits. Requires moderate skills in model rocket construction and finishing. Features multiple laser cut balsa fins and parts, unfinished body tubes, complex designs and plastic nose cones. Assembly may take a couple of days

Past and Future of Rocketry

Early History

• In the beginning….– Circa first century AD China, according to legend…

• Casual experimentation with mixtures of powered sulfur, charcoal & saltpeter gave off lots of bright light & smoke

• If this mixture was confined to a bamboo tube with plugged ends & thrown into a fire, there would be a loud bang. Many evil spirits were thus frightened away

• That’s how fireworks were invented• But, sometimes one end of the bamboo tube was imperfectly

closed, and the bamboo went flying• That’s how rockets were invented!

– Circa tenth century AD China• Rockets were developed as weapons of war

– Early rocket technology diffused over East Asia

More History

• Sir William Congreve (1772-1828)– British artilleryman, stationed in

India, observed rockets used as weapons of war

– He inspired the Royal Army & Navy to adopt rockets as weapons

– Most famous application was the British naval attack on Fort McHenry, Md, in 1814. Documented in Francis Scott Key’s poem, “The Star Spangled Banner” with the phrase, “the rocket’s red glare”

– After the Napoleanic wars, the British military abandoned rockets (only for a while) because they were less accurate than guns

Konstantin E. Tsiolkovskii (1857-1935)

– A poor provincial school teacher working in Kaluga far from Moscow was the first to begin the theoretical mathematical study of rocket flight

– In 1903, he published, in Russian, “The Exploration of Cosmic Space by Means of Reaction Devices”

– It included what’s now called Tsiolkovskii’s law (more later on this), one foundation of ballistic missile and interplanetary rocket flight

– First proposed multi stage rockets…lower stage velocity (V) added to upper stage V to reach very high total velocity

– First proposed liquid oxygen (lox) – hydrogen propellants

– Envisioned humanity spreading into space

                                                                           

                         

Dr. Robert H. Goddard (1882-1945)

• Did the work for which he’s most famous while a professor at Clark Univ. in Worcester, MA

• Patented a vacuum tube amplifier before de Forest!

• First applied the de Laval steam turbine nozzle to rockets…significant performance improvement

• Built & launched the first liquid rocket in Auburn, MA in 1926

• With Guggenheim funding, continued to build ever more sophisticated rockets until 1935

• Later rockets were launched from Roswell, NM

• Published “A Method of Reaching Extreme Altitudes” in 1919

• Widely scorned by the media (esp. The New York Times) for his “errors”

• After the 1969 Apollo landing on the moon, the NY Times finally published a “correction”

Dr. Werner M. M. Freiherr von Braun (1912-1977)

• Mother gave him a telescope as a confirmation present at age 12

• While at the Technical University of Berlin joined the Spaceflight Society

• Hitler came to power while he worked on his Doctorate, & Wehrmacht funded his studies

• Joined the Nazi Party & SS and led the V-2 development team at Peeneműnde

• Emigrated to U.S. after the war and led U.S. Army ballistic missile (Redstone & Jupiter) development at Redstone Arsenal

• Responsible for Jupiter C that launched first U.S. satellite (Explorer 1)

• Joined NASA when it was established and led the Saturn (Apollo) development work

Von Braun & Saturn V first stage

V-2

ICBMs and SLBMs: The Space Race

• The two most significant World War II technologies, the atomic bomb and the ballistic missile, were integrated by the USSR & the USA starting in the mid 1950s

• The object of this quest was a practical Intercontinental Ballistic Missile (ICBM) with a nuclear warhead. The country with ICBMs was thought to be secure.

– A variant was the Submarine-Launched Ballistic Missile (SLBM)

– It was possible to attack ICBM bases before they could launch their missiles, but the submarines hosting SLBMs were much harder to locate & destroy

• The USSR’s rocket program was the more extensive during the late 1940s and early 1950s…they first deployed large ballistic missile weapons

– The West was thoroughly frightened

– “Catch up to the Russians” had the highest priority

• Most early space launches used ICBMs as boosters

– Provided a public window onto secret military capabilities

Proficiency in space exploration implied proficiency in ballistic missiles

Sergey Korolyov (1907-1966)

• Caught up in Stalin’s purges and sent to Siberian Gulag

• His identity was a state secret throughout his lifetime…press only referred to him as the “Chief Designer”

• Led the design bureau creating all early Soviet ballistic missiles

• Responsible for building and launching Sputnik, the first earth satellite

• Led the team building & launching the first successful lunar probes…Luna 3 took the first photographs of the Moon’s far side

• Died due to a botched surgical procedure

Cosmonauts, Astronauts (& Taikonauts)

• First man in space was Russian Cosmonaut Yuri Gagarin

– Fighter pilot

– First single orbit flight (12 April 1961)…Awarded the Hero of the Soviet Union

– Died in a MIG-15 crash in 1968

• First man to step onto the lunar surface was Astronaut Neil Armstrong (1930-)

– Commander of Apollo 11, first Moon landing (16 July 1969)

– Taught at Univ. of Cincinnati (1971-1979)…now retired

• Today, hundreds from many nations have flown in space – 294 Americans

– 72 Russians

– Others from Saudi Arabia, France, Canada, Italy, Israel, Japan, Spain, Belgium, Germany, Mexico, Ukraine, Switzerland, Netherlands, etc.

• Now, the first two Chinese Taikonauts have orbited the earth!

Gagarin

Armstrong

Ballistic Missile Defense• Ballistic missile defense schemes have been around since the 1960s

• In the 1970s, the US studied Sprint, Spartan & Safeguard while Russia deployed Galosh

– All used nuclear warheads to negate incoming reentry vehicles

– Problem was, the nukes did vast damage via Electro-Magnetic Pulse (EMP) to the assets they were trying to protect

– Hence the Anti-Ballistic Missile (ABM) treaty…If you couldn’t make it work, then you might as well sign a treaty against it

• Modern hit-to-kill warheads make ballistic missile defense practical…no EMP

– Consist of tracking systems (radars and infrared (IR) sensing satellites), rocket-boosted hit-to-kill warheads (based on dry land or on ships), and command, control and battle management elements

– Main issue with current systems is their inflexibility…improvements in the pipeline are

• Migrating from ground-based radars to space-based IR satellites for vastly better coverage

• Migrating from fixed-site silo launchers to ship-based launchers to better engage evolved threats and scenarios

• Improved sensors for better discrimination between reentry vehicles and decoys

Back to the Moon, on to Asteroids & Mars

• Constellation system

– Orion is the new Crew Capsule…slightly larger than that used by Apollo

– Ares I is a two stage booster for the Orion Crew Capsule…first stage is a stretched Space Shuttle Solid Booster rocket, & second stage uses an improved version of the Apollo J2 LOX-hydrogen rocket engine

– Ares V is an unmanned cargo carrier…also uses legacy Space Shuttle & Apollo hardware

• After the Space Shuttle is grounded around 2010, Constellation provides follow-on capability

• Manned missions include rendezvous with the International Space Station, return to the Moon, establishment of a permanent lunar base, rendezvous with near-earth asteroids and finally, landing on Mars

• Time frame is next two decades

– Early testing has begun…static firings, capsule drop tests, etc.

Ares I Ares V

Orion

Theory of Rockets

Dr. Eric Besnard

California State University, Long Beach

Project Director, California Launch Vehicle Education Initiative

http://www.csulb.edu/rockets/

How does a rocket work?

• Exercise 1:

– Take a balloon and blow it up – Do not tie it

– Release the balloon

– What happens? Why?

• Exercise 2:

– Take a cart with a pile of bricks on it

– Stand on the cart and throw bricks backward

– If there is no friction on the wheel, what happens? Why?

Thrust• This effect comes from conservation of

momentum– Momentum:

• Definition: mass x velocity (speed)• A truck at 40 miles per hour has more

momentum than a car at 40 miles per hour

• A car at 40 miles per hour has more momentum than a car at 20 miles per hour

– Newton’s first law of motion: When no external forces are applied on the object, momentum is conserved

– Mass exits backwards at a certain speed or velocity

– Therefore object moves forward at a speed which will conserve momentum:

→ THRUST is generated

Rocket

(large mass, “small” velocity)

Gas

(small mass, large velocity)

81

Rocket Safely Returns to Earth

Recovery Systems Deployed

Rocket Accelerates & Gains Altitude

Touchdown, Replace the Motor, Igniter & Recovery Wadding. Ready to Launch Again!

Motor Burns Out

Rocket reaches Apogee Altitude. Ejection Charge Activates Recovery System

8

Tracking Smoke Generated During Time Delay / Coast Phase

Electrically Ignited Rocket Engine Provides Lift-Off

Newton’s second law of motion: forces acting on the object will change the momentum of the object:

F = m a - F: sum of all forces - m: mass of object - A: acceleration of object

Forces on our rocket:Drag (air)Weight (gravity)Thrust (engine)

Fins stabilizethe rocket

Launcher rail guides the rocket

Rocket Flight

• Liquid Propellants– Fuel & Oxidizer stored separately

• Liquid oxygen (LOX) and liquid hydrogen (Space Shuttle)• LOX-alcohol, LOX-kerosene (early ballistic missiles)

– Combined in combustion chamber– Combustion pressure attained by

• Turbopumps• Stored gaseous pressurant

• Solid Propellants– Heterogeneous, aka composites, (modern ballistic missiles)

• Oxidizer & Fuel, while mixed intimately, are stored as distinct molecules

• Oxidizer (NH4ClO4) and fuel (Al) held in a rubber matrix (also fuel) • Black powder…this is what most model rockets use (10% powdered

sulfur, 75% salt peter (KNO3) & 15% powdered charcoal)…plus a teeny bit of binder

– Homogeneous • Fuel & Oxidizer are part of the same molecule• During combustion, molecule decomposes and components burn• Gun cotton

Propellants

Nozzles

• All modern rockets use a de Laval concept

– Subsonic converging section

– Sonic throat

– Supersonic diverging section

• Conical: easy to manufacture & ~98% efficient…this is what model rockets use

• Bell: more difficult to manufacture & ~99+% efficient

• Multiple cooling concepts

– Regenerative: Propellant flows thru hollow nozzle walls until it’s injected into combustion chamber

– Ablative: Nozzle wall chars, & the char insulates the uncharred nozzle wall

– Film: A thin propellant film coats the nozzle wall and insulates it

– Heat sink: The nozzle just gets hotter during firing…this is what model rockets use

Rocket engines• Generate high velocity gas by chemical reaction (burning)

of propellants:

– Something which burns: fuel

– Something which carries oxygen: oxidizer

• Unlike aircraft engines which take the oxygen from the atmosphere (“air-breathing” engines), rocket engines carry their own oxygen so they can fly in space (where there is no atmosphere)

LOX tank

LH2

tank

Solid Rocket Booster

Orbiter

• Examples of Propellants:– Estes rockets: black powder– Space Shuttle Orbiter:

• Oxidizer: liquid oxygen LOX (≈ -320 F) & liquid hydrogen, LH2 (≈ -425 F)

– Space Shuttle Solid Rocket Boosters:

• Composite solid propellant– Space Ship One:

• Hybrid; nitrous oxide (laughing gas) & rubber

A Really BIG rocket engine

• 5 F-1 engines were used on the Saturn V on its way to the Moon

• 1.5 million pounds thrust

each!

Smaller rockets, same technology…

Designed and integrated by Long Beach State students

Aerospike rocket engine static fire test

When something goes wrong…

Prospector-4 flight

A slightly bigger rocket: sized for 20 lb to orbit!

Model Rockets

Partial Model Rocket System Architecture

Model Rocket System

Flight Segment

Ground Segment

Airframe Propulsion Launcher Controller Facilities

Fins

Tube

Nose Cone

Lug

Parachute

Motors

IgnitersLauncher

Anemometer

Controller

Batteries

Field

Ground Support Equipment

Data Segment

Training MaterialsSimulations

Typical Model Rocket Components

10) Fin

9) Motor Hook

8) Motor Mount

7) Body Tube

6) Shock Cord Mount2) Shock Cord

1) Nose Cone

5) Shroud Lines

11) Launch Lug

3) Parachute 4) Tape Rings

Rocket Motor Cutaway

Get a printable version of this information in Apogee e-zine newsletter #114.

Paper Case

Clay Cap

Ejection Charge

Delay Composition

Black Powder Propellant

Clay Nozzle

Your rocket

Nozzle

Solid propellant

Ejection charge for deployment of recovery system

Non-thrust delay and smoke for tracking charge

High thrust charge for lift-off and acceleration

This letter indicates total impulse produced by the motor. Each succeeding letter denotes twice the total impulse as for the previous letter. Example: B motors have twice the impulse of A motors.

This number shows the motor’s average thrust in newtons, or the average ”push” exerted by the motor.

This number is the delay in seconds between the end of thrusting (burnout) and ejection charge action. Motor types ending in 0 have no delay or ejection charge, and are for use in booster stages only.

How to Read the Motor Code

Estes motors are color-coded for recommended use. GREEN motors are for use in single stage models; PURPLE motors for the top stages of multi-stage rockets and very light single stage rockets; RED motors for all booster and intermediate states of multi-stage models. BLUE are “plugged” and are used for rocket powered racers and radio controlled gliders, they contain no delay or ejection charge.

Rocket Motor Impulse Classes

Type  Total Impulse (newton - seconds)

¼A 0.31-0.62

½A 0.63-1.25

A 1.26-2.50

B 2.51-5.00

C 5.01-10.00

D 10.01-20.00

E 20.01-30.00

B6-4 Thrust Profile

Max.Thrust

Ejection Charge Activates

Time (seconds)

Propellant Burnout

(pou

nds)

Thr

ust (

new

tons

)

Delay Period – No Measurable Thrust

Average Thrust Total Impulse / Duration=

Compressed Black Powder Propellant

Specific Impulse – 80-83 sec

Exhaust velocity – 2550-2650 ft/sec

Each rocket engine has a code printed upon the outer jacket. An example of one such code is A8-3.The capital letter (e.g., A) indicates total impulse produced by the engine. Each succeeding letter represents a power range with maximum total impulse twice the impulse as the previous letter. (Example: A single C engine can produce anywhere from 5.01 to 10 newton-seconds of impulse, a G engine 80.1 to 160 newton-seconds.) Anything over a G engine is considered high power model rocketry.The first number (e.g., 8) specifies that engine's average thrust in newtons or the average push exerted by the engine. Thus a B6-0 and a C6-0 will both produce the same average thrust of 6 newtons, but the C6-0, having twice the total impulse, will fire for twice as long. The rocket engines produce maximum thrust shortly after ignition and thrust declines to a steady-state which is maintained for up to 2.5 seconds prior to burnout.[2]

The final number (e.g., 3) indicates the delay between burnout and the ejection charge, in seconds. Engines with a delay of zero are typically used as booster engines in multi-stage rockets and there is no ejection charge. In this case, the burning propellant ruptures through the top and hot bits of propellant enter the nozzle of the upper stage engine, thus igniting that engine and forcing the booster assembly away, usually to tumble safely to earth.

Estes Rocket Motor Code

Thoughts on Payloads

• A payload is something “useful” that flies on a rocket• Even though most beginning rocket hobbyists do not attempt to fly

payloads, the issue merits discussion• Payloads considered to be acceptable to the larger community include

– Eggs…usually to meet a requirement that they be returned to earth intact

– Cameras…Estes Astrocam 110™, kit no. 1327. Can take great pictures from altitude

– Aircraft such as rocket-boosted gliders…e. g., Estes Screaming Eagle, kit no. 2117, and many more

– Any onboard sensors, including any telemetering system, acoustic or radio-based

• Payloads NOT considered to be acceptable to the larger community include– Any vertebrate life form, especially mice. The SPCA takes a strong

stand on this point. Insects, however, are OK– Anything that goes bang upon impact, and, even worse, any incendiary

device

Typical Model Rocket Launcher & Controller

Launch Rail

Slot for tilting Launch Rail

Package it comes in

Package it comes in

Launch Button

Status Light

Launch Key

Solid Rocket Motor Functionality

Rocket Day Organization

Rocket Day Organization• Range Safety Officer (RSO) - Yourself or the leader who is in charge. The

RSO has the final say in all situations. The RSO carries the safety key at all times and checks the air-worthiness of all rockets.

• Launch Control Officer (LCO) - This person is responsible for actually firing the rocket. Control panel set-up and dismantling is also this person’s responsibility.

• Tracking Officer (TO) - This person is responsible for the set-up, operation and coordination of the tracking sites (TO).

• Data Control Officer (DCO) – In competitions involving apogee altitude & time of flight, this individual collects, organizes and disseminates all preflight and flight data.

• 1-2 Tracking Crews - These could consist of several positions at each site. Positions could include: tracking the rocket to measure its altitude, recording altitude data

• Recovery Crews - Consist of several people who follow the flight, recover and return the rocket to the Preparation Table under the RSO’s direction.

• Staffing Sources – Older, more experienced students should be recruited for most of these positions. Potential sources include Boy Scouts, Civil Air Patrol, Junior ROTC, or members of a local model rocket club (see the NAR web site for a listing of these)

     Tracker 2

     Range Safety Officer

     Data Recording Table & Data Control Officer

     Preparation Table

     Recovery Team

     Launch Control Officer

     National or Club Flag

     Range-In-Operation Pennant (optional)

     Student-Observers

     Parking Area (optional)

     Launching Pad

             Tracker 1

Launch Site Layout

Further Rocket Day Suggestions

• In addition to the above suggestions, a table could be set up for preparation

of the rockets before flight with someone responsible to coordinate the flow

of rockets to the pad. After the data is recorded, the Data Control Officer is

responsible for collecting and compiling the individual data cards into one

report.

• Preparing for a Rocket Day well in advance and rehearsing the various

operations, including misfire responses, prior to a public performance will

ensure a high level of safety and provide a well-coordinated program that

everyone will enjoy. The importance of staging a Rocket Day has its value in

stressing teamwork during the ground operations while promoting good

competition during the flight portion.

• Cross training your students in all of the various roles mentioned above will

familiarize them with the entire launch operation and increase the level of

interaction each student experiences. The possibilities of a Rocket Day are

unlimited and it is a wonderful way to bring any rocket or space unit to a

conclusion.

Safety ConsiderationsEstes Alpha III Starter Set Rockets

• What’s a reasonable field size?

– Keep in mind that most rockets will come down on their parachutes

– Biggest hazard from an impact outside the field is it would put the rocket someplace where it couldn’t be easily recovered

– For an Alpha III the predicted apogee altitude is about 1100 ft = 335 m. Then 85% of all impacts would fall into a square field about 85m = 280 ft on a side.

• What government rules must we pay close attention to?

– Federal Aviation Regulations Part 101.25 require you notify your local FAA office at least 24, and not more than 48 hours in advance of launch

– Federal Aviation Regulations Part 101.23 (mostly common sense) should also be considered compliant

• This material is covered in detail in other reference material

A Rocket Day Logistics Check List

• Things you the teacher should plan to provide– Rocket Launchers and Controller Panels (one for every dozen students

is a good planning number)– Fresh batteries to power ignition circuits– Fire extinguishers and first aid kits If you bring them, they won’t be

needed & v.v.– PortaPotty (if no other facilities are available)– A loud hailer so all can hear the count down and RSO instructions– Inclinometers (2) and either a traffic wheel, GPS or a long tape measure

are needed to measure apogee altitude. A good inclinometer choice is Estes Industries Altitrak™ #302232, $23.75 each

– A hand held anemometer to measure launch winds. A good choice is Edmund Scientific’s SkyMate Windmeter #30823-43, $99.95. A nice-to-have, but not essential.

• Things you should remind each participant to bring– Sun screen & hats– Water & soft drinks. Possibly food also– Folding chairs for the old folks. Also blankets in cold weather– Cell phones for the two Trackers to communicate with the Data

Recording Table, the Data Control Officer, the Range Safety Officer, the Launch Control Officer & yourself

Procedures for One- and Two-Tracker Estimation of Apogee

Based on Estes Technical Report TR-3, “Altitude Tracking”, 1988

Quest Inclinometer

Quest Skyscope inclinometer No. 7812, $7.00

Altitude Estimation with a Single Inclinometer

• First, acquire an inclinometer, either by making your own from a protractor with a weighted string, or by buying an Estes Altitrak™

• Next position an observer up wind from launcher by a distance (d in the sketch) approximately equal to the predicted apogee altitude. Measure the distance d– Estes catalog provides predicted

apogee altitudes for their rocket kits• After liftoff, the observer tracks the rocket by

sighting along the instrument spine– Or by pointing the Altitrak™

• When he perceives the rocket has gone as high as it will, he notes the angle (e in the sketch) on the instrument scale/protractor

• Use formula to estimate apogee altitude

Observer Launcherd

H

Line of Sight

e

Wind

H = d tan(e)

Estes Altitrak™

• How high did it really go? Next time, measure it with this easy to use device. Follow the rocket in the sights to apogee, release the trigger to lock the reading. Easy-to-read display gives you your altitude in meters along with the elevation angle. Use two Altitraks for greater accuracy. Great for school and science projects!

• Estes 302232– $23.75

Two-Tracker Layout

Launcher TrackerTracker

Wind

• Locate the two Trackers equidistant from the Launcher along a line parallel to the average wind

• The distance from the Launcher to each Tracker is approximately equal to the predicted apogee altitude h*

• Minimizes bias error in estimated apogee altitude

h* h*

Apogee Altitude Estimation

LauncherTracker

d

Trackere1 e2

h*

• Measure maximum elevation angles e1 and e2 with Estes Altitraks™, or Quest Skyscopes

• Measure distance d with a traffic wheel, or tape measure, or GPS

• Estimate apogee altitude h* from tan(e1) tan(e2)

tan(e1) + tan(e2)h* = d

Line of SightLine

of Sigh

t

Federal Aviation RegulationsPart 101

 101.21   Applicability.      top This subpart applies to the operation of unmanned rockets. However, a person operating an unmanned rocket within a restricted area must comply only with §101.23(g) and with additional limitations imposed by the using or controlling agency, as appropriate.[Doc. No. 1580, 28 FR 6722, June 29, 1963]§ 101.22   Special provisions for large model rockets.      top Persons operating model rockets that use not more than 125 grams of propellant; that are made of paper, wood, or breakable plastic; that contain no substantial metal parts, and that weigh not more than 1,500 grams, including the propellant, need not comply with §101.23 (b), (c), (g), and (h), provided:(a) That person complies with all provisions of §101.25; and(b) The operation is not conducted within 5 miles of an airport runway or other landing area unless the information required in §101.25 is also provided to the manager of that airport.[Amdt. 101–6, 59 FR 50393, Oct. 3, 1994]

Federal Aviation Regulations

 101.23   Operating limitations.

     top No person may operate an unmanned rocket—(a) In a manner that creates a collision hazard with other aircraft;(b) In controlled airspace;(c) Within five miles of the boundary of any airport;(d) At any altitude where clouds or obscuring phenomena of more than five-tenths coverage prevails;(e) At any altitude where the horizontal visibility is less than five miles;(f) Into any cloud;(g) Within 1,500 feet of any person or property that is not associated with the operations; or(h) Between sunset and sunrise.(Sec. 6(c), Department of Transportation Act (49 U.S.C. 1655(c)))[Doc. No. 1580, 28 FR 6722, June 29, 1963, as amended by Amdt. 101–4, 39 FR 22252, June 21, 1974]

101.25   Notice requirements.

     top No person may operate an unmanned rocket unless that person gives the following information to the FAA ATC facility nearest to the place of intended operation no less than 24 hours prior to and no more than 48 hours prior to beginning the operation:(a) The names and addresses of the operators; except when there are multiple participants at a single event, the name and address of the person so designated as the event launch coordinator, whose duties include coordination of the required launch data estimates and coordinating the launch event;(b) The estimated number of rockets to be operated;(c) The estimated size and the estimated weight of each rocket; and(d) The estimated highest altitude or flight level to which each rocket will be operated.(e) The location of the operation.(f) The date, time, and duration of the operation.(g) Any other pertinent information requested by the ATC facility.[Doc. No. 1580, 28 FR 6722, June 29, 1963, as amended by Amdt. 101–6, 59 FR 50393, Oct. 3, 1994]

Model Rocketry Safety Code

Estes Industries

Model Rocketry Safety Code

1.MaterialsMy model rocket will be made of lightweight materials such as paper, wood, rubber, and plastic suitable for the power used and the performance of my model rocket. I will not use any metal for the nose cone, body, or fins of a model rocket. 2.Motors/EnginesI will use only commercially-made NAR certified model rocket engines in the manner recommended by the manufacturer. I will not alter the model rocket engine, its parts, or its ingredients in any way. 3.RecoveryI will always use a recovery system in my model rocket that will return it safely to the ground so it may be flown again. I will use only flame-resistant recovery wadding if required. 4.Weight and Power LimitsMy model rocket will weigh no more than 1500 grams (53 oz.) at lift-off, and its rocket engines will produce no more than 320 Newton-seconds (4.45 Newtons equal 1.0 pound) of total impulse. My model rocket will weigh no more than the engine manufacturer’s recommended maximum lift-off weight for the engines used, or I will use engines recommended by the manufacturer for my model rocket. 5.StabilityI will check the stability of my model rocket before its first flight, except when launching a model rocket of already proven stability

6.PayloadsExcept for insects, my model rocket will never carry live animals or a payload that is intended to be flammable, explosive, or harmful. 7.Launch SiteI will launch my model rocket outdoors in a cleared area, free of tall trees, power lines, buildings, and dry brush and grass. My launch site will be at least as large as that recommended in the following table.

LAUNCH SITE DIMENSIONS

Minimum InstalledTotal Impulse

(Newton-seconds)

Equivalent Engine Type Site Dimension

(feet) (meters)

0.00 1.25 1/4A & 1/2A 50 15

1.26 2.50 A 100 30

2.51 5.00 B 200 60

5.01 10.00 C 400 120

10.01 20.00 D 500 150

20.01 40.00 E 1000 300

40.01 80.00 F 1000 300

80.01 160.00 G 1000 300

160.01 320.00 2Gs 1500 450

8.LauncherI will launch my model rocket from a stable launching device that provides rigid guidance until the model rocket has reached a speed adequate to ensure a safe flight path. To prevent accidental eye injury, I will always place the launcher so that the end of the rod is above eye level or I will cap the end of the launch rod when approaching it. I will cap or disassemble my launch rod when not in use and I will never store it in an upright position. My launcher will have a jet deflector device to prevent the engine exhaust from hitting the ground directly. I will always clear the area around my launch device of brown grass, dry weeds, and other easy-to-burn materials. 9.Ignition SystemThe system I use to launch my model rocket will be remotely controlled and electrically operated. It will contain a launching switch that will return to “off” when released. The system will contain a removable safety interlock in series with the launch switch. All persons will remain at least 15 feet (5 meters) from the model rocket when I am igniting model rocket engines totaling 30 Newton-seconds or less of total impulse and at least 30 feet (9 meters) from the model rocket when I am igniting model rocket engines totaling more than 30 Newton-seconds of total impulse. I will use only electrical igniters recommended by the engine manufacturer that will ignite model rocket engine(s) within one second of actuation of the launching switch.

10.Launch SafetyI will ensure that people in the launch area are aware of the pending model rocket launch and can see the model rocket’s liftoff before I begin my audible five-second countdown. I will not launch a model rocket using it as a weapon. If my model rocket suffers a misfire, I will not allow anyone to approach it or the launcher until I have made certain that the safety interlock has been removed or that the battery has been disconnected from the ignition system. I will wait one minute (60 sec) after a misfire before allowing anyone to approach the launcher. 11.Flying ConditionsI will launch my model rocket only when the wind is less than 20 miles (30 kilometers) an hour. I will not launch my model rocket so it flies into clouds, near aircraft in flight, or in a manner that is hazardous to people or property

12.Pre-Launch TestWhen conducting research activities with unproven model rocket designs or methods I will, when possible, determine the reliability of my model rocket by pre-launch tests. I will conduct the launching of an unproven design in complete isolation from persons not participating in the actual launching.

13.Launch AngleMy launch device will be pointed within 30 degrees of vertical. I will never use model rocket engines to propel any device horizontally. 14.Recovery HazardsIf a model rocket becomes entangled in a power line or other dangerous place, I will not attempt to retrieve it. As a member of the Estes Model Rocketry Program, I promise to faithfully follow all rules of safe conduct as established in the above code.

Signature__________________________________________ *This is the official Model Rocketry Safety Code of the National Association of Rocketry and the Model Rocket Manufacturers Association.

Important Note: “G” engines must be sold to and used by adults (18 and up) only. To launch large model rockets weighing more than one lb. (453 g) but no more than 3.3 lbs. (1500 g) including propellant or rockets containing more than 4 oz. (113 g) but no more than 4.4 oz. (125 g) of propellant (net weight), you must notify and perhaps obtain authorization from the Federal Aviation Administration (FAA). Check your telephone directory for the FAA office nearest you or contact Estes Industries for further information.

National Association of Rocketry Model Rocket Safety Code

Ref: NAR website

Model Rocket Safety Code  

1. Materials. I will use only lightweight, non-metal parts for the nose, body, and fins of my rocket. 2. Motors. I will use only certified, commercially-made model rocket motors, and will not tamper with these motors or use them for any purposes except those recommended by the manufacturer. 3. Ignition System. I will launch my rockets with an electrical launch system and electrical motor igniters. My launch system will have a safety interlock in series with the launch switch, and will use a launch switch that returns to the “off” position when released. 4. Misfires. If my rocket does not launch when I press the button of my electrical launch system, I will remove the launcher's safety interlock or disconnect its battery, and will wait 60 seconds after the last launch attempt before allowing anyone to approach the rocket. 5. Launch Safety. I will use a countdown before launch, and will ensure that everyone is paying attention and is a safe distance of at least 15 feet away when I launch rockets with D motors or smaller, and 30 feet when I launch larger rockets. If I am uncertain about the safety or stability of an untested rocket, I will check the stability before flight and will fly it only after warning spectators and clearing them away to a safe distance.

6. Launcher. I will launch my rocket from a launch rod, tower, or rail that is pointed to within 30 degrees of the vertical to ensure that the rocket flies nearly straight up, and I will use a blast deflector to prevent the motor's exhaust from hitting the ground. To prevent accidental eye injury, I will place launchers so that the end of the launch rod is above eye level or will cap the end of the rod when it is not in use. 7. Size. My model rocket will not weigh more than 1,500 grams (53 ounces) at liftoff and will not contain more than 125 grams (4.4 ounces) of propellant or 320 N-sec (71.9 pound-seconds) of total impulse. If my model rocket weighs more than one pound (453 grams) at liftoff or has more than four ounces (113 grams) of propellant, I will check and comply with Federal Aviation Administration regulations before flying. 8. Flight Safety. I will not launch my rocket at targets, into clouds, or near airplanes, and will not put any flammable or explosive payload in my rocket. 9. Launch Site. I will launch my rocket outdoors, in an open area at least as large as shown in the accompanying table, and in safe weather conditions with wind speeds no greater than 20 miles per hour. I will ensure that there is no dry grass close to the launch pad, and that the launch site does not present risk of grass fires.

10. Recovery System. I will use a recovery system such as a streamer or parachute in my rocket so that it returns safely and undamaged and can be flown again, and I will use only flame-resistant or fireproof recovery system wadding in my rocket. 11. Recovery Safety. I will not attempt to recover my rocket from power lines, tall trees, or other dangerous places.

Installed Total Impulse (N-sec)

Equivalent Motor Type

Minimum Site Dimensions (ft.)

0.00--1.25 1/4A, 1/2A 50

1.26--2.50 A 100

2.51--5.00 B 200

5.01--10.00 C 400

10.01--20.00 D 500

20.01--40.00 E 1,000

40.01--80.00 F 1,000

80.01--160.00 G 1,000

160.01--320.00 Two Gs 1,500Revision of February, 2001

LAUNCH SITE DIMENSIONS

Tripoli Safety Code for Advanced Rocketry

Tripoli Safety Code - August 1, 1987

Tripoli Safety Code for Advanced Rocketry• 1. ROCKET MOTORS: 1.1 Tripoli members will use commercially

manufactured motors that have met Tripoli's Motor Listing Committee's requirements for performance and fitness for rocket propulsion, and listed as such on the Recommended Motor List.

• 1.2 An Advanced Rocket Motor will be electrically ignited as the manufacturer suggests using ignition materials supplied or approved by the manufacturer.

• 1.3 Advanced Rocket Motors will not be altered or modified to change their thrust performance, nor will they be reloaded once spent.

• 1.4 Commercially Manufactured custom designed or new experimental motors may be used without being listed on the Recommended Motor List provided the manufacturer supplies proof of satisfactory static tests.

• 2 ADVANCED ROCKET VEHICLES: • 2.1 Advanced Rockets will be built as light as is reasonable for the intended

purpose of the rocket. The use of metal will not be permitted in the nose cone, airframe, motor mount, or fins of an Advanced Rocket.

• 2.2 An Advanced Rocket will have a suitable means for providing stabilizing and restoring forces necessary to maintain a substantially true and predictable upward flight path.

• 2.3 An Advanced Rocket shall be constructed so as to be capable of more than one flight. It will be provided with a means of slow and safe descent. If a rocket is to descend in more than one part, then the parts should conform to this code requirement.

Tripoli Safety Code for Advanced Rocketry

• 2.4 Any equipment, devices, or material which relies upon flammable, smoldering, or otherwise combustible substances, which is not a motor, shall be designed, built, and implemented, or otherwise used in a manner which will minimize the possibility to cause a fire after launch.

• 3. LAUNCH PLATFORMS AND IGNITION SYSTEMS: • 3.1 A launching device, or mechanism, must be used which is sufficiently

rigid and of sufficient length to guarantee that the rocket shall be independently stable when it leaves the device. This launching device shall be sufficiently stable on the ground to prevent significant shifts from the planned launch angle, or the accidental triggering of any first-motion ignition devices.

• 3.2 The launch pad, or device, shall have a blast deflector sufficient to prevent damage, or fire hazard, to surrounding equipment, the launch pad, or the surrounding area.

• 3.3 A launch angle of less than 30 degrees from vertical must be used when flying Advanced Rockets.

• 3.4 Any and all ignition systems on Advanced Rockets must be remotely activated electrically.

Tripoli Safety Code for Advanced Rocketry• 3.5 The launch of any rocket must be completely under the control of the

person launching it. When flying alone, the individual person is responsible for range safety, and launch control safety. When flying at a non-Tripoli sponsored meet it is recommended that a Range Safety Officer (RSO), in control of the launch range be present. The RSO will turn over control of the launch, for the duration of the countdown to the designated Launch Control Officer (LCO) when the launching range is deemed safe to launch. When flying at a Tripoli sponsored meet, a Tripoli approved RSO must be present in addition to the LCO.

• 3.6 Minimum requirements for a Tripoli approved RSO are (a) Confirmed Tripoli membership in good standing, (b) Advanced Rocketry experience similar or equal to that expected at a particular launch, and (c) Satisfactory completion of Tripoli's RSO Training Program, or equivalent.

• 3.7 The launch system firing circuit must return to the off position when released if a mechanical launch system is used or reset if an electronic launch system is used. A permissive circuit controlled by the RSO at all times, and capable of releasing the firing circuit is advisable.

• 3.8 Excessive lengths of fuse, or complex pyrotechnic ignition arrangements should be avoided. The simplest and most direct ignition trains are encouraged to promote range safety.

• 3.9 Igniters should be installed at the last practical moment, and once installed, electrical igniter wires should be shorted and/or pyrotechnical systems mechanically protected to prevent premature ignition from EMI or heat sources.

Tripoli Safety Code for Advanced Rocketry

• 3.10 When flat blast plates are used on a launch pad, a stand- off will be used to keep the nozzles of the motors a minimum distance from the blast plate of one body diameter.

• 4. FLYING FIELDS AND CONDITIONS: • 4.1 All launches of Advanced Rocket vehicles must be conducted in compliance

with Federal, State, and Local law. • 4.2 Rocket flights must be made only when weather conditions permit the average

person to visually observe the entire flight of the rocket from lift-off to the deployment of it's recovery system. No Advanced Rockets will be launched when winds exceed 20 miles per hour.

• 4.3 No Advanced Rocket shall contain an explosive warhead, nor will they be launched at targets on the ground.

• 4.4 An Advanced Rocket flying field must be equipped with an appropriately rated fire extinguishing device. Each launch pad must have a five gallon container filled with water within 10 feet of the pad. A well stocked first aid kit, and a person, or persons, familiar with their use must be present.

• 4.5 Advanced Rockets shall be launched from a clear area, free of any easy to burn materials, and away from buildings, power lines, tall trees, or flying aircraft. The flying field must be of sufficient size to permit recovery of a given rocket within its confines.

Tripoli Safety Code for Advanced Rocketry• 4.6 At no time shall recovery of an Advanced Rocket vehicle from

power lines or other dangerous places be attempted. Any rocket that becomes entangled in a utility line (power, phone, etc.) is a hazard to the utility line and untrained persons who may be attracted to it. The owner of the vehicle will make every effort to contact the proper utility company and have their trained personnel remove it.

• 4.7 No Advanced Rockets shall be hand caught during descent. • 4.8 All persons in the vicinity of any launches must be advised that a

launching is imminent before a rocket may be ignited and launched. A minimum five second countdown must be given immediately prior to ignition and launch of a rocket.

• 4.9 All launch pads will not be located within 1,500 feet of any permanent structures. A spectator line will be established parallel with the launch controller's table. No vehicles will be parked within 50 feet of the spectator line. Launch pads for class B motors will be no less than 150 feet from the spectator line. Launch pads for motors exceeding J class, or clusters of G, H, and/or I's shall be set 200 feet from the spectator line.

• 4.10 No one will be permitted to sit within the area between the parked vehicle line and the spectator line, other than the RSO, LCO, and designated assistant(s) at the launch control table.

Tripoli Safety Code for Advanced Rocketry

• 4.11 No one will be permitted in the launch area between the LCO table and the launch pads except vehicle crew for prepping purposes. Crew photographers or event photographers permitted in the launch area will maintain a distance of 75 feet from the launch pad.

• 4.12 All rockets to be launched must be presented to the RSO for inspection, assignment, and logged into the flight record with the LCO. A copy of the flight records will be sent to Tripoli Headquarters for documentation purposes.

National Fire Safety Protection Association

• Developed and adopted ANSI/NFPA 1122 Code for Model Rocketry setting standards for the safety of the activity of model rocketry. To purchase a copy of NFPA 1122 write or call:

• NFPAOne Batterymarch ParkQuincy, MA 022691-800-344-3555 In addition, many states have adopted their own model rocketry laws and regulations.

Safety & Security• We have provided files for you to read off line

– Model Rocketry Safety Codes• Estes Industries• National Association of Rocketry (NAR)

– Tripoli Safety Code (High Power Rockets)– NAR Range Safety Officer Training– Safety Laws (Federal & State)– Federal Aviation Agency Federal Aviation Regulations, Part 101– National Fire Safety Protection Association– Range Safety Real Estate (Use only this information!)– Security (Homeland Security)– It Should Be Obvious

• Note also that closely related material is found in the Rocket Day Organization file

• Key things to remember – Notify the FAA at least 24 hours in advance of launching– Rehearsal is the key to safe flight operations

Homeland Security Act and Model Rocketry

The Homeland Security Act includes the "Safe Explosives Act" which has placed even more responsibility on the Bureau of Alcohol, Tobacco and Firearms in an effort to keep explosives out of the hands of terrorists. As would be expected there are now more explosives regulations. However, some of the information that has been provided to and reported by the media has several issues confused. Visit http://www.atf.treas.gov/explarson/safexpact/modelrockets.htm to obtain accurate information with regard to the ATF and model rocketry. UPS, FedEx and other carriers continue to carry model rocket engines (model rocket motors that contain no more than 62.5 grams of propellant per device) that are properly packaged, marked, labeled and documented in accordance with the regulations of the U.S. Department of Transportation (49 CFR). The same is true with regard to the United States Postal Service for Toy Propellant Devices (Model Rocket Motors and Igniters that are pre-approved for mailing by the USPS) that contain no more than 30 grams of propellant per device.

It Should Be Obvious, But

• The experience-based rules are

– Everyone should stand at least (15 feet for Motors “D” size, or smaller) or (30 feet for Motors “E” size or larger) away from the launcher before starting the countdown

– Don’t pick up a freshly fired rocket motor…they’re very hot, and they will burn you. Remember they can burn other things also

– Don’t ignite a rocket while holding it in your hand…the fumes are very stinky, and if you drop it, Heaven knows where it’ll go

– If your rocket comes down in power lines, tall buildings, etc. and becomes tangled there, buy a new one

– Never launch your rocket toward a low blue-black cloud…lightning could follow the exhaust plume back down to the launch rail, and hence to the poor dumb sod who just pushed the button

– Never attempt to reload a model rocket motor!

Field Size Needed

Field Size Needed

Motor Type Code

Total Impulse, Newton-sec

Max. Altitude, meters

Min. Field Size, meters

Max. Field Size, meters

¼ A 0 – 0.625 <75 15 <75

½ A 0.625 – 1.25 <120 15 <120

A 1.25 – 2.50 <250 30 <250

B 2.51 – 5.00 <400 60 <400

C 5.01 – 10.00 <600 120 <600

D 10.01 – 20.00 <700 150 <700

E 20.01 – 40.00 <800 300 <800

F 40.01 – 80.00 <1000 300 <1000

• Min Field Size is the Estes recommendation (nominal case)

• Max Field size is the greatest distance the rocket could fly (worst case)

Field Size Depends on Apogee

d

d

• Considerations are safety & ease of recovery

• Field width needed is proportional to apogee altitude

• Higher capture (impact in the green area) probability implies bigger field

• Apogee is predicted for each Estes kit, or can be estimated knowing motor type

Aim Point

Minimum Field Width, d

0

50

100

150

200

250

300

350

0 200 400 600 800 1000

Apogee Altitude, m

Fie

ld W

idth

(d

), m 90% Capture

80% Capture

70% Capture

60% Capture

50% Capture

Model Rocket Competitions

Altitude Competition

• No, this isn’t about seeing whose rocket can go higher

• Bigger rocket motors (brute force) will always dominate this kind of competition

• But, one can define a variation on this: It’s a class competition in which all competitors build from a common kit design, and compete for the highest apogee altitude

• Significant factors will be

• Surface finish (drag)

• Best rocket weight

• Most nearly vertical trajectory

• Coming closest to predicted apogee altitude is a favorite competition

• Metric used is (predicted apogee – measured apogee)

predicted apogee

• Careful testing and adjustment is the most significant factor

• For more ideas, see “Model Rocket Contest Guide” by Robert L. Cannon, Estes Catalog No. 2815

Error =

Team America Rocketry ChallengeThe Team America Rocketry Challenge (TARC) is the world’s largest model rocket contest.  This national model rocket competition is for U.S. middle and high school students.  It is sponsored by the Aerospace Industries Association (AIA) and the National Association of Rocketry (NAR) in partnership with NASA, the Department of Defense, the 39 AIA member companies and the American Association of Physics Teachers.     The 2008 Challenge was to design, build and fly a model rocket carrying two raw eggs and return them safely to the ground while staying aloft for exactly 45 seconds and reaching an altitude of exactly 228 meters. 

National finals were held at Great Meadow, The Plains, VA in May 2008. The winner was a team of 10 students from Enloe High School, Raleigh, NC

If a team's score is one of the 100 best, they were invited to compete for a share of the $60,000 prize package that includes cash, savings bonds, scholarships and other special prizes at the 2008 National Finals.   For more information and an application, visit www.rocketcontest.org.       

To find an NAR club in your area and for information about the NAR, visit www.nar.org.                         

Wind Compensation to Maximize Apogee Altitude

• It’s well known that boosting rockets head into the wind– Were nothing done about this, the results would

be reduced apogee altitude and greater apogee sensitivity to winds

• Targeting rockets to place apogee more closely above their launcher causes the trajectory to behave more like a no-wind, 90otrajectory– Apogee altitude is maximized– Apogee altitude sensitivity to errors in elevation

angle and wind speed are minimized• Accomplished in three steps

– Measure the wind speed and direction…using a hand-held anemometer and a flag

– Compute elevation angle to maximize apogee– Adjust launcher azimuth and elevation angles…

launcher rail should be pointed downwind by an amount found from the next chart

Altitude

Wind

Range

Flight Path

Launcher

Wind compensation provides a competitive edge

Wind Compensation• Use trajectory simulation (Rocksim) to generate the elevation angle that

maximizes the apogee altitude

– Maximum apogee does not occur directly above the launcher

– Modest dependence of the choice of rocket motor

Use this data with measured wind speed to estimate the desired launcher elevation angle

Wind Compensation for Maximum Apogee Altitude for Estes TR-11

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0 5 10 15 20 25

Measured Wind Speed, ft/sec

An

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Lau

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An Introduction to the Mathematics of Rocket Flight

Trajectory Analysis is Complicated

• First, mathematical analysis of rocket flight is complex

– True of model rockets

– Even more true of large rockets used to launch satellites

– Accurate results can only be obtained if computer and a trajectory simulation are used

– RockSim™ by Apogee Components is an example of a popular, commercially available model rocket trajectory simulation

• Reasons include

– Many rocket flights have a complex sequence of many Phases and Events

– Dynamic equations, in general, cannot be solved other than numerically

• Simplified examples, however, promote understanding, and are described in the following slides

– Galilean parabola

– Tsiolkovskii V equation

– Basis of both are the physical laws discovered by Isaac Newton (who, BTW, also invented the artificial earth satellite)

The Galilean Parabola

• By rolling a small sphere down an inclined board covered with flour, Galileo Galilei (1564-1642) discovered that the sphere’s trajectory was always a parabola

• The reason why awaited Isaac Newton’s (1642-1727) discoveries of the laws of gravitation and motion

• For a particle moving in a constant gravitational field subject to no forces other than gravity

Vertical displacement = Ho + Vo sin() t – ½ g t2,

Horizontal displacement = Ro + Vo cos() t,

Vertical velocity = Vo sin() – g t,

Horizontal velocity = Vo cos(),

Apogee time = Vo sin() / g, and

Impact time = Vo sin() / g + √(Vo sin() / g)2 + 2 Ho / g

• Here, Ho and Ro are the initial altitude and range, Vo is the initial velocity magnitude, is the initial angle between the velocity and the horizontal direction, g is the acceleration due to gravity and t is time.

Critique of the Galilean Parabola

• The Galilean parabola was derived by integrating Newton’s First & Second Laws of Motion for constant gravity

• If gravity were not constant, instead of a parabola, the result would be an ellipse if the particle were on orbit, or a hyperbola if the particle were on a trajectory that escaped from the earth. That part of an ellipse near apogee is approximated well by a parabola

• Apogee is defined as that point where the altitude is a maximum (vertical velocity = 0)

• In spite of what you might think watching a model rocket fly, the Galilean parabola is a very poor description of a model rocket trajectory

• The reason is aerodynamic drag has a huge influence on model rocket trajectories. That’s why a computer trajectory simulation is needed for accurate work.

Tsiolkovskii’s Delta V Formula

• Tsiolkovskii’s formula describes the impact of a thrust force – Here, the thrust force is the reaction force acting on a rocket due to the

escape of a pressurized gas in the opposite direction (Newton’s Third Law)

– Tsiolkovkii’s insight was to realize that thrust was inevitably accompanied by a loss of rocket mass

• The relative exit velocity c can take alternative formsc = Isp g,

where g is the acceleration due to gravity, and Isp is the rocket specific impulse

• Tsiolkovskii’s Delta V (V) formula isV = Isp g loge(Mo / Mf) – (g sin() tb),

where Mo and Mf are the initial and final masses of the rocket, tb is the burn time, and V is the velocity increase due to thrust.– The term (Mo / Mf) is called the “mass ratio” and is of great importance

• The term in parentheses only applies to rockets leaving the earth (or any other planetary body). For a burn on orbit, gravity is balanced by centripetal acceleration with the consequence that this term vanishes.

Critique of Tsiolkovskii’s Delta V Formula• First, the function loge(x) is called the natural logarithm of x . It’s related to

common logarithm, log10(x) through the formula2.302585… loge(x) = log10(x)

• Again, Tsiolkovskii’s Delta V formula is not very accurate for model rockets because it does not reflect aerodynamic drag

• Tsiolkovskii’s second great insight was to note that it would be possible to build multi-stage rockets– That is, the total V is the sum of the Vs of the individual stages– The second stage starts out with V1 from stage 1 andf then adds its

own contribution to get V1 + V2 for the stack• The multistage formula can be used to estimate the optimal stage masses

to meet a payload mass & mission V requirements with the smallest (and cheapest) liftoff mass– It’s often much less risky to use several stages of routine design rather

than fewer stages with higher technology– For example, it’s possible to build a single stage booster to launch a

satellite to low earth orbit. But, it’s less risky and expensive to use a two stage design for this mission.

Other Resources

Other Resources

Books1. “50 Model Rocket Projects for the Evil Genius”, by Gavin D.J. Harper. Fun

projects for students.2. “Handbook of Model Rocketry, 7th Ed.”, by G. Harry Stine, Walthers

Publications. For many years, the bible of model rocketry, but now somewhat dated.

3. Rocket Science Books, P.O.Box 1401, So. Lake Tahoe, CA 96158, rocketscience@att.net. Technical books, reports, patents, etc. for the amateur interested in serious technology

Manufacturers4. Estes Industries, Inc.,1295 H Street, P.O. Box227, Penrose, CO 81240-

0227. www.estesrockets,com, The largest manufacturer of model rockets. Also have a significant educational program.

5. Quest Aerospace, Inc., P.O.Box 2409, Pagosa Springs, CO 81147-2409, www.questaerospace.com. Specialized rocket motors, kit and educational literature

6. FlisKits, Inc., 6 Jennifer Drive, Merrimack, NH 03054, www.fliskits.com, jflis@fliskits.com. Hobby rocket manufacturer

Other Resources

7. AeroTech, 2113 W.850N. St., Cedar City, UT 84720 specialized rocket motors & high power rockets

8. LOC/Precision, P.O. Box 470395, Broadview Heights, OH 44147, (330)745-9755. Mainly high power rockets

9. Apogee Components, Inc.,3355 Fillmore Ridge Hts., Colorado Springs, CO 80907-9024, www.apogeerockets.com. Trajectory simulation software, rocket kits, how-to-books. Good stuff for the serious amateur

10. Aerorocket, www.aerorocket.com, Truly nifty advanced software covering many topics from aerodynamics to interstellar trajectories.

Organizations 11. National Association of Rocketry, P.O. Box 407, Marion, IA 52302 (800)

262-4872. The premier amateur rocketry organization. Note that membership dues fund liability insurance

12. Tripoli Rocketry Association, P.O. Box 87, Bellevue, NE 68005-0087. The other major amateur rocketry organization, focused on high power rocketry. They also provide liability insurance to their members

Other Resources

Educational Materials

13. The eMINTS National Center. www.emints.org, Go to Science: Rockets │ eThemes │ eMINTs for lots & lots of good stuff, lesson plans, etc., for the K-12 science teacher

14. Estes Educator, www.esteseducator.com. Select content/curriculums, and find lots of lesson plans & background material. Part of Estes Industries, Inc. See 4. above.

15. Besnard, E., “Rockets 101”, http://www.csulb.edu/~besnarde/Rocket-101/

This is the presentation material used by Prof. Besnard for a “Rocket Day” in Orange County, CA in 2008.

16. http://passporttoknowledge.com/scic/forceandmotion/educators/Educational material