54:
40:
20:
30:
140:
fuze: simple deceleration or change of direction would not activate it, only direct physical contact between the hammer projecting from the nose and an external object. The basic mechanism was a steel hammer on the end of a spindle projecting forward from the nose of the fuze. The slightest movement inwards of this spindle caused the fuze to detonate and hence explode the shell before it penetrated the ground.
152:
fuze body forced the tape wrapped around the spindle against the underside of the hammer head, preventing the tape from unwinding. When acceleration ceased shortly after the shell left the gun barrel, the hammer and fuze body were travelling at the same speed and the hammer ceased to "set back", freeing the tape. The shell's rotation then caused a weight on the end of the tape to unwind the tape through
278:"Compared with the French 75-mm H.E. which gave instantaneous effect on graze or burst very soon after ricochet, the British 18-pdr. H.E. shell that buried themselves on graze or burst from 10 to 15 ft. in the air after ricochet were comparatively valueless for wire-cutting". History of the Ministry of Munitions Volume X Part II, page 5, on the situation in early 1916.
106:
limited sensitivity: they could not detect contact with a frail object like barbed wire or soft ground surface. Hence they would penetrate objects or ground slightly before detonating, instead of on the ground surface as required for wire cutting. These graze and impact fuzes continued to be used as intended for medium and heavy artillery high-explosive shells.
287:"Authority was given to replace No. 100-type fuse by No. 106 in a large proportion of the medium shell and to adopt it in certain heavy natures between August and November 1916, but there was considerable delay before the new fuse was produced in large numbers". History of Ministry of Munitions, Volume X, Part V, page 48
97:), intended to burst above head-height for anti-personnel use. British heavy artillery was expected to attack fortifications, requiring high-explosive shells to penetrate the target to some extent before exploding. Hence British artillery fuzes were optimised for these functions. Experiences of trench warfare on the
125:
for cutting barbed-wire defences. The disadvantage of shrapnel for this purpose was that it relied on extreme accuracy on setting the fuze timing to burst the shell close to the ground just in front of the wire: if the shell burst fractionally too short or too long it could not cut the wire, and also
101:
in 1914–1916 indicated that
British artillery was unable to reliably destroy barbed-wire barricades, which required shells to explode instantaneously on contact with the wire or ground surface: British high-explosive shells would penetrate the ground before exploding, rendering them useless for
159:
After the tape detached during flight, the hammer was prevented from being forced inward by air resistance by a thin "shearing wire" passing through the hammer spindle, which was easily broken by the hammer encountering any physical resistance. The spindle was prevented from rotating relative to the
139:
The number 106 fuze drew on French technology to provide a mechanism for reliably detonating a high-explosive shell instantaneously when the nose made physical contact with the slightest object like a strand of barbed wire or the ground surface. Hence it was a "direct action" rather than a "graze"
151:
The first safety mechanism was a length of brass tape wrapped around the spindle between the fuze body and the hammer head, which prevented the spindle from moving inward. On firing, the hammer's inertia caused it to "setback" fractionally i.e. it resisted acceleration, and hence the accelerating
105:
British No. 100 and later Nos. 101, 102 and 103 nose "graze" fuzes available in the field from August 1915 onwards could explode a high-explosive shell very quickly on experiencing a major change in direction or velocity, but were not "instantaneous": there was still some delay in activation, and
164:
firing, the shutter resisted acceleration ("setback") and the accelerating shell body pushed against it, preventing the shutter from moving. When acceleration ceased shortly after the shell left the gun barrel, the shutter ceased to "set back" and was free to spin outwards, activating the fuze.
163:
Later versions (designated "E") incorporated an additional safety mechanism: an internal "shutter", also activated by rotation of the shell after firing, which closed the channel between the striker in the nose and the powder magazine in the base until it was clear of the gun which fired it. On
156:, hence activating the fuze. Because of this, usage of this fuze in action was characterised by British troops in the front lines noticing the descending tapes detached from the fuzes as they travelled overhead towards the enemy lines.
242:
and six-inch field guns were targeted on enemy artillery, and by bursting above ground could cause maximum damage to enemy artillery, mountings and crew. It was also approved as the primary fuze for high-explosive shells for
176:
in late 1916, and entered service in early 1917. From then onwards
British forces had a reliable means of detonating high-explosive shells on the ground surface without merely digging holes as they had previously.
126:
the spherical shrapnel balls were not of an optimal shape for cutting strands of wire. While the 2-inch mortar bombs cut wire effectively, their maximum range of 570 yards (520 m) limited their usefulness.
208:
Hammer encounters physical resistance (e.g. earth, rocks, wire) and decelerates, causing the momentum of the fuze body to snap the shearing wire and force the detonator onto the pointed end of the hammer
143:
The steel hammer had a softer aluminium cap which absorbed the force of a glancing blow and prevented the spindle from bending or breaking, reducing the risk of misfire.
335:
Official
History of the Ministry of Munitions, 1922. Volume X : The Supply of Munitions. Facsimile reprint by Imperial War Museum and Naval & Military Press
386:
253:
There were many versions of the No. 106 and it remained in service in the form of its streamlined variant, the No. 115, until World War II.
34:
Later No. 106 E Mk IV with safety shutter, showing before use, before firing, during flight and on impact, and action of tape and shutter
238:
6-inch field guns at long range. Its instantaneous action also made it useful for counter-battery fire: high-explosive shells fired by
340:
330:
199:
Fuze continues to spin between 1,300 and 1,700 revolutions per minute: safety shutter spins out ("E" models from 1917 onwards)
187:
Fuze accelerates violently on firing: the setback of the hammer prevents tape from unwinding while still in or near gun barrel
269:
Ministry of
Munitions History 1922. Volume X The Supply of Munitions. Part V: Gun Ammunition Filling and Completing. Page 55.
212:
Detonator explodes, sending flame through the centre of the fuze body to C.E. (composition exploding) magazine in fuze base
160:
fuze body in flight, and hence from snapping the shearing wire, by a guide pin passing through a cutout in the spindle.
223:
98:
226:
in 1917 and 1918, the No. 106 fuze was typically employed on high-explosive shells for cutting barbed wire, fired by
308:
Farndale 1986 page 158, quoting War Office
Artillery Notes No. 4 - Artillery in Offensive Operations, January 1917.
231:
325:, History of the Royal Regiment of Artillery. Western Front 1914–18. London: Royal Artillery Institution, 1986.
227:
118:
94:
90:
62:
58:
53:
45:
39:
244:
235:
122:
173:
110:
336:
326:
202:
153:
196:
Fuze exits gun barrel and ceases accelerating: the hammer ceases to setback, freeing up tape
322:
205:
of weight on the end of the tape causes tape to unwind and detach from the hammer spindle
381:
353:
114:
86:
74:
19:
29:
375:
239:
172:
The fuze was first used experimentally in action in the later phases of the
77:, first tested in action in late 1916 and deployed in volume in early 1917.
180:
The chain of events necessary to allow the fuze to activate a shell were:
190:
52:
38:
218:
Flame activates shell function, typically high-explosive or smoke
193:
in gun barrel causes the shell and hence fuze to spin rapidly
299:
History of
Ministry of Munitions, Volume X, Part V, page 56
215:
C.E. magazine detonates, sending flame into the shell nose
24:
Early model No. 106 Mk II, without safety shutter, 1917
184:
Gunner removes the fuze's safety cap before loading
85:Britain entered World War I with a policy of using
354:"Chapperton Down Artillery School [film]"
250:This fuze was also used to burst smoke shells.
73:was the first British instantaneous percussion
16:British instantaneous percussion artillery fuze
8:
121:and spherical high-explosive bombs fired by
295:
293:
65:, with 106 Mk II fuze with safety cap on
28:
18:
262:
7:
48:shell, 106 Mk II fuze and safety cap
360:. Imperial War Museum. 10:05:25:00
113:in 1916, British forces relied on
14:
230:at short to medium range, and by
387:Artillery of the United Kingdom
1:
123:2-inch "plum-pudding" mortars
102:destroying surface targets.
403:
358:film.iwmcollections.org.uk
147:Arming and safety features
247:from August 1916 onward.
109:Up to and including the
66:
50:
36:
26:
245:QF 4.5 inch howitzers
228:18-pounder field guns
119:18-pounder field guns
56:
42:
32:
22:
257:Notes and references
135:Detonation mechanism
89:for its field guns (
63:18-pounder field gun
174:Battle of the Somme
111:Battle of the Somme
67:
51:
37:
27:
203:Centrifugal force
154:centrifugal force
394:
369:
367:
365:
309:
306:
300:
297:
288:
285:
279:
276:
270:
267:
402:
401:
397:
396:
395:
393:
392:
391:
372:
371:
363:
361:
351:
349:
323:Martin Farndale
318:
313:
312:
307:
303:
298:
291:
286:
282:
277:
273:
268:
264:
259:
170:
149:
137:
132:
115:shrapnel shells
87:shrapnel shells
83:
71:number 106 fuze
49:
35:
25:
17:
12:
11:
5:
400:
398:
390:
389:
384:
374:
373:
348:
347:External links
345:
344:
343:
333:
317:
314:
311:
310:
301:
289:
280:
271:
261:
260:
258:
255:
220:
219:
216:
213:
210:
206:
200:
197:
194:
188:
185:
169:
166:
148:
145:
136:
133:
131:
128:
82:
79:
75:artillery fuze
43:
33:
23:
15:
13:
10:
9:
6:
4:
3:
2:
399:
388:
385:
383:
380:
379:
377:
370:
359:
355:
346:
342:
341:1-84734-884-X
338:
334:
332:
331:1-870114-00-0
328:
324:
320:
319:
315:
305:
302:
296:
294:
290:
284:
281:
275:
272:
266:
263:
256:
254:
251:
248:
246:
241:
237:
233:
229:
225:
224:Western Front
217:
214:
211:
207:
204:
201:
198:
195:
192:
189:
186:
183:
182:
181:
178:
175:
168:Use in action
167:
165:
161:
157:
155:
146:
144:
141:
134:
129:
127:
124:
120:
116:
112:
107:
103:
100:
99:Western front
96:
92:
88:
80:
78:
76:
72:
64:
60:
55:
47:
41:
31:
21:
362:. Retrieved
357:
352:War Office.
350:
321:General Sir
316:Bibliography
304:
283:
274:
265:
252:
249:
221:
179:
171:
162:
158:
150:
142:
138:
108:
104:
84:
70:
68:
44:Unassembled
376:Categories
364:1 November
240:60-pounder
95:18-pounder
91:13-pounder
81:Background
46:18-pounder
117:fired by
57:Complete
222:On the
209:spindle
191:Rifling
339:
329:
236:Mk XIX
232:Mk VII
130:Design
382:Fuzes
59:round
366:2013
337:ISBN
327:ISBN
234:and
93:and
69:The
61:for
378::
356:.
292:^
368:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
