USNBD, Bombs and Fuzes; Section III - Bomb Fuzes: AN-M100A2, AN-M101A2, AN-M102A2

U.S.N.B.D. - UNITED STATES - BOMBS AND FUZES; PYROTECHNICS

SECTION III - BOMB FUZES

DATA:		U.S. ARMY NOSE FUZE
		AN-M100A2 AN-M101A2 AN-M102A2
BOMBS USED IN
AN-M100A2	AN-M30, 100 lb. G.P.
	AN-M57, 250 lb. G.P.
	AN-M88, 220 lb. Frag.	(Service)
	M81, 260 lb. Frag.	MECHANICAL IMPACT
AN-M101A2	AN-M43, 500 lb. G.P.
	AN-M64, 500 lb. G.P.	M100 AN-M100A1
	AN-M58, 500 lb. S.A.P.	M101 AN-M101A1
	AN-M76, 500 lb. Incend.	M102 AN-M102A1
	AN-M78, 500 lb. Chem.	(Obsolete)
	M32, 600 lb. G.P.
AN-M102A2	AN-M44, 1000 lb. G.P.
	AN-M65, 1000 lb. G.P.
	AN-M59, 1000 lb. S.A.P.
	AN-M79, 1000 lb. Chem.
	M33, 1100 lb. G.P.
	AN-M34, 2000 lb. G.P.
	AN-M66, 2000 lb. G.P.
	M103, 2000 lb. S.A.P.
	AN-M56, 4000 lb. L.C.
FUNCTIONING:	M14 interchangable primer detonator with delays of .01, .025, .1 or .24 second or nondelay
ARMED CONDITION	When gear carrier stop protrudes less than 1 inch below vane cup.
FUZES USED WITH	AN-M 103 normally, M139, AN-M139, M140, AN-M104A1, M163, M164, M165, M135, M135A1, M136, M136A1, M166, Mk243, T50E1, T50E4, T62, T91, T92.

ARMING DATA		Vane Revs.	Air Travel	Min. Vert. Drop
	AN-M102A2	150-170	445-485 ft.	40-50 ft.
	AN-M101A2	150-170	555 ft.	60-70 ft.
	AN-M102A2	150-170	465-665 ft.	85 ft.

VANE SPAN	5 in. (4 vanes)
MAX. BODY DIAMETER	1.5 in.
OVERALL LENGTH	AN-M100A2 9.6 in.; AN-M101A2 12.6 in.; AN-M102A2 16.6 in.
MATERIAL	Cadmium plated steel with brass striker block, primer detonator holder and other small parts.

GENERAL:

These three fuzes are identical except for length of arming stem. Larger bombs re-quire a longer arming stem so that vanes can catch the air slip from the bomb.

OPERATION:

As the vanes rotate, the pinion gear which is attached to the vane assembly revol-ves around the stationary gear. Since the movable gear has 30 teeth and stationary gear 29 teeth, the movable gear is rotated clockwise one tooth per revolution of the pinion and hence unthreads from the firing plunger as the movable gear is rotated. In unthreading, the arming stem lifts the movable gear and since the stationary gear is held by a collar threading into the lower extension of the movable gear sleeve, the sta-tionary gear is lifted also. After 150-170 revolutions of the vanes, the double-threaded arming stem will have unthread from the firing plunger and the fuze will be armed. Further air travel will unthread the arming stem from the fuze body and the entire as-sembly will fly off. On impact, the firing plunger will overcomes the creep spring and the striker will function the primer detonator.

EARLY DESIGNS:

The M100, M101 and M102 fuzes had a fixed delay of .1 sec., and had 24 single threads on the arming stem. Had eight broad vanes less pitch and required approxima-tely 720 vane revolutions to arm. AN-M100A1, AN-M101A1, and AN-M102A1 incorpora-ted interchangeable M14 primer detonator. The A2 modification then reduced the num-ber of vanes to four, and the number of threads to 16 double threads, thus decreasing the arming time to 150-170 vane revolutions.

REMARKS:

When these fuzes are used in the 2000 lb. Frag., 500 lb. Incendiary, 500 lb., 1000 lb., 2000 lb. chem. and 4000 lb. L.C. the M14 primer detonator should have non-delay functioning. On G.P. and S.A.P. bombs the length of the short delay will be gou-verned by the tactical use. The .24 second delay primer detonator was developed for these fuzes for use in connection with the Mk243 nose fuze. Fuzes equipped with this primer detonator will function at a depth of 25 ft. and are more accurate than the AN-Mk230, especially on high velocity impact.