Rockets Powerpoint

Last week we conducted presentations about rockets, here's a summary of it
(Diogo Falcao, Daniel)

Safety Thurst Pulse Newton Burn Time Weight DATA Reliability Classes


NAR safety code

Materials-I will use only lightweight, non-metal parts for the nose, body, and fins of my rocket.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Recovery Safety-I will not attempt to recover my rocket from power lines, tall trees, or other dangerous places.


  • Thrust, just like in airplanes, is produced according with Newton’s third law.
  • Mass is pushed out the back of the rocket which propells it through the air.


  • In terms of motors it is called a multiple pulse solid rocket motor
  • This type of design overcomes some of the limitations of standard rocket motor as it allows us to program it to burn in segments(or pulses).
  • Each segment can be individually egnited by the onboard program or a pre-planed phase.
  • Each pulse can have different thrust level or burn time or both.


  • Abbriviated as N
  • Is a unit of measure of the metric system
  • it is the force that produces an acceleration of 1 meter per second per second when exerted on a mass of 1 kilogram

Burn Time:

  • the total operating time of a rocket engine
  • for solid rocket motors it is the time that it takes to burn all of its fuel
  • for a liquid motor it is the rated thrust duration of the motor for a single operation

Weight DATA:


Reliability of rocket engines

  • Rocket engines can be a pain as when they are ignited they will burn until empty, in other words the throttle cannot be controlled.
  • However if you use a pulse rocket, you can program it to do a certain job or follow a calculated path.
  • If you use a liquid fuel then you can control the output.
  • A rocket’s reliability is determine by its purpose and the kind of rocket/fuel used

Engine class suggested uses

Class Total Impulse(Newton-sec)
1/4A 0.000 - 0.625
1/2A 0.626 - 1.25
A 1.260 - 2.50
B 2.510 - 5.00
C 5.010 - 10.0
D 10.01 - 20.0
E 20.01 - 40.0
F 40.01 - 80.0
G 80.01 - 160.0
H 160.01 - 320.0
  • Everything bellow G is considered ok for model rocketing
  • However some classes involve age requirements and some require licenses/certifications
  • Also certain classes, since they can climb to high altitudes, need FAA approval in order to launch them.

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