Assault on Bin Laden: mystery of the downed chopper

[quellish]

A few more hours of coding and and simulation of the tail suggest that not only is the acoustic signature of the tail rotor reduced, but it is also managed into spikes. NASA has done quite a bit of work with Sikorsky measuring and modeling the acoustics of a Blackhawk that was very helpful in creating a basic model of the tail rotor dynamics though I had to assume the rest of the vehicle was unmodified.

Based on this and the RCS simulation I did the past 2 days, I would estimate that the aircraft is designed to be quiet going in, and less observable to radar going out. The tail seems to be optimized to have a lower radar signature from a rear, overhead aspect, as if to evade look-down shoot-down radars. The ACM had similar characteristics, but also had a reduced signature from the front.

No match yet on the color, sorry.

 

[Grey Havoc]

Keep up the good work!

 

[Grey Havoc]

On another note, the Washington Post's blogPost has a piece on the 'Dogs of War' angle:

http://www.washingtonpost.com/blogs/blogpost/post/belgian-malinois-german-shepherd-breeds-under-spotlight-as-possible-war-hero-dogs/2011/05/05/AFGpoHyF_blog.html

;D

 

[blackstar]

Yeah. Just like Iraq was supposed to be the Nighthawk's first operational use in 1991... Never mind Panama in 1989... :

Yeah, but that hinged on the definition of "operational." It was no secret that the F-117 was used in Panama.

 

[bobbymike]

There has been also some reports of the noise masking capabilities of this helicopter. People on the ground say they did not hear anything until it was right overhead and also some say they heard the helicopter but sounded like it was going away from their location (although the acoustics in built up areas might explain this)

 

[Grey Havoc]

Steven Trimble over at the DEW Line is claiming that the mystery chopper was just a MH-60 Blackhawk with a bolt-on kit. I'm more than a bit sceptical myself about that explanation, but we'll have to wait and see I suppose.

http://www.flightglobal.com/blogs/the-dewline/2011/05/flightglobals-3-d-super-graphi.html#comments

 

[robunos]

better view of Diamond shaped aperture on top of Tail:

Regarding this, it should have some kind of cover over it.
If you look closely at the picture

http://www.secretprojects.co.uk/forum/index.php?action=dlattach;topic=12597.0;attach=131754

you can see the lugs that the fasteners for the cover pick up on...


cheers,
Robin.

 

[Machdiamond]

Steven Trimble over at the DEW Line is claiming that the mystery chopper was just a MH-60 Blackhawk with a bolt-on kit.

We already know that it is not the case. The most complex part of the helicopter, the main rotor hub, is different.

 

[quellish]

better view of Diamond shaped aperture on top of Tail:

Regarding this, it should have some kind of cover over it.
If you look closely at the picture

http://www.secretprojects.co.uk/forum/index.php?action=dlattach;topic=12597.0;attach=131754

you can see the lugs that the fasteners for the cover pick up on...


cheers,
Robin.

Could be a couple of things:
- Attachment point for a radar reflector
- Attachment point for a light (or a light that is also a reflector)
- Vent for the gearbox assembly

Based on the location, the first two possibilities seem most likely.

The Flight Global model appears to be pretty far off.

 

[Gridlock]

A few more hours of coding and and simulation of the tail suggest that not only is the acoustic signature of the tail rotor reduced, but it is also managed into spikes.

And what can you do with a spiked acoustic signature? Noise cancellation! Destructive interference from an 'active aural stealth' bit of fast computer could not only keep the dB down but also manage the remainder in much the same way Dazzle Camo did for ships, visually? So you've got a special forces insertion platform that is low n quiet coming in, radar-evasive going out when it might be being looked for a bit more enthusiastically, and never really sounds like it is where it is, or even hovering? Cunning.

No match yet on the color, sorry.

Looking at the admittedly lo-res photos of the destroyed main body, I see no globules of aluminium on the ground. The tail obviously has no nasty rivets to add to RCS, so I assume it's an exotic skin. CF? Ti?

The colour most reminds me of unpainted aerodynamic titanium I've seen in an unrelated field.

It's not the same as the early F117s is it?

 

[Gridlock]

- Vent for the gearbox assembly

Based on the location, the first two possibilities seem most likely.

The Flight Global model appears to be pretty far off.

Could you vent exhaust gases through a thrust vectoring nozzle in that location to a) compensate for a very weak tail rotor and/or b) produce a very non-traditional thermal signature for a helicopter? I know the straight-up orientation doesn't intuitively suggest thrust vectoring would do anything other than induce pitch but I've given up trying to perform CFD in my head.

 

[royalistflyer]

A friend - ex US helicopters Army - suggests a special version of the S-92 - big enough to carry out all the people and stuff that had to be carried after one went down.

 

[royalistflyer]

He went on to say: "that might be the right size - and the tail-rotor on it has the same angle as the downed aircraft
the skin on it is silver like the experimental light-bending film... I can only guess that they finally figured out how to mylarize it to make it durable".
Just a suggestion though. The S-92 shape is something that would seem to lend itself to stealthising.

 

[geeshockbloke]

"The S-92 shape is something that would seem to lend itself to stealthising."

The deck crew on the Forties Charlie call them "Skips". Nice and angular, like a skip. Capacious, like a skip. Fast, not like a skip.

mark

 

[bipa]

If this is a UH-60 derivative, the changes are more than skin deep.
Compare the rotor head pitch link attachment of the wreakage (top image) with one from the UH-60 (detail from a photo taken here http://www.b-domke.de/AviationImages/Rotorhead.html#Sikorsky.)
This is definitely different. It IS a Sikorsky helicopter, but it is quite different than the UH-60. Maybe it has one or two additional blades and the rotor hub has been entirely redesigned.

We already know that it is not the case. The most complex part of the helicopter, the main rotor hub, is different.

Sorry but in the pictures you posted, it looks to me like it is exactly the same part...???
Could you elaborate on the differences you mention?
Not saying this is a Blackhawk (obviously the tail and tail rotor are heaviliy modified), but it would seem that the main rotor at least is based on the Blackhawk.

 

[CJGibson]

Skip indeed. Give me a Skip any day.

Certainly the shape would lend itself to electronic LO, but (we have one on the deck of the Forties Delta as I type) they are very noisy and have a highly energetic down-draught. We have warnings about this all around the platform and the whole platform shakes when they lift.

Would be interesting landing in a compound.

Chris

 

[flanker]

Also, the base that the 160th is attached to in Google maps has a large area of the tarmac "blanked out".

Could you be more specific what base you mean? If you have a link, that would be even better.

 

[lastdingo]

Btw, it should be noted that the NH 90 helicopter has quite similar features (especially hull shape) as we know from the downed U.S: helicopter, so the Americans probably merely catched up to European new standard with their pimped Blackhawk (I don't believe in a completely different type, at most it's based on S-92. The Pentagon is simply too incompetent to pull off such a development project at costs that are acceptable for small quantity procurement purposes).

 

[Stargazer]

Not saying this is a Blackhawk (obviously the tail and tail rotor are heaviliy modified), but it would seem that the main rotor at least is based on the Blackhawk.

I seem to recall that the mechanics of the S-92 build quite a bit on S-70 technology, doesn't it?

 

[bipa]

Not saying this is a Blackhawk (obviously the tail and tail rotor are heaviliy modified), but it would seem that the main rotor at least is based on the Blackhawk.

I seem to recall that the mechanics of the S-92 build quite a bit on S-70 technology, doesn't it?

Check link (provided in Machdiamond's post): http://www.b-domke.de/AviationImages/Rotorhead.html#Sikorsky.

 

[Machdiamond]

Sorry but in the pictures you posted, it looks to me like it is exactly the same part...???

The picture I posted was focusing on the pitch link which indeed looks the same (or is very close).

However if you look at the original pictures with a wider view, one can also see that the rotor mast is different - and I am not completely sure but my impression is that it is quite a bit shorter than the original UH-60. There are other main components of the rotor that are clearly different such as main blade attachment lug.

Royalistflyer, it is definitely not an S-92 derivative. The main hub of the S-92 is totally different. The tail is totally different.

 

[quellish]

Also, the base that the 160th is attached to in Google maps has a large area of the tarmac "blanked out".

Could you be more specific what base you mean? If you have a link, that would be even better.

36.680450, -87.478970
Campbell Army Airfield, part of Ft. Campbell, KY. This is where POTUS spoke on Friday.
Sabre Army Heliport is here:
36.568155, -87.481863

There is also a battalion at Hunter Army Airfield:
32.019559, -81.137513

And one other location I can't recall. The 160th also regularly operates form Pope AFB, Simmons AAF, Lawson AAF, and other locations.


The Las Vegas Review Journal is running an article about an earlier LO helicopter tested at NCTF:
http://www.lvrj.com/news/stealth-craft-in-bin-laden-raid-has-nevada-ties-121433629.html
The 1995 article mentioned is here:
http://www.reviewjournal.com/webextras/area51/1995/special/stealthcopter.html

 

[crusader97]

Delta Company 3rd Battalion was at NS Roosevelt Roads in Puerto Rico for several years, from '99 to '03 or '04.

 

[xstatic3000]

So evidence is now pointing to at least 3 LO rotary-wing projects - the MD500 based testbed, the Sikorsky x-wing demonstrator, and the MH-60 development that led to an operational version.

Now I'm wondering if these are related to either GREATER SLOPE or GRASSBLADE.

 

[Gridlock]

I guess we're starting to see the edges of all that juicy 2001-onwards military spending coming out, RQ-170 and stealth SF helicopters.. Still waiting for a sexy fast jet though

 

[quellish]

So evidence is now pointing to at least 3 LO rotary-wing projects - the MD500 based testbed, the Sikorsky x-wing demonstrator, and the MH-60 development that led to an operational version.

Now I'm wondering if these are related to either GREATER SLOPE or GRASSBLADE.

GREATER SLOPE, IIRC, would correspond to approximately the correct time period for the "MD 500" in Nevada.

GRASS BLADE was PE code 0603317A, which SHOULD translate to "Research & Development, Advanced Technology Development (ATD), Missiles & Related Equipment, Serial 17, Army". Since it's an early 80s program, however, it's possible that the PE code maps to a different set of categories. I haven't had time to look into wether that may be true. The PE code system has changed several times over the years.

There were other classified rotorcraft programs in the DoD and Army budgets, such as TRACTOR NAIL which is ongoing. TRACTOR NAIL funding levels do not indicate procurement or an operational system, however. TRACTOR HIP and TRACTOR PULL may be others. There are also programs like 0603754A, which could be anything.

Sikorsky, Boeing, and DoD have RCS ranges that can accomodate rotorcraft. Sikorsky, NASA, and DoD have open air acoustic ranges for measuring the acoustic signature of rotorcraft. In 2002 the Air Force opposed construction of a wind farm in NV, officially because it would interfere with radar at Nellis. Supposedly the real reason was that it could interfere with DoD's very sensitive acoustic range at NTS.

There have been other programs. OH-58X, for example, did not come out of nowhere. In 2000 RAND published a very interesting study about helicopter penetration into denied airspace. A notional VLO helicopter was part of the study. Mission planning, intelligence support (the locations of enemy AAA), signatures, and SEAD were all variables. One of the lessons learned from the study was the a lowered signature on its own did not do much, but combined with intelligence support and SEAD it had a great effect.
It would be very interesting to use a stealthy drone as a pathfinder for a deep penetration mission, mapping threats in real time, and suppressing them using non kinetic technology.
The RAND report is here:
http://www.rand.org/pubs/documented_briefings/2005/DB321.pdf

So far there is not much that points to the SSSSH-60 being a modified blackhawk. The rotorhead is not from a Blackhawk, but is more like a Blackhawk than an S-92, S-76, or RAH-66. I could believe the aircraft having commonality with the Blackhawk, but there do not seem to be Blackhawk parts in the wreckage that we can see. Two serial numbers on parts recovered from the wreckage indicate manufacturing dates in 2009.
An enterprising individual could use the photos available in this thread and measure the main rotor blade chord, and possibly length, to determine the size of the rotor disk and potentially where the rotors came from.

 

[Gridlock]

It would be very interesting to use a stealthy drone as a pathfinder for a deep penetration mission, mapping threats in real time, and suppressing them using non kinetic technology.

Wouldn't it just. WE IS IN UR AIRSPACE PLAYIN WITH UR IADS indeed.

Two serial numbers on parts recovered from the wreckage indicate manufacturing dates in 2009.

You do get around don't you!

 

[Stargazer]

What about this secret type being designated as the H-69 after all?

I for one never believed the preposterous story that the number had been skipped because of its sexual implications...

 

[xstatic3000]

Fascinating insight from Quellish, as usual. Based on the info that we have available, I'm leaning towards the hypothesis that if this actually is some sort of MH-60 development, it has been reworked enough to be an entirely new vehicle. I'm starting to sense that the stories about this being some sort of "Add on Kit" that seem to originate from "Government Sources" may just be some form of disinformation.

I'm cautiously optimistic that, just maybe, we could be looking at a recently developed new type of Special Operations helicopter. This new bird could be the culmination of work started in the early 80s to develop a LO aircraft for insertion and extraction without detection. This new type would have been dictated by the post-9/11 threat environment and, while advanced, would not nearly need to be as exotic as a SENIOR CITIZEN type. The Cold-War era SENIOR CITIZEN would have been expected to operate from bases outside of theater, and would need to penetrate deep into enemy territory. It would not be expected to launch from a FOB or a carrier like a Rotorcraft.

I'm speculating that this aircraft is part of a Black Special Ops system involving unmanned, LO sensor and EW nodes, most likely part of SUTER.

One thing is clear- it's probably not a Stealth Blimp.

 

[robunos]

This from today's 'Daily Mirror' :-

http://www.mirror.co.uk/news/top-stories/2011/05/09/osama-bin-laden-s-pakistan-hideout-to-be-bombed-to-stop-it-becoming-a-sick-shrine-as-home-videos-spark-backlash-fears-115875-23117318/

'Afterwards, bin Laden’s corpse was laid out and one of the crack troops was asked to lie next to it to compare heights.
Reports suggested that when Mr Obama was told he said: “We donated a $60million helicopter to this operation.
Could we not afford to buy a tape measure?”
[my bold]

How much does a stock Black Hawk cost?..........


cheers,
Robin.

 

[Mat Parry]

http://www.globalsecurity.org/military/systems/aircraft/h-60.htm

The unit cost varies with the version. For example, the unit cost of the Army's UH-60L Black Hawk is $5.9 million while the unit cost of the Air Force MH-60G Pave Hawk is $10.2 million.

 

[robunos]

...so what comes extra for $60 million?.........


cheers,
Robin.

 

[Mat Parry]

...so what comes extra for $60 million?........

the cynic in me can't resist suggesting.... B-2 style development costs and a 4 chopper fleet? ;D

EDIT
typo corrected

 

[robunos]

...exactly...


cheers,
Robin.

 

[Mat Parry]

I seem to remember reading that in the event of some kind of 'unfavourable' revolution occurring in Pakistan, the US has plans in place for a very frightening mission to race to Pakistan's nuclear warheads and take them by force

This kind of nuke heist would seem to require some kind of 'low profile' rapid insertion, to say the least! With all the time available for planning the OBL neutralisation mission I'd be surprised if some kind of capability masking deceptions haven't been used here. The use of stealthy helicopters along side unstealthy MH-47's is strange, (MH-47's?...WTF, you might as well crank up the stereo and blast out ride of the Valkyries!) Possibly the selection of stealthy helicopters was primarily driven by their low acoustic signature i.e. less warning time for the compound inhabitants to react and then let the perimeter security force chinooks turn up 30 seconds later when things had already got noisy.

Was a SUTER-like electronic invasion actually the mechanism for hiding this helicopter armada? In the unlikely event of having to snatch Pakistan's nukes within the next few years, presumably the US would like to appear to have a second trick up their sleeve. To mask SUTER capabilities was a stealth helicopter donated?

Taking the earlier army times articles at face value, e.g. blackhawk modifications that were moderately successful (but culled before the full requirement of 4 choppers was fullfilled), was this ultimately disappointing "$60million helicopter", "donated" as a deception tactic?

The above is probably all bollocks but the one thing that surprises me is the lack of damage that the wrecked tailboom did the the compond wall (it just seems to have bent the barbed wire.... a bit)

Maybe I've missed the relevant photo's of the damaged wall?

EDIT
typos corrected

 

[quellish]

http://www.globalsecurity.org/military/systems/aircraft/h-60.htm

The unit cost varies with the version. For example, the unit cost of the Army's UH-60L Black Hawk is $5.9 million while the unit cost of the Air Force MH-60G Pave Hawk is $10.2 million.

The MH-60K would be a reasonable starting point. The K is the most "custom" blackhawk.

http://www.dote.osd.mil/pub/reports/FY2000/army/00mh47e.html

MH-60K unit cost in FY00 dollars: $27.52M

The use of stealthy helicopters along side unstealthy MH-47's is strange, (MH-47's?...WTF, you might as well crank up the stereo blast out ride of the Valkyries!) Possibly the selection of stealthy helicopters was primarily driven by their low acoustic signature i.e. less warning time for the compound inhabitants to react and then let the perimeter security force chinooks turn up 30 seconds later when things had already got noisy.

Historically mission planning and nap of the earth flight has been used to mask the approach of special operations helicopters. Very low, very fast, very well masked by terrain and ground clutter. High speed, low level night approaches are the Night Stalkers' bread and butter.

Maybe I've missed the relevant photo's of the damaged wall?

Portions of the walls appear to have been explosively breached as part of the operation. Given trees, overhead wires, and other hazards, it looks like one of those walls would have been along the ingress route for the helicopter - not the wall where the tail was photographed.

 

[Grey Havoc]

Portions of the walls appear to have been explosively breached as part of the operation. Given trees, overhead wires, and other hazards, it looks like one of those walls would have been along the ingress route for the helicopter - not the wall where the tail was photographed.

Satchel charges you think?

 

[blackstar]

Saw this on the NY Times site. Don't think it has been posted here yet.

 

[Orionblamblam]

In the unlikely event of having to snatch Pakistan's nukes within the next few years, presumably the US would like to appear to have a second trick up their sleeve.

No longer. The OBL raid was handled EXTREMELY poorly by the administration, for any purpose beyond Obama-promotion. The purpose of Special Forces raids are not for PR, but to get a job done quietly. The proper response by the administration should have been... utter silence. Express mild surprise if the raid is ever brought up in a press conference. Let rumors that the US had taken out OBL fly, and *eventually* confirm that OBL was no longer a concern. This way, nothing is confirmed. The raid on the compound is left a mystery. Other Al Queda targets that could/would/should be targetted afterwards would not get nearly the same level of warning.

And Pakistans military would not get the same major wakeup call that they need to upgrade their air defenses against rapid stealthy incursions.

By going so blatantly public with this, Obama has made future military missions that much harder or even potentially impossible, while tacking on needless diplomatic problems.

So... good job.

 

[UpForce]

I think we're going to be left to our own devices in deducing just what sort of a helo got stuck on OBL's service yard; at least I've seen no-one from the armed forces, CIA or the White House willing to discuss anything about it. Not that anyone's asked them either? Some people here have (what to me appear superhuman) skills of going through impenetrable seeming documents and sources from airspace restrictions to federal budget footnotes and come up with reasonable assumptions. I'm in awe.

From a design standpoint a helicopter doesn't seem like a prime candidate for stealth, even with the RAH-66s of this World ... I've bookmarked a couple of links to bespoke rotor flow softwares which seemed exclusively flow dynamics related. It's been a couple of years since I've visited them, but both were billed "state of the art" at the time and even now - it seems to me - it'd be a bit of a stretch to make them "multiphysics enough" to include both acoustics and RCS and coalesce all the design goals into a perfectly integrated product. Dunno, perhaps finite element methods have leaped forward in the mean time and this sort of thing is within the reach of any wet behind the ears mech BEng these days. I do vaguely remember a German Prof. Whatshisname working on reducing noise by adding small, actuated control surfaces to the main rotor - but that was for Eurocopter, I think. Me, I was just slightly surprised to see the tail rotor "stealthized", I would've thought NOTAR an obvious choice for such an "application". But then again I don't design helicopters.

About the raid being handled "extremely poorly" vis-a-vis a ficticious Pakistan nukes-grab and general political expediency ... I think our "allies" have clearly stated that the US will not be privy to their weapons' location; the existence of any agreement to "secure" the stockpiles in case of a radical uprising has been debunked. US intel dropped the ball way back with AQ Khan already (even instructing European spooks to stand down, I think), directly resulting in the worst rogue nukes profileration in memory - at the bare minimum Libya, North Korea and Iran got their goods (or "bads") from them. The idea of DevGru or even a battalion of Rambos solving this by the way of stealthy insertion ... is fanciful. On top of the manifest tenuousness of trust, it's the old guard, the Musharraf generation that was at least willing to play give-us-military-aid-and-we'll-behave-ball; worryingly there's increasing radicalization in the younger ranks coming up. And to add to the reality check - Pakistan ranks as the 6th most populous country in the World; by mid-century there'll be more folks there than there are in the US now. Can you imagine, say, the Chinese sending a commando force to "forcibly disarm" the US, or the UK?

By the way of "operational quietness" this option was the most stealthy put on the table by those who actually have to execute such things; having a couple of B-2s drop a precision payload on the compound would've also been linked to the US fairly instantly, I think. That the Pakistanis had to be excluded from the planning (as per McRaven's doctrine and previous "relations empiricism" i.e. high value targets getting tipped off) obviously necessitated accepting a level of exposure after the fact. As to the element of surprise, I think Al Qaeda - after at least a decade of relentless pursuit - has had more than a fair warning by now. We play the hands we are dealt and right now OBL's catch-me-if-you-can "mystique" is coming back to bite him and his pet projects. Besides, in a couple of predominantly islamic countries there have already been revolutions based on ... "On Strategic Nonviolent Conflict" (Robert L. Helvey, AEI) and social media tools specially engineered by human rights activists.

Not a resounding success for OBL and his band of blowhard acolytes, for I doubt said "Arab Spring" revolutionaries' ideal is to have an omnipotent medieval caliph replace their decrepit and/or dynastic strongman. Especially as we have competing examples of such religiously driven systems on full display in Iran and Saudi Arabia.