Torpedo friction test tests

A common hazard in the handling of explosives is for them to be subjected to the effects of a blow which is to some extent at a glancing angle. This corresponds neither to pure impact, nor to pure friction. A corresponding simple and useful test for the safety of an explosive during handling is the torpedo friction test illustrated in Fig. 6.8. In this, a torpedo... 

Torpedo friction test. A test of sensitiveness to impact and friction (see p. 70). 

A small amt of the expl was spread on a large stone table and then struck a glancing blow with a mallet made either of rawhide or beech wood. The expl was thus subjected to the combined effect of shock and friction. If the sample exploded, the test was repeated by hitting the expl a glancing blow with a broomstick held at an angle of 60° against the table, taking care that the movement of the stick is in the direction of its axis. If an expin were obtd, the test was repeated on a hard wooden table and finally on a soft wooden one. If an expl, other than those used for caps, detonators, etc exploded, even partly on soft wood, it was considered to be too sensitive for use (Compare with Torpedo Friction Test, described as quantitative test i, Fi g F22)... 

Sliding Torpedo Test. See under Torpedo Friction Test in Vol 6, F205-L to F206-L... 

Friction tests that utilize violent rubbing against a hard or abrasive surface are the Pantex skid test, the oblique impact test, and also the friction-impact torpedo test [12]. These tests also are for secondary explosives and involve the shear strength and penetration hardness of the softer materials. 

Water is the best hydrophilic substance and it has often been asked whether an object moving in water should be hydrophilic or hydrophobic for reduced friction. Both types of coatings are available on the market but based on the hydrophilic nature of fish scales, it is most likely that a boat with a hydrophilic surface may move faster or consume less fuel than a boat with a hydrophobic surface, This can be tested by dropping a torpedo (with successive characteristics) in a water column and timing the fall between two points along the column. 

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