OP 1664 - U.S. Explosive Ordnance (Vol. 2); Part 6 - Bombs and Bomb Fuzes; Chapter 20 - Bomb Fuzes; Section 2 - Army-Designed Bomb Fuzes: T50E1 and T50E4 (V.T.) (Cancelled)

U.S. EXPLOSIVE ORDNANCE

PART 6 - BOMBS AND BOMB FUZES

Chapter 20 - BOMB FUZES

Section 2 - ARMY-DESIGNED BOMB FUZES

T50E1 and T50E4 (V.T.) (Cancelled)

Bombs
T50E1	100-lb. G.P. AN-M30 250-lb. G.P. AN-M57 2,000-lb. G.P. AN-M66 220-lb. Frag. AN-M88 260-lb. Frag M81
T50E4	500-lb. G.P. AN-M64 1,000-lb. G.P. AN-M65 500-lb. Chem. AN-M78 1,000-lb. Chem. AN-M79
Functioning	10 - 40 feet avove ground
Armed condition	If vanes are free to rotate, assumed to be armed
Arming time	3,600-ft. min. S.A.T. (some lots of T50E4 3,100-ft.)
Fuzes used with	AN-M1002 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: These are V.T. fuzes of the ring type. They are designed to detonate the bomb at a point above the earth which will give effective fragmentaion. 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 the present stage of development, approximately 80 per cent of the fuzes will ope-rate properly upon approach to the target; up to 15 per cent may function spontaneous-ly after arming bur before approaching the target; and 5 per cent will be inoperative.

Operation: When the bomb is dropped, the arming wire is pulled, releasing the spring-loaded vane locking pin, which jumps out, freeing the vanes for rotation. The vanes ro-tate and drive the electric generator and the worm and spur gear reduction train. After the required number of vane revolutions, the detonator lines up with the booster lead-in and at the same time becomes electrically connected to the firing circuit. The rotor de-tent in the detonator rotor snaps into a hole in the rotor housing, locking the detonator in the armed position and at the same time withdrawing from the keyway in the arming stem. The vanes continue to rotate at high speed, driving the generator, which, in the meantime, has activated the V.T. element and charged the firing condenser. The fuze is now armed. Upon approach to the target under the proper conditions, the V.T. element activates the firing circuit,, which discharges the firing condenser through the electric detonator, initiating the explosive train.

Remarks: These fuzes are mechanically interchangeable with the Nose Fuze AN-M103; but are not tactically interchangeable with impact fuzes or with each other. If the V.T. Fuzes T50E1 are used in bomb sizes for which the V.T. Fuzes T50E4 are specified, very low air bursts will result. The same is true for the reverse transposition.

Some lots of the T50E4 cannot accommodate the Air-Travel Arming Delay M1 because of a much heavier steel ring around the vanes. No delayed arming can be accomplished on these lots of fuzes. If a fuze is found with the vane locking pin gone and the vanes free to rotate, it must be considered armed and should not be used.

Vanes may be either ten-bladed steel vanes or three-bladed platic vanes, interchan-geably.