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System C, SAM.72 and MSAM musings

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An effort to get to grips with what might be required for two missile systems.

1. what might be different from System B that lead to Sea Wolf in the more demanding System C the French wanted.
2. what might be required for SAM.72 and MSAM

Firstly what do we know about System C?
Intercept any missile at 7km that will cross within 4km of the ship, providing local area defence.
Projected missile was 140kg if SARH and 80kg if command guided.

We also know that System B's limit of length was dictated by the height of a standard deck, about 2m.
Ergo the demands of System C either require something that is longer, and stored either horizontally or in a special magazine upto two decks high, OR the missile is increased in diameter.

Mathematically, simplifying the missile to a cylinder, we'd increase diameter from 11.8" to 15.4", we cover the increase from 82kg to 140kg. This to retain the length of 6ft 2.8" (1.9m)
Alternatively, we can increase length while retaining the same diameter, such that we go from 6ft 2.8" (1.9m) to 10ft 7.7" (3.25m).

An interesting aside....
The Weight is itself a revealing figure by of all things the standards on lifting and handling, Sea Wolf being under 90kg is essentially within the scope of being moved by two people or in extremis by one.
However the formula would place a limit of 160kg using four people, but 140kg excludes three people who would limit it to 120kg.

Back to the main thrust.
Conceptually this means either illuminating the target, and this suggests a continuation of the earlier Orange Nell concept. I would presume this being 1967, the level of Q-band (Ka-band I suspect) systems has notably improved from the 1950's.

Certainly a SARH seeker in Q-band would not need to be more than 12" homing dish to accurately engage a target from 10km distance, as per the much earlier Red Dean. So 11.8" (30cm) is more than enough diameter.
Such a choice like Orange Nell avoids some issues with clutter.

Or tracking the target, separately from the intercepting missile, which also would need tracking. Because of the demands of the intercept, target tracking and missile tracking would have two distinctly separate dishes, which would impose some design limits. Possibly one would have to stack the dishes one above the other?
Which would ensure the single 'post' of these two dishes and a link transmitter dish can perform the control of the intercept.

Considering much later efforts, and some earlier, I'm again wondering if the trackers would best be monopulse or ideally FMICW but in Q-band, which though limited in range provide a high degree of accuracy.

That said Sea Wolf used I-band, and Rapier used Q-band. Though the upgraded Sea Wolf 911 system includes the Rapier's Blindfire Q-band radar.

I shall have to sit down and get my calculator out to estimate the absolute range of the weapon. But it does depend on the guidance solution....Command guidance means the missile can be sent on the most efficient path to hit the target by 7km. Which suggest's it's not much more.
In theory, the VLS Sea Wolf missile, could do this with the improved guidance and control system.

While SARH would need more absolute range as it's flightpath is less efficient.

MSAM/SAM.72.....
This particular range for MSAM's (30km) requirement is somewhat between actual real life systems which tend to either aim for limits of 20km or 40km and have produced a number of wildly differing solutions over the years.
Contemporarily we have.
I-Hawk
Sea Sparrow, RIM-7E took range out to 22km
Sea Pheonix...? which has something around 25km range
S-125 or SA-N-1 or M-1 Volna, NEVA/PECHORA (aka NATO "Goa")
Aspide
Indigo

Notably Buk started around 1972, bang on the time for SAM.72

JC Fuller has revealed the various Landpax offerings used various differently sized boosters for VLS Sea Wolf, presumably retaining the actual missile. What likely imposes hard limits are the guidance system and the thermal limits of the missile, as any larger booster would drive it beyond then to achieve the range. Such boosters would also impose minimum range limitations, likely unattractive.

So conceptually to meet MSAM or SAM.72 we'd need to increase the missile over Sea Wolf, and the VLS version.

Sea Flash is perhaps an option here, with the larger motor, and could be tied in with it's Skyflash progenitor. Conceptually it's more idea to repackage the technology in a different missile, upping the seeker size.
But curiously in my stumbling around I suspect it's Sea Pheonix that represents the best solution.

However the logical way forward is surely to expand on System C.....
 

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