Sport Rocketry

vented the failure and allowed for a fully successful flight. Instead, the grid fins all shattered and the rocket body suffered irreparable internal damage upon ground impact (see Figure 16). The nosec- one landed softly some time later, and neither it nor the launcher suffered any damage. Conclusions, and What's Next? These two ICBM projects illustrate a valu- able principle. Even when the most complex el- ements of experimental systems operate as de- signed, the most routine and ordinary functions remain equally critical and must also perform to enable an overall success. In the case of the model Minuteman II and SS-25, custom tube launch- ers, sabots, experimental materials, grid fins, and non-traditional stability measures all performed adequately or even spectacularly. Yet premature nosecone separation put at risk one otherwise successful flight, and failure to protect a piston strap left another rocket body to plummet to its destruction. Despite the hiccups and setbacks, my over- all conclusion is that scale ICBMs are great fun. They are challenging in wonderful ways, and are ideal for high power enthusiasts looking to take on something new and different. Based on limited observational data collected at these two launch- es, I am confident that fliers and spectators alike would welcome the chance to see more model ICBMs on the field. For myself, I look forward to further exploration and experi- mentation along these lines. This might begin with rebuilding the SS-25 body, using lessons learned to refine the design and con- struction. One obvious next step could be to grad- uate from single-warhead missile variants to mod- eling a multiple-warhead missile, or MIRV. Mock payloads could separate at apogee and trail smoke down to lower altitudes where they can then deploy individual parachutes prior to soft landings. Still fur- ther down the line, who knows? Maybe an underwater launch of a model SLBM? As with all good endeavors, the possibilities are more than sufficient to occupy available time and resources. SPORT ROCKETRY JANUARY/FEBRUARY 2020 47 Figure 15 (Left). SS-25 first flight showing the grid fins deployed and a stable boost. Photo credit: Craig Klimczak. Figure 16 (Above). SS-25 body, after ground impact. Photo credit: Lauren Miles. Lifetime membership is available to any new or renewing senior member of the National Association of Rocketry. Pay a one-time fee of $1,000 and become a NAR member for life. Call NAR headquarters at (800) 262-4872. Marie will fulfill your lifetime membership over the phone; life memberships can not be purchased online. N A R ® N A R ® LIFETIME LIFETIME MEMBERSHIP MEMBERSHIP Make the Commitment! Make the Commitment! Make the Commitment! Make the Commitment! LIFETIME LIFETIME MEMBERSHIP MEMBERSHIP

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