Comparison by Spurts

New and old developments in aviation technology.
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wrightwing

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Unread post20 Apr 2021, 19:21

eloise wrote:Do you think air launched sm-6 can reach hypersonic

The current version of the SM-6 is high supersonic. The 1B models will be hypersonic, and have even more range.
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eloise

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Unread post20 Apr 2021, 20:06

wrightwing wrote:The current version of the SM-6 is high supersonic

Yes but that when launched from ground surface.
air launch increase range and velocity a lot, as in case of air launched Iskander => Kinzhal
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sprstdlyscottsmn

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Unread post20 Apr 2021, 20:25

The thing with SMs though is the booster part (not seen in that Rhino shot) gets it to "air launched" conditions before the missile itself fires off. There may be no performance boost at all, possibly even a degradation, between an AEGIS launched SM-6 and an SM-6 launched from a Rhino flying over the AEGIS.
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eloise

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Unread post22 Apr 2021, 10:03

sprstdlyscottsmn wrote:The thing with SMs though is the booster part (not seen in that Rhino shot) gets it to "air launched" conditions before the missile itself fires off. There may be no performance boost at all, possibly even a degradation, between an AEGIS launched SM-6 and an SM-6 launched from a Rhino flying over the AEGIS.

SM-1MR and SM-2MR also top out at Mach 3.5 without booster :?
It is a bit strange, the top speed is the same with and without booster. And the booster is also very heavy, almost as heavy as the missile itself
1280px-RIM-66_Standard_missiles_on_launcher_aboard_USS_Ticonderoga_(CG-47)_during_tests_off_Puerto_Rico_March_1983.jpg

sm-6.jpg

MK 72 Booster brochure.jpg
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hornetfinn

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Unread post22 Apr 2021, 11:57

eloise wrote:
sprstdlyscottsmn wrote:The thing with SMs though is the booster part (not seen in that Rhino shot) gets it to "air launched" conditions before the missile itself fires off. There may be no performance boost at all, possibly even a degradation, between an AEGIS launched SM-6 and an SM-6 launched from a Rhino flying over the AEGIS.

SM-1MR and SM-2MR also top out at Mach 3.5 without booster :?
It is a bit strange, the top speed is the same with and without booster. And the booster is also very heavy, almost as heavy as the missile itself


I think there could be couple of explanations for that. First, the stated top speeds might not be true top speeds of the missiles. Second and rather likely explanation is that while top speed might not be that much higher for SM-6, it can probably maintain it longer with longer burning sustainer rocket motor. Or it could be a combination of both of these.
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eloise

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Unread post02 May 2021, 14:19

sprstdlyscottsmn wrote:The thing with SMs though is the booster part (not seen in that Rhino shot) gets it to "air launched" conditions before the missile itself fires off. There may be no performance boost at all, possibly even a degradation, between an AEGIS launched SM-6 and an SM-6 launched from a Rhino flying over the AEGIS.

After some research, I think I figure out roughly the speed and range of air launched SM-6
RIM-66A (SM-1MR block I) with MK-27 dual thrust rocket motor has a top speed of Mach 1.8 and max range of 32 km
RIM-66B (SM-1MR Block V) with MK-56 dual thrust rocket motor has a top speed is Mach 3.5 and max range of 46 km
RIM-66C (SM-2MR Block I) with the same MK-56 rocket motor but with new INS guidance logic increased its range to 74 km but keep same top speed.
RIM-66G (SM-2MR Block II) with the new Thiokol MK-104 rocket motor has a top speed of Mach 3.5 and max range of 166 km.
RIM-156A (SM-2ER Block IV) still use the same MK-104 rocket motor but with the additional MK-72 booster, range got extended to 370 km
RIM-174 (SM-6) same MK-104 rocket motor and MK-72 booster as RIM-156A but use an active radar seeker instead

AGM-78 which is an air launched derivative of RIM-66A (SM-1MR block I) with the same airframe and the same MK-27 MoD 4 dual thrust rocket motor. The only thing changed is the AGM-45A-3Aa seeker. That missile has a top speed of Mach 2.5 and max range of 90 km. In short, compared to ground launched version, the air launched version of standard missile can increase top speed by 1.38 times and max range by 2.8 times.
Air launched SM-6 doesn't have the MK-72 booster but it still got the MK-104 motor section, so the kinematic when launched from ground will be similar to RIM-66G (SM-2MR block II), when launched from air, we can expect it to reach top speed of Mach 4.83 and max range of 465 km.
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Unread post02 May 2021, 15:51

Just having the ability to air-launch gives off-ship launch ability to help conceal fleet assets OTH. That is if you can get targeting information to do so. I'm guessing that hypersonic weapons would be spotted by ships. Long range airborne targets would be spotted by Hawkeyes. And land targets designated through a command structure.
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Unread post20 Jul 2021, 20:34

So, the 7th anniversary of my first iteration of this is coming up. I had hoped to have this finished by then but I simply have not had the time. I am streamlining some of the comparisons and I am happy with the results so far. Right now I hope to have this version finished and any technical issues found by you all corrected by the end of this year.
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Unread post21 Jul 2021, 20:15

sprstdlyscottsmn wrote:So, the 7th anniversary of my first iteration of this is coming up. I had hoped to have this finished by then but I simply have not had the time. I am streamlining some of the comparisons and I am happy with the results so far. Right now I hope to have this version finished and any technical issues found by you all corrected by the end of this year.


Thanks for your effort. Can't wait, to see the results. :D
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sprstdlyscottsmn

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Unread post20 Jan 2022, 19:26

sprstdlyscottsmn wrote:So, the 7th anniversary of my first iteration of this is coming up. I had hoped to have this finished by then but I simply have not had the time. I am streamlining some of the comparisons and I am happy with the results so far. Right now I hope to have this version finished and any technical issues found by you all corrected by the end of this year.

Sigh.

Well that didn't happen either.

I was unable to work on the project for quite a while and now that I am able to come back to it "hard and fast" I am finding I am quite unhappy with my ECM estimation implementation. I know all that is classified and I can't possibly do it right but right now it is a glaring error that a given ECM system imparts a fixed dB of noise on another given Radar system or provides a set degradation in shot pK regardless of range. I need to figure out a better system that has ECM become less potent as range decreases (to simulate burn through).

Go back and fix it now and redo the comparisons where it matters, or finish it under the current system just to finish it and then do a revision later?
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hornetfinn

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Unread post21 Jan 2022, 08:58

Could you just calculate Jamming to Signal ratio:
https://www.rfcafe.com/references/electrical/ew-radar-handbook/jamming-to-signal-ratio-constant-power.htm

and estimate the chance of break-lock happening:
https://www.sciencedirect.com/science/article/pii/S2215098615001123

I think you could make some kind of simplifications for these calculations. But range and target RCS definitely needs to be taken into account for somewhat realistic ECM implementation.
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sprstdlyscottsmn

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Unread post21 Jan 2022, 11:21

Thanks for the sources hornetfinn, I'll give them a look this weekend and see what I can make out of them.
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garrya

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Unread post22 Jan 2022, 20:03

sprstdlyscottsmn wrote:Well that didn't happen either.

I was unable to work on the project for quite a while and now that I am able to come back to it "hard and fast" I am finding I am quite unhappy with my ECM estimation implementation. I know all that is classified and I can't possibly do it right but right now it is a glaring error that a given ECM system imparts a fixed dB of noise on another given Radar system or provides a set degradation in shot pK regardless of range. I need to figure out a better system that has ECM become less potent as range decreases (to simulate burn through).

Go back and fix it now and redo the comparisons where it matters, or finish it under the current system just to finish it and then do a revision later?

You can try this sheet
On the left hand side: stand off support jamming: ex: EA-18G, mald-n, spear-ew
On the right hand side: self protection jamming: ex APG-81, Spectra, Falcon edge
seft-protection-jammer.xlsx
(238.23 KiB) Downloaded 107 times
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sprstdlyscottsmn

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Unread post23 Jan 2022, 16:57

garrya wrote:You can try this sheet

Did you make this? This looks like exactly what I was trying to do for determining burn through range. Between this and the links hornetfinn sent me I should have what I need to get a much better ECM setup.

You two have been invaluable to me for improving my understanding of radar over the years.

Edit* so looking at the self protection burn through I feel like something is implemented incorrectly. The "For example" setup yields a burn through range of 89 meters. Okay. If I up the radar output from 1kW to 30kW, increase radar gain from 30dB to 38dB, and increase target RCS to 18.5m^2 (representing my AESAClcTrial file for an S-400 tracking an F-15EX at 574km, basically horizon and instrumentation limited) with the same 100W jammer with a 10dB gain, then the burn through range is a mere 1.67km. So something is either off in the calculations or 100W power for jamming and a 10dB gain antenna are insanely powerful.

Edit 2* looking through the material Hornetfinn sent, it looks like the mysterious "-71dB" in the 20log(Dt)=... equation is the culprit. Getting rid of that yields a burn through range of a 100W 10dB jammer defending a Strike Eagle from an S-400 of 765km, useless as I would expect. 1kW jamming power reduces burn through to 242km. 1kW jamming and 20dB gain (EPAWWS is marketed as jamming multiple sources so I would think gain would have to be higher than 10) reduces burn through to 76km.

Reducing radar power and gain to 20kW and 35.8dB (what AESAClacTrial is using for F-15EX Radar) the EPAWWS is good until 46km. That sounds like it might be a bit too close, but at this point I will have to make assumptions about power and gain for the ECM systems. I was having to make other assumptions already.

Okay, I think I'm heading in the right direction.
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sprstdlyscottsmn

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Unread post26 Jan 2022, 21:23

oh futzing with new equations, misinterpreting them, figuring it out.
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