![\"\"](\"https:\/\/www.verticallimits.nl\/wp-content\/uploads\/\/DECA.03.01.00-motor-17-05-20101.jpg\" "\\"DECA.03.01.00")
<\/a><\/p>\nPropellant mass: 1700gr<\/p>\n
Total impulse: 1730Ns<\/p>\n
Average thrust: 690N<\/p>\n
Thrust\u00a0time: 3,5s<\/p>\n
ISP, delivered: 104s<\/p>\n
Motor classification: K670<\/p>\n
Propellant type: KNER (Erytritol) 65\/35<\/p>\n
Goals\u00a0<\/h3>\n\n- 12 bates grains in a 54mm motor<\/li>\n<\/ul>\n
Design & Construction<\/h3>\n
Motor<\/strong><\/p>\nThe DECA 12 grain\u00a0is\u00a0a 54mm motor\u00a0quite\u00a0similar to the DECA\u00a08 grain\u00a0but instead carries\u00a012 bates grains.\u00a0Total impuls\u00a0will be\u00a0 approximately 1700-2100Ns. The nozzle has a 16mm throat and\u00a0is optimised for the 20mm core Bates grains\u00a0(core-to-throat ratio of about 1,5:1 to avoid erosive burning). Ae\/At ratio is 6,0:1. The nozzle is held in place with 2 rows of 6x –\u00a0M3\u00a0countersunk hex socket bolts. Forward bulkhead is retained by the coupler which is secured the same way as\u00a0the nozzle.<\/p>\n
Ignition<\/strong><\/p>\nUpdate: for the flight motor a revised\u00a0igniter a 50\/50 (8gram total) mix is felt to work better, e.g. lower initial peak and more heat transfer.<\/p>\n
Igniter static test 04.09.2010: 8,0 grams of ignition mixture. Peak pressure 32 bar requires approximately\u00a05gr BP igniter charge.\u00a0 Mixture used: 5,0 grams of\u00a0blackpowder & 3,0 grams of magnesium powder. Additionaly all grains coated with BP isopropanol slurry. Thrust curve shows initial peak with extended delay in pressure built up.<\/p>\n
\u00a0
\nPc . At = ( F \/ g ) \/ CF<\/p>\n
Pc \u2022 2,02=\u00a0 ( 700 \/ 9,81 ) \/ 1,10\u00a0<\/p>\n
Pc =\u00a032 Bar<\/p>\n
CFmax = 1,10<\/p>\n
Throat aera\u00a0( At = 2,02 )
\n\u00a0
\n(g = 9,81 m \/ s)
\n\u00a0<\/p>\n
Propellant<\/strong><\/p>\nFor\u00a04 grains, weigh out the right amount of KN &\u00a0ER in a bowl: 468gr KN + 252gr\u00a0ER = 720gr KNER and mix \/ blend thoroughly.<\/p>\n
Per bates grain 143gr + 2 gr = 145gr.<\/p>\n
Casting pan set at mid 165\u00b0 C.<\/p>\n
While casting KNER bates grains the freezing characteristic of Erythritol was observed and found to be annoying. The top closure froze the KNER to the inhibiter and when pressure was applied it crumbled the inhibiter rather then compressing the propellant. An cold closure did not work but a\u00a0closure heated to 100\u00ba C. also did not do the trick. The procedure which gave a 50\/50 succes rate was carefully poor the propellant in 2-3 times. Clear the\u00a0in hibiter and\u00a0to push down the closure untill molten KNER (mostly ER) was extruded between coring rod and closure. Then waited for the KNER on top of the closure\u00a0to freeze after which the spring was tightened.<\/p>\n
Notes<\/h3>\n
.<\/p>\n
Static Test I – 04.09.2010<\/h3>\n
54mm, 12 BATES grains, KNER 6535 Static Test I \u2013 04.09.10<\/a><\/p>\nDECA III motor – 12 grains KNER – 25.08.2010<\/a>\u00a0– pre-static tests actuals.<\/p>\nDECA, 12 bates grain igniter charge calculator – 01.09.2010<\/a>\u00a0– 32 bar requires approximately\u00a05gr BP igniter charge.<\/p>\nPre test mass = 3517gr.<\/p>\n
Post flight analysis<\/h3>\n
\u00a0.<\/p>\n
Conclusion<\/h3>\n
.<\/p>\n
Library<\/h3>\n\n- DECA 12 grain – 2010 Rocket Motor Assembly Propellant Loading Manual – 28.09.2010<\/a><\/li>\n
- CAD drawings<\/li>\n
- Straightcut<\/a>\u00a0– Throat Design Criteria for Conical Nozzles with Straight-Cut Throats<\/li>\n
- Propellant Data & Burn Rate KNER<\/a><\/li>\n
- Richard Nakka’s Experimental Rocketry Web Site – Technical Notepad #5 — KNER Ideal Performance Calculations<\/a><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
Introduction Propellant mass: 1700gr Total impulse: 1730Ns Average thrust: 690N Thrust\u00a0time: 3,5s ISP, delivered: 104s Motor classification: K670 Propellant type: KNER (Erytritol) 65\/35 Goals\u00a0 12 bates grains in a 54mm motor Design & Construction Motor The DECA 12 grain\u00a0is\u00a0a 54mm motor\u00a0quite\u00a0similar to the DECA\u00a08 grain\u00a0but instead carries\u00a012 bates grains.\u00a0Total impuls\u00a0will be\u00a0 approximately 1700-2100Ns. The nozzle<\/p>\n
Design & Construction<\/h3>\n
Motor<\/strong><\/p>\n The DECA 12 grain\u00a0is\u00a0a 54mm motor\u00a0quite\u00a0similar to the DECA\u00a08 grain\u00a0but instead carries\u00a012 bates grains.\u00a0Total impuls\u00a0will be\u00a0 approximately 1700-2100Ns. The nozzle has a 16mm throat and\u00a0is optimised for the 20mm core Bates grains\u00a0(core-to-throat ratio of about 1,5:1 to avoid erosive burning). Ae\/At ratio is 6,0:1. The nozzle is held in place with 2 rows of 6x –\u00a0M3\u00a0countersunk hex socket bolts. Forward bulkhead is retained by the coupler which is secured the same way as\u00a0the nozzle.<\/p>\n Ignition<\/strong><\/p>\n Update: for the flight motor a revised\u00a0igniter a 50\/50 (8gram total) mix is felt to work better, e.g. lower initial peak and more heat transfer.<\/p>\n Igniter static test 04.09.2010: 8,0 grams of ignition mixture. Peak pressure 32 bar requires approximately\u00a05gr BP igniter charge.\u00a0 Mixture used: 5,0 grams of\u00a0blackpowder & 3,0 grams of magnesium powder. Additionaly all grains coated with BP isopropanol slurry. Thrust curve shows initial peak with extended delay in pressure built up.<\/p>\n \u00a0 Pc \u2022 2,02=\u00a0 ( 700 \/ 9,81 ) \/ 1,10\u00a0<\/p>\n Pc =\u00a032 Bar<\/p>\n CFmax = 1,10<\/p>\n Throat aera\u00a0( At = 2,02 ) Propellant<\/strong><\/p>\n For\u00a04 grains, weigh out the right amount of KN &\u00a0ER in a bowl: 468gr KN + 252gr\u00a0ER = 720gr KNER and mix \/ blend thoroughly.<\/p>\n Per bates grain 143gr + 2 gr = 145gr.<\/p>\n Casting pan set at mid 165\u00b0 C.<\/p>\n While casting KNER bates grains the freezing characteristic of Erythritol was observed and found to be annoying. The top closure froze the KNER to the inhibiter and when pressure was applied it crumbled the inhibiter rather then compressing the propellant. An cold closure did not work but a\u00a0closure heated to 100\u00ba C. also did not do the trick. The procedure which gave a 50\/50 succes rate was carefully poor the propellant in 2-3 times. Clear the\u00a0in hibiter and\u00a0to push down the closure untill molten KNER (mostly ER) was extruded between coring rod and closure. Then waited for the KNER on top of the closure\u00a0to freeze after which the spring was tightened.<\/p>\n .<\/p>\n 54mm, 12 BATES grains, KNER 6535 Static Test I \u2013 04.09.10<\/a><\/p>\n DECA III motor – 12 grains KNER – 25.08.2010<\/a>\u00a0– pre-static tests actuals.<\/p>\n DECA, 12 bates grain igniter charge calculator – 01.09.2010<\/a>\u00a0– 32 bar requires approximately\u00a05gr BP igniter charge.<\/p>\n Pre test mass = 3517gr.<\/p>\n \u00a0.<\/p>\n .<\/p>\n Introduction Propellant mass: 1700gr Total impulse: 1730Ns Average thrust: 690N Thrust\u00a0time: 3,5s ISP, delivered: 104s Motor classification: K670 Propellant type: KNER (Erytritol) 65\/35 Goals\u00a0 12 bates grains in a 54mm motor Design & Construction Motor The DECA 12 grain\u00a0is\u00a0a 54mm motor\u00a0quite\u00a0similar to the DECA\u00a08 grain\u00a0but instead carries\u00a012 bates grains.\u00a0Total impuls\u00a0will be\u00a0 approximately 1700-2100Ns. The nozzle<\/p>\n
\nPc . At = ( F \/ g ) \/ CF<\/p>\n
\n\u00a0
\n(g = 9,81 m \/ s)
\n\u00a0<\/p>\nNotes<\/h3>\n
Static Test I – 04.09.2010<\/h3>\n
Post flight analysis<\/h3>\n
Conclusion<\/h3>\n
Library<\/h3>\n
\n