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Top shooter . Why settle for twirling tops with your fingers when you can shoot them at stuff instead? (You know you want to.) . Please feel free to look over the images and skip the verbiage. This rubber band-powered "top shooter" was inspired by a vintage American toy -- the Shoot-a-Top introduced by Lapin Products in the late 1940s. ∨ Below is a later Chinese knock-off marketed under the name "Whirl-a-top Gun & Top Set". ∨ My LEGOŽ knock-off looks and works less like a gun, and it's probably harder to wind and load, but at least I got comparable performance. (See this clip of the Chinese version in action at 5:37. ∨ When one has a shooter, shooting stuff is of course mandatory. (This primal human urge -- most strongly developed in the male of the species for partly anatomic reasons -- is partly why we have wars.) ∧ Impromptu shooting games are part of the fun -- here in the dark under blacklight. (The orange cylinder at center belongs to the top about to be lauched.) You can even play golf -- as at 3:01 above. (Truth be told, golf never crossed my mind till the top happened to disappear down the table's umbrella hole on the 10th take or so.) << Back to top Design notes ∨ Shooter: Even though I'm right-handed, I find winding and loading much easier with the frame set up for left-handed shooting. But it's easy to reverse if you'd rather shoot right-handed. ∨ The energetic launches seen in the video demand a lot of elastic band tension, and the shooter's structure must resist this tension without deforming. These one-piece forks (Bionicle Visorak torsos, 50904) have the advantage of not spreading apart when the shooter is loaded. ∨ A longer handle would be more ergonomic for an adult, but this one works well enough. ∨ Elastic band: Finding the right elastic band was a challenge. The black silicone "ouchless" hair band shown here is almost too thick for the 2x1 band spool (61510), but it's by far the best I've found in every other respect. Unfortunately, the next larger spool (3x2, 32012) is much too big. ∧ This band is short enough for clean releases, strong enough to deliver exciting high-energy spins, and durable enough to survive repeated use without weakening. Regular household rubber bands are generally too long and too weak and last only a few shots before becoming overstretched. ∨ Plan A was to loop the band over this red post, but that did little to keep it from flying off on launch. ∨ So far, 3 bands remain MIA, and even Roxie the LEGOŽ search-and-chew dog can't find them. (Or maybe she did and ate them.) ∨ Replacing the band post (red) with a tight-fitting band hook (orange) fixed the problem without altering the loading process. ∨ Top: Unlike my usual all-purpose top starters (below), a rubber band-powered top shooter needs its own special top. And twirling this top in any other way won't be easy. ∨ Top design options are especially limited at this shooter size. The top can't exceed 27 mm in maximum radius, and the upper and lower guide bearings (yellow half-bushes here) have to be exactly 48 mm apart on center. ∨ Moreover, the top needs a ratchet (here a 40-tooth gear) for the trigger pawl to engage, and vertical ratchet-pawl alignment must be perfect to avoid misfires. Hence, workable ratchet heights on the top are limited to the pawl's 2 workable vertical positions on the shooter frame. ∧ Since the ratchet is generally the widest and heaviest part of the top, its height along the axle tends to control the height of the top's center of mass (CM) above the tip, and that can have a significant impact on the top's behavior after landing. ∨ For example, if you want the sweeping spiral top trajectories seen in the video, you'll need a top with a broad tip and a relatively high CM. The latter requires the higher pawl position. ∨ But if you want the top to travel less -- perhaps to serve as a target for other tops -- lower the top's CM by putting the ratchet one stud lower on the axle so as to align with the lower pawl position, like so... Room for improvement:Winding and loading take some finger strength, dexterity, and practice.Slow winding and loading make for a low firing rate (roughly 2 shots per minute).Top designs are further limited by the fact that a loaded top will stay put in the shooter only when the band spool sits directly below the upper guide bearing.The top needs frequent maintainance, as parts tend to drift along the central axle over time, and misalignments lead to misfires. Every few shots, the upper and lower guide bearings have to be realigned with their respective fork bearings (dark gray), and the ratchet has to be recentered on the trigger pawl.Enlarging the shooter would make these issues easier to address while expanding top design options. Stay tuned. ≪ Back to top Specifications Shooter dimensions:102x40x86 mm (LxWxH) without bandShooter mass:34 gTop dimensions:38x65 mm (DxH)Top mass:10 gElastic band:Silicone "ouchless" hair bandFiring rate:~2 shots per minuteModified LEGOŽ parts:NoneNon-LEGOŽ parts:Elastic bandCredits:Original MOC inspired by a vintage toySee also:Electric top starter, planetary top starters, String theory top starter, Revatron wind-up top starter, and LEGOŽ top folder << Back to top


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