#41
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A relay launch system (the "Handbook of Model Rocketry" covers them) enables just two "D" batteries to reliably ignite clusters, because the very short--just 6" (150 mm) or so--ignition leads between the batteries and the igniters doesn't suffer the voltage drop that the normal 15' (5 meter) ignition wires cause. An ordinary Estes or Quest launch controller activates the relay when the ignition button is pressed, dumping the full power of the "local" batteries into the multiple igniters. ALSO: A pneumatic firing switch activation system (like that used in the Centuri SERVO-LAUNCHER: http://www.ninfinger.org/rockets/no...a/72cen052.html [which used only two "D" size "Photoflash" batteries; today's alkaline "D" batteries likely have more "oomph" than those]) also enables smaller and/or fewer dry cell batteries to be used to reliably ignite clusters. As with a relay launch system (if one of the model rocket companies--even one of the smaller ones--offered a ready-made relay launch system, it would be a mighty convenient and popular product), a pneumatic system also enables the ignition leads to be extremely short, thus causing virtually no voltage drop between the batteries and the igniters. If the ignition leads (regardless of length) were of larger-gauge wire (say, like speaker wire [18 AWG - 16 AWG] or "zip cord" [lamp cord]), they would present still less resistance to the current flow. PLUS: If the launcher was securely affixed to the ground (using tent pegs--like the Day-Glo plastic ones--affixed to its legs, or to its "cabinet" [its body, if it was like the "flat on ground" Estes ELECTRO-LAUNCH http://www.ninfinger.org/rockets/no...a/69est086.html pad]), a 15' (5 meter) long pull-cord could activate (via a short lever on the launcher, if needed) an ignition button (or a rocker switch) on the launcher. A three-position, lighted rocker switch (like these: https://www.google.com/search?q=3+p...sclient=gws-wiz ) might be ideal, because one position--with an appropriate-value resistor connected in series, if necessary--would enable continuity to be checked first with one pull of the cord, and a second pull would close the other position, pouring juice into the igniters, and: The lever could be omitted if a two-cord C/L (Control Line) model airplane control handle was used; the switch would be centered (OFF) to connect the igniters, then from 15' (5 meters) away, turning the C/L handle in one direction would check continuity via the rocker switch's light, then turning it the other way would close the other contact, igniting the rocket's motors. (*OR*--with a lever on the launcher--two spring-loaded, normally-open push-button switches [one being a lighted, locking switch, for checking continuity] could be used, with the two-cord C/L control handle. After launch, the lighted locking continuity switch would be reset by pressing it again [one with a deep "recess" in its mount would clearly indicate, by its position, that it needed to be reset].)
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR Last edited by blackshire : 06-10-2021 at 03:19 AM. |
#42
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I question the entire premise of those that participate in this hobby that don't travel to launches via automobile.
Most likely well under 1%. I did not say it had to be a 12v CAR battery. A 6Ah "motorcycle" battery has enough power to ignite virtually all clusters, yet weighs relatively little. The last few launches I have used a 5Ah gel-cell pulled from a car jumper-box. Even lighter snd sealed.
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When in doubt, WHACK the GAS and DITCH the brake !!! Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't ! Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY. ALL systems are GO for MAYHEM, CHAOS, and HAVOC ! |
#43
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When we lived in the Blue Ridge mountains of northern Georgia, I often walked to my flying field (a ten-acre corn field about a thousand feet from our house). Other local kids I knew who were into model rocketry also, more often than not, had flying fields within walking distance. In Miami, the model rocket club at my school (Kensington Park Elementary) flew their rockets in the field behind the school, and members who lived in the neighborhood (I walked there, too, with my mother) walked there with their own rockets and motors, in addition to the club's launchers that were kept in their room. (I never had a chance to join the club because my parents transferred me to a local Lutheran school, St Matthew's, in the fourth grade, the "youngest" grade in which kids could join the rocket club). Also: Carrying only a motorcycle battery isn't terribly difficult, but carrying one *plus* a launcher, launch system, motors, and one or more rockets ^is^ burdensome. This--plus the fact that many kids *do* walk, bicycle, or take a bus to their flying fields--is why Estes developed the original Solar igniters and Solar Launch Controller. (Even G. Harry Stine, in his "Handbook of Model Rocketry," mentioned this much-anticipated and much-appreciated portability; he even wrote gratefully about how "we have been divorced from the large wet-cell batteries.")
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#44
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Flash pan...one tiny battery, one tiny igniter, one big cluster!
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I love sanding. |
#45
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Agree with tbzep above.
NOBODY walks to launches (nor really anywhere) anymore. The 60's (and 70's which it is NOT anymore) were a different time. Most people travel long distances to launch anything now. You just can't "Blast-Off" in just any old park anymore. I travel 12 miles just to get to my R/C airstrip to fly R/C. If I had to carry a launch pad, controller, motors, wadding, and rockets by FOOT to a launch site, I can guarantee you I would never launch ANYTHING. When my home bordered a large 500acre Soybean farm, I launched almost every week in good weather. Through small "H" power in my BACKYARD.
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When in doubt, WHACK the GAS and DITCH the brake !!! Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't ! Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY. ALL systems are GO for MAYHEM, CHAOS, and HAVOC ! |
#46
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If only a nearly vanishingly small number of people walk (or bicycle, or take buses) to their flying fields, Estes and Quest would be making 12 volt car/motorcycle battery-powered launch controllers, yet--to my knowledge--they do not. The question is: "How many people walk, bicycle, or take public transportation (buses, jitneys, subways, trams, Uber, Lyft, etc.) to their flying fields?" I would find the answer interesting, whether or not it confirmed my supposition that a significant number of model rocketeers travel to their flying fields via methods other than vehicles that they own.
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#47
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Quote:
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Black Shire--Draft horse in human form, model rocketeer, occasional mystic, and writer, see: http://www.lulu.com/content/paperba...an-form/8075185 http://www.lulu.com/product/cd/what...of-2%29/6122050 http://www.lulu.com/product/cd/what...of-2%29/6126511 All of my book proceeds go to the Northcote Heavy Horse Centre www.northcotehorses.com. NAR #54895 SR |
#48
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IIRC, there was a brass tube one used on a Saturn 1 or 1B in a NAR mag article/pictorial. I think it was called a spider in the mag, maybe because of the 8 motors. Those are cool, but you have to build an individual spider for each cluster rocket. A flash pan is just that. It's a flat surface with powder spread on it. It leaves soot on the back end of the rocket, but it's generic so it will work on two or twenty motor clusters. Big, tall, short, small, it works on 'em all. As for soot, even a clean ignition of several motors will soot up a rocket if you use a perpendicular blast deflector and don't stand the rocket off far enough.
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I love sanding. |
#49
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Perhaps you might be thinking of this article: http://meatballrocketry.com/pvc-spider/
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John YORF #003 SAM #004 |
#50
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Instead of taking the "minimalist" approach to Cluster Ignition, just use a Car Battery . . .
"Overkill" does not exist and you probably drove to the launch site in a vehicle with a Car Battery . . . Hook up and "Rock & Roll", Old School style ! Dave F. |
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