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USMRSC Rule 35: Dual Egg Lofting Duration Competition (DED)


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This primer presents, in one place, all the information you need to succeed in this event.

TCC has provided a link to the official rules whenever we discuss a rule.


All Entries

Your entry must:

* Comply with the NAR Model Rocket Safety Code: USMRSC 2.2

* Be a model rocket as described by the United States Model Rocket Sporting Code. USMRSC 3.1-3.9

* Use NAR Contest Approved motors: 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:

* Full USMRSC:


General Competition Tips:

TCC NAR Competition 101

TCC NAR Competition Strategy and Tactics

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?

* The main rules are 9, 15, and 34.


What is the Goal?

The goal of this competition is to achieve the longest flight duration, while carrying two Grade A Large hen’s eggs, and return the eggs unbroken. USMRSC 35.1


Are There Any Special Considerations?

* The model may not separate into two or more parts or eject the motor(s). USMRSC 15.2

* Recovery wadding does not count as a part of the model. USMRSC 1.1

* 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 35.3

* The Contest Officials will provide the eggs. USMRSC 35.2

* Each egg will weigh between 57 and 63 grams and not be more than 45 millimeters in diameter. USMRSC 35.1

* Nothing (tape, glue, etc) can be affixed to the egg. USMRSC 35.1

* Your entry must be single stage, but can be clustered. USMRSC 35.1

* If your entry is clustered, the sum of the total impulse of the motors you use cannot be more than the total impulse limit for the event class you are flying. USMRSC 4.6, 4.8, 35.4

* If your entry is clustered, enough motors must ignite to meet the impulse limits for the event class you are flying. USMRSC 4.6, 4.8, 35.4

* Rule 10.4 does not apply.


Do I Have to Return the Model to Place?

* You must return your entry to receive any points in Egg Lofting Duration. USMRSC 35.3

* Rule 10.4 does not apply.


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 best single duration achieved by your entry on up to two official flights. USMRSC 10.1


What Will Disqualify My Entry?

Your entry will be disqualified if:

* Either egg is broken upon return. USMRSC 35.3

* You cannot return the model. USMRSC 35.3

* You remove either of the eggs without a contest official present. USMRSC 35.3

* It separates into two or more parts or ejects the motor(s). USMRSC 15.2

* If your entry is caught or cushioned through human intervention. USMRSC 16.7

* If it is unsafe in operation. USMRSC 11.1, 11.2


How About Some Suggestions for New Competitors?

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.


Dual Egg Lofting Duration (DED) requires you to carry two eggs in your entry. Generally, you’ll want to fly your eggs in tandem, one on top of the other. You will not find a Dual Egg Lofter on your local hobby store shelves. You can order Dual Egg Lofters from ASP and QCR. You can get Dual Egg capsules from Pratt Hobbies.


In C DED, your entry should weigh less than 2 ounces empty. The Quest Courier and Estes Eggscaliber are too heavy for C DED.


You may find these egg lofters at your local hobby store. They can be modified for C and D Dual Egg Lofting Duration by adding an extension between the upper and lower halves of the egg capsule:

            For C DED - Custom Elite

            For D DED (with 24mm motor mount) - Quest Courier

            For D and E DED – Estes Eggscaliber

These kits were designed to be flown with black powder motors. You can fly them as Dual Egg Lofters using APCP motors if you build them to take the stronger thrust.


You can make the extension from commercial model rocket tubing or an old paper towel roll. If the tubing you select is smaller in diameter than the halves of the egg capsule, you can expand it. Slit its side along its vertical axis, spread it open to the right diameter and insert strip to fill the gap. If you need to make it smaller, simply slit the tube and overlap the sides of the split. In either case, you will have to provide a solid bulkhead between the upper and lower eggs to prevent the upper egg from breaking the lower egg during boost.


Some of the vendors on the TCC Competition Vendor list offer egg capsules and/or advanced egg lofting kits.


Your recovery system must deploy if you are to get the best possible duration. The Custom Elite is at a disadvantage because its 3/4in diameter will not hold a large parachute. The Elite can be competitive in C Dual Egg Lofting Duration can go higher than other egg lofters because of its light weight. The Quest Courier is better for D Dual Egg Lofting. Use the largest parachute that you can pack into your rocket and still have reliable deployment. Lightly dust the parachute on both sides with talcum powder before you fold and pack it (


Your parachute must be stronger than normal or than for ELD. See the two parachute links below.


What Next and What Else?

Good info on building/selecting and packing competition parachutes:


Piston Launching for Egg Lofters – the Hot Ticket!


Online Egg Lofter Plans

NAR Competition Plans

Tim Van Milligan, Apogee Components


TCC NAR Competition Bibliography


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


Complex Tower:


Piston Launchers Explained – Apogee Components:


Floating Head Piston Launcher – The Odd Couple Team T-085, Jeff Vincent NAR 27910 and Chuck Weiss NAR 35775:


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 32 -

* Free sink rate simulation:


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:


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