Mk 20 Rockeye's?

[Recluse]

According to a post by Razbam_ELMO,  some time ago on the BUGS forum:

 

"Note: the MK20 CBU in PRI fuse mode will open and release the bomblets at 1500FT ASL while the OP fuze will open up at 1500FT AGL."

 

 

Edited March 28, 2021 by Recluse

[Wisky]

according to @RAZBAM_ELMO PR will release bomblets at 1.500 ft above sea level. OP will release them at 1.500 ft above ground level.

 

so its recommended to drop in OP and at least 4000 - 7000 ft above the target

[Chaders]

On 3/28/2021 at 6:32 PM, Recluse said:

According to a post by Razbam_ELMO,  some time ago on the BUGS forum:

 

"Note: the MK20 CBU in PRI fuse mode will open and release the bomblets at 1500FT ASL while the OP fuze will open up at 1500FT AGL."

 

 

 

 

I’ve never understood this answer as the MK20 has a mechanically timed fuse (not a barometric or RADALT) according to all the references I’ve found online. 

[Fisherman82]

26 minutes ago, Chaders said:

 

I’ve never understood this answer as the MK20 has a mechanically timed fuse (not a barometric or RADALT) according to all the references I’ve found online. 

Indeed, I saw that to and wondered how he means the Mk20 knows its altitude AGL.

[Frederf]

5 hours ago, Chaders said:

 

I’ve never understood this answer as the MK20 has a mechanically timed fuse (not a barometric or RADALT) according to all the references I’ve found online. 

Some have Mk 339. Some have FMU-140. Most (all?) of the Rockeye II in DCS have FMU-140.

[Chaders]

On 4/1/2021 at 7:06 PM, Frederf said:

Some have Mk 339. Some have FMU-140. Most (all?) of the Rockeye II in DCS have FMU-140.

Ahh yeah I’d forgotten they could be fitted with the FMU-140 although in that case would they still have the PR/OP wires? I didn’t think they had the two fusing wires when used with 140s.

[Frederf]

FMU-140 has two wires. Primary is Doppler radar proximity, primary plus option is a fixed time to open. Option only is a dud.

[Fri13]

https://cat-uxo.com/uxo-types/fuzes/fmu-140-fuze

 

So only adjustable by the weapons crew and for 10 pre-defined altitudes between 300 and 3000 feet (90-900 meters). And then a secondary timed fuze.

 

https://cat-uxo.com/uxo-types/fuzes/mk-339-fuze

 

And that has in-flight (pilot) selectable fuze mode from two options, both that weapons crew sets on the ground for wanted timers. 

 

It makes more sense to use the Mk 339 as all the pilot needs to do is to check which timer has needed fall time / altitude before release, and then simply fly over the target at the proper altitude related to that (like have a timer of 1.2 seconds that gives example ~800 ft fall time and then fly 800 + wanted spread altitude (ie 300 ft) over the target, so 1100-1200 ft to get proper release)

 

Edit: So what we have here again is that ED should require pilot to set the fuzes in kneeboard/rearming/mission_briefing screen before take-off. And then pilot to fly based the set parameters for the fuzes. 

Edited April 7, 2021 by Fri13

[Shrike88]

Why was the TER removed from the MK-20's  ?