MODEL ROCKETRY - THE LAST FRONTIER

[Music] so oh [Applause] just like the real thing model rockets can provide the excitement and demonstrate the knowledge learned in the field of rocketry dynamics miniature transmitters and cameras can be carried along for you to test and to take pictures of your flights if you've never built or launched your own rocket a whole new world of excitement awaits you everything from single-stage beginner rockets to the more sophisticated star trek command ship [Applause] enterprise when brown goddard used model rockets to teach themselves the technique of rocketry now that hobby has developed into a countrywide weekend pastime rocket kits are available as our individual rocket packages manufacturers have taken great steps in providing scaled down materials with strong guidelines and plans for rocket construction it is important that you follow these plans as we shall see later aerodynamics rocketry dynamics are exacting even with model rockets nasa has guidance systems that are electronic yours will be static in other words what you glue down has to be exact or your flight path will be less than accurate this rule follows for every model of rocket from beginner to expert follow the directions exactly cut all the parts to the right size sand and shape properly and don't be stingy with sealer and use plenty of glue [Music] just as with professional and private pilots your rocket firing has a procedural checklist that is prepare for your launch after your rocket is built step by step missing any one step could cause a mistake further down the line actually compound it can be awfully embarrassing for instance to launch your new rocket only to discover a few seconds into flight that you forgot to pack your parachute recovery system a checklist is necessary because of other variables for instance weather plays a major role in the angle of launch [Applause] pilots use wind socks and so can you if you wish to construct one at your launch site or use a streamer or pennant or the old standby a little grass into the air the simple truth is however that with the rocket engine the rocket will in fact go somewhere but where well if the rocket is not stable if its center of gravity has been shifted in construction or through some other force then the rocket may fly erratic enough and end up nowhere [Applause] every airplane pilot is aware of center of gravity and its meaning to the pilot of an aircraft the center of gravity is that point at his airplane where earth's gravity is pulling against his aerodynamic lift the most if the weight of their load shifts then the center of gravity shifts and they must adjust for this airplanes have horizontal elevators to assist with this as well as variable power control model rockets have neither and a model rocket will tend to spin at the center of gravity when unstable the balance point therefore is the center of the rocker however with added weight that of the engine the center of gravity of the rocket shifts that's one reason the nose cones for your rockets must also be mounted as straight as possible there are forces working both for and against both airplanes and rockets thrust drag lift and gravity as long as the forces on the fins of the rocket are great enough to counteract the forces on the nose and any off-center thrust a rocket will fly straight fins therefore must be straight in line with the rocket body your construction plans provide special marking guides the rest is up to you with proper fins your rocket will fly straight and true with fins that are not the right size your rocket will tend to seek its new center of gravity and end up flying nowhere one other force that can affect your rocket center of gravity and flight path is a side force or weight not accounted for in the design of the rocket this rocket however is designed for a piggyback bladder and flies straight and through with a glider mounted a rocket returns by parachute the glider is launched at the apex and returns on its own the easiest way of testing the stability of a model rocket is to fly it without launching it make the test on your model by forming a loop at the end of a six to ten foot string install an engine in the rocket slide the loop to the proper position around the rocket so the model balances horizontally swing it overhead in a circular path if the rocket is stable it will point forward into the wind created by its own motion move the string back a little and let the nose fall about 10 degrees if it will still fly straight it is stable enough for a launch now that we understand our center of gravity and its importance we come to another important area recovery systems most model rockets just as the space capsules that carried our astronauts safely to their landings use parachutes which are packed into the body of the rocket other recovery systems include streamers and tumble recovery a motion that produces extremely high drag on the rocket so that it falls slowly and helicopter recovery thin veins creating a high drag which keeps the rocket from falling fast and glide recovery such as the scissor wing our checklist points out one other important step fire proof wadding between the engine and the parachute fireproof wadding is mandatory [Music] let me show you why we built a plastic tube and installed a parachute engine and fireproof wadding don't use ordinary tissue paper towels or other non-fireproof wadding in the air as high as 1500 feet this wadding if not fireproof could float depending upon the wind to a rooftop [Music] our plastic rocket allows us to see exactly how the parachute carefully wrapped is pushed into the body of the rocket above the wadding followed by the nosecone now we've reached another similarity between nasa and model rocket firing our engines are ignited electronically we have control and a countdown but our checklist demands we carefully insert the igniter in the engine carefully inserted 9 out of 10 failures are because the igniter was not inserted properly and that means fully into the engine make sure the igniter portion is touching the fuel in the engine tape it down tap it with your finger or a pencil to secure the tape and it should hold and fire clean the igniter clips and install arm the launch system and proceed with the countdown three two one lift off the fuel in your rocket burns from the rear down the center of the fuel chamber forward this time-tested design is what prevents the engines from exploding after burning there is generally a delay which allows for the rock to slow down for parachute ejection the checklist is complete the rockets are built it's time to fire to launch our rockets and test our theories it's best to find an open area for your launches for more reasons than one first recovery is generally easier and landings are safer secondly it's easier to observe wind conditions and check for other obstructions even the possibility of low-flying aircraft [Music] make sure spectators are at least 20 feet away attach your clips insert your launch pins and start your countdown four three two one zero we have commit we have we have lived off at 7 15. [Music] [Applause] [Music] there are some interesting model rockets in the array of equipment available today the cinerock camera super 8 camera takes excellent shots of your launch area and your rockets parachute ejection and to me one of the finest rockets on the scene today the scissor wing glider this fascinating model is spectacular in flight and as enjoyable to watch as they are to build the boost glider also offers the interested budding aerodynamic engineer an area of research that is current for instance this very principle is working today in the space shuttle program watch the rocket climbs [Applause] [Music] the engine pops its wadding and the wing of the glider spreads the engine mount parachutes to earth and the glider flies for more than a minute generally back to earth for a gentle landing here we see it again [Music] want to know how high your rocket flies well tracking is easy and you can build this altitude tracker in less than an hour follow the path of the rocket as it reaches its apex close down on the plastic tube holding the thick kerosene liquid rotate the preset table of tangents and read off the rocket's altitude it's a protractor scale in action oh i mentioned my favorite rocket a moment ago this is my turn now we're going ahead warp factor one [Music] so [Music] [Applause] [Music] bye [Music] so you