Posted a few tweets on the VL-SRSAM's VLU recently :
Continuing from that :
The plume deflector has a Glass Phenolic(GPh) Coating. Excellent choice of material I think. GPh has very high ablation resistance, low thermal conductivity, low toxicity & is relatively easy to formulate. Only downside is that is it very brittle, so any coating has to be thin & uniformly spread out. Processes like Chemical Vapour Deposition(CVD) are ideal for making such coating. It is an expensive & time consuming process though.
The VL-SRSAM has Jet Vane Control (JVC) as was previously discussed here. I reckon this will be a common feature across most new missiles irrespective of use or size. The Dhruvastra, AAD, QR-SAM has it, the upcoming NASM-SR will have it. From the 2 pics released so far it seems the Akash-NG has it too.
The rear rupture disc is also made of butadiene rubber. Is there a PSU in South India that deals with rubber manufacturing ?
@Ashwin @Amal @randomradio et al.
The tender makes mention of purchasing the same from that PSU. South India has a lot of rubber plantations. But the rubber in question here is not the natural poly-isoprene rubber but a synthetic rubber. Maybe they have similar processing requirements, I don't know.
The VLU is placed on a ramp and is secured in place by means of some side support turnbuckles. The turnbuckles will prevent movement that maybe caused by the rolling of the ship.
Notice the two handles on the top panel. Those are to be used to pull the cannister out of the VLU in case of reloading.
The Limit switch ensures a number of fail safe procedures are in place. For example if the missile is not properly seated between the mid body & rear latches of the "Article Locking Mechanism" then Limit switch will prevent the hatch door from being shut.
There are 2 doors : (1)The service door & (2)The Hatch door.
The hatch door is sealed shut by the manufacturer & will remain shut unless the cannister needs to be re-loaded or a loaded cannister is handed back to them in case of some form of failure.
The service door is sealed shut by means of explosive bolts. After the bolts go off & the service door is flung in air, the missile ignition command is passed. Every step is monitored by a couple of sensors, in case something didn't work or didn't work in the right sequence the limit switch will prevent the missile firing. In case of re-loading, the manufacturer will take the used cannister, run safety checks, open the hatch door to load another missile, bolt on a new service door & seal the cannister.
Additional care is put on to fire safety as it is an hot launched missile( i.e. the ignition happens while the missile is still inside the cannister).
There is also an "Wing rail" inside the cannister that prevents the missile's folded wing from rubbing off or getting stuck anywhere during the missile's ejection.
And here is the Guide rail on which the missile remains mounted :
The entire point of having such a rail in the cannister is to minimize the contact surface area between the missile & the cannister. This in turn reduces friction & any friction related damage. There was some older DRDO documents that stated the intention to coat the rail with a thin layer of rubber. That was for the Nirbhay missile, the Nirbhay missile's launcher also has a guide rail.
But the idea was rather dropped as the gains were minimal & was considered not worth the trouble.