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  • Space Derby help needed....

    Hello, I'm an Assistant Cubmaster with my local Pack tasked with putting together our first-ever Space Derby. I'm hoping to get in contact with another adult leader who has actually tried to run this race, as we're running into an issue with our testing Rockets.

    We've put together a great adjustable length track, with electronic timing (compatable with our Pinewood Derby software), however these Rockets just refuse to fly consistently. The rubber bands that are coming with the kits are complete junk, so we've been experimenting with better rubber bands out of the following kit:

    The problem is, these rubber bands are about 1-2 inches longer than the kit rubber bands, so 100 winds is completely out the window. We have to wind these a minimum of 200 turns to go about 20 feet. We are consistently winding these 250 to 300 turns, and they are lasting about 10-15 races before we start to get breakage. That said, they are not always unwinding completely, and some are getting stuck after only going 10 feet with plenty of windings still left in the body.

    We have one test rocket that is your basic rocket (just google for pictures, and you'll find it), another that is a "wedge" design, then two "flying bricks" that are just taped together. There's more than enough power to drive any one of these rockets the full track length (as we've had the "flying bricks" win several test races).

    We're thinking that telling the boys to make the inner cutout wider before they glue their rocket body together is the solution, but we don't have a way to confirm this at the moment. One of our den leaders is working on another test rocket with completely open sides (so we can see what is going on with these rubber bands), but I wanted to get some thoughts from others on this issue.(This message has been edited by gr8sailor)

  • #2
    I suggest asking at your local Roundtable.


    • #3

      First of all good luck with your space derby and I hope you have better luck than we did. I have two suggestions for you, hopefully you are soaking your rubber bands in glycerin or dish soap ahead of time. This will make the bands more elastic and help prevent breakage. We gathered up all the rubber band ahead of time and soaked them for the pack so that everyone had the same advantage and we could keep the race going rather than worrying about breakage. The other resource I will suggest is to look in Derby Talk the link is here 694f4. They have 45 topics on Space Derby with a good search generator that can help provide you with a recommendation.


      • #4
        Personally I'm not a big fan of Space Derbies. They tend to be difficult to make work well in my experience.

        Pinewood Derbies and Raingutter Regattas work well.

        Also, search for "stomp bottle rocket" on U-tube for a great way to make rockets from a sheet of paper and then launch them from an easily built launcher, stomping on 2 two liter pop bottle.

        Stomp bottle rockets are a fine competition and inexpensive to do. We do our fall recruiting night combined with our initial Pack meeting of the year making and launching stomp bottle rockets.

        New families get a great family experience making and launching rockets with their boys and existing Cub Scouts are drawn back to a first Cub Scout fall activity with a lot of appeal.

        I made six launchers from some PVC pipe, so we do six launches at a time. Boys each get a rocket pilot license, and the rocket traveling the farthest on each launch gets a sticker for their license.

        Boys and parents both love it!(This message has been edited by seattlepioneer)


        • #5
          Yes we are doing both of those suggestions with our rubber bands. I'll definitely take a look at that forum when I get a free moment, it was not coming up in any on-line searches.

          Nobody in our district leadership has direct experience with the Space Derby. We're the first Pack even attempting it within the last 10 years. I had to talk to a "retired" Scout leader, who was the last person with direct experience, just to get our attempt off the ground.

          I'll definitely put that in my notes. Sounds like lots of fun. The Council has a "Cub Scout Day" every year, and they had something very similar using 2-liter bottles and Bicycle pumps.


          • #6
            Our pack uses points for each heat (4 for longest distance traveled to 1 for shortest - 4 "lanes"). Very few rockets travel the full length of the "track". We lay dish towels over the fishing line about 1' from the end of each lane to minimize propeller damage.

            Each scout runs on each lane then the three highest scores run in a championship run-off.

            This makes the event run pretty simply. We use 75 winds with 3 rubber bands in each rocket. Some go 40 feet and some go 10 feet - balance and weight seem to be the biggest factors.


            • #7
              This is my lest favorite derby.

              My recommendation would be to really stress the "fun" of this event over the "competition."

              In our experience of running this event for many years, this is the derby where Murphy makes the most appearances. Rubber bands are always breaking, rockets are falling off the carrier or falling apart. If you try to structure it like a regular derby, chances are you will be waiting on rocket repairs, etc. Also, there seems to be no rhyme or reason why one rocket wins over another. I'm sure there is but we haven't found it. There have been some rockets that won't make it halfway down the course, but we could not tell what was wrong with them.

              We do this event as a "race when ready" event. We start running rockets as soon as we have enough to start running. Boys race X number of times, and we mark a card for W/L. After everybody is done racing we race off the boys with the most wins.

              BUT the prizes are very low big derby trophies.

              Also a few pointers from experience:

              -A good percentage of people will have the nose cone messed up one way or the other--glued on, put on backwards, missing the red wire protecting sleeve, etc. This year we took all the nose cone assemblies out of the kit and one dad put them all together beforehand. It took time, but less time than undoing prop assemblies that were done wrong.

              -We have soaked rubber bands in glycerine, but found they get really slippery to work with. Another option is to put the rubber bands in without lube, then give a shot of WD-40 down the inside of the rocket, wind it up and let it release, then it is ready to race.

              -Be sure to crimp the hook on the prop assembly quite tight otherwise the rubber bands will come off.

              -On the winding peg at the back of the rocket, attach a small zip tie through the rubber band to make a loop about the size of a quarter. Use the loop to attach the winding hook, rather than putting the hook on the peg itself. This makes it easier to take the winder off the rocket. Hard to describe this one.


              • #8
                This is my favorite derby as well, space derbies only require a potato peeler to carve the shape and they are easy to paint as well. Its much more about looks than speed for the scouts.

                But Space Derbies take better planning to run a lot of rockets in an evening. We had a lot of dads around for winding the rocket propellers to keep things moving.

                I think the secret with rubber bands is having a lot of spares and refitting as they break, which happens a lot.

                As for why some do better than others, its all about "Weight". Usually the lightest derbies will be in the finals. But the races also depend a lot of the rubber bands.



                • #9
                  At the moment we have a grand total of 36 boys who have picked-up their kits. We have already bought enough rubber bands to give them each 3 brand-new bands for competition day, and we have stressed to use them sparingly (use the kit bands for testing). I did a bunch of testing last evening, and found that as long as we lubricate the bands before racing we're getting 10 runs on our test rockets before we start running into band breakage (usually due to defects identified beforehand, which can be avoided).

                  As far as winding...we have that taken care of too (as one of the online complaints was that the boys get tired of winding their rockets). I built a 4-position drill-powered winder, with an electronic counter for about $50. We're going to put 150 turns on all the rockets, and then let the boys wind them more or less from there. Brewmeister, we're actually using what I'd describe as "double-handled slalom ski rope"....completely home-brewed to hold the dowel, and hook onto the drill winder.

                  Also with our latest testing, I've found that installing & balancing the prop is going to be "key" with these things. I did that with our most consistent "rocket" tester, and it consistently runs the full 40' length of the track. We went ahead and balanced the rest of the props, and now all the designs (including the bricks) are consistently hitting the 40' mark.

                  We were noticing that when the rockets were initially taking-off, the ones that "vibrated" the most, were traveling the least distance. Sometimes releasing them "just right" would produce a good run...but then the next run would be pathetic.

                  As far as running the races...we're definitely leaning toward running "race as ready" format. I'm just trying to figure-out if the Grand Prix Race Manager software can be configured in that format. I've been concentrating on getting the track and timing circuits working properly together, over how to actually run the races. Now that we have some time to step back and evaluate, this is definitely the next thing we're going to look at.

                  Thanks for all the suggestions everyone, please keep them is a BIG help. :-D


                  • #10
                    Hello gr8sailor,

                    If it's of interest to you, Boeing is hiring engineers these days...
                    Last edited by SeattlePioneer; 11-12-2014, 04:34 PM.


                    • #11
                      How do you balance the prop? Are you hanging it and shaving the heavy side?


                      • #12
                        Brewmeister, we have three different methods. You've outlined one.

                        The easiest method is just to add scotch tape to the "light" side until it's balanced.

                        Depending on the shape of the prop, we also added a bead of 5-minute Epoxy to the leading or trailing edges of the "light" side. When looking at the prop head-on, you could tell one of the blades was "bent" to either the left or right of the centerline (probably due to improper packaging).


                        • #13
                          Well done, you have made sure your guys will have a lot fun. It's important to understand that most of your cubs will remember this race for the rest of their lives. We don't think about that much as adults, but every step of the race from check into the awards presentation should be performed with the greatest respect for a young boys sense of adventure. Many of your scouts have lost sleep thinking about their space derby flying 1000 mph on race night.

                          Oh how I love that cub scouting stuff.



                          • #14
                            It's been a while since the topic of Space Derby was discussed, but I'm cubmaster of a Pack in CT that is doing SD for the first time. I must say that this forum but also the various internet postings of units throughout the country (as well as the YouTube videos) has been very helpful in getting us stated.

                            One thing I continued to get steamed about, though, are the very sketchy instructions that come with the original kits. Because of their briefness, the YT videos really do turn out to be godsends. (BSA could do something to get the manufacturer to beef this up, but I digress)

                            After spending hours upon hours putting together a BestTrack track, this feels like a very stupid question....but are there any directions on internet re assembling the BSA-sourced rocket carriers? Of course, there are no directions in the kit box...


                            • #15
                              We use a rag with silicone lubricant sprayed on it to wipe down the fishing line. This makes a huge improvement on the distance the rockets travel.
                              gr8sailor- would love to see the rocket winder you built.