USMRSC Rule 26: Egg Lofting Altitude Competition (ELA)
This primer presents, in one place, all the information you need to succeed in NAR model rocket competition in this event.
TCC has provided a link to the official rules whenever we discuss a rule.
Your entry must:
* Be a model rocket as described by the United States Model Rocket Sporting Code. USMRSC 3.1-3.9
* Use NAR Contest Approved motors: http://www.nar.org/SandT/pdf/CombinedMotorsByImpulse.pdf USMRSC 4.1, 4.4
* NOT eject its motor casing(s) without a recovery system. USMRSC 9.2
* Have your NAR number or your name on the outside, large and clear enough that the contest officials can easily read it. Teams must use the Team number or name. USMRSC 9.4
* Have been constructed by yourself or by one or more members of your Team. You may not enter Ready-To-Fly rockets (no construction required) in NAR sanctioned competition. USMRSC 9.9
Know the rules
Your having a grasp of the bigger picture can increase your enjoyment of NAR competition. You can read the Pink Book Lite to see only the rules for competitors, not for Contest Directors or other contest officials. Read the full USMRSC (Pink Book) to see all the rules.
* Pink Book Lite: http://ojames3.tripod.com/tccnarcontesttips/USMRSCLight.html
* Full USMRSC: http://www.nar.org/pinkbook/
General Competition Tips:
Contest Etiquette by Kevin Paul Wickart, NAR 59720, cr 1998, the author
Beginning Competition -- The RSVP Principle by Kevin Paul Wickart, NAR 59720, cr 1998, the author
Guide to NAR Contest Rocketry Information for Beginners by Jeff Vincent, NAR 27910, Northeast Regional Contest Chair
Which are the Main USMRSC Rules for This Event?
What is the Goal?
The goal of this competition is to achieve the highest flight while carrying a Grade A Large hen’s egg and return the egg unbroken.
Are There Any Special Considerations?
* ELA is divided into classes based on the total impulse of the motor(s) you must use. USMRSC 26.4
* No one may catch the model as it descends. It must be allowed to strike the ground. USMRSC 16.7
* After the flight, you must present the model, unopened, to the contest officials and only remove the egg in the presence of the contest officials. USMRSC 26.3
* The Contest Director will provide the egg. USMRSC 26.2
* The egg will weigh between 57 and 63 grams and not be more than 45 millimeters in diameter. USMRSC 26.1
* Nothing (tape, glue, etc) can be affixed to the egg. USMRSC 26.1
* Your entry can be staged and/or clustered as USMRSC 26 does not specify “single stage”.
* Rule 10.4 does not apply.
Do I Have to Return the Model to Place?
How Many Flights Can I Make?
* You can make up to two flights. USMRSC 10.1
* You can use more than one model. USMRSC 9.7
How is the Competition Scored?
Your official score is the highest single altitude achieved by your entry on up to two official flights. USMRSC 26.1
What Will Disqualify My Entry?
Your entry will be disqualified if:
* The egg is broken or you break the egg while removing it from your entry USMRSC 26.3
* You cannot return the model. USMRSC 26.5
* You open the model without a contest official present. USMRSC 26.3
* If it is unsafe in operation USMRSC 11.1, 11.2
How About Some Suggestions for New Competitors?
Egg Lofting Altitude Competition is different from Altitude Competition in that you have to have a model designed to safely hold an egg. You may find on your local hobby store shelves:
Estes Eggscaliber http://www.estesrockets.com/rockets.php?pid=002123
Some of the vendors on the TCC Competition Vendor list offer egg capsules and/or advanced egg lofting kits.
Hen’s eggs are more durable than most folks think they are as long as they are vertical. You don’t need thick padding. I use the foam filter for a room air conditioner. I use two or three layers on the top and bottom and one layer around the egg if it fits in the capsule. The trick is to keep the egg from hitting on the side. After all, that’s how you break one for breakfast, isn’t it? Any of the capsules from the kits and/or vendors above, with a little padding, will adequately protect your egg.
* Optically tracked: The trackers/officials MUST be able to see your entry to track its altitude. This is easier for the lower powered events. For higher powered events or if trackers are having difficulty spotting the rockets, you should consider using “tracking powder”. Tracking powder is colored powdered chalk or dry Tempra paint that you pack in your rocket so that it is ejected with the recovery system. You can buy chalk for a carpenter’s chalk line at almost any hardware store. Chose a color that contrasts with the cloud/sky conditions you expect to encounter. Red works well in most conditions. Don’t use blue unless white clouds cover the sky. When you pack your recovery system, leave some space at the top for the powder. Tracking powder is messy. You can simply pour the powder in or wrap the powder in a small piece of recovery wadding to minimize the mess. Powder adds weight. Experiment before the contest to determine the minimum amount you can use and still get a noticeable cloud of powder at ejection. For example, for B ALT (about 1000 feet), using a ¾ inch body tube, use enough powder to fill the tube for ¾ inch (one caliber). This will be about 0.1 ounce of carpenter’s chalk.
More on using tracking powder: http://www.apogeerockets.com/education/downloads/newsletter76.pdf
* Electronic Altimeter: Follow the manufacturer’s instructions and USMRSC 14.10. Things you should remember when using altimeters in NAR completion. Check with your HPR buddies or others who use electronic altimeters for suggestions.
* Use a streamer for recovery. It’s easier to pack and will make your entry easier to recover.
* Use a piston launcher, tower launcher or pop-lug to reduce drag by eliminating the launch lug.
Piston Launcher: Qualified Competition Rockets: http://www.cybertravelog.com/qcr/pistons.html
Simple Tower: by Bob Supak, NAR 65523
- Take 3 1/4" aluminum rods, each about 24" long.
- Depending on what size model you want to launch, take an 18" piece of same body tube and put a few wraps of tape at each end.
- Place the 3 rods in a triangle around the body tube and secure with rubber bands, leaving 6" of the ends of the rods exposed.
- Now place the rods into a coffee can full of wet cement or plaster and let set. Voila - launch tower!
Pop-lug: Competition Model Rockets, Howard Kuhn http://www.oldrocketplans.com/pubs/CMR/pop_lug.pdf
* Motor Selection:
Select a motor that fits the event class. A impulse for A ALT, B motor for B ALT, etc. Generally, a lower average thrust (the number after the motor letter) will achieve a higher altitude and be easier to track. Use the minimum body tube diameter for the motor you want to use. Use a computer simulation (wRASP http://www.wrasp.com/ or wRASP32 http://tccnar.tripod.com/sims/082_wRASP32_221.zip) to help you select the best motor.
* Delay Selection:
Check with the contest officials to see if trackers will follow your entry to apogee or to ejection. If they are tracking to apogee, select a delay time such that ejection occurs after apogee. If they are tracking to ejection, select a delay time such that ejection occurs as close to apogee as possible; before or after apogee. Use a computer simulation (wRASP http://www.wrasp.com/ or wRASP32 http://tccnar.tripod.com/sims/082_wRASP32_221.zip) to help you select the best delay time.
Many vendors have competition models and/or competition supplies:
What Else & What Next?
Good info on building/selecting and packing competition parachutes:
Piston Launching for Egg Lofters – the Hot Ticket!
NAR Competition Plans http://www.nar.org/competition/plans/eggloft.html
Tim Van Milligan, Apogee Components http://www.apogeerockets.com/education/downloads/Newsletter247.pdf
TCC NAR Competition Bibliography
Yahoo group for discussing model rocket competition:
Use computer simulations to determine altitude and sink rate for various rocket/motor/parachute combinations.
* Free altitude simulations:
wRASP - http://www.wrasp.com/
* Free sink rate simulation:
George Gassaway’s General Competition Tips (note: Some links on George’s page are inactive):
George Gassaway’s Competition Tips – Take No Prisoners!
US Spacemodeling (International Competition Tips):
US Spacemodeling Home Page (International Competition):
rmr Frequently Asked Questions – Part 9: Competition and Records: