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Tobius
Post subject: Re: Request for sources to design CIWS MyriadPosted: March 20th, 2017, 3:13 pm
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odysseus1980 wrote: *
Because Myriad came after Sea Zenith, it is possible that vibration problem solved. Oerlikon KBD was a seven barrel gatling, it would have large kick also. But a gatling gun is balanced from its design : If you imagine it rotating in slow motion, there are always two opposite barrels in near or exactly opposite positions. If the latter achieved, the gatling is perfectly balanced.

From the pictures I have seen from Myriad, including the Fincantieri DV800 corvette, its turret looks very similar with that of GDM-A cannon.
I perfectly agree with that. My fault. I might have been unclear. The Gatling should be visualized as a blender with the air being whipped cream. Now imagine rifled bullets spinning into that air storm. As long as you have one set of barrels whipping the air and creating the single vortex, you are fine. But two sets of barrels or four? The corkscrew vortex patterns introduce (wind) side shove forces at the muzzles that have to divert bullets streams'. The mutual interference of bullet paths might not be avoided unless the revolver barrel assemblies are quite widely separated, one might suggest. That could make for a heavy and complex mount, one that could be too much for a small ship or a small deck-space footprint.


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odysseus1980
Post subject: Re: Request for sources to design CIWS MyriadPosted: March 20th, 2017, 5:50 pm
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I say ithat again : Oerlikon KBD (Myriad gatling gun) had seven barrels.

http://www.navweaps.com/Weapons/WNIT_25mm-80_Myriad.php

Above page say weight of mount 7.7 ton, which is quite heavy. Only penetrating part however is the magazine. I am not sure which way those guns rotating, but believe that they rotated inwards. If they rotated outwards, there was a serious problem. Look the F-82 Twin Mustang and you will understand what I mean. Every rotating thing produces torgue, from a prop to a gatling gun. Especially modern high revving gatling guns.

Best nearly profile picture is this :
https://www.secretprojects.co.uk/forum/ ... pic=1672.0

The mount looks to be based on the GDM-A.

This comparison is really interesting. Myriad is the second better CIWS after the Russian Kashtan.

https://defence.pk/pdf/threads/naval-artillery.230134/


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Tobius
Post subject: Re: Request for sources to design CIWS MyriadPosted: March 20th, 2017, 7:06 pm
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I think I understand.

The F-82 Mustang had down flexion angular momentum induced loading (torque) from its two Allison engines. This had the load stress concentrated on the midwing that forced an up bend in the air-frame at that bridge load span. Reversing the spin of the props had the exact opposite effect with the stress load now down and still stressed the mid span beyond its bend factor, so I don't understand what that problem has to do with an electric gatling gun. I need clarification on that point so I understand the connection.

Phalanx (the US version with radar, optics, ammo bin and gun and unitary articulated mount) all up is about 92 tonnes. I think that explains the weight factor. The thing is designed as a complete bolt on to have as small a deck print as possible. The Myriad does not look to have that small footprint. And I suspect the barrels are too close together. Zenith's barrels most certainly are.

As for efficacy. The table at https://defence.pk/pdf/threads/naval-artillery.230134/ is most interesting, but of those CIWS weapon systems, AFAIK of the "western guns" only GOALKEEPER and PHALANX have been shot at for real under combat conditions (Iraq and in the land versions in Afghanistan.). I happen to like GOALKEEPER better. The Russian gatlings are highly suspect because they have been shot at as well (Same wars.). The ships those were mounted upon... sank.

By reputation alone, I like Oto systems a lot, Siemens/Signal as well. Radar/gun/optical/lidar integration is good. Kashtan... (The 230s, no 630 pair has been tried yet); not so much. Russian CIWS fire control is highly suspect. Again, proof of war.

Testing on the missile range at Sardinia or off the Kola Peninsula missile range is not the same as dodging Termits or CS-4s off Al Bakir.

Until that proof in battle, one cannot really assess any claim as to the authenticity of effectiveness.

At least Phalanx has that much going for it. It actually works against all kinds of incoming (including mortar shells and free flight rockets), rather well.

https://youtu.be/ILcVt9p7cug


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odysseus1980
Post subject: Re: Request for sources to design CIWS MyriadPosted: March 20th, 2017, 7:40 pm
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The Sea Zenith had 4 cannons firing all together in a mount with very high elevation and this created the vibration problem when firing. Germans tested also the Sea Drakon, which had quadruple BK-127 guns.

Indeed guns of Myriad are too close together. Example with the twin Mustang aimed in torgue created from twin rotating
things. An electric gatling gun creates much less torgue than twin Merlins with props. It would be very interesting to find data from Myriad test firings.

The comparison is interesting, but as you said its authenticity is questionable.

Russian fire control systems were inferior from Western in the past, newer are much improved.

I know about Phalanx.

A drawback of Millennium CIWS is the small magazine (only 225 rounds). Denel CIWS has only 280 rounds.


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Tobius
Post subject: Re: Request for sources to design CIWS MyriadPosted: March 21st, 2017, 2:45 am
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The F-82 uses ALLISON engines. The Americans did not use Merlins in the Twin Mustang because the war was over and the Packard license from Rolls Royce to make them lapsed. Maybe the Americans finally figured out how to make a decent supercharger?

Actually since the revolver barrels are longer in moment arc than the usual aluminum prop blade and 90 to the plane of spin, the torque might be worse.

Enough may have to be sufficient. The rounds are not as small as some might think, and the land version does have to be vehicle mobile in the Millennium. So 6 seconds ready use onboard is probably adjudged good enough when each engagement pulse is about 1- 3 seconds long. Reloads are fairly quick. They fight in pairs.

Can't speak about the Denel because I know very little about it as a system.


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