PLAN Anti-ship/surface missiles


Tetrach

Junior Member
Registered Member
But why does an "almost horizontal booster rocket trajectory" exclude a hypersonic missile?

Projectiles moving through air encounter air drag proportional to the square of their velocity (Quadratic formula). Just as friction (which is a thermodynamic effect constant at all velocities, different from air resistance) increase at lower altitude, so does air resistance. I presume hypersonic speed at low altitude would put too much structural constraint to make a flight possible.
 

Tam

Colonel
Registered Member
Projectiles moving through air encounter air drag proportional to the square of their velocity (Quadratic formula). Just as friction (which is a thermodynamic effect constant at all velocities, different from air resistance) increase at lower altitude, so does air resistance. I presume hypersonic speed at low altitude would put too much structural constraint to make a flight possible.

Plus it would burn the s**t up.
 

ougoah

Major
Registered Member
Projectiles moving through air encounter air drag proportional to the square of their velocity (Quadratic formula). Just as friction (which is a thermodynamic effect constant at all velocities, different from air resistance) increase at lower altitude, so does air resistance. I presume hypersonic speed at low altitude would put too much structural constraint to make a flight possible.

Air drag? Drag is referring to a property of the airfoil. It is affected by the air density so altitude of flight and the shape even the material of the airfoil. Quadratic formula? Not sure I follow with that one. The quadratic formula is useful for solving quadratic equations but little to do with this except for some maths that might be involved in calculating certain properties but they are going to be off charts.

Air resistance is a subtype of friction. Friction between denser atmosphere and airfoil (air resistance) is greater at lower altitudes but speed and temperature also matter. Unlikely for a vehicle to pick up much speed if it remains low altitude the whole flight which is another reason this is unlikely to be hypersonic.

The problem isn't really a structural one, if it can sustain hypersonic controlled flight at high altitudes, its structure and heat management can surely deal with it near sea level. After all most targets for an anti-ship missile will be at sea level. The problem is kinetic energy. Most hypersonic weapons will make use of something delivering the vehicle to very high altitudes and still boosting it and/or propelling it to even greater speeds through staged rockets and/or scramjets to achieve and sustain speed. They also make use of shock waves and effects between the atmosphere and its body. Most of this stuff is probably tightly held state and corporate secrets developed by academics.

So a relatively small rocket booster going pretty much horizontal has very little chance of carrying enough energy give its payload the boost required to get above Mach 5 unless the payload itself is scramjet powered. So it isn't impossible that the rumours of this "new" missile being hypersonic but it is very questionable. Also doesn't seem to be designed for VLS so it'll have to be positioned along the coast which really limit its range which is the other side of the energy problem. Only place it fits would be onboard warships that have room for those old slanted launchers or stationed on island chains, but that makes them pretty easy targets to detect and attack.

Chinese hypersonic anti-ship missiles include the AShBM and their payloads which most certainly carry hypersonic warheads or MaRVs in the form of HGVs similar (but probably much smaller) than the DF-ZF vehicles shown with DF-17 missiles. DF-100 probably could be modded to include anti-ship capabilities if not already. So that's DF-21, DF-26, and possibly DF-100 hypersonic anti ship weapons. They all seem to be pretty much top attack so that makes them even harder to intercept with the disadvantage of easier and long ranged detection. YJ-12 and YJ-18 are already much more formidable than the range of more standard subsonic or low supersonic anti-ship cruise missiles and sea-skimming ones. I don't think any more anti surface is really necessary considering the gaps that need to be caught up on below the surface. China's anti-shipping capabilities are far beyond formidable. Pushing in the same way isn't going to do much more good for it. Instead it needs to expand the networks of its platforms and look into the types of countermeasures the adversary is developing/fielding.
 
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