Chapter 9 — Discussion and Conclusion

Tests of bursting warimono shells that were manufactured under various conditions were conducted on the ground, and the position of moving stars were analyzed by a photographic method. To make the analysis easy, ring star shells were employed as test shells. The results showed the quantitative relations among design factors, which were not clear until …
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Chapter 8 — Examples of Designing Chrysanthemum shells

8.1 Comparison of Calculated and Experimental Values The accuracy of the empirical equation for the initial velocity of a star was examined in Section 6.5.5. The accuracy of flight velocity can be examined by the probability deviations of the constant n' and log vo. Therefore, the author only compared the results obtained from the empirical …
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Chapter 6 — Formulae for Calculating the Velocity of Stars

First, the author studied the law of motion of stars in the air. The velocity of stars at distant points from the shell burst was then related to the initial velocity of each star. The conditions that produced these initial velocities were investigated, and from this information, equations useful in the designing of shells were …
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Chapter 5 — Supplementary Experiments: Measurement of the Burn Velocity of Burst Charges and Stars in the Normal Atmosphere

To obtain these data, the 16-mm movie camera was used. A Black Powder pasted paper strip was arranged on a piece of metal mesh. Grains of burst charge, or stars, were arranged on the strip at intervals of about 5 cm, and the paper strip was ignited at one end. The grains or stars ignited …
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Chapter 4 — Method for Experiments on Shell Burst, Preparation and Preliminary Calculations

4.1. Experimental Method Three types of bursting charge were prepared: a) potassium perchlorate b) black powder c) potassium chlorate The stars were made with potassium perchlorate as the oxidizer. Sample 5- and 6-inch chrysanthemum shells were prepared with these materials. The shells were reinforced by pasting them with Japanese or Kraft paper. The samples were …
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Chapter 3 — Problems in Designing Chrysanthemum Shellspj

In manufacturing chrysanthemum shells, most of the effort of fireworkers has been directed towards obtaining a certain number of ‘petals’ and at the same time obtaining a large flower radius. In this paper the author evaluates the fundamental conditions required to meet these objectives. The problems are two-fold. The first problem is the initial velocity …
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Chapter 2 — Construction of Chrysanthemum Shells

Japanese firework shells are of two principal types, the so-called poka and the warimono (chrysanthemum). The poka breaks just hard enough to disperse its contents into the air. The shell is made only as strong as it needs to be to withstand the shock of being fired. In contrast, the chrysanthemum shell must be strong …
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Chapter 1 — Preface

The beauty of fireworks arises from their creation of organized patterns, mainly of fire, that consist of colors, lines and their movement and change in space and time. Chrysanthemum shells, also called ‘warimono’ (which means hard-breaking shell’), produce uniquely beautiful effects by creating patterns resembling chrysanthemums on the background of the sky. Until now, the …
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