CBU 97 burst height question

[555]

When programming in burst height of the CBU97, the manual says "BURST HEIGHT: determines the altitude (in feet MSL) at which the
bomblets will be released" (page 496). I'm not sure that this makes sense to me - the highest value that can be set is "K" or 3000 feet. What if you wanted to drop these on a target at say 4000 ft MSL? Surely this setting should be AGL?

[LordOrion]

3 minutes ago, 555 said:

When programming in burst height of the CBU97, the manual says "BURST HEIGHT: determines the altitude (in feet MSL) at which the
bomblets will be released" (page 496). I'm not sure that this makes sense to me - the highest value that can be set is "K" or 3000 feet. What if you wanted to drop these on a target at say 4000 ft MSL? Surely this setting should be AGL?

I might be worng but IMHO can't be AGL, unless the weapon has a altitude measurement device on board (like a radar).

Likely the fuze uses pressure to compute the altitide thus should be MSL

[KlarSnow]

The fuze is a radar proximity fuze... If it doesnt have that it opens based on time.

[555]

10 minutes ago, LordOrion said:

I might be worng but IMHO can't be AGL, unless the weapon has a altitude measurement device on board (like a radar).

Likely the fuze uses pressure to compute the altitide thus should be MSL

I would think that using a radar altimeter would be able to measure AGL, but the manual specifically mentions MSL so it must be a barometric altimeter. That said, I go back to my question then this method of deployment would not work at any point over 3000 ft MSL which doesn't make sense to me. I suppose then you would need to use the "Burst time" option, which seems a little like guesswork as you would need to understand the time based on your altitude etc...

[MagicSlave]

Indeed, there are two fuze options: internal and the fzu-39/b. The former has a timer and the latter a small radar altimeter, see for example: https://cat-uxo.com/explosive-hazards/fuzes/fzu-39-fuze

Sent from my FP4 using Tapatalk

[KlarSnow]

google FZU-39... this is the radar proximity fuze you are setting.

If the manual says MSL it is a typo.

[555]

1 minute ago, KlarSnow said:

google FZU-39... this is the radar proximity fuze you are setting.

If the manual says MSL it is a typo.

Yep - the manual says MSL so clearly a typo - thanks for clarifying this.