OP 1664 - U.S. Explosive Ordnance (Vol. 2); Part 6 - Bombs and Bomb Fuzes; Chapter 20 - Bomb Fuzes; Section 2 - Army-Designed Bomb Fuzes: T91 and M168 (V.T.)

U.S. EXPLOSIVE ORDNANCE

PART 6 - BOMBS AND BOMB FUZES

Chapter 20 - BOMB FUZES

Section 2 - ARMY-DESIGNED BOMB FUZES

T91 and M168 (V.T.)

Bombs
M168	100-lb. G.P. AN-M30 250-lb. G.P. AN-M57 220-lb. Frag. AN-M88 260-lb. Frag. M81 2,000-lb. G.P. AN-M66
Functioning	30 - 60 feet above ground when released below 8,000 feet
Armed condition	If vanes are free to rotate, assumed to be armed unless safety pin can be inserted
Arming time
T91	2,000 ft. min. S.A.T.
Fuzes used with	AN-M100A2 series normally; M160 series
Over-all length, inches	10.4
Body diameter, inches	3.4
Material	Steel body, plastic top, metal ring, steel or plastic vanes

General: This is a V.T. fuze of the ring type, similar to the T50E1 series. The V.T. Fuzes T91 differ from the T50E1 group in that they have greater sensitivity and are spe-cially designed to be used for low-level, medium-level, dive, and toss bombing. These ring-type fuzes are especially sensitive to "passing" objects and therefore are useful in defoliating by blast and in getting roof-top bursts in city areas.

At present, about 85 per cent will operate properly upon approach to the target; 5 to 10 per cent may function spontaneously after arming, and 5 per cent will be inoperative. These fuzes have minimum S.A.T. reduced to 2,000 feet for use in low, medium, dive, and toss bombing. S.A.T. can be extended by use of the Air-Travel Arming Delay M1.

Operation: Like the T50 series.

Remarks: These fuzes are not to be used for horizontal bomb runs, because the mi-nimum S.A.T. is such that the fuzes may be completely armed when only 250 feet below the carrying aircraft, and early bursts in this production would cause damage to the plane.

Figure 355. V.T. Fuze M168 - Arming Device