117
edits
Changes
Jump to navigation
Jump to search
Line 1:
Line 1: − {{Problems}}+ − + − A note on painting your rocket: if you do not do it, we will not let you launch.+ − − = Background Information = − − NASA's online [https://spaceflightsystems.grc.nasa.gov/education/rocket/shortr.html Beginner's Guide To Rockets] will get you started on many of the basic principles governing rocketry. If you manage to make your way through all of these, you will understand the vernacular often used in rocketry. − − == Jargon == − − === Impulse and its Specificity === − − Impulse is defined as equal to force multiplied by time - it is a measure of how powerful motors are, and can easily give you your change in velocity (Impulse / Mass, assuming no drag or gravity losses. There will always be drag and gravity losses.) − − It turns out that impulse alone is not a good measure for rocket fuel performance; it is technically possible to use wood and air as rocket fuels, and to get an insanely large impulse by making the engine really big. That will never get you to space. Instead, rockets really care about a number called the specific impulse, defined as impulse divided by the mass of the propellant and the gravitational constant. This gives a far better picture of what constitutes a good rocket fuel, although there are definitely other considerations. − − === Motor Systems (DMS and RMS) === − − DMS stands for Disposable Motor System. These motors are one time use only, and are very easy to work with. − − RMS stands for Reloadable Motor System. These types of motors are harder to work with, since they require the maintenance of a motor casing and proficiency in loading, cleaning, and reloading the casing. After purchasing the relatively expensive casing, one must learn how to assemble it with motor reloads. If not assembled properly, your rocket will most likely not make it through the flight. − − === Motor Retention (Positive or Otherwise) and Adaptors === − − Retaining rings. Lip of motor on airframe or retainer. Positive = not falling out the bottom. − − Adaptors allow use of different diameters in your rocket. − − == Stability == − − === Center of Gravity === − − An objects center of gravity is its (rigorously and mathematically defined) middle point. The force of gravity can be simulated to act here, and the object will tend to rotate about this point, making it crucial to finding rocket stability. − − === Center of Pressure === − The center of pressure is the location at which we can model the aerodynamic effects as acting. In other words, the drag on the rocket acts at this point. If the center of pressure is below the center of gravity, then the downwards force of drag will keep the rocket upright, while a center of pressure above the center of gravity will flip the rocket. A CP and CG at the same point will create a neutrally stable rocket, meaning that any incidental forces could theoretically spin it. This makes the distance between the CP and CG critically important for determining whether flight will be safe and successful. − − The main tool we have to change the center of gravity is the size of the rocket's fins - larger fins will bring the center of pressure lower down on the rocket, increasing its stability. − − To calculate center of pressure, you can use the Barrowman equations ([https://www.apogeerockets.com/downloads/PDFs/barrowman_report.pdf link to the original document]) or the [https://www.apogeerockets.com/education/downloads/Newsletter18.pdf cardboard cutout method]. − − === Calibers === − − Calibers are a way of measuring the distance between CP and CG - it doesn't make sense to solely measure based on distance, as a 3'' difference on a 2'' OD, 24'' long rocket is very different from a 2'' difference on a 10' long, 6'' OD one. − − Instead, calibers measure the length between CP and CG, divided by the outer diameter of the rocket, allowing for a much more fair comparison between different rocket sizes. For context, a CP of 1.5-2 is considered good, while numbers outside of that range tend to be either under-or-over-stable. − − == Motor Specs == − − Solid rocket motors have a fairly standardized labeling system. On the casing (or reload) itself there is a three-part code which denotes what the total impulse range is, the average thrust, and the delay grain length. All these numbers are in standard metric units. − − === Aerotech H550ST-14A === − − Here is the spec sheet for this motor[http://www.aerotech-rocketry.com/uploads/4e952284-bb4b-4943-8904-9a0719e8ee3a_AT%20H550ST%20SU%20jun%2019.pdf]. Interestingly enough, SSI will be using this motor for its L1 certifications. − − Using this motor as an example, we know that this motor is classified in the range of impulse from 160 Ns - 320 Ns. The 550 denotes that the motor's average thrust is 550 N. The ST denotes what type of propellant is in the casing. In this case, ST stands for "Super Thunder". Aerotech has cute names for their different types of propellants. They often only denote the color of the flame. Finally, the 14 denotes that the motor will fire its ejection charge 14 s after burnout unless it is adjusted, as indicated by the A. Motor delay times can be adjusted with a motor delay tool. − − == Simulations == − − It is always important to know what your rocket will do (assuming that things go according to plan), and we use a program called OpenRocket to find the flight profile of our rockets. The program is free, and can be found here[http://openrocket.sourceforge.net/] − − OpenRocket is quite easy to learn, and is quite accurate for sub-Mach rockets (those that fly faster should use RasAero to model drag forces.) OpenRocket includes ascent, including a massive database of thrust curves, as well as a simulated descent using the parachutes included in the rocket. If used properly, it can output data from height of apogee to time of flight to drift distance, all of which are incredibly useful while designing your rocket. (Hint: the center of pressure calculation is extremely important.) − − One other program of note is called FinSim, which can model possible vibrations within fins. If unchecked, these vibrations can grow and shear the fins off, likely dooming the rocket. The program is required for transonic and supersonic flights, and can be found here[http://www.aerorocket.com/finsim.html] − + − + Line 159:
Line 98: − + Line 186:
Line 125: + + Line 208:
Line 149: − + Line 234:
Line 175: + + − + − = Launch Day Procedures =+ − + − + − The RSO is responsible for pre-flight inspection and approval of hobby rocket vehicles within a specified motor impulse range. They give the final word on whether your rocket will launch. Jump to Range Safety Check [[Range Safety Check]] to read about what you need to prepare for inspection or read this document [https://www.nar.org/wp-content/uploads/2014/05/RSO-Operations-Manual-Blue-Mtn-Rktrs.pdf] if you're interested in the nuts and bolts of what an RSO does.+ − − === Launch Control Officer (LCO) === − − The LCO is responsible for control of the range and the actual launching of the rocket vehicles themselves. − − == What You Need To Bring == − − === Rocket Fuel === − − *Epoxy − *Tools to apply epoxy (i.e. popsicle sticks and paper plates) − *Power Drill and Impact Driver − *Correct drill bits and heads − *Dremel − *Igniters − *Bolts (what kind?) − *Screwdrivers − *Adjustable spanner − *Masking and duct tape − *Sandpaper (120 grit) − *Measuring tape − *Calipers − − If doing L2 also bring these things along: − − *Wire strippers − *Small needlenose pliers − *Black powder − *Extra igniters and ematches − *Soldering iron − *Power supply − *Rosin solder − *Altimeters − *Altimeter USB cables − *Batteries − *Multimeter − *Precision Screwdriver − *Laptop − − === People Fuel === − − *Cases of water − *Cooler for drinks − *Snacks (bring your own food) − *Cash for launch fees and purchasing miscellaneous parts − *Nice cameras − *Inverters and power strips for power from car − *Sharpies and pens − *Pre-filled out documentation − *First aid kits − *Tent − *Chairs − *Folding tables − − === Appropriate Clothing === − These requirements obviously change per season, but the running theme is that you will be exposed to the elements all day. − *Sunglasses − *Hats − *Scarves − *Pants − *Walking boots or sneakers − *Rain boots (for walking in muddy farmland) − *Jacket − − == Vendors == − − Bay Area Rocketry is a local supplier of rocket parts and motors, and will often travel to launches, allowing us to pick up our motors at the site. Since SSI does not store motors on campus, this is a very nice perk. − − Apogee Rockets is a website selling everything from guides to motors to fiberglass tubing, and are a very good starting point for any rocket-related parts. − − Giant Leap Rockets has a large selection of components, and tends to stock parts for larger rockets. They also sell the Firestorm 54 kit, which we have used extensively. − − Public Missiles sells very large components - think rockets with diameters >6in. − − == Range Layout == − − Depending on which launch site you go to, this will be different. However, there are some basic themes. − − The main areas of a launching range are the launch pad and control tent, and the parking area. Most high powered rocketry ranges have at least one launch pad that is set up 100ft away from the control tent, a distance specified by the NFPA, section 1127, as the "Minimum Personnel Distance" for any non-complex motor under 1,280 Ns (J motor). However, quite a few ranges also have a second pad, 300ft away, to be able to launch an L motor rocket, or any complex motor combinations up to J motors. − − The control tent is where you check in your rocket with the RSO, and get your pad assignment from the LCO. This is also where you can take your L2 exam, if you have not done so already, and also where you bring your rocket back to get your certification. − − == Packing Your Parachute == − − When packing your parachute it should not fit too tightly within your airframe. You can test this yourself by giving a quick pull on the shock cord attached to the parachute. For the L1s, and most of the L2s, the parachutes are small enough that you should be able to have the entire parachute pop out of the airframe by doing this. If you find yourself having trouble either inserting your parachute into your airframe, removing it, or simply have no idea where to start there are a couple of styles of folding that may help. − − − '''''Half Fold:''''' This style is recommended if you have a relatively skinny airframe and are not concerned about airframe space. − − '''''Triple Fold:''''' This style of folding results in a slightly thicker packed 'chute but it has a shorter length than the half fold. − − Diagrams* − − Here is a video.* − − − Some other techniques you may want to try: − *folding your lines in with your 'chute rather than wrapping them around the 'chute − *taping the folded lines with a bit of masking tape to act as a way of creating a "slider" to help slow the opening of the parachute. This essentially creates a faux dual deploy to help reduce recovery drift. − − − Don't forget to wrap the bottom end of your parachute in a heat resistant cloth like Nomex or Kevlar to prevent the ejection charge from burning holes into your parachute. − − ''coming soon*'' − − == Prepping Your Motor == − − If using a single use motor or Disposable Motor System, make sure to check that the delay on the ejection charge is correct using a simulation software (i.e. OpenRocket). If needed adjust the length of the delay grain. Then place the correct quantity of ejection propellant in the correct location. Cap it. − − Here is a great video to watch. − − == Range Safety Check == − − Before you get cleared for launch, the RSO will inspect your rocket structures, motor certification, and dynamic properties. You should be prepared to answer any and all questions the RSO may have about your rocket. Remember -- the RSO has the final say on whether your rocket gets to launch or not, so it is in your best interest to prepare beforehand all the necessary paperwork, calculations, safety procedures, and proper assembly and convince the RSO you know what you are doing and your launch is unlikely to fail. A full documentation of what the RSO does (or doesn't) do can be found here [https://www.nar.org/wp-content/uploads/2014/05/RSO-Operations-Manual-Blue-Mtn-Rktrs.pdf]. − − === Administrative === − *'''Is the flier over 18 years of age?''' If you are not over 18, you legally cannot launch mid or high power rockets. Sorry. − − *'''Is the flier certified to the power level being flown?''' Not really an issue for L1's since you have no certification (yet) and will not be attempting to use any motors that require a certification, but if you are flying a motor that requires a high power certification later on, you '''must bring your NAR/TRA membership card''' indicating your current membership and certification level. − − *'''Will the flight of the model rocket vehicle “bust” the launch site's FAA waiver?''' This is very important. You must be able to anticipate the altitude your rocket will fly to and be prepared to show simulation data if asked for it. For a single motor, you may be denied a launch if you expect to reach within 15% of the waiver height (15,000' for LUNAR and 16,800' for TCC). This won't be an issue for L1's, but you will certainly be asked what your rocket's expected apogee is, and you better be prepared to answer with an accurate model to back your number. − − *'''Will the rocket penetrate cloud cover? − − === Motors === − − *'''Is the motor certified?''' − − *'''What is the motor type and average thrust? Is the delay time is approximate for rocket?''' − − *'''Is the igniter a low-current igniter?''' − − *'''Does your rocket motor have the ejection charge installed?''' − − *'''Is sufficient wadding/Kevlar installed?''' − − *'''What kind of motor retention system is installed?''' − − *'''What prevents the motor from flying-through the rocket?''' − − === Rocket Construction === − − *'''Is the rocket stable? Is the CG in front of the CP? Be able to identify both.''' − − *'''Is the nose cone fitted correctly?''' − − *'''Launch lugs and/or rail guides properly installed, positioned, and aligned?''' − − *'''Are the fins mounted parallel to the roll axis?''' − − *'''Is an appropriately-sized recovery system installed and attached?''' − − *'''Are there vent holes?''' − − == Launch Pad Procedure == − − The rocket should slide freely on the rail. The pad angle should be within 20 degrees of the vertical axis (normal to the surface of the earth). Flight critical electronics (if there are any) should be armed before putting in igniters. Any radio control equipment should also be nominally operating before arming the igniters. − − === How to install an igniter === − − Place in the nozzle of rocket, and tape the igniter to the rocket so it does not slide out. '''Make sure not to short the leads of the igniters. ''' − − Here is a great video to watch. − = Final Steps =+ + + − == Mailing It In ==+ + + − You must mail in your certification form to have the rocketry association acknowledge your achievement. These are the addresses of NAR and TRA.+ +
→Mailing It In
[[File: CameronRocket.jpg|thumb|right|400px|Cameron Ramos before his L1 certification flight]]
In order to understand high power rocketry enough to launch and successfully recover an L1 rocket, you must read, live, and understand the following information. Level 1 Certification allows flyers to fly High Power Rockets with a total installed impulse up to 640 newton-seconds.
In order to understand high power rocketry enough to launch and successfully recover an L1 rocket, please make sure you have already read [[HPR Background Information]]. Level 1 Certification allows flyers to fly High Power Rockets with a total installed impulse up to 640 newton-seconds.
Once you've read through this page, visit [[Launch Day]] for critical information on what to bring, wear, etc.
= Safety Codes =
= Safety Codes =
== NFPA 1127 and FAA 101 ==
== NFPA 1127 and FAA 101 ==
Note: Might be better to just give summaries of each relevant sections and only post links to full documents. Someone please fix.
'''''Note: Might be better to just give summaries of each relevant section and only post links to full documents. Someone please fix.'''''
The National Fire Protection Association has multiple documents spanning different types of rocketry. Section 1122 governs model rockets and 1127 governs high powered rockets. We are most interested in 1127.
The National Fire Protection Association has multiple documents spanning different types of rocketry. Section 1122 governs model rockets and 1127 governs high powered rockets. We are most interested in 1127.
[http://unh.edu/rocketcats/NFPA-1127.pdf NFPA 1127] states:
[http://unh.edu/rocketcats/NFPA-1127.pdf NFPA 1127] sets the rules and regulations for high power rocketry, including the motor classification system, rules for Range Safety Officers, and guidelines for the safe construction, use, and storage of rocket materials. Critically, it also includes the formal definition of High Power Rocketry, and it is this definition that is referenced in ITAR.
The Federal Aviation Administration Regulations also has a relevant section to the high powered rocketry community. [http://www.ecfr.gov/cgi-bin/text-idx?rgn=div5&node=14:2.0.1.3.15#sp14.2.101.c FAA 101 Subpart C, Amateur Rockets]. Here are the extremely relevant sections.
The Federal Aviation Administration Regulations also has a relevant section to the high powered rocketry community. [http://www.ecfr.gov/cgi-bin/text-idx?rgn=div5&node=14:2.0.1.3.15#sp14.2.101.c FAA 101 Subpart C, Amateur Rockets]. Here are the extremely relevant sections.
*[http://www.tripoli.org/Portals/1/Documents/Safety%20Code/HighPowerSafetyCode%202012%20v1.0.pdf TRA's Code for High Power Rocketry]. This resource is pretty scarce, would not look here for explicit instructions.
*[http://www.tripoli.org/Portals/1/Documents/Safety%20Code/HighPowerSafetyCode%202012%20v1.0.pdf TRA's Code for High Power Rocketry]. This resource is pretty scarce, would not look here for explicit instructions.
For reference, here is a summary of NAR's saftey code. For an non-edited version of NAR's code, check out the links above.
For reference, here is a summary of NAR's safety code. For an non-edited version of NAR's code, check out the links above.
*Certification. I will only fly high power rockets or possess high power rocket motors that are within the scope of my user certification and required licensing.
*Certification. I will only fly high power rockets or possess high power rocket motors that are within the scope of my user certification and required licensing.
= L1 Requirements =
= L1 Requirements =
[[File:Rocket_Launch_Pad_Group.jpg|thumb|600px|right|Four L1 certification rockets on the pad at SSI-R1 at Snow Ranch]]
Sources of information: [http://www.tripoli.org/Level1 TRA L1 certification info] and [http://www.nar.org/high-power-rocketry-info/level-1-hpr-certification/ NAR L1 certification info].
Sources of information: [http://www.tripoli.org/Level1 TRA L1 certification info] and [http://www.nar.org/high-power-rocketry-info/level-1-hpr-certification/ NAR L1 certification info].
=== Pre-flight Inspection ===
=== Pre-flight Inspection ===
The model will be subjected to a safety inspection prior to flight. The safety inspection form is on the back of the NAR High Power Certification Application. During the safety inspection the modeler will be expected to provide oral answers to technical questions related to the safety and construction of his model. The questions may include (but not limited to) identification of the model’s center of gravity and center of pressure, methods used to determine model stability, and interpretation of the rocket motor’s designation. The certification team will initial (or check) the blocks indicating that model safety, motor certification, and the existence of a FAA waiver (if required) in effect were verified prior to flight.
The model will be subjected to a safety inspection prior to flight. The safety inspection form is on the back of the NAR High Power Certification Application. During the safety inspection the modeler will be expected to provide oral answers to technical questions related to the safety and construction of their model. The questions may include (but not limited to) identification of the model’s center of gravity and center of pressure, methods used to determine model stability, and interpretation of the rocket motor’s designation. The certification team will initial (or check) the blocks indicating that model safety, motor certification, and the existence of a FAA waiver (if required) in effect were verified prior to flight.
=== Certification Flight ===
=== Certification Flight ===
Tripoli hosts launches on the third Saturday of each month. Details, calendar, updates, and directions, as well as other pertinent information, can be found on their website here[http://www.tccrockets.com].
Tripoli hosts launches on the third Saturday of each month. Details, calendar, updates, and directions, as well as other pertinent information, can be found on their website here[http://www.tccrockets.com].
Be aware that Tripoli has slightly different policies and forms from NAR, as well as requiring a separate Tripoli membership in order to launch. However, certification levels from either are accepted at the other, i.e. if you are certified L1 through Tripoli, you can get your L2 certification at NAR, as long as you are a registered member of both.
Be aware that Tripoli has slightly different policies and forms from NAR, as well as requiring a separate Tripoli membership in order to launch. However, certification levels from either are accepted at the other, i.e. if you are certified L1 through Tripoli, you can get your L2 certification at NAR, as long as you are a registered member of both.
[[File:Del_Norte_Launch_Site.jpg|thumb|frame|center|1000px|Del Norte launch site (TCC)]]
=== Livermore Unit of the National Association of Rocketry ===
=== Livermore Unit of the National Association of Rocketry ===
LUNAR hosts launches on the first Saturday of each month - details can be found here[http://www.lunar.org/]
LUNAR hosts launches on the first Saturday of each month - details can be found [http://www.lunar.org/ here].
[[File:Snow_Ranch_Launch_Site.jpg|thumb|frame|center|1000px|Snow Ranch launch site (LUNAR)]]
== Who You Will Meet ==
= Final Steps =
=== Range Safety Officer (RSO) ===
=== Mailing It In ===
You must mail in your certification form to have the rocketry association acknowledge your achievement. These are the addresses of NAR and TRA.
National Association of Rocketry HQ <br/>
P.O. Box 407 <br/>
Marion, IA 52302<br/><br/>
Tripoli Rocketry Association, Inc.<br/>
P.O. Box 87<br/>
Bellevue, NE 6800<br/>
=== Clean Up ===
Make sure to wash off all the metal components of your rocket so they do not corrode from left over motor fuel.
[[Category: Rockets]]
[[Category: Rockets]]