I have this secret weapon you can't detect
but I'm not going to use it in case you do...
The top-secret "Stealth Hawk" helicopters aboard which elite US Navy SEAL operatives travelled into Pakistan to kill Osama bin Laden were by no means the most sophisticated aircraft available, according to a new book on the operation. Apparently, even stealthier "Ghost Hawks" - also known as "Jedi rides" - were kept out of the …
Jallalabad to Abbottabad is about 150 km, Kabul is about 240 km. An hours flight or less in most helicopters.
Plain old Blackhawks or the standard SF Pave Hawks would probably have done the job just as well - go for the slightly better variant because it has better radar/night vision and the specialist pilots are trained on that.
The US special forces have a choice of three different types of Blackhawk alone, while the UK special forces air assets consist of an old Lynx painted black. :(
judging by some of the other media reports on this chap, he has a little bit of a cross to bare with the current administration, not sure how or why nor do i care, but i guess we have to take his word as gospel, though, i am pretty certain none of the involved seals are really allowed to talk about things like this to ex military and were probably told not to mention certain aspects of the mission and technology due to them being classified and stuff.... but if he sells his books then good on him, no one said entertainment had to be truthful, even if he thinks it is himself
Why not replace the terrain following radar unit with something similar based on a laser? Surely if if you can have laser guided missiles that home in on a laser source, you must be able to build a similar seeker function into a nav system, with a terrain "designator" laser to accompany it? That sort of tech has been around since the 70's
How much in the way of EM emissions from one of those?
Its not as though a H-60 does 200+ Knots at treetop height either, so the processing requirement must be less than fitting something similar to a fast jet.
"No electromagnetic radiation" would mean that the chopper maintained a temperature of 0K. It would not appear on radar of any kind, but would be very visible to visible and infrared sensors as a hole in the universe.
If they meant "emits electromagnetic radiation in a manner indistinguishable from background noise", then they should have said so. Terrain radar can be low-powered and focused enough to be undetectable by anything outside of the area affected by rotor wash.
Based on the reports, the choppers used were stealthy enough-they got in and got out before anybody noticed. Maybe the other choppers were performing operations that haven't been admitted to yet.
I thought electromagnetic radiation was along the lines of not being able to watch TV when your neighbour has their old lawnmower out, or being able to remotly view your CRT screen from a van (http://www.surasoft.com/articles/tempest.php).
If know there is a particular frequency of radiation given off by, say, the CPU driving the rotor speed control, you can monitor it and track your target.
It could have an emissivity of 0, meaning it also absorbs no light, and so is totally transparent to all wavelengths, or totally reflective at all wavelengths (unlikely, since it's "invisible to radar"). A team of navy seals flying with no visible support would certainly have a low radar signature.
Because they use the radar for the "terrain following" bit. That is, they check to see if the hill in front of them is higher than their current flight path.
GPS is notoriously inaccurate for elevations. Whilst you can get down to sub-meter accuracy horizontally, the accuracy vertically is way way worse. For cruise missiles, flying one into the side of a hill is unfortunate. Chopper pilots tend to have slightly more conservative sense of what is an acceptable error.
Remember, it's perfectly acceptable for a cruise missile (or so it seems) to miss its target by a few hundred metres or fail to reach its target. I mean, we've seen those cruise missile barrages. What's it matter if a conventional warhead hits a tree or a crane that wasn't on the GPS map?
When it's a heli full of live people, that actually need to get there to do the job, I think hitting an unexpected newly erected power pylon or something like that might not be quite so acceptable so some form of obstacle avoidance is necessary rather than blindly flying on a GPS map.
Yes, brave men, those seals, but equally crazy and brave would be those heli pilots. They probably go more unappreciated and unnoticed than they should be. I'm sure they have pretty good night vision aids, and a few other nice things we don't know about to deal with when they can't see the ground through smoke or fog or whatever.
But perhaps with good passive night vision aids and good weather, maybe such a mission could be flown without anything active. And for all we know for a good leg of the journey where detection wasn't an issue, they might have been flying high with weather radar on but went cozy with the ground when it became an issue.
Whatever the case, these pilots are probably crazy and deserve as much applause and commendation as their passengers...
Feats of daring like this are truly epic.
Can't be THAT hard to get it down really, really low with techies like DARPA. Paint it matt black, dump the heat into the fuel tank or a tank of liquid nitrogen (or even better liquid helium cool the fuel tank- after all, we're not talking amateurs on limited budgets here!), with a vent setup that releases gas only when it's at ambient temperature. It's dangerous and expensive, and difficult to engineer, but seems like it'd work beautifully.
Then drop active Radar, Sonar, LIDAR, whatever. It's totally unnecessary for a night-time raid on a building; the building's hardly likely to move, is it? So you use your spy satellites and use multiple photos from multiple angles/positions, feed that through a computer program/team of boffins and get back a georeferenced 3D terrain map (potentially even with other details gleaned from the spy sats overlaid). Then use the accurate military GPS, an INS and a bunch of accelerometers to give you an accurate position fix. Stick the map up on a HMD that shows you where you're looking at. You can now see the terrain as clear as day, despite potentially having no windows and it being night time.
Similar technology is already employed in some high-end subsea ROV systems, so it's definitely feasible.
If you need more up-to-date imagery (say, live IR footage) or the possibility of a 'call off' signal, either mount a suitable camera or have a UAV do a flypast and get the relevant data sent to you by satellite (with a receive-only dish on the 'copter, naturally). It coming from a satellite means that they can only know that there's someone receiving something in a thousands-of-square-miles area.
Comms emissions can be kept low by... well, by not talking over radio until you land. Pretty common sense, that one. Remember those telephones with wires from the last century? Using tech like that (using lower voltages and over STP or even fibre rather than regular phone cable to keep external emissions down) you can get internal comms that are basically impossible to see with a radio receiver and yet are again clear as day to the users. External comms would be receive-only.
As we're talking DARPA, how about some mad science in the form of some sort of vehicle-cladding in a material / meta-material that works like the frequency doublers for lasers? A glance at the physics says it looks like it could work for a sound wave as well as for light... and there's no need to make the engine silent when you can knock the noise up >120kHz so you're not even annoying the local bats! Smaller, faster-rotating, more-bladed rotors would provide a totally non-helicopterish sound from the rotors, too.
Now the 'traditional' stealth bit- shape it and build it from appropriate materials to screw up radar. Cover the rotors with a fine radar-absorbent mesh.
So we've now got a helicopter which, although massively expensive to build and run, is capable of producing little or no heat (at least until the liquid He runs out- give it a big tank!), flying at an entirely reasonable speed very quietly (at the very least with a non-helicopterish sound) and which produces no radio signals for navigation or communications.
Have I missed anything? Except my mad-scientist calling in life? :D
that's 180mph max. Supercar speeds, rather than jet-fighter speeds. So reactions aren't too much of a problem assuming you've got good visibility. And you would- you'd have a pretty up-to-date terrain map. Fly above the height of a streetlight and there's not much going to change from one hour to the next. The space directly above my street, for example, barely changes. And above the nearby dual carriageway? Nope, nothing above the streetlights for a good long time until you hit thousands of feet and start getting occasional aircraft. So they'd be flying through otherwise unoccupied space.
ROVs use Sonar to see what's around them and how far away things are. They use LBL/USBL/etc for knowing where they are in relation to the LBL array.
9 odd paragraphs of utter drivel and you still gave your imaginary top-trumps nonsense-copter a conventional engine. Why not go the whole hog, and give it a warp drive fuelled by top secret wibble fields? How about an invisibility cloak? And i've heard that owls are an almost undetectable method of communication.
is that getting 3D images from static pictures is impossible? Or that you can't georeference static pictures? How about knowing where you are in the world using GPS (with INS providing a higher update rate)? Oh, wait- it'll be the HMDs with headtracking. Those will never happen. Yeah.
Maybe your problem is someone navigating using a 3D map?
Maybe your problem is with the idea of 'not talking over comms' to cut radio comms emissions. I'd have thought that not deliberately creating any radio emissions would have done a good job of cutting radio emissions, but hey- that's just me.
The helium-chilled fuel was a bit of a stretch, I'll admit. The insulation would be pretty bulky. And the meta-materials bit may be another stretch.
Aside from the chilled fuel, perhaps you'd like to enlighten me about what's impossible or even massively hard about it?
* Stereophotogrammetry is a common trick- there are even FOSS programs that'll do it.
* Showing a 3D environment is done every day by millions around the world.
* Georeferencing maps is pretty simple, so lining up your 3D map with the real world would take very little time.
* GPS and INS tracking is done every day by... well, by a handful of vehicles. But it's still done daily.
* I'm pretty sure turning off the radio and radar would cut down on the EM emissions pretty significantly.
* With a satellite link, there's nothing stopping the map from being updated 'live' with data from a UAV.
Aside from the chilled fuel and sound deadening, It's barely even DARPA's normal level of science-fiction project.
Once they're no longer in-transit, they can turn on the whole sensor suite/open the windows and start shooting.
And it explains the use of the term 'Jedi'- you'd be flying 'with the blast shield down', relying on something other than your own eyes to tell you where you're going.
Ben Rich's excellent book Skunk Works mentions that before Stealth 'bombers' were first used in anger, they were almost used on Gadaffi. Apparently the Colonel 's regime didn't warrant the revelation of what was a secret weapon back then. True secrecy is not even letting your opponent know that the secret exists. Anything else is Privacy.
Anyone who has seen Blackhawk down knows that when speed is of the essence, US doctrine is to use air assets to come in from above. With 2 possible outcomes (dismount and enter via the ground floor or come through the roof), potential opponents have to plan for both, dilluting their Concentration of Force(s). Maybe the ground troops were a diversion, maybe that was plan B if a Helo went down (which is about the only undisputed fact). Lots of 'maybes' and not enough to say if this was an assasination mission by design.
Finally, 'Zero Electro Magnetic radiation' may be a relative term. As the writer (of the book) is not a scientist, I think we can cut him some slack. Previous Stealth improvements have reduced emmitions by orders of magnitude. Suppose a normal, current generation helo emits 1000 units of noise/IR/RF and then defensive systems are looking for around 1000 units. If THEY doubled the sensitivity of sensors, 500 becomes the threshold. However, if I work realy hard and throw money, science and materials at the problem and reduce my emmissions by an order of magnitude (2nd generation), MY low noise/IR/RF helo emits 100 units, one fith of what the sensors are looking for. If I do it a second time (3rd generation), I'm emitting 10 units.
Arriving with 10, when they are looking for 500-1000 is zero emisions in my book, paricularly when you factor in other sources that are making more noise than you.
I recall the Tweets from folks in Abbotabad that night mentioned how much noise the choppers made - much more than regular choppers. I imagine the "ghosts" are worse.
I once saw (heard) a fly-over of a "steath" fighter once, and was amazed at how much noise it made too - if you're really interested in detecting these things, try an array of microphones.
Knowing that something laden with guns and / or bombs is about to be on top of you / has just been on top of you isn't very useful in a defence sense.
Hence the invention of RADAR for early detection of German aircraft in the early part of the 20th century.
...that we aren't going to use it on a high profile mission to kill or capture public enemy number one.
But we are going to let our guys chat about it to a Hollywood screenwriter, who'll then publish a book which will be sold around the world and syndicated in national newspapers.
Sadly the author is such US-military fanboy that the obvious contradictions with this line are not even mentioned.
SunTzu said, when your enemy is close, make him think he's far. When he is far, make him think he is close. He might also have said when you don't actually have a sooper dooper secret squirrel spycopter better than one which was shot down, make your enemy think you do.
One thing I love about the people of The Register is that they don't go spewing hyperbole and buzz words like other "reputable" news outlets do (I'm looking at you, CNN, MSNBC, FOX, BBC, etc.) when it comes to things like stealth technology. This attention to detail, and the effort to NOT be sensationalistic, is the reason I trust this website more than any of the other tech news sites.
One aspect of emissions control not mentioned in the article, perhaps because it was likely not a part of the Abbottabad raid, is the stealth aircraft's use of an in-flight data link. Instead of having to use a "stealthy radar", aircraft such as the F-22 have the ability to fly with their nose cold (i.e. radar off or in standby) and rely on the radar data collected from an AWACS or JSTARS aircraft orbiting far inside friendly lines.
Mine's the coat with the wings on it.
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