nighthawk2174

New guidance would be a new loft and APN, the interaction between the AWG-9 and missile doesn't really fall into that realm. Also I thought it was reported that it was intermittent in it working. I myself tested this and noticed that the missile would still go active even if you did break away. Now that was a while ago tbf so maybe it got fixed in the meantime.

Yeah its been an issue for quite some time -since it was released- and won't get fixed until the 54 gets the new guidance implemented. IIRC the latest news was its still not working in MP and not even really in SP so it will probably still be a while (unless it gets fixed this next patch).

In the worst case scenario maybe 2-2.5x not 3x-4x. Often though it'll be much less Also the AIM-54 doesn't have the new guidance yet and as such exiting the loft it pulls a lot and like the old amraams and excessively high lift induced drag makes it worse. As such it results what your seeing.

something to consider for this source: https://basicsaboutaerodynamicsandavionics.wordpress.com/

From what i've seen (no research yet) the amraam is ku band. You probably could get a rough approximation based off the size of the dish and take into account its known to be a 4 element monopulse. I have no sources on exactly how FFT is done only that its a possibility based on the 1959 paper I posted earlier which was about anti-chaff techniques that had been developed/were being developed. But i'd be surprised if something like it couldn't and isn't being done in modern seekers like the amraam.

What are these source called? Yes if the chaff isn't cut to the proper length for the radar its effect will be substantially reduced. And different types of chaff have different properties in terms of number of dipoles per unit mass or how quickly they fall. And your evidence that their wrong? Burden of proof is on you here i've based what i've said on a minimum of 8 different sources that are largely in agreement. If it doesn't want to get filtered out it does, if the doppler shift from the cloud is below a certain level returns from that source will be ignored. If its outside the main beam iirc you'll often see that returns on on the order of 40db lower than in the main lobe. And one of the whole points of stuff like range gatting, velocity gatting, and even various filtering techniques is to minimize the error created by sidelobe clutter. Yes as chaff is dropped there will be a brief moment that the target will appear larger and may drag the aimpoint behind the target. I've never disagreed on this point. Just that this would have much of an effect in the long run. Especially if you are not dropping chaff essentially continually. As the time the bundle would stay in the main lobe, let alone the res cell, is very small. Again monopulse seekers like on the amraam can start to solve for unresolved targets after only a few pulses. In the end I just don't see this being enough to either A) through off the seeker or B) how it could give enough time or produce enough error to cause a large enough miss for the proxy fuze to not hit. As was shown in MACE the chaff was in the main lobe of the seeker inbetween the seeker and the target. Yet it was filtered out. The level of simulation in MACE is insane and I fully trust its results there as its in agreement with many different sources about what would happen. No getting into the notch will absolutely break a lock. I just don't see chaff breaking the lock on a PD based missile, especially monopulse based seekers. As it falls out away from the target very quickly. A towed decoy will stay in the main beam up until a short time before impact. Even then based on what i've read it is still possible for seekers like the 120's monopulse to determine there is a false target, the towed decoy in our case, in the main beam and track towards the real target. This is why more sophisticated and monopulse specific jamming techniques have had to be developed. And even if it somehow does force a break lock it should still be fully possible for the seeker to reacquire the target. For SARH if the main radar maintains lock, and for active if the target is still in the seekers fov/search pattern. No, i'll reference you to my cloud metaphor above. But the amount of chaff that would need to be used to get the effects that your visualizing is quite high. Higher than what is loaded on aircraft in SP systems. And even then it would have to be in the correct geometry to ensure that it fully blocked LOS. Which would be quite rare. With SARH/Active if a continuous stream is released this is my visualization of what would happen. It would drag the aimpoint behind the target. Just a question of specific circumstances and target size, radar characteristics, and geometry if this is enough to matter. Chaff will generate a doppler shift but based on what i've read and understand is that this return will fall below the minimum doppler gate of the radar very quickly and as such will be filtered out. And I think you are severely overestimating its effectiveness. No the whole point of that was to show how much chaff is needed to fully hide a target not that it couldn't cause increases in miss distance or break locks on the older pulse systems. The thing though is that the return is still going to have a minimal doppler shift is the chaff is just hovering there in the air. So all you need is a larger doppler gate like 100kts to ensure your safe from this happening. It would screw over just radio based ones like on the SA2/3/4 but if its a mini-doppler system then not so much. Not perfectly but enough to make the chaff not very effective. Also you claim to have sources but what are they? They would run counter to everything I have including what i've been told by multiple pilots at this point. From my current understanding the use of chaff is it being used in large bursts right as one enters the notch (in combination with ECM) to attempt to throw off immediate automatic re-acquisition attempts. Maybe not fully obsolete but in comparison to towed decoys and against monopulse or AESA seekers quite nearly; especially if just deployed alone and not used in conjunction with jammers.

Hmmm yeah that ain't, from what little footage i've seen it doesn't loft at all but flies right at the target with PN.

This is not what is said in various papers on the subject, so do you have a source for this claim? ? As indicated though from the above papers though the amount of chaff to generate this effect is immense and the fractions of lbs of chaff released from a self-defense loading are unlikely to affect modern PD radars too much. Yes you can, the scattered returns don't pick up a ton of doppler shift (except in the milliseconds right after release) its not enough to get past Vgates. As indicated in the image I posted chaff will appear to have a variation of only a few m/s above and below the wind speed. Yeah and as such chaff on a fighter is not going to be effective at all against stuff like the amraam. It will always be able to range gate and Vgate out chaff from any aspect. If not just reject it outright once its outside the res cell, hec with monopulse even inside the res cell. Hence why towed decoys became a thing. I just don't see how, if it was this susceptible then it would loose lock even to rcs induced glint. So I don't buy that chaff could cause a break lock that easy if at all. Not to mention that it could just reacquire the target once the doppler returns of the chaff are dropped moments latter. And its very likely the target will still be in the seeker FOV. Not to mention the chaff would have to defeat both range gatting/Vgatting, and a whole other suite of possible countermeasures. Including the PD filtering. Well this is why things such as MTI/MTD and rcs edge tracking were all developed for older pulse radars. Plus its not going to be going in a left to right manner for tracking, even the SA2 uses a conical scan with a very tight 1° beam. I think your severely underestimating the rate at which pulses are being sent out and the target data updated. I know for a fact that, for example, on the mig-23 in its guidance mode the prf is 100khz. Lets say you need 10 pulses to know for certain a targets position/speed/azimuth/solve for multiple targets in the res cell. And further that the system can process data only at 5khz. This still allows you 500 updates per second... This is probably exceptionally low compared to something like the amraam but still that is fast. And considering that monopulse seekers can solve for the angle between two targets in the res-cell after only two pulses... The amount of time were talking about here makes all of the effects that chaff could induce very very very minimal. This is assuming that the range to the target isn't fed into the proxy fuze and isn't only turned on moments before impact or isn't its own doppler based system. While this could be a thing actually getting the missile to fly through the chaff or close enough to actually, and only if the above assumptions are false, trigger the warhead will be rare. Again as is stated in multiple papers though these multiple speeds are very low and can all be filtered out. Hec its indicated in the previously classified one that this could even be a good way to filter out chaff as a target will be a pinprick in the doppler spectrum compared to chaff. And that you will still get returns from the target with a doppler return. Again do you have a source for this? I'll leave you with this (go too 1:10) this is a vid from a 20,000usd (per license) sim made for customers like militaries. And here the two targets deploy chaff even while cold yet the amraam still tracks them due to range gatting and doppler.

Yeah I did but I didn't take screenshots lol I should have XD,one day out of curiosity I will.

It seems you were curious as too why they perform badly in certain regimes, well I just finished up my high res cfd run for the Adder and this is why: Mach 1.0: Mach 5.0:

Well which specific data? The first image is from a report called "Optimal Estimation of Target in Clutter (Chaff) From Radar" dated 1985. The second is from a formally classified report Chaff Countermeasures and Air Defense Radar Design dated 1959. The chaff laying also comes from this source, the number of lbs of chaff is for a x-band tracking radar at medium range (nike Ajax ranges) assuming a target echo of 40m^2. Which, considering the tech probably means the number required for modern radars is MUCH higher as indicated in the final image. The final bit comes from a book called Radar Homing Guidance for Tactical Missiles dated 1986 and it was just a general statement concerning missile seekers and chaff.

You have a source for this? Haven't seen these numbers before. Well again from my current understanding its not like a wall you can still get target returns through the chaff cloud (and as it disperses i'm certain that this effect would only diminish). Additionally not all of the chaff cloud is going to be cut to the appropriate length to have an impact on the radar. Which will only compound the above as the chaff cloud disperses. Just keep this in mind the amount of chaff being used to create corridors in Vietnam (for short periods) was thousands of pounds of chaff. 12lbs at the low end per/NMi. If you wanted more coverage or where using heavier chaff materials which could be up to 20-25lbs per/NMi. Also if it is not cut to the proper length the apparent RCS falls off rapidly. So there's also a question is the chaff cut in a way that the frequencies being used by the amraam or TR's are covered? Or are they out of the chaff "envelope" Well one reason off the top of my head is to not interfere with civilian weather and air traffic radars. Yes you'll see a lot of speed variations but, as is indicated in the radar handbook the average difference can be measured in only a few m/s. Which is going to be significantly lower than the Vgate on just about every PD radar. But by how much? Like I can't imagine that the effect would do enough to cause it to miss.

Python 4/5 would be super cool to have. Not sure if there's really enough on it to get it 100% accurate but i'm sure that one could get enough info from cfd and approximations of its motor type to get something that would be somewhat close. Spice though would be more work as, at least if bms is accurate, depends on additional functionality in the UFC and DED. But would not be opposed to ED doing this. Who knows maybe an F-16I as a future module would be nice.

I mean I don't think it's really comparable here as were talking dumping this out at hundreds of mph. Additionally there are some declass documents out there on this stuff and the average time i've seen is generally in the 2-4 second range for a chaff cloud too fully bloom. Also no it doesn't have to completely separate but the effect will be greatly diminished from the full bloom. You can get a rough idea of what the res cell would be in both azimuth and depth with: From my current understanding the accuracy in depth is often in the range of hundreds of feet if not much less. With the accuracy in azimuth being larger but iirc the beamwidth on the amrram is quite small (only like 1°-2°) and considering the fact it will usually be at much shorter ranges when you a) get the lock tone and b) react it may be as little as 5 miles or less this won't be that large either. Keep in mind this fact, at 400kts your moving at 675ft/s. Which exceeds theses values by a lot. And considering that chaff will drop to the current wind speed almost instantaneously (which iirc means under .5sec) its likely the chaff will only have fractions of a second to have any impact. More if slower, less if faster. If anything my current visualization of this is that the target will appear to for a brief moment get larger in size. By how much is highly variable but probably not by much especially if the chaff bundle falls out of the res cell quickly. Additionally monopulse systems unique way of working they will be able to tell if there is multiple targets in the resolution cell. In general two targets will not be at the *exact* same distance and this will cause the return to shift in phase from what would be expected with one target. With this being maximized if the two targets are moving away from each other, in our case our chaff bundle and the targeted airplane. This is measurable and ultimately, if I understand correctly, one can take this and 'weight' the radar towards one or the other target. On Top of all of this its possible, and I see no reason the 120 doesn't have, to have a velocity gate as well to supplement the range gate. Meaning anything with a rapidly changing velocity or a apparent velocity not close to the targets can be filtered out as well. No the higher the frequency, smaller the beamwidth, and the shorter the pulse width the more accurate it is. Just for example the AWG-9 is not as good as the APG-63 at picking out close targets. I mean we're not talking seconds here, were talking incredible small periods of time hundreths of a second.

From what i've read, from multiple sources, it acts more like a noise jammer it doesn't fully block the signals just degrades the power. It's a lot like a cloud, does a thin cloud stop the sun's light (instead in our case the sun would be our radar) from coming through entirely? Or does it just reduce the intensity of that light? So a powerful enough radar or a large enough target can still see/be seen through a chaff cloud. On top of this the returns from the cloud can still be range gated out so long as the return from the main target beyond it is above the noise level of the radar. And yes the AMRAAM is quite an advanced missile its resistance to things such as chaff and basic ECM techniques is indisputable excellent to superb. Edit: grammer/clarification

Yeah this is a big issue and has been around for a long time. The amraam should continue to fly towards the last known intercept if notched and not just return to 1g flight (i'm also wondering if chaffed will the missile even attempt to reacquire in game right now?). Chaff wise, irl it takes time to bloom to its full rcs (2-4 seconds depending on exact conditions) which is much longer than the time it takes to slow down to the current wind speed (often under .5 seconds). Which should make it fall into the doppler filter. Beyond this chaff that falls outside of the res cell of the radar should have no impact, but currently in game the missile will pull max G towards it if it gets "decoyed". Even if all of this fails the missile could still discriminate based on range gatting irl as well. Not to mention I wouldn't be surprised if algorithms exist to detect when a target is chaffing and to either apply some sort of filtering or target edge tracking. Methods being developed in the late 1950's. Just treat chaff like a flare but for radar missiles and the behavior we see in game makes more sense.

Drag wise their worse than conventional across the board except at high Mach and subsonic where their pretty close. Their main advantage is making the missile VERY maneuverable at subsonic and supersonic speeds (allows for lower aoa for similar maneuverability which as was pointed out above could be a way to reduce power drain just a theory though). And as such you don’t need as large actuators for them so they will fit in a much smaller form factor (which iirc was one big reason for using them).

There are two main reasons A) larger diameter which will increase drag by 10% over the 120B B) the grid fins on the adder, these are well known for being a lot draggier in the M.8-1.6 area and similar but still a touch more draggy than the conventional (and smaller) fins on the 120B at speeds above and below this region.

TBF as well the exact burn time is also dependent on the motor temperature as well. And it may not be a small variation either. Also either way the Adder will still suffer more though due to higher drag. And its not like it has ton of weight when its empty either, iirc both the 120B and 77 are similar in weight once both of their motors burn out.

Hmm interesting may be worth a look at the file see if anything changed since I last messed with it thanks for the heads up.

Concerning motor on and motor off differences this is what were talking about: it's about a 20-22% difference. It already got a partial treatment and the drag nearly matches my own CFD stuff for it, within a few %. Biggest concern I have is that the motor burn time fell by a decent amount. Edit: graphs To simplify, silver = my cfd with new ED thrust, blue = ED stuff with new thrust. Yellow is Old ED drag with new thrust. Orange is my CFD with old thrust.

I ran my own CFD some time ago on a full 3-D model with tapered wings feel free to compare. Now this was one of the first missiles I did which was on much older hardware so the mesh resolution was nowhere near as high for my latter stuff like the HARM and SD-10 which were both within 3%'ish of ED's stuff. Additionally I didn't run the intermediate values around M1.0 (.95,1.05,1.1,1.15) so the shape of the curve left of the peak at M1.2 is probably not correct either. 27R 27T

Thanks for bringing this up again this is one of the issues that was pointed out by habu and I as well I'm not hopefull it'll get fixed but who know maybe it will. Habu even shared an in cockpit picture he took where ITT was higher on one of the engines as well guess we'll see.

Updated the mod to V1.9.1, very minor teaks. https://gitlab.com/Nighthawk2174/nhawk---weapons-mod-public-release ------------------------------------------------------------------------------------ V1.9.1 - AIM-120B, boost and sustain thrust adjustments finalized

Yeah its a good start but needs some tweaking imo just a bit too good at the 15+ miles range. But is pretty good for the 6-15 mile range.