Nitrate
Chemical formula: KNO3
Also known as:
Saltpeter or Saltpetre
| Potassium Nitrate Chemical formula: KNO3 Also known as: Saltpeter or Saltpetre |
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| Sugar Products used in these tests |
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Marshmallow
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Video 3-7-09C Playtime: 25 seconds Granulated dry propellant Spectracide stump remover mixed with granulated sugar, just as they came from the container without grinding. Burn is slow, incomplete. |
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| Video 4-19-08A Playtime: 20 seconds Finely ground dry propellant About 1 gram of dry KNO3/sugar burned on a brick to illustrate its burning characteristics. It burns much more rapidly than in Test 4, with yellow/purple variegated flame and a lot of smoke. This is the mix that is compressed in a PVC tube to make the Q3 replicas. |
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Video 4-19-08C Playtime: 126 seconds KNO3/Karo Syrup wet mix First mix of 60% KNO3 and 40% Karo Syrup would not burn, despite several seconds' application of torch flame. Second mix of 70% KNO3 and 30% Karo Syrup burned via "dancing pearls" of molten KNO3 that appeared to feed off the mix below them. |
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Video 3-11-09D Playtime: 62 Seconds Wet Mix in Tube Burns OK Placing the KNO3/Karo Syrup mix in a short piece of tube constrained the "dancing pearl" to the surface of the mix, and obtained a lengthy burn. About 1/3 of the mix remained in the tube after the burn. |
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Video 4-18-08B Playtime 143 seconds Demonstrates the effects of overcooking on KNO3/Sugar propellant. Comparison of open-air burn rates for 5 strands of recrystallized propellant, each one inch in length. Starting with very light propellant, ending with dark propellant Strand 1, light ivory color, burned one inch in 9.9 seconds Strand 2, dark ivory brown, burned in 12.4 seconds Strand 3, "peanut butter" brown, burned in 16.5 seconds Strand 4, darker, burning strand self-extinguished twice during burn. Total burn time 25 seconds Strand 5, "caramel" brown, self-extinguished three times, total burn time 26 seconds |
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Video 4-19-08B Playtime: 22 seconds Melted granulated propellant, cooked light brown Melted-sugar propellant made with USP-grade KNO3 and cane sugar. "Peanut-butter" color, burns 10.4 seconds per linear inch at 1 atm. This propellant was cooked darker, to the point that it would not burn continuously at 1 atm. |
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Video 3-7-09A (excerpt) Playtime: 55 seconds Melted granulated propellant, cooked dark brown Melted-sugar propellant made with USP-grade KNO3 and cane sugar. Cooked until color is good match for propellant shown in police photos Burn rate is much slower, but continuous. |
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| 60% KNO3, 40% Dark Karo Syrup Six grams of stump remover KNO3 mixed with 4 grams Dark Karo Syrup yields a light-brown color. This color is much lighter than seen in the police photographs of seized mixtures Sample burned much as in Test 3, but when 70:30 mix was placed in a small paper tube (Mixture Test 4), more than half of it burned. |
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| Device Tests - Q1 and Q2 Propellant processed by melting or recrystallization |
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| Video 4-18-08C Playtime: 34 seconds Recrystallized Propellant, Stochiometric mixture Q2 Replica 1, 66.3grams of dark recrystallized propellant, similar in color and burn rate to strand 5 in Test 2 KNO3 is USP grade. Burned vigorously for about 10 seconds, chuffed once, blew out clay plug and self-extinguished. Propellant burned about 1/3 of it's length, the majority remained unburned in the tube I erroneously used SCH40 PVC pipe in this test, later realizing that the original devices were made with SCH1120 "thinwall" PVC tubing. |
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Video 4-18-08D Playtime: 28 seconds Attempt to measure thrust Q1 Replica 1, made with same mixture as in Test 3, and behaved about the same Fired in static test stand to determine if there were significant thrust. There was not. As in Test 3, it burned vigorously for about 10 seconds then chuffed out. Majority of propellant remained in tube, unburned. |
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| Video 4-27-08B Playtime: 122 seconds Melted dark propellant, USP KNO3 Q1 Replica, 70% KNO3 (USP grade), 30% Cane sugar, melted, brown in color, burns very slowly. Motor burned for a few seconds and went out. Nozzle was enlarged a bit but otherwise intact, so I inserted another fuse and fired it again. Second time it burned for a few more seconds and went out. Kitty litter nozzle plug had fallen away, majority of propellant remained in casing, unburned. |
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| Video 4-27-08C
Playtime: 20 seconds Light recrystallized propellant Q1 Replica, Made with recrystallized propellant containing 60% KNO3, 40% sugars. This fast-burning propellant is expected to be as good as the best melted propellant that might have been used in the original device. Burned briefly, popped kitty litter plug, and went out. Most of the propellant remained in casing, unburned. |
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| Video 4-20-08A
Playtime: 95 seconds Melted, Gordon's Stump Remover Q1 Replica made with melted propellant using 65% Gordon's Stump Remover as KNO3, and 35% cane sugar. Melted in electric skillet, browned until color is a near-match for that seen in photos of propellant in original devices. This propellant burns very slowly, in fact, does not support its own combustion at 1 atmosphere pressure. Four attempts at ignition failed. First two with standard Visco fuse, 0.5 inch penetration into propellant, third with strobe fuse, 1/2 inch penetration, fourth with strobe fuse, 1.5 inch penetration. Propellant burned only while fuse was burning, extinguished immediately when fuse burned out. |
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| Video 3/7/09A Playtime: 187 seconds Basic Melt, coarse KNO3 Q1 Replica made with melted propellant using 65% Spectracide Stump Remover as KNO3, and 35% cane sugar. Melted in electric skillet, browned until color is a near-match for that seen in photos of propellant in original devices. This propellant burns very slowly, in fact, does not support its own combustion at 1 atmosphere pressure. |
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| Video 3/7/09B Playtime: 57 seconds Melted, with finely ground KNO3 Q1 Replica made with melted propellant using 65% Spectracide Stump Remover as KNO3, and 35% cane sugar. This time, the KNO3 is ground in an electric coffee mill to a fine powder before the propellant is processed. Melted in electric skillet, browned until color is a near-match for that seen in photos of propellant in original devices. |
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| Video 3/8/09A Playtime: 72 seconds Recrystallized and cooked dark Q1 Replica made with recrystallized propellant using 65% Spectracide Stump Remover as KNO3, 23% cane sugar, and 12% corn syrup. Propellant was at first very light in color, but was intentionally overcooked to try to match the photos provided. |
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| Device Q3 Dry-Rammed propellant |
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Video 4-18-08A Playtime: 58 seconds Rammed dry mix, 71:29, heavy tube Q3 Replica 1. Dry-packed propellant, 71% KNO3 (USP), 29% confectioner's sugar. Kitty litter plug at either end. Fuse hole 1/8th inch diameter. Burned with vigor, shooting smoke but not much visible flame. Burn time 35 seconds Error: Using SCH40 pipe in this test. I discovered afterward that originals were made with thinwall PVC |
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| Video 4-19-08A Playtime: 27 seconds Rammed dry mix, lighter tube Second replica of Q3 fired on a static test stand to determine if there were any appreciable thrust. 65% KNO3 (USP), 35% confectioner's sugar. Burned for about 1 second then clay plug "nozzle" blew out. Remaining propellant burned up in about 14 seconds There was a slight peak when nozzle failed, and a few other small peaks I can't explain. Otherwise, no significant thrust was recorded. |
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| Video 4-20-08B1
Playtime: 27 seconds Dry rammed mix, Ground Test. Propellant made with 65% USP-grade KNO3 and 35% confectioner's sugar, packed dry. Fired on sheet of roofing metal so that it would slide easily. Motor accelerated off sheet metal and lodged in grass about 20 feet away. Shows some potential to fly, so flight test attempted next, that will be test 4-20-08B2 |
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Video 4-20-08B2 Playtime: 60 seconds Dry Mix, Flight Test Previous ground test jumped around a bit, so it's time to see if this motor can fly. Propellant with finely ground USP-grade KNO3 and confectioner's sugar. Flew a few feet up, fell, and burned most of it's propellatn on the ground. Note the scorch-mark around the stick. Nozzle enlarged substantially, thought to be cause of low performance. |
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Video 4-26-08B Playtime: 81 seconds Second flight test, ground kitty-litter clay nozzle Q3 Replica, 60% KNO3 (USP), 40% Confectioner's sugar, rammed dry propellant. Stabilized with stick. Popped nozzle, flew a few feet into the air, fell to ground and burned. Clay had been ground in coffee mill before packing, assuming that finely-ground clay would make a better nozzle - that assumption could be wrong. |
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| Video 4-26-08C Playtime: 68 seconds Third flight test Q3 Replica, 60% KNO3, 40% Confectioner's sugar, rammed dry propellant Stabilized with stick. Popped nozzle, flew a few feet into the air, fell to ground, extinguished. About half the propellant remained in the casing. |
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Video 4-26-08A Playtime: 63 seconds One more flight test Q3 Replica, 70% KNO3 (USP), 30% Confectioner's sugar, rammed dry propellant. Stabilized with stick, this one flew about 100 feet up, landed about 300 feet away. The kitty-litter plug held OK this time, remaining in the tube and serving as a nozzle. This one is not eroded as badly as 4/20/08B2, reinforcing my notion that nozzle erosion is prime limiter of performance in these motors. |
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| Reference Motor Test |
Video 4-18-08E Playtime: 17 seconds Widely available, entry-level rocket motors For comparison, a commercial model rocket motor was fired to illustrate how a proper motor should work. This one is and Estes C6-5 motor, very commonly used in model rocket launches. Such motors are available at retailers such as Wal-Mart, hobby shops, and through web order. Quick ignition, 2-second burn, 5 second smoke/delay, then ejection charge fires, expelling the motor from the test stand. Thrust curve is shown at the end of the video. |
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