054/A FFG Thread II

duncanidaho

Junior Member
So how about a tri-pack?

Geometry was never my strong suit.

If you can tri-pack the missiles, you also can quad-pack them, except you tri-pack different missiles with different diameters. So if you are not able to quad-pack them, you are not able to duo-pack them too.
 
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Totoro

Major
VIP Professional
tri packing and dual packing is actually plausible if the missiles have to be hot launched and the whole package inside one large tube is really a mini self contained launcher with two/three VL mini-tubes and rocket motor exhaust occupying the rest of the volume.
 

Iron Man

Major
Registered Member
tri packing and dual packing is actually plausible if the missiles have to be hot launched and the whole package inside one large tube is really a mini self contained launcher with two/three VL mini-tubes and rocket motor exhaust occupying the rest of the volume.
If you can't quad-pack a missile in a given tube, you certainly won't be able to tri-pack or dual-pack the same missile in the same tube, especially a missile with non-folding cruciform strakes like the HQ-16.
 

Iron Man

Major
Registered Member
Actually, I just did some calculations using the photograph of the slanted HQ-16 mounted on the show vehicle. It seems the total width of the HQ-16 including the cruciform strakes comes in at about 1.42x the diameter of the missile body.

Taking a square VLS tube measuring 800mm x 800mm on the inside and subtracting 20mm from each dimension for the middle divider walls, you get a 390mm x 390mm box for each quad-packed missile to use.

Using the Pythagorean theorem of 2a^2 = c^2 with a = 390 and solving for c, you get c = 551mm (rounding down). So the allowable total width of the HHQ-16 would have to be less than this number, meaning that the missile body diameter would have to be less than 388mm.

Since we can't be 100% sure what the diameter of the HHQ-16 actually is, I suppose it is possible that it could be quad-packed into the universal CCL VLS if it is in fact a narrower missile than the Buk, as in narrower than 551mm total width.

The caveat would be that there is no room for a concentric exhaust manifold, meaning the HHQ-16 would have to cold launch out of the canister. The land-based HQ-16 is cold-launched out of its canister so this is obviously an option. OTOH, cold-launching this type of missile out of a ship VLS seems counterproductive to its role as a defense against saturation attacks since cold launch is much slower than hot-launch, which can be serially ripple-fired nearly simultaneously from all of the modules in a VLS bank. If a hot-launched missile doesn't actually launch, it just stays in the tube and does not occupy the space above the VLS modules. With cold launch only a single missile could be fired from an entire bank of VLS modules at a time. There may even be an additional delay with a man-in-the-loop to make sure the ejected missile's motor actually fired before manually authorizing another cold launch from the same bank of VLS modules.
 
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schenkus

Junior Member
Registered Member
If you can't quad-pack a missile in a given tube, you certainly won't be able to tri-pack or dual-pack the same missile in the same tube, especially a missile with non-folding cruciform strakes like the HQ-16.

I think Totoro meant that even if 4 missiles fit into a VLS cell, if the missile is hot launched and the VLS system doesn't have a central vent for missile exhausts you might not have enough space left in the cell to vent the exhausts. In that special case you might only pack 3 missiles into the cell and use the remaining space for the exhaust vent.

The way I understand it, the "new VLS" doesn't have a central vent so in order to quad-pack a hot launched missile you need space not only for 4 missiles but also leave enough space to vent exhaust gases.

I'm not sure if cold launching quad-packed missiles is technically possible to avoid this. I guess that with a missile intended for short to medium ranges the additional time it takes to first cold lauch the missile and only later start the engine might also be a problem.
 
cool post:
Actually, I just did some calculations using the photograph of the slanted HQ-16 mounted on the show vehicle. It seems the total width of the HQ-16 including the cruciform strakes comes in at about 1.42x the diameter of the missile body.

Taking a square VLS tube measuring 800mm x 800mm on the inside and subtracting 20mm from each dimension for the middle divider walls, you get a 390mm x 390mm box for each quad-packed missile to use.

Using the Pythagorean theorem of 2a^2 = c^2 with a = 390 and solving for c, you get c = 551mm (rounding down). So the allowable total width of the HHQ-16 would have to be less than this number, meaning that the missile body diameter would have to be less than 388mm.

Since we can't be 100% sure what the diameter of the HHQ-16 actually is, I suppose it is possible that it could be quad-packed into the universal CCL VLS if it is in fact a narrower missile than the Buk, as in narrower than 551mm total width.

The caveat would be that there is no room for a concentric exhaust manifold, meaning the HHQ-16 would have to cold launch out of the canister. The land-based HQ-16 is cold-launched out of its canister so this is obviously an option. OTOH, cold-launching this type of missile out of a ship VLS seems counterproductive to its role as a defense against saturation attacks since cold launch is much slower than hot-launch, which can be serially ripple-fired nearly simultaneously from all of the modules in a VLS bank.
I think I got it until here; now hope you won't mind me asking:

If a hot-launched missile doesn't actually launch, it just stays in the tube and does not occupy the space above the VLS modules.
what do you mean by 'space above the VLS modules', why do you mention it here?


With cold launch only a single missile could be fired from an entire bank of VLS modules at a time.
why?


There may even be an additional delay with a man-in-the-loop to make sure the ejected missile's motor actually fired before manually authorizing another cold launch from the same bank of VLS modules.
I'm guessing (actually bluffing :) there could be an option like
LAUNCH ASAP
to be only used while under a massive attack
 

Iron Man

Major
Registered Member
I think Totoro meant that even if 4 missiles fit into a VLS cell, if the missile is hot launched and the VLS system doesn't have a central vent for missile exhausts you might not have enough space left in the cell to vent the exhausts. In that special case you might only pack 3 missiles into the cell and use the remaining space for the exhaust vent.

The way I understand it, the "new VLS" doesn't have a central vent so in order to quad-pack a hot launched missile you need space not only for 4 missiles but also leave enough space to vent exhaust gases.

I'm not sure if cold launching quad-packed missiles is technically possible to avoid this. I guess that with a missile intended for short to medium ranges the additional time it takes to first cold lauch the missile and only later start the engine might also be a problem.
Co-opting some space meant for a missile as an exhaust manifold instead is definitely a possibility. The only realistic arrangement IMO is a quad-pack configuration with only 3 missile and a quarter of a tube used for exhaust. My only concern is whether this quarter-tube sized exhaust will be sufficient to vent the exhaust of the missiles without overheating, especially if ripple-fired in quick succession. If insufficient then it would be down to 2 missiles in the tube with the rest of the space used for exhaust. Which would then bring up the interesting question of whether only 2 HHQ-16 is worthy of the space of 1 HHQ-9.
 

schenkus

Junior Member
Registered Member
great post from Iron Man (I only saw it after my earlier reply)

The caveat would be that there is no room for a concentric exhaust manifold, meaning the HHQ-16 would have to cold launch out of the canister. The land-based HQ-16 is cold-launched out of its canister so this is obviously an option. OTOH, cold-launching this type of missile out of a ship VLS seems counterproductive to its role as a defense against saturation attacks since cold launch is much slower than hot-launch, which can be serially ripple-fired nearly simultaneously from all of the modules in a VLS bank. If a hot-launched missile doesn't actually launch, it just stays in the tube and does not occupy the space above the VLS modules. With cold launch only a single missile could be fired from an entire bank of VLS modules at a time. There may even be an additional delay with a man-in-the-loop to make sure the ejected missile's motor actually fired before manually authorizing another cold launch from the same bank of VLS modules.

These problems with cold launched missiles might actually be a good reason to "triple-pack" a hot launched missile using the remaining space as a vent.

"Triple-packed" missiles would still dramatically increase the number of missiles one can fit in the VLS.

This way even if a 054B only had 24 cells of the "new VLS" they could fit 72 medium range missiles or perhaps use only 12 cells for 36 AAW missiles and use the rest for ASROC style ASW missiles.
 

Iron Man

Major
Registered Member
what do you mean by 'space above the VLS modules', why do you mention it here?
If you watch some cold launch videos there is always a small delay between missile ejection and missile motor launch, which amounts to less than a second's worth of time. Between the time the missile is ejected out of the tube and the time the motor ignites, no other missile can be launched from the same bank of VLS modules because the currently ejected missile is taking up the space above them.

Now compare that to this (skip to 2:35 for the fireworks):

There is no hang time for these missiles. You can see that the rear bank of VLS modules on the AB launched two missiles nearly simultaneously, along with one missile from the forward VLS bank. I've seen other videos where 5 or 6 were ripple-fired from the same bank in less than half a second.

Cold launched missiles start tilting even as they are ejected and continue tilting as the motor starts firing. Now just imagine multiple cold-launched missiles tilting every which way and firing all over the place right on top of each other.

I'm guessing (actually bluffing :) there could be an option like
LAUNCH ASAP
to be only used while under a massive attack
I'm guessing this is probably an option.
 
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