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.
PLAN Anti-ship/surface missiles
- Thread starter tphuang
- Start date
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.
antiterror13
Brigadier
deleted
Plus it would burn the s**t up.
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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by78
General
Illustrations from a research paper on the effectiveness of the terminal 'pendulum' maneuver against 'typical' defense systems (i.e. RIM-7 Sea Sparrow and Standard II missiles). A swing radius of 1000m or above can guarantee penetration.
The chart below shows the probability of penetration against Standard-II (solid line) and RIM-7 Sea Sparrow (dashed line). The Y-Axis is the Probability of Penetration (P), and the X-axis is the Swing Radius (R/m). So basically, a swing radius above 500m is at least 95% effective against either defense system.
The chart below shows the probability of penetration against Standard-II (solid line) and RIM-7 Sea Sparrow (dashed line). The Y-Axis is the Probability of Penetration (P), and the X-axis is the Swing Radius (R/m). So basically, a swing radius above 500m is at least 95% effective against either defense system.
by78
General
Illustrations from a research paper on the effectiveness of the terminal 'pendulum' maneuver against 'typical' defense systems (i.e. RIM-7 Sea Sparrow and Standard II missiles). A swing radius of 1000m or above can guarantee penetration.
The chart below shows the probability of penetration against Standard-II (solid line) and RIM-7 Sea Sparrow (dashed line). The Y-Axis is the Probability of Penetration (P), and the X-axis is the Swing Radius (R/m). So basically, a swing radius above 500m is at least 95% effective against either defense system.
I forgot to add that this is a sub-sonic anti-ship missile.
plawolf
Lieutenant General
70% penetration probably for a subsonic missile doing minimal swings seems...almost too good to be true unless there are omitted assumptions/factors at play.
I am also curious where they got detailed performance specs for American missiles to base their analysis on. Seriously doubt it’s based on actual real world test results.
I think we need to be mindful that just because something is listed in a scientific paper doesn’t automatically make it true or even accurate.
I am also curious where they got detailed performance specs for American missiles to base their analysis on. Seriously doubt it’s based on actual real world test results.
I think we need to be mindful that just because something is listed in a scientific paper doesn’t automatically make it true or even accurate.
by78
General
True. However, subsonic could mean a wide range of speeds, including high sub-sonic to speeds just under the threshold of supersonic, which can make a significant difference. As for where the author(s) of this paper got the performance parameters of SM-2 and Sea Sparrow, that we can only speculate. Perhaps they are educated guesses based on open source information, or they have obtained accurate performance data through others means, including espionage. With SM-2 and Sea Sparrow having been in service for decades, I can’t imagine it’d be that difficult to have a good idea of how they perform.
Since I don’t have access to the full paper, the above are just my thoughts and speculation.
Is there any information on df100 being a AShM?
I havent seen any info on df100 after 2019 military parad.
I also wonder how plaaf/plan position their AShMs. What would be the weapon of choice against large fleet supported by awacs, fixed wing fighter and integrated air defense?
Seems to me there is no ideal choice at all.
I havent seen any info on df100 after 2019 military parad.
I also wonder how plaaf/plan position their AShMs. What would be the weapon of choice against large fleet supported by awacs, fixed wing fighter and integrated air defense?
Seems to me there is no ideal choice at all.