Sunburst: The Invincible?

[Grand Danois]

- On a mid-flight site of a trajectory.................................14000-15000
- On low-high trajectories...........................................................10-15
- Near the target .......................................................................5-10

I like those numbers much better. But 'stealth' of this missile appear to be a matter of size, not shaping or RAM. I would hazard the Yakhont will be picked up at the relevant ranges.

This missile is certainly a challenge for a single ship, without the benefit of NCW and offboard ISR. However, toss in a Hawkeye or similar capability and it should be OK.

On another note. Curious comparison with subsonic ASM's, as they work along an entirely different concept. But it may be the market they want to get in on...

My 0.02€.

 

[Viktor]

Logical explanation. It's a supersonic missile at sea level. It is glowing red hot from friction with the atmosphere. Actually it radiates so much that the Americans decided to add an IR seeker to the SM-2 Blk IIIA and call it SM-2 Blk IIIB. Any RAM coating will burn away pretty fast. No LO for the Sunburn I'm afraid, neither in RCS nor IR. It's the other way around: Everybody will know the missile is there.

Btw, considering wave spectra (and ground effect?), claiming a missile is flying at 3 m is obviously a brochure stat.

Im afraid this argument has no basis in logic. If so than how can you have RAM coating on F-22/F-35/Rafale etc fighters whitch have similar max speed but mutch greater surface whitch means more heat will be developt because of friction with atmosphere.
I dont know how mutch heat is developt because of friction but Mach 2 -3 is not like its entering earth atmosphere. Besides more speed means more heat will be carried away by relative speed of the air so temperature on the surface will be smaller.

Im not sure but I think you can apply RAM on Mach 2-3 missile.

 

[Grand Danois]

Im afraid this argument has no basis in logic. If so than how can you have RAM coating on F-22/F-35/Rafale etc fighters whitch have similar max speed but mutch greater surface whitch means more heat will be developt because of friction with atmosphere.
I dont know how mutch heat is developt because of friction but Mach 2 -3 is not like its entering earth atmosphere. Besides more speed means more heat will be carried away by relative speed of the air so temperature on the surface will be smaller.

Im not sure but I think you can apply RAM on Mach 2-3 missile.

RAM on supersonic sea skimming missile.

The platform needs to be sympathetic to the application of RAM.

The larger the better, as you can apply thicker RAM to a large platform, gives better absorbing and spectrum width. Generally it also only works against fire control trype radars. Not search radars. For those you need shaping.

Then there is the heating/friction issue.

An F-22A achives M1.7 supercruise (ie. sustained) at 55,000 ft, as an extreme example. How is that compared to M2.4 at sea level? Operational word: Sea level.

Chart A
I.C.A.O. Standard Atmosphere Table

Altitude Density Speed of Sound
(Feet) (d) (Knots)
0 .002377 661.7 -> M1.0 ~ 1,226 km/h
15,000 .001496 626.7 -> M1.0 ~ 1,160 km/h
55,000 .000285 573.8 -> M1.0 ~ 1,063 km/h

In other words when the sea skimming Yakhont goes sustained at sea level it flies at 2,942 km/h (M2.4), whereas the supercruising F-22A flies at 1,807 km/h (M1.7). But that is not the only important thing. At 55,000 ft air density is only 11% of that on sea level. And 63% at 15,000 ft.

IIRC drag is from friction (and turbulence) with the air, and if all else is equal, then

Fd = (air density)*(speed)^2

Using index numbers of drag as a measure of friction (air resistance is probably a more appropriate term).

0 ft = 20574 (Yakhont)
55,000 ft = 931 (F-22A)

Note, this has no dimension, and applies to 1 unit of area.

The flight profile and speed of the Yakhont makes it a very hot missile. Actually an order of a magnitude or more. It is not sympathetic to RAM, uses metal alloys, would be my guess. And well, if air flow carries the heat away, then ablational shields on reentry vehicles should be unnecessary... Friction with the air is what heats the missile - thus the air is heated too.

 

[Wooki]

I agree with GD. RAM is not the issue here, it is heat. The IR signature of this type of missile is it's principle weakness.

Not much more to say about it, really.

cheers

w

 

[gf0012-aust]

The flight profile and speed of the Yakhont makes it a very hot missile. Actually an order of a magnitude or more. It is not sympathetic to RAM, uses metal alloys, would be my guess. And well, if air flow carries the heat away, then ablational shields on reentry vehicles should be unnecessary... Friction with the air is what heats the missile - thus the air is heated too.

The issue for Yakhont (and by association Brahmos) is that its also one of real estate. That friction is condensed and doesn't have as lot of area mass to be dissipitated. Planes, by inference and implication have a larger mass to absorb and thus disperse heat.

It (supersonic cruise missile) will electronically glow in the dark.

There are causal similarieties between aerodynamics and fluid dynamics. Subs are like transducers, the bigger the sub, the bertter the opportunity to disperse and manage vibration - heat signature management is similar. generally, the larger platform has greater opportunity to manage heat spots.

in general terms (and I stress general terms) small high speed missiles "broadcast" more efficiently than a larger sig managed plane.

 

[Viktor]

RAM on supersonic sea skimming missile.

The platform needs to be sympathetic to the application of RAM.

The larger the better, as you can apply thicker RAM to a large platform, gives better absorbing and spectrum width. Generally it also only works against fire control trype radars. Not search radars. For those you need shaping.

Then there is the heating/friction issue.

An F-22A achives M1.7 supercruise (ie. sustained) at 55,000 ft, as an extreme example. How is that compared to M2.4 at sea level? Operational word: Sea level.

Chart A
I.C.A.O. Standard Atmosphere Table

Altitude Density Speed of Sound
(Feet) (d) (Knots)
0 .002377 661.7 -> M1.0 ~ 1,226 km/h
15,000 .001496 626.7 -> M1.0 ~ 1,160 km/h
55,000 .000285 573.8 -> M1.0 ~ 1,063 km/h

In other words when the sea skimming Yakhont goes sustained at sea level it flies at 2,942 km/h (M2.4), whereas the supercruising F-22A flies at 1,807 km/h (M1.7). But that is not the only important thing. At 55,000 ft air density is only 11% of that on sea level. And 63% at 15,000 ft.

IIRC drag is from friction (and turbulence) with the air, and if all else is equal, then

Fd = (air density)*(speed)^2

Using index numbers of drag as a measure of friction (air resistance is probably a more appropriate term).

0 ft = 20574 (Yakhont)
55,000 ft = 931 (F-22A)

Note, this has no dimension, and applies to 1 unit of area.

The flight profile and speed of the Yakhont makes it a very hot missile. Actually an order of a magnitude or more. It is not sympathetic to RAM, uses metal alloys, would be my guess. And well, if air flow carries the heat away, then ablational shields on reentry vehicles should be unnecessary... Friction with the air is what heats the missile - thus the air is heated too.

Well I can take this as an answer, but,
first your formula for aerodinamical drag you provided is incompllete and even as compleate makes only one part ( of two ) nessessery to calculate the drag. This is formula calculates only frontal drag , you have drag along the body too.

0 ft = 20574 (Yakhont)
55,000 ft = 931 (F-22A) ---- does this numbers include differences in surface area? (where did you find those numbers?)

And well, if air flow carries the heat away, then ablational shields on reentry vehicles should be unnecessary... Friction with the air is what heats the missile - thus the air is heated too.

LOL. It is surpassingly larger difference in flight speed betwen re-enty vehicle and Yakhont than Yakhont and F-22 (thus F-22 has at least 10 times larger surface).

 

[Grand Danois]

Well I can take this as an answer, but,
first your formula for aerodinamical drag you provided is incompllete and even as compleate makes only one part ( of two ) nessessery to calculate the drag. This is formula calculates only frontal drag , you have drag along the body too.

That is because I use per unit of area. All else being equal - which means I deliberately leave out the other parameters (they're on both sides of the equation). This was no error as this gives the direct comparison. I am describing the resistance of the media the object moves through per frontal area. Dissipation of that energy is also applied this way, thus an index is a proper measure. I'm not looking for drag frontal area/body as such, and if I added it, it would likely favour my argument the same way. Drag for the airframe is not what we are discussing, but the heating of a unit of area of the airframe.

0 ft = 20574 (Yakhont)
55,000 ft = 931 (F-22A) ---- does this numbers include differences in surface area? (where did you find those numbers?)

I didn't find them. Insert numbers from prev post. Difference in surface area is accounted for, see prev comment. They are independent of surface area, Cd, etc.

What the numbers mean is that the Yakhont meets 20+ times the resistance (friction) at M2.4 at sea level, than the F-22A at M1.7 at 55,000 ft. This is per unit of area, as the transfer of energy is per unit of area, and dissipation and radiation is per unit of area. This is the correct measure.

LOL. It is surpassingly larger difference in flight speed betwen re-enty vehicle and Yakhont than Yakhont and F-22 (thus F-22 has at least 10 times larger surface).

Reentry vehicle. Yes, speed is different. But the qualitative description is the same.

Surface area matter when you calculate drag for the entire airframe. Heating from friction is done per unit of surface area, read: energy balance.

 

[Grand Danois]

Besides more speed means more heat will be carried away by relative speed of the air so temperature on the surface will be smaller.

and later derived from above

LOL. It is surpassingly larger difference in flight speed betwen re-enty vehicle and Yakhont than Yakhont and F-22 (thus F-22 has at least 10 times larger surface).

Further on why air flow does not cool an object moving through it.

Ask A Scientist

Friction: Cool to Hot
2002067

name Mehile O.
status student
age 20s

Question - At which point (in measurements of speed) does air
friction start heating instead of cooling?
Example: If you were to hold a spoon out of a car window, the spoons
temperature would drop, while supersonic jets must have every nut,
bolt, and rivet made out of special alloys because anything made out
of steel or aluminum would turn to putty due to the heat generated by
the friction with the air.
Just something I have wondered for YEARS.
Thanks-a-bunch,
Mo
Note: If there is not a specific span or point of conversion due to a
multitude of inherent variables, is there at least range that can be
offer through an educated guess? I just hope to get some sort of
answer before this quandary drives me to the point of madness
Curiosity has always gotten the best of me.
------------------------------------------------
Mo,

When you stick a spoon out of the car window it does not cool unless it
has been heated above room temperature first or it is damp. The air
flowing over the spoon simply removes excess heat (i.e., heat that
results in the temperature being higher than that of the air). If the
spoon is damp you will get a slight evaporative cooling but once the
moisture is gone the temperature will come to the air temperature.

Note that this means that if the spoon is initially cooler than the air
(been eating ice cream again?) it will heat rather than cool when you
stick it out the window.

In summary, at low speeds, the effect of air flow over an object will
depend on the relative temperatures of the air and the spoon.

At all speeds you are doing work on the air as the spoon (or airplane)
flies through it (compressing the air in front of it). Just like
friction with solids, this work is stored as heat energy resulting in
increased temperatures.

Greg Bradburn

http://www.newton.dep.anl.gov/askasci/phy00/phy00488.htm

There are to statements here.

1. In summary, at low speeds, the effect of air flow over an object will depend on the relative temperatures of the air and the spoon.
   
   
2. At all speeds you are doing work on the air as the spoon (or airplane) flies through it (compressing the air in front of it). Just like friction with solids, this work is stored as heat energy resulting in increased temperatures.

An example of 1) is when you make a cup of tea and it cools as it works it way towards the ambient temperature of your living room.

An example of 2) is when a supersonic cruise missile is working the air at extreme speeds and the component from 2) >> 1). The temperature of the missile increases until the amount of energy radiated away from the missile equals the amount of energy transferred into the missile from interaction with the atmosphere. The missile increase the amount of energy it radiates as its temperature increase until equilibrium is achieved.

In our discussion 1 square metre of missile frontal area experiences 20 times the resistance of 1 square metre of F-22A. Thus 1 square metre of missile will get much, much hotter than 1 square metre of the F-22A as the F-22A is in equilibrium at lower temperatures.

Thus RAM applied to the ramjet missile is compromised by the much more severe environment it has to work in.

 

[Viktor]

Grand Danois, thanks man - I get it now.

 

[Grand Danois]

Thats cool!

 

[Aussie Digger]

I agree with GD. RAM is not the issue here, it is heat. The IR signature of this type of missile is it's principle weakness.

Not much more to say about it, really.

cheers

w

Hence the fitting of Western Naval vessels with IRST systems in recent years I'd imagine????

 

[Grand Danois]

Hence the fitting of Western Naval vessels with IRST systems in recent years I'd imagine????

And RIM-116 RAM, I'd guess?

 

[Aussie Digger]

And RIM-116 RAM, I'd guess?

And the Mistral/SADRAL variants?

Given the ranges and lack of "background" I suppose infra-red/UV homing missiles would be very effective at sea?

 

[Grand Danois]

And Stinger of course (whose IR seeker is used on the RAM). The RDN uses Stinger.

But I think the RAM has it! Cued by the ships combat systems, slightly faster and better range than the MANPADS.

That would give the USN and users of similar system the advantage of a layered defence with diversified homing methods for their missiles. SM-6* is active, SM-2/EESM are semi-active, and RAM is IR. No single point of failure. Like it.

* When it gets around.

 

[AegisFC]

And Stinger of course (whose IR seeker is used on the RAM). The RDN uses Stinger.

But I think the RAM has it! Cued by the ships combat systems, slightly faster and better range than the MANPADS.

That would give the USN and users of similar system the advantage of a layered defence with diversified homing methods for their missiles. SM-6* is active, SM-2/EESM are semi-active, and RAM is IR. No single point of failure. Like it.

Add to it EW, chaff, flares, and point defense it will take quite a lot to get through the defenses of any alert air defense ship.

 

[Todjaeger]

Add to it EW, chaff, flares, and point defense it will take quite a lot to get through the defenses of any alert air defense ship.

Where would something like the Nulka fit in? As I understand it, it's a hovering decoy. Would that be something deployed in place of chaff or flares, something that is designed to attract the attention of in-bound AShM seekers?

Also, any idea how far away from a ship this is designed to normally operate? I could see if it is too close, then it might not do any good. The missle could hit the decoy, then the debris could still end up spraying the vessel causing damage and possibly taking it out of action.

-Cheers

 

[Grand Danois]

Add to it EW, chaff, flares, and point defense it will take quite a lot to get through the defenses of any alert air defense ship.

That's right. Got carried away by all the fireworks.

 

[gf0012-aust]

Where would something like the Nulka fit in? As I understand it, it's a hovering decoy. Would that be something deployed in place of chaff or flares, something that is designed to attract the attention of in-bound AShM seekers?

-Cheers

In the 60's and 70's some poor sucker (skimmer) played "lamb" on behalf of the carrier - now the skimmer is replaced by nulka.

 

[Todjaeger]

In the 60's and 70's some poor sucker (skimmer) played "lamb" on behalf of the carrier - now the skimmer is replaced by nulka.

Umm... What's a skimmer?:unknown

Are you referring to a hovering naval helicopter? I have read of a tactic where a helicopter would hover will everything on to try and confuse incoming AShM. Not sure if it is something that would actually ever be used or work.

-Cheers

 

[gf0012-aust]

Umm... What's a skimmer?:unknown

Are you referring to a hovering naval helicopter? I have read of a tactic where a helicopter would hover will everything on to try and confuse incoming AShM. Not sure if it is something that would actually ever be used or work.

-Cheers

A skimmer is a warship that floats for normal work - ie the opposite from a sub

it typically used to be a DE or DDG.