There's No Place Better - EMRR! EMRR Rocks!
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Space Exploration Merit Badge
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By Brian Ray

Over the past decade or so I have had the privilege of working with many youth groups teaching about rocketry. I have loved the opportunity to introduce a new batch of youngsters to the hobby that has provided so much enjoyment and satisfaction for so many years. (And, selfishly, any chance to put a few rockets in the air is wonderful.) While most of the youth groups with whom I have worked have been Boy Scout troops, one of my favorite traditions was the end-of-year launch with my wife's fifth graders during the years she taught. Former students will still comment on how much they loved making and launching rockets as a class.

My most recent foray into this area was teaching the Space Exploration Merit Badge to my local Scout troop. We spent three troop meetings on the badge: 1) doing the book work and beginning construction on the rockets, 2) completing and finishing the rockets, and 3) launching the rockets.

Regarding the book work for the Merit Badge, I have developed a packet that each Scout is expected to complete as part of the requirements. In fact, I generally inform the Scouts that the first one to complete the paperwork having done his best gets first choice of rocket. It tends to motivate them not just to work quickly, but to put some real thought and effort into it. Posters with all of the necessary information to complete the packet are placed on the walls around the room in which the Scouts work. They are able to go at their own pace and spend additional time on areas that are of particular interest. They have the opportunity to draw and design to their creative hearts' content as well as record and process information.

Generally I spend the time prior to the event "making" kits for the Scouts to build. I am aware of the many high-quality options from various manufacturers as far as educational kits go. However, I prefer to have the boys build a scratch rocket for two reasons: 1) the cost is minimized, an extremely important consideration for a Boy Scout troop with limited resources; and 2) I like for the boys to see that rocketry is not limited to the prepackaged offerings in their local superstore. My feeling is that if the boys can experience rocketry at its most basic - in the form of paper towel tubes and Easter eggs - they will be more likely to stick with it in that their creativity will be more engaged and their thin 12-year-old wallets won't be hit too hard. Of course they are still fascinated by the kits that are out and those that stick with rocketry invariably buy one shortly after my time with them.

KitIn creating kits for the boys to make, I did the following:

  • Body Tube - For this event the body tubes were paper towel tubes, toilet paper tubes, and wrapping paper tubes. In the case of the toilet paper tubes I hand-rolled an 18mm motor that was extra long that protruded several inches from the end of the larger tube. My experience with toilet paper tubes is that they are generally too short to be stable. By extending the motor mount tube the stability is improved significantly. It also creates a design that the boys seem to like, and refer to affectionately as a "corn dog rocket." ·
  • Motor Mount - Each motor mount was hand-rolled by me using an index card, spent motor casing, and a glue stick. In the case of the longer mounts used with the toilet paper tubes, I used either a ¾ inch dowel rod or the core from a roll of fax paper that is just a hair wider than 18mm. We didn't use an engine hook; the motors were merely friction fit. Small pieces of balsa were glued in the end to serve as the engine block. ·
  • Centering Rings - I made the centering rings for these rockets just like I do my own. I measure the inside diameter of the body tube and the outer diameter of the motor mount. I then use Microsoft Publisher to draw the circles. Publisher has a feature where you can "snap" a shape to the corner of the margins. Using this feature I can draw a circle for the inner diameter of a BT-50 and the outer diameter of a BT-20, for example, and then "snap" them together for perfect alignment. I copy and paste as many of the rings as I need and print them on standard white paper. The printed rings are glued with a glue stick to a piece of standard consumer cardboard (like from a cereal box, for example). This is as far as I went with the Scouts' rockets. ·
  • Nose Cone - The nose cones were primarily plastic Easter eggs, although I did include two plastic tops (the cheap, party favor variety) and the nipple cover from a baby bottle. To make these items usable I first create a coupler using an index card and a glue stick. If concerned about durability I will double it for strength. Once the coupler has dried (which I do with the coupler inside the top of the rocket so that it retains its shape) I rough up the inside of the nose cone with sandpaper and then glue the coupler in the cone with wood glue. While some may deride this method because the glue only forms a relatively weak surface bond with the plastic, this method has worked well for me as I've scratch built for 25 years.
  • Fins - In the past I have used cardboard to make fins for this type of project. This time, however, I decided that we would use balsa both for its strength and durability and for how quickly it attaches when compared to cardboard. I chose a number of different fin shapes and cut the fins myself prior to the actual build.
  • Launch Lug - We used drinking straws wrapped with masking tape.
  • Shock Cord - the shock cord material was the cheap elastic found at your local superstore.
  • Recovery System - Most of the rockets were recovered under a streamer made from fluorescent construction material. A few of the boys wanted to make parachutes, which we made from black trash bags and kite string.
  • Adhesive - All construction was done with Elmer's wood glue. In the past I have used hot glue at certain points because of time (boys sometimes get impatient waiting for white glue to set up). This created some obvious issues along the way. A motor mount assembly made with hot glue will get soft and move around with the heat of a motor. Also, fins don't stay attached too well with just hot glue; they need to be filleted with white or yellow glue in addition to the hot glue to keep from being torn off during acceleration. I have learned, however, that a double glue joint with yellow glue dries almost as fast as hot glue and is a much better choice than hot glue for reasons that certainly don't need to be stated here.

When the Scouts finished their packet and it came time for them to begin working on their rockets, they each came forward and picked out the one they wanted to build, which selections were based solely on the size of the tube and the shape of the nose cone. Each step provided me the opportunity to teach them about the purpose and function of each component.

The first thing I had them do was assemble the motor mount. They cut the centering rings (both outside and inside circles) with some close adult supervision as some of these boys are inexperienced, and thereby dangerous, with a hobby knife. The centering rings were glued around the motor sleeve and the whole assembly was put to the side to dry. It was during this portion of the experience that I did a great deal of teaching about rocket motors and how they work.

Next came the fins. Each of the boys came up as he finished his motor mount and picked a set of fins that had already been cut. I tried to help them choose a set that matched the size of their rocket, both for reasons of aesthetics and stability. Having selected their fins the boys marked their respective body tube for fin placement. As mentioned previously, we used wood glue and the double glue joint method. Now, while telling a 12-year-old boy that he needs to be patient is usually like telling water not to be wet, the Scouts did a great job on this part. My instruction was to put a little glue on the root edge of the fins, press the fins to the body tube where they were to go, pull them off, and rub the excess glue into both the fin root and the tube. At this point I told them to put their stuff down and go get a drink or use the bathroom or something; they needed to let the glue dry completely before they did anything else. When they returned they tacked on each fin with a small amount of glue, made sure it was well-aligned, and left again to get a drink.

Before the boys left they glued the motor mount assembly into the body tube. I explained to them about glue fillets on the fins and told them that I would apply them over the next week. With that our first session was over.

Our second session was devoted primarily to painting the rockets. All of the patience exhibited by the boys in our first session went out the window when a can of spray paint was in their hands. I spent some time teaching them about how to paint: sanding, priming, masking, etc. I placed special emphasis on the fact that with paint less is more; it's better to spray a little bit several times than to spray a lot all at once. Unfortunately it is very rare to encounter a young man who will do it right the first time. In the boys' defense I've also noticed that many adults struggle painting a rocket well the first time. I have to remind myself that my painting skills - which, admittedly, aren't spectacular - have been developed and practiced over many years. And ultimately the rocket is his; if he likes how it looks in all its many-colored, blotchy, run-streaked, and fingerprinted glory, what do I care.

RecoveryAt the end of the second session the Scouts also attached the shock cord by way of the tri-fold method and some form of recovery system, typically a streamer.

Shortly thereafter we gathered to launch the rockets. There is a wonderful spot behind the local junior high school where we generally go. It is a nice, wide-open space with a number of sports fields bordered by open desert. With all of the open space we have rarely lost a rocket, even the fire-and-forget types that usually disappear. We talked about a number of matters prior to launching - from rules for safety to how to install an igniter and how it worked. We spent almost two hours launching their rockets as fast as we could. The question that was asked over and over again was, "Can I please launch my rocket again?" I responded excitedly every time, "Of course! Load it up!" Some boys launched their rockets upwards of eight times that afternoon.

There were a few rocket casualties, but not many. Some fins broke (generally because the young man had not paid attention when I explained grain direction on balsa fins) and nose cones detached. Many of those issues were fixed (more or less) on the spot with super glue or tape. Some of the fixes were ugly but they held together.

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For me it was another great experience launching rockets and being a teacher. There is great satisfaction in working with young people and exposing them to an activity that will be so much more beneficial in the long run than time spent in front of a TV. I don't know how many of these Scouts will stick with the hobby, but I'm confident that several of them will. I will extend the invitation to launch again with our little group the next time we go and hope that most, if not all, of them come again.

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