It must remain safe in stowage, while it is handled in normal movement, and during loading and downloading evolutions. It must remain safe while being carried aboard the aircraft. It must remain safe until the bomb is released and is well clear of the delivery aircraft (arming delay or safe separation period). Depending upon the type of target, the fuze may be required to delay the detonation of the bomb after impact for a preset time (functioning delay). Functioning  delay  may  vary  from  a  few milliseconds to many hours. It should not detonate the bomb if the bomb is accidentally released or if the bomb is jettisoned in a safe condition from the aircraft. To  provide  these  qualities,  a  number  of  design features are used. Most features are common to all types of fuzes. Electrical Fuzes Electrical  fuzes  have  many  characteristics  of mechanical fuzes. They differ in fuze initiation. An electrical impulse is used to initiate the electrical fuze rather  than  the  mechanical  action  of  arming  vane rotation. An  electrical  pulse  from  the  delivery  aircraft charges capacitors in the fuze as the bomb is released from the aircraft. Arming and functioning delays are produced by a series of resistor/capacitor networks in the fuze. The functioning delay is electromechanically initiated, with the necessary circuits closed by means of shock-sensitive switches. The  electric  bomb  fuze  remains  safe  until  it  is energized by the electrical charging system carried in the aircraft. Because of the interlocks provided in the release equipment, electrical charging can occur only after the bomb is released from the rack or shackle and has begun its separation from the aircraft; however, it is still connected electrical y to the aircraft’s bomb arming unit. At this time, the fuze receives an energizing charge required for selection of the desired arming and impact times. SPECIAL  SAFETY  FEATURES Some fuzes incorporate special safety features. The most important safety features are detonator safe, shear safe, and delay arming. Detonator safe fuzes do not have the elements of their firing train in the proper position for firing until the fuze is fully armed. The elements remain firmly fixed and out of alignment in the fuze body while the fuze is unarmed. This  increases  safety  during  shipping, stowing, and handling of the fuze. The arming action of the fuze aligns the firing train. A shear-safe fuze does not become armed if its arming mechanism is damaged or completely severed from the fuze body, The arming mechanism of the fuze protrudes from the bomb, and it might be severed from the  fuze  body  if  the  bomb  is  accidentally  dropped. Shear-safe fuzes give additional security for carrier operations and for externally mounted bombs. Delay arming mechanically or electrically slows the arming of the fuze. It keeps a fuze in the safe condition until the bomb falls far enough away from or long enough from the aircraft to minimize the effects of a premature explosion. Delay arming helps to make carrier operations safe because a bomb accidentally released during landing or takeoff ordinarily will not have sufficient air travel, velocity, or time to fully arm the fuze. Q1. Q2. Q3. Q4. Q5. Q6. Q7. Q8. REVIEW NUMBER 1 Name the device that controls bomb detonation. The time or number of vane revolutions needed for  the  firing  train  to  align  after  a  bomb  is released is the ________. Describe the functioning time of a fuze. The distance along the trajectory that a bomb travels from the releasing aircraft in an unarmed condition  is  the________. List the two basic classes of fuzes. Describe the basic principle of the mechanical fuze. What means is used to initiate an electrical fuze ? List   the   three   special   safety   features incorporated into fuzes. 1-2