Sport Rocketry

SPORT ROCKETRY MARCH/APRIL 2022 7 L2 behemoths, and has been useful on all of them. And the weight penalty is a mere 8 to 10 grams (0.28 to 0.35 oz) full up with battery and clip. Once you get to L2 and L3 rockets, you probably have a GPS, and might think this system redundant or unnecessary. But, un- less you are launching on a hundred square mile salt flat, you would be wrong! In most wooded or swampy launch range terrain, you might know, within the limits of GPS, where a rocket landed, go there, and still not see it! I have stood directly under a treed rocket, and was not able to see it! But, if you have an aural reference, you can de- termine its exact location within inches! is is really helpful in tall grass or trees where you could be standing on the GPS coordinates and still not see any part of your beloved rocket. So how much does it cost? Cost is what everyone always worries about first. We are all budget conscious! If you buy parts to make ten (the lowest quantity sold for several components) the unit cost is $4.11 each, or $41.10 total project cost, assuming you already have the basic tools required. All this device consists of is: 1) a piece of plastic shim stock (making a pull tab switch) 2) some epoxy 3) a battery holder 4) a piezo siren buzzer 5) a battery 6) some stiff wire 7) solder 8) a paperclip at's it! Locate your rocket anywhere with something you can build in 20 min- utes with just some simple parts and for less than $5.00! e time per unit is even less if you and a friend make all ten as a production event! It's a great club project! We (ROAR, NAR Section 795, Orlando, Florida) always have a dozen or so to loan out at events so that recovery goes faster! e quicker you clear the downrange area, the quicker you can return to launching! How the System Works Briefly, this is how the system works (this is explained in detail later in the In- stallation step). e shim stock pull tab, the pink part in Figure 1, is inserted be- tween the battery and the leaf contacts on the base of the battery holder through a slot you cut in the holder. is acts as a switch, and when the pull tab is removed the circuit is switched on. is pull tab will be connected to the nose cone lug or screw eye of your rocket using a paperclip. A stiff wire ring (also visible in Figure 1) is made that is part of the body of the Screamer. is ring gets attached to the shock cord a short distance below the nose cone, but far enough that there is slack in the shock cord when the pull tab is insert- ed. At deployment, the ejection charge blows out the nosecone, which takes the screamer with it, and when the shock cord tensions, the tab is pulled out and the screamer, now attached only to the cord by its ring, starts screaming! It will continue to scream on a fresh battery for almost 24 hours! e interesting thing about the sound at this particular fre- quency is that it carries over a fair distance (I have heard them from 1/4 mile away on a calm day) and of course it turns your head Figure 3. Tools. Figure 4. Scribe a line for the cut in the battery holder. Figure 5. Cutting the slot for the pull tab in the battery holder.

• Cover