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TCC NAR Competition Primer:  USMRSC Rule 21, Super-Roc Altitude Competition (SRA)

 

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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.

 

All Entries

Your entry must:

* Comply with the NAR Model Rocket Safety Code: http://www.nar.org/NARmrsc.html 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:  http://www.nar.org/SandT/NARenglist.shtml 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:

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, 14 and 21.

http://www.nar.org/pinkbook/9_Entries.html

http://www.nar.org/pinkbook/14_Altitude_Data.html

http://www.nar.org/pinkbook/21_SRA.html

 

What is the Goal?

* The goal of Super-Roc Altitude Competition (SRA) is to attain the highest flight with a single stage model rocket the length of which is equal to or greater than the minimum length for the event class you enter. USMRSC 21.1

 

Are There Any Special Considerations?

* SRA is divided into event classes based on the total impulse for the class, with each event class having a minimum and maximum length. Contest officials will not award points for excess length. USMSRC 21.5

Motor

Min (cm)

Max (cm)

Min (inches)

Max (inches)

1/8A

12.5

25

4.9

9.8

1/4A

25

50

9.8

19.6

1/2A

50

100

19.6

39.4

A

75

150

29.5

59.0

B

100

200

39.4

78.7

C

125

250

49.2

98.4

D

150

300

59.0

118.1

E

175

350

68.9

137.8

F

200

400

78.7

157.5

G

225

450

88.6

177.2

* Also, Contest Officials will not allow your entry if the body or significant structural parts are made from hard or potentially unsafe material (e.g., hardwood doweling or fiberglass shaft), under the provisions of Rule 1.1. USMRSC 21.4

* Your entry must be single stage, but can be clustered. USMRSC 21.1

* 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, 21.5

* 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, 21.5

* This event can be flown as Multi-Round.

 

Do I Have to Return My Entry?

* No, not for Altitude Competition. However, the Contest Director can require that you return your entry. USMRSC 9.10

 

How Many Flights Can I Make?

* You can make up to two official flights. USMRSC 10.1

* A disqualified flight is an official flight. USMRSC 14.9

* Your flights must be made during the period allocated for tracked flights. USMRSC 14.9

* A flight for which the altitude cannot be determined is NOT an official flight. If your flight is not disqualified for another reason, you can continue to attempt to make an official flight. USMRSC 14.9

 

How is the Competition Scored?

* Short Answer:  Entry’s length in centimeters (from nose tip to motor nozzle) times flight altitude in meters. USMRSC 10.1, 33.4

 

* Long Answer: SRA scoring has two point types: static points and flight points. Contest officials will multiply the static and flight points for each official flight to determine your entry’s score. USMRSC 21.5

Static Points: Contest officials will measure your entry from the tip of the nose cone to the nozzle of the motor and award 1 point per centimeter up to the maximum length for the event class. USMRSC 21.5

Flight Points: Contest officials will award 1 point for each second of altitude. USMRSC 21.5

Example: If the event class is A SRA, the maximum length is 150cm. If your entry is 155cm from nose cone tip to motor nozzle, contest officials will award 150 static points. If your entry then achieves a flight of 366 seconds, contest officials will award 366 flight points. Your entry’s final score is then the static points multiplied by the flight points:  150 x 366 = 54900 points.

 

* If the contest officials cannot determine the altitude of your flights, you cannot place in the event (be awarded 1st, 2nd, 3rd or 4th place). However, you will receive flight points if your entry is not disqualified. USMRSC 13.1, 14.9

 

What Will Disqualify My Entry?

* Your entry will be disqualified if it ejects the motor(s) without an attaché parachute or streamer. (USMRSC 9.2)

* Your entry may be disqualified if, in the opinion of the contest officials, it does not comply with the competition rules or is unsafe in operation. (USMRSC 11.1, 11.2)

* Your entry will be disqualified if it comes apart, bends so as to crimp the body, or has a similar structural failure prior to ejection. (USMRSC 21.2)

 

How About Some Suggestions for New Competitors?

General:

DO NOT use any hard materials such as dowels, rods or fiberglass reinforcing. Use the same cardboard, paper, balsa, light wood and plastic that you would for any other model rocket.

 

One of the main points to remember is that you do NOT have to build an entry that is the maximum length for the event class. If your maximum length SRA entry crimps or comes apart, you get ZERO points. For event classes D SRA and above, you should consider building an entry that is less than the maximum length and larger than the motor(s) you use. When you join tubes together, use a coupler that is at least two body diameters long. Further, you don’t have to use the full impulse allowed by the SRA class you are flying. For example, this is a G SRA/SRD model that uses three Estes E9 motors, is 1.64 inches in diameter and 7.5 feet long:

http://ojames3.tripod.com/bpcmr/index.album/g-srd-model-three-estes-e9-motors?i=4&s=1

 

Test your model to ensure that it operates safely and as intended. Remember, you don’t have to use more than the minimum impulse allowed. For example:

http://ojames3.tripod.com/bpcmr/index.album/g-srd-model-thunderbird-g-a-black-powder-g-three-estes-e9-motors?i=6&s=1

 

Kit Selection:

You won’t find many kits suitable for SRA in your local hobby store. Determine the minimum length for the event class and pick the lightest kit that is over the length for the event class. For example:

You can “kit-bash” (use the parts from one or more kits) two Estes Skywriters into one A SRA.

You can “kit-bash” two Estes Blue Ninjas into one C SRA.

The Estes Mean Machine is suitable for D and E SRA.

 

Commercial kits are available for 1/8A, A-G SRA. For 1/4A and 1/2A SRA, you can “kit-bash” an entry by using parts from more than one kit or adding parts you already have to a kit. Qualified Competition Rockets has kits for 1/8A, A, B, C, and D SRA.  QCR’s D SRA is also long enough for E, F and G SRA. You can add an extension to the QCR or ASP 13mm altitude or parachute duration model to make a rocket long enough for 1/4A, 1/2A and A SRA. ASP sells 13mm tubing and bulkheads. Just glue the bulkhead half way into a 30 inch extension tube, insert the existing nose cone into the other end and use the assembly as the nose cone for your 13mm model.

 

Body Size:

For 1/8A to D SRA, use the minimum body tube diameter for the motor you want to use. For D to G SRA, using a body diameter that is larger than the motor will give your model more structural strength.

 

* Weight is your enemy. The more paint your use, the more your rocket will weigh. You can use permanent markers to add color without adding a lot of weight.

 

* Weigh your model using a scale that is accurate to at least 0.1 ounce or 0.5 gram. If don’t weigh your model, fly it on different motors (before the contest) to see which goes higher. See Motor Selection and Delay Selection below.

 

Tracking:  Check with the contest officials to see if trackers will follow your entry to apogee of 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. USMRSC 14.3

 

* 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.

http://ojames3.tripod.com/tccnarcontesttips/tcctrackingpowder.html

More info on using tracking powder:  http://www.apogeerockets.com/education/downloads/newsletter76.pdf

 

* Electronic Altimeter:  Follow the manufacturer’s instructions and USMRSC 14.10. Check with your HPR buddies or others who use electronic altimeters for suggestions.

 

Motor Selection and Delay:

You don’t have to use the maximum impulse of the SRA event class. You will receive ZERO points if your SRA model crimps or comes apart. For SRA E to G, consider using a less-than-maximum impulse composite motor, a single black powder motor or a cluster of black powder motors. Select a delay time such that ejection occurs as high as possible. Use a computer simulation (wRASP32  wRASP http://www.wrasp.com/ or wRASP32  http://tccnar.tripod.com/sims/082_wRASP32_221.zip) to help you select the best delay time.

 

Vendors

Many vendors have competition models and/or competition supplies:

http://ojames3.tripod.com/tccnarcontesttips/competitionrocketvendors.html

 

What Else & What Next?

Super-Roc Theory and SR Plan:

http://www.rocketrycarolina.org/index.cgi?ltros=730

 

TCC NAR Competition Bibliography

http://ojames3.tripod.com/tccnarcontesttips/TCCNARCompArticleBib.html

 

Yahoo group for discussing model rocket competition:

http://groups.yahoo.com/group/contestRoc/messages

 

Use computer simulations to determine altitude and sink rate for various rocket/motor/parachute combinations.

Free altitude simulation:  wRASP http://www.wrasp.com/ or wRASP32  http://tccnar.tripod.com/sims/082_wRASP32_221.zip

Free sink rate simulation (and others): http://www.mrhq.org/software/clcltrs/clcltrs.shtml

 

US Spacemodeling (International Competition Tips):

http://www.spacemodeling.org/new/how_to/construction.html

 

US Spacemodeling Home Page (International Competition):

http://www.spacemodeling.org/new/home.html

 

Aerospace Specialty Products Streamer and Parachute Tips:

http://www.asp-rocketry.com/model-rocket-tips.cfm

 

George Gassaway’s Competition Tips – Take No Prisoners!

http://tccnar.tripod.com/tcctnp/

 

Detecting Thermals:

http://www.apogeerockets.com/education/detecting_thermals.asp

 

rmr Frequently Asked Questions – Part 9: Competition and Records:

http://www.ninfinger.org/rockets/rmrfaq.9.html

 

 

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