1. Fuze safe/arm indicator
7. Fuze arming wire
13. Indicator observation window
2. Timer starting pin
8. Safety pin assembly
14. Nose fairing (reference)
3. Timer starting pin bracket
9. Impeller
15. Option time wire
4. Option time setting adjustment
10. Impeller band assembly
16. Retainer slide
5. Primary time setting adjustment
11. Time setting observation window
17. Clip
6. Band release stud and nut
12. Option time pin
18. Safety pin assembly guide tube
Figure 1-3.—Installed mechanical time fuze Mk 339 Mod 1 (with option time wire bomb clusters Mk 20 Mods 3, 4, and 6.
A1.
A2.
A3.
A4.
A5.
A6.
A7.
REVEIW NUMBER 2 ANSWERS TO QUESTIONS Q1. THROUGH Q7.
The M904 is a detonator-safe, mechanical impact nose fuze.
The M904 series fuze is used with Mk 80 (series) bombs.
The M904 fuze has nine arming delays, which you can set for 2 to 18 seconds in
2-second increments; there are any combination of six functioning delays from
instantaneous to 250 milliseconds.
It is important for the M904 to be thermally protected because it increases the
"cook-off" time of bombs subjected to intense heat or flame.
There are three conditions of the M904 fuze—safe, partially armed, and fully
armed. You can check for these conditions by looking in the two observation
windows in the fuze body.
If you can't tell if a fuze is “safe,” you should notify explosive ordnance disposal
(EOD) personnel.
The M904 arms and functions by rotation of arming vanes and alignment of
internal components.
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