Type 052C/052D Class Destroyers


AndrewS

Major
Registered Member
Just read ans article of Henri K where he says YJ-18A can only be loaded in the front VLS of the type 52D. Anyone knows why?
You wouldn't want or need every VLS cell to be strike-length.

There are 3 lengths listed on the VLS specifications.
 

Totoro

Captain
VIP Professional
I've got a question on the VLS. The inner walls of the square cell seem to be visible. And they're 69 pixels across. Then there's the circular opening though which the missile exits. Which seems to be 56 pixels across, as there's plenty of clearance between the edges of the circle and the cell walls.

Why so much clearance? Why a circular opening? Circular shape means the missile inside has to be even smaller, so the fins (Even if folded) still go through.

Also, this seems to be a hot launch. But where exactly is the exhaust coming from? Is it the from the circular tube? If so, that'd mean the missile would be even smaller still, as there's not enough room for the missile to take up maximum theoretical area of the circle and still have enough area for the hot exhausts to clear the tube.

Assuming 850mm inner wall distance, as suggested by that old research paper, the circle diameter works out to 690mm. Or roughly up to some 600mm for the missile body diameter, since there's got to be at least part of the folded fin sticking out for missile such as hq-9.

For missiles using hot exhaust, i don't really know how they do it, as the missile needs roughly the area of its diameter for the exhaust.
 

Lethe

Senior Member
Doesn't the exhaust for hot launch vent through the space between the inner circular missile housing and the square wall of the cell?
 

Totoro

Captain
VIP Professional
Looking at the image above, I am not seeing that it works that way. The exhaust plume looks as if it's coming from the circular opening.
 

Rachmaninov

Junior Member
Registered Member
I've got a question on the VLS. The inner walls of the square cell seem to be visible. And they're 69 pixels across. Then there's the circular opening though which the missile exits. Which seems to be 56 pixels across, as there's plenty of clearance between the edges of the circle and the cell walls.

Why so much clearance? Why a circular opening? Circular shape means the missile inside has to be even smaller, so the fins (Even if folded) still go through.

Also, this seems to be a hot launch. But where exactly is the exhaust coming from? Is it the from the circular tube? If so, that'd mean the missile would be even smaller still, as there's not enough room for the missile to take up maximum theoretical area of the circle and still have enough area for the hot exhausts to clear the tube.

Assuming 850mm inner wall distance, as suggested by that old research paper, the circle diameter works out to 690mm. Or roughly up to some 600mm for the missile body diameter, since there's got to be at least part of the folded fin sticking out for missile such as hq-9.

For missiles using hot exhaust, i don't really know how they do it, as the missile needs roughly the area of its diameter for the exhaust.
Assuming your measurements are correct (I didn’t take mine) the diameter of the circle would be 690mm, which is 80mm each side from the 850mm VLS cell inner wall in terms of “clearance”, which isn’t too much for a canister some 8m-ish deep with tolerance to be loaded in. Not so sure about the exhaust (is it only me or is it rather difficult to judge?)...
 

Totoro

Captain
VIP Professional
Yeah it's difficult to judge. I'm not saying it's 100% sure that it's coming from inside the circle or the outside of the circle. Or perhaps there could be a combination. What the thickness of the plume does suggest is that even if there is some exhaust coming from the sides, it's not uniform, and some parts of the side wall do not seem to feature any exhaust plumes.

Coincidently, Mk41 vls has 569 mm inner cell width. Diameter of Tomahwk missile body is 520 mm. So, assuming there's not an piece of folded fin protruding outside of that diameter, there's still roughly 25 mm of clearance between the missile and the cell wall.
 

Tam

Major
Registered Member
Yeah it's difficult to judge. I'm not saying it's 100% sure that it's coming from inside the circle or the outside of the circle. Or perhaps there could be a combination. What the thickness of the plume does suggest is that even if there is some exhaust coming from the sides, it's not uniform, and some parts of the side wall do not seem to feature any exhaust plumes.

Coincidently, Mk41 vls has 569 mm inner cell width. Diameter of Tomahwk missile body is 520 mm. So, assuming there's not an piece of folded fin protruding outside of that diameter, there's still roughly 25 mm of clearance between the missile and the cell wall.
You're going to have to figure it out with computational fluid dynamics.

3-Figure4-1.pngEEq-Ci7WwAAbWcX.jpg
 

ZeEa5KPul

Junior Member
Registered Member
Doesn't the exhaust for hot launch vent through the space between the inner circular missile housing and the square wall of the cell?
Apparently not, although @Interstellar mentioned that CASC was investigating the concept. I remember seeing a schematic of the CCL posted here a while back and it showed the gas vents sandwiched between the inner and outer walls of the launch tube. If the gas vented as you describe, it would have a four corners pattern like this
 

Lethe

Senior Member
If the exhaust is vented between inner and outer circular walls of the missile housing, with material thicknesses and spacing at each level, that does call into question the maximum missile diameter for hot launch and whether it is in fact any larger than Mk. 41/57.

I would assume that the maximum missile diameter for cold launch missiles is somewhat larger, lacking the inner circular wall and corresponding venting space that hot launch requires, but with reduced maximum length to accommodate the compressed gas ejection system at the base of the missile.
 
Last edited:

Top