July – September 2004
Editor’s Message …
Author: Ian MacDonald
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This is a short newsletter to follow up the special edition on NARAM 46. We held our annual C.R.A.S.H. picnic on Saturday September the 11th and it was a wonderful success. The highlight of the picnic was Bruce Markielewski guiding a workshop on building flexi-wing gliders. This was a timely workshop in light of the 14th Annual Colorado Model Rocketry Championships Regional Contest which C.R.A.S.H. is hosting October 16 and 17th. See the Announcements link of our website for more information. Russ has contributed a great article as a guide to new competitors. Also note you can download a plan for building a flexi-wing like the one we built at the picnic.
As always, C.R.A.S.H. members and other interested parties are welcome to submit articles for our newsletter. Perhaps you have an exciting project you would like to share with others. Maybe you went to a rocketry related event or attraction we might find interesting.
You may contact me at
[removed email]
Please note this email address will change soon, I will update it when it does.
Colorado Model Rocketry Championships XIV…
October 16th and 17th, 2004 (10:00 AM – 5:30 PM both days)
A Guide for New Competitors
Author: Russ Anthony
Welcome to competition flying! If any of you read my last guide, written for the CARCIS XII contest last spring, you will recognize many sections. Feel free to skip to the individual events, since most other sections are repeated. This guide will help you in understanding how contests are run and specific tips for this competition. Some of the terms in this guide may not be familiar to you, so feel free to ask someone after reading it if you still have questions. The CMRC XIV Regional is a National Association of Rocketry (NAR) sanctioned competition. You may still enter if you are not a NAR member, but you will not receive NAR points. If you have just joined the NAR and have not yet received your membership number, you may enter the competition as a “pending” member.
You do not have to enter all of the events! If you have a small rocket lying around, it will likely be fine for the spot landing event. I encourage you to enter as many events as you can, but even flying in a single event will award NAR contest points to you, and help our C.R.A.S.H. section 482 with the overall section points total. It will also help you build better rockets. Prepare for the meet the same way Olympic athletes prepare for the decathalon: don’t go in with the intention of trying to win every event. Focus on those events that you are best at and/or in which you have a reasonable chance of being a contender; for the other events just try to get a qualified flight so that you can get flight points and learn more. You can be any age, we especially need youngsters to compete because they are the future of this hobby!
Upon entering the competition, be sure to fill out a contest entry blank. Be sure to fill the form out completely, including parent/guardian’s signature on the back for contestants under 18 years old. Likewise, fill out flight slips completely, including the event you are flying and what motor you are using. All of these forms will be submitted to the NAR along with the contest results.
Age Divisions:
A: 7 to 13 yrs. old
B: 14 to 18 yrs. old
C: 19 yrs. old and up
T: Registered NAR teams
Launch Policies and Procedures –
The official rule book for NAR Competition is the United States Model Rocket Sporting Code, or “Pink Book”. At first glance this booklet full of rules may look intimidating to a beginner, but that’s just because there are a lot of different competition events described within the booklet. For the most part, the rules are intended to make the contest fair for everyone, and are fairly easy to follow.
* When you are ready to launch a rocket for competition, go to the Pre-/Post-Flight Check Station and fill out a competition flight sheet. These will be different from the flight sheets used for sport flights. Once you have filled out the form, the Pre-Flight Check officer must examine your rocket to make sure you are using the appropriate motor for the event and that your rocket is reasonably safe to launch. Once your rocket has been approved for launch, the flight sheet will remain with the contest officials
* All rockets flown in competition should have the contestants’ NAR number printed somewhere on the outside of the rocket. If you have yet to join, you still should have your name and phone number on the rocket so someone can return it to you in case of loss. Many a rocket has been returned months later after weathering the elements in a meadow.
* Only motors certified by the NAR for contest use may be flown. – In the interest of fairness, only motors that are manufactured in large enough quantities to be reasonably available to all contestants are approved for use in NAR competitions. Be sure to check the current Certified Motor List (available at the pre-flight check table or ask a contest official) before preparing your rocket for flight to see whether the motor you wish to use is permitted. In general, most Estes and Quest motors are certified at this time, but if you have an older supply more than a few years old, double check. Many Apogee motors are NOT currently certified. The NAR website should also have a listing of contest certified motors.
* “Return” Rule: – Most duration events require the contestant to present their rocket to the Pre-/Post-Flight Check officer after the flight to show that the rocket has been successfully recovered. If you do not present your rocket to the officials after the flight, your score will not be counted for the event, but the flight will still be considered an official flight. Yes, this is an inconvenient rule, but hey, we didn’t make the rules, we just follow them.
* Pitch in and help. – It takes many people to make a competition run smoothly, from Pre-/Post-Flight Check to Trackers and Timers. Since these people are usually also contestants, give them a chance to get their flights in by volunteering to fill one of these jobs for a few minutes. Timing rockets is really quite easy and fun to do. Trackers will not be used for official contest events for CMRC XIV, but may be needed for record attempts.
Scoring –
Contest beginners do not need to know the details of how points are awarded to enter events, so don’t worry if you don’t understand them fully. Just fly and have fun! The contest director and regular competitors will handle the points and official scoring. If you want to understand the details, read on. In some events, the winner is determined by a contestant’s single best flight. In many duration events, the winner is determined by adding the times of each contestant’s two permitted flights. In super-roc competition, the score is determined by multiplying the length of the rocket by the altitude or duration achieved. See the individual event descriptions, below, for more information.
For each event, placement points are awarded in the following manner:
1st Place: 10 pts.
2nd Place: 6 pts.
3rd Place: 4 pts.
4th Place: 2 pts.
Qualified flight: 1 pt.
Weighting Factors and Contest Factors-
Again, don’t worry about the weighting and contest factors if this is your first time competing. Each event has a weighting factor that indicates the relative difficulty of the event. For example, Spot Landing doesn’t require building any special type of rocket, so it has a contest factor of 4; Boost Gliders, Rocket Gliders, and Helicopters are fairly complicated and take more work to get them to fly properly, so they have weighting factors ranging from 18 to 28.
Each competition has a contest factor that illustrates the relative size of the event. Section and Local Meets have contest factors of 1, Open Meets have a contest factor of 2, and Regional Meets have a contest factor of 3. The annual National Meet, NARAM, normally has a contest factor of 8. CMRC XIV is classified as a regional meet, so it has a contest factor of 3.
Points for an event are determined by multiplying the placement points by the weighting factor and contest factor. For example, if you place second in Spot Landing in an Open Meet, your score is 6 x 4 x 2 = 48 points. The overall winner of a meet is determined by adding each contestant’s points for each event. Winners are designated for each division so youngsters don’t have to compete against our experienced old timers!
Cumulative Points and Contest Year –
A contest year runs from July 1 to June 30 of the following year, and includes the NARAM immediately following. The most number of meets an NAR member enter during the year is determined by adding the contest factors of those events; no NAR member may exceed a sum of 12 (NARAM does not count against this total).
All points earned by each NAR member during the contest year are added together to determine the national champion for the contest year. The NAR web site has a listing of the current points standings for the year which is updated every few weeks.
United States Model Rocket Performance Records –
The NAR keeps a record of the highest scores ever achieved in each event in each age division during sanctioned competition. These scores are the official U.S. national records for these events. Our club, C.R.A.S.H., (section 482), now has over 70 national records and is adding more all of the time. The NAR web site has a listing of the current records if you need a list. It is important to remember that you may try for national records that are NOT sanctioned events of the contest. That means you may try for a parachute duration national record even though the CMRC XIV contest does not list that as a contest event. Also, remember that records are recorded by age division, so if you are 8 years old, you are trying to set a national record for kids 7 – 13 years old, not adults!
Helpful Tips –
Experience plays a significant role in how well one does in competition; however, there are a few simple things that even beginners can do that will greatly improve their performance.
Build simple, build solid –
The key to doing well in competition is to keep your rockets simple and lightweight (the “Three fins and a nose cone” rule, or 3FNC). Experienced competitors sometimes get really experimental in their design and construction techniques in a gamble to get a little more performance out of their rockets (a gamble that can pay off handsomely IF everything works right), but as a general rule of thumb, the more complex the design, the more things that can go wrong. Since points are awarded simply for achieving a successful (“qualified”) flight, and no points are awarded for a flight that is disqualified because the rocket didn’t work right, you can earn a decent number of points, and sometimes even win an event, by being conservative in your designs.
The biggest sources of heartache in competition rocketry, even for those building simple designs, are recovery system failures and rockets lost to sight during recovery. During construction, use durable materials (such as Kevlar) for shock cords, make sure the shock cords are good and long, and make sure they are solidly attached AT BOTH ENDS. Don’t try to stuff a larger parachute or streamer into your rocket than will easily slide out at ejection, and use plenty of wadding. Improve your rocket’s visibility by using tracking powder (a colored powder, usually tempera paint or line chalk, that is poured into the body tube after the recovery system has been loaded, and which makes a colorful cloud at ejection), color your rocket with a mix of dark and florescent colors, and use florescent or reflective (such as mylar) materials for your parachute or streamer.
Events for this competition –
Streamer Spot Landing (WF 4) –
Just about everyone should be familiar with this event: try to get your rocket to land as close to a marked target as possible. To add just a bit of difficulty, you must use a streamer as the sole means of recovery. The size is up to you, however, the length of the streamer must be at least five times the width. The recovery system must fully deploy in order for the flight to count, the rocket must come down as one piece. Measurements are made from the target to the tip of the nose cone.
In NAR competition, only one flight is permitted for this event, with no practice flights allowed. Helpful hint: watch what other rockets (both sport and contest) are doing, especially those similar to the one you plan to fly, to get an idea of what motor size to use and what direction to aim the launch rod.
1/2A Boost Glider Duration (WF 17) –
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The purpose of this event is to achieve the longest flight duration using a 1/2A-powered boost glider whose sole means of recovery is via a fixed wing gliding flight. The wings of the glider must be rigid; in other words, the wings cannot be folded up during boost and then unfold for recovery. The entry may separate into multiple pieces and only the gliding portion of the rocket is timed. Often, you will see the piece that does not glide referred to as a “pod”, and it usually returns via parachute or streamer. This event is distinguished from Rocket-glider by allowing the model to separate into separate parts, whereas a rocket-glider must remain in one piece.
Two flights are permitted, and the winner is determined by adding the times of the flights. The return rule applies to this event, so it is important to get the glider back. One hint that may help is to slightly weight one wing of the glider with clay so that it always glides in a slight circle.
A Flexi-wing Boost Glider Duration (WF 18) –
The purpose of this event is to launch an A-powered flexible winged glider that recovers with the longest flight duration. The glider portion must use gliding surfaces made of flexible materials, such as mylar, or nylon. This event has the highest number of points in the contest, but a flexi winged glider is notoriously easy to build. The problem is trimming them to glide well. The glider itself is usually carried inside a body tube housing both the motor and flight fins.
Two flights are permitted, and the winner is determined by adding the times of the flights. The return rule applies to this event, sometimes difficult to achieve with these light gliders
http://www.crashonline.org/nwsltr/vol13no05/images/Flexi.pdf
(Download a Flexi-wing plan Here).
C Eggloft Duration (WF 16) –
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The purpose of this event is to fly an exceedingly fragile payload for as long a time as possible and recover the payload without damage. The payload must be a USDA Large hens egg with mass no less than 57 grams and no more than 63 grams, and measure no more than 45 mm in diameter. Don’t worry about bringing eggs for this event, as that is part of the entry fee, and the contest director will bring and hand them out. Each egg will be numbered, and must be removed in view of a contest official after the flight in order for the flight to count. If the official cannot examine the egg, then the flight is disqualified. Of course, if the egg breaks or has any visible signs of cracking, the flight is DQ’d as well. Contest beginners may want to put their eggs inside a sandwich bag before packing it inside that gorgeous rocket. Unless you happened to paint it yellow and white, that is!
Two flights are permitted for this event, but only the single longest time is used for scoring.
1/4A Super-roc Duration (WF 13) –
The purpose of this event is to launch a longer-than-normal rocket on an 1/4A motor for the longest flight possible without the body tube folding or crimping during flight. The score for this event is determined by multiplying the length of the rocket (in centimeters) by the duration of the flight (in seconds). Entries must be at least 25 cm long, and the maximum length that can be used for calculating the score is 50 cm. A contest official is required to measure your rocket before flying so the length can be recorded. The hardest part of this event is getting a big enough parachute into that narrow body tube to get a respectable time. Parachute folding skills are very important in this event, so practice often. Another trick used by experts is to add a bit of baby powder to the chute and tube to help the parachute slide out easily during ejection.
Two flights are permitted for this event and the winner is determined by adding the times of the flights.
E Streamer Duration (WF 12) –
This is a rather deceptively difficult event for competitors. After all, who can’t find some old big rocket and add an E9-6? Well, it’s just not that simple. The purpose of this event is to launch a rocket using a streamer for recovery for the longest duration. A rocket this size can be very hard to keep together. Even 120 LB kevlar shock cords tend to rip under the stress of E powered ejection charges. Light streamers made of mylar tend to rip easy, but Nylon tends to be heavy and take up too much space in the body tubes. Tough choices abound in this event, including engine choices. Will you use the reliable but under powered single-use Estes E9 or the more powerful Aerotech E18 with its expensive reload case and half-hour build times?
Two flights are permitted, and the winner is determined by adding the times of the flights. The return rule applies to this event, so color that rocket brightly. Balsa doesn’t show up very well, even on cloudy days. Paint does add a touch of weight, but greatly increases your chances of finding the rocket, particularly if it separates from the streamer, for any reason.
That’s all the events for the CMRC XIV. Everyone builds and flies a bit differently, so keep your eyes open. The best way for a beginner to learn and become competent in competition rocketry is to watch, listen, and ask questions. Most participants in competition rocketry will be more than willing to share their ideas and techniques with you. You will never find a more helpful bunch of competitors in one place. C.R.A.S.H. has many people with tons of competing experience, including the defending National and NARAM Champion. Someday, we hope to bring home a Section National Championship as well, but we need more people in C.R.A.S.H. competing in NAR competitions for that to happen. If you enter and manage to pull out a victory in any event, you can be proud to have defeated many of the best rocket modelers in the country! Good luck!
The Flight of Thistle III
Author: Ian MacDonald
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The weather was partly cloudy and a comfortable temperature the day I flew Thistle III and an Apogee F10. Although the F10 is not a high thrust motor it has almost an eight second burn. Everyone present knew the lightweight Thistle was going for a high flight. Jim Lambert was nice enough to give me an igniter so we wouldn’t have the uncertainty of the Copperhead.
The three of us who had cameras “ready” for the launch were taken by surprise with how quickly the rocket took off. Everyone was saying with the slow burn engine how we’d have lots of reaction time for pictures. 20 Newtons of initial thrust pushing a 4.3 oz rocket sent it up in a hurry.
Thistle III took off fairly straight, and if it had been an under 2 second burn I would have called it a straight flight. The reality of the long burn combined with the long delay however is that a little bit of arc turns into a much more arc by the time it deploys. Unfortunately it was arcing towards the lake. People watching guessed the rocket went up to 3 or 4 thousand feet. I was able to follow the smoke on the way up, but I never did see it deploy or pick it up on the way down. Fortunately Bill Tigar was able to follow it with his binoculars and went with me for the recovery.
As feared, it landed in the lake. We stood there awhile passing Bill’s binoculars back and forth looking at a log in the lake, which we thought might be the rocket. A canoe passed near the log so I waved to him, hoping he would recover it. As the canoe got closer we could see the streamer from the rocket on board. The paddler had already recovered it and was nice enough to bring the rocket to shore.
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Thistle III survived its dunk in the lake. It did take some effort to get the motor out. I finally had to drill a hole through the motor, which I then looped some wire through. The other end of the wire was attached to some storage shelves. Being careful of the tube fins I pulled. It finally let go sending me backwards against my wife’s car.
Pictured is Thistle III after the flight showing the redundant streamers and shock cords. I will fly it again on a 29mm motor to see what happens. I will wait for an ideal day, and aim it a bit away from the lake.
C.R.A.S.H. Landings is published by:
Colorado Rocketry Association of Space Hobbyists (NAR section #482)
No responsibility is assumed for unsolicited material. All submissions become the property of C.R.A.S.H. Landings. Submissions should be delivered in electronic format by e-mail or diskette. For other formats, please contact the editor:
Ian MacDonald – [removed email]
