SCALP / Storm Shadow / MdCN

[Forest Green]

The sub-launched version would fly at a very low altitude throughout the entire flight to avoid revealing the submarine's position, whereas the frigate-launched version could fly at a significantly higher altitude in the early phases… Thus burning much less fuel

That makes sense, in which case the actual missile range capability isn't different, it's just using a different flight profile that gives shorter range.

 

[WatcherZero]

The kick booster provides underwater propulsion after launch and the DCM is capable of manoeuvre following a pre-set underwater course before surfacing, the missile is also lugging the extra weight of the DCM until it its jettisoned after breaching the surface and the air duct opened. The kick-booster then continues to power the missile to its cruising altitude before being jettisoned, the wings extended and the turbojet engine engaging. When launched from a ship rather than a submarine the kick-booster has far less work to do.

The warhead is referred to officially as a '250kg class HE/Frag' warhead which leaves some ambiguity on size but is often referred to as 300kg. Similarly the 450kg Broach warhead of Storm Shadow/SCALP EG was a 500kg 'class' weapon with a range greater than 300km under the Missile Technology Control Regime and on export versions of the weapon to comply the range was capped at 290km and a smaller 400kg HE warhead supplied.

The reduction in warhead size to a single warhead on the MdCN was part of the engineering optimisation of the development programme to the payload/range trade-off favouring range to meet the target 800-1000km when launched from Barracuda according to Captaine De Fregate Jean-Yves Martin (MdCN/Exocet Development Program Officer).

The other two internal changes from Scalp-EG being the cylindrical form factor to fit the Barracuda torpedo tube and ability to be programmed by a SIC-21 network computer workstation or receive datasets in that format.

https://www.calameo.com/read/000151499001282fcabf3

 

[Scott Kenny]

One of the possible explanations i've read behind the difference in range between the sub-launched and the surface-launched versions is their flight profile.

The sub-launched version would fly at a very low altitude throughout the entire flight to avoid revealing the submarine's position, whereas the frigate-launched version could fly at a significantly higher altitude in the early phases… Thus burning much less fuel

That does make sense.

The kick booster provides underwater propulsion after launch and the DCM is capable of manoeuvre following a pre-set underwater course before surfacing, the missile is also lugging the extra weight of the DCM until it its jettisoned after breaching the surface and the air duct opened. The kick-booster then continues to power the missile to its cruising altitude before being jettisoned, the wings extended and the turbojet engine engaging. When launched from a ship rather than a submarine the kick-booster has far less work to do.

Really? I mean, the launch capsule is leaving the sub at about 50 knots just from the impulse pump. And a rocket kicking off underwater is going to deafen the launching sub and reveal position.

 

[WatcherZero]

Yeah the first four seconds after launch is from the initial kick (they use a pusher plate on the missile to distribute the load and avoid damaging the rocket nozzles), then the rocket motor ignites and about two seconds later it surfaces then after another two seconds the DCM is released and the missile begins exiting its container.

 

[BonPlan2]

1,000km is the sub launched version range and 1,400km is Sylver cell ship launched version, both have a 300kg warhead. The missile itself is identical with no extra or enlarged booster for the underwater version (or rather the original kick booster is retained by the later ship launched version), but there is a protective torpedo casing for the sub launched variant "Dispositif de Changement de Milieu" or DCM. The missile itself weighs 1,400kg, the DCM another 600kg.

View attachment 822620

View attachment 822619

Are you sure?
The sub launched and Sylver launched missiles are exactly the same. They are fired from same level, used the same booster.

Question is : is the booster fired in the sea in the sub lauched version ? The sole real explanation for a range reduction.

 

[BonPlan2]

If it's the same missile, why would range be reduced by 400km? This has been discussed here before, there is a link somewhere, stating that the shorter-ranged version has a 500kg warhead and the longer-ranged version has a 300kg warhead. Otherwise I can't see how simply launching it from slightly underwater would wipe 400km from the range, since the DCM is rejected after it reaches the surface.

No. There is only one version with 250kg warhead.