Assault on Bin Laden: mystery of the downed chopper

[Colonial-Marine]

Updated version of MH-X, Stealth Hawk, etc.

 

[Grey Havoc]

From the same blog, speculation about what the 'modified' MH-47, that may have been used in the operation, might look like:

 

[frank]

Black Hawk.......BLACK HAWK. 2 words. Blackhawk is the S-67 prototype.

There was, actually, a reduced signature kit produced for (some) Blackhawks and fielded in very limited numbers - a long time ago. These were somewhat consistent with the descriptions of "snap on kits". Apparently they were not easy to maintain, and the units that had them did not have the facilities for maintaining the vehicle's signature.

Similar kits were produced for some other Army rotocraft. One of these - the most successful - may have been mentioned earlier in this thread.

HOWEVER, the Blackhawk kit is definitely *not* what was used for NEPTUNE SPEAR. What is visible in the photos is not consistent with that kit, or what could be accomplished with any "kit" (see earlier post about composite tail).

 

[quellish]

Black Hawk.......BLACK HAWK. 2 words. Blackhawk is the S-67 prototype.

Noted. Removed.

 

[Abraham Gubler]

From the same blog, speculation about what the 'modified' MH-47, that may have been used in the operation, might look like:

Why would they go to all this trouble of changing the rotors and outer mould line and still keep circular window frames conveniently providing a right angle surface to every possible radar angle?

Updated version of MH-X, Stealth Hawk, etc.

I very much doubt they could make the main gear disappear so easily. Also there would be less need to chine the fuselage as opposed to reducing circular reflectors. They aren’t going to kit up a Black Hawk to make it a -30 dbsm platform but they can provide a tactically significant radar reduction by removing all the reflection and diffraction black spots.

 

[Stargazer]

No matter all the faceting and blade redesign... isn't the flat bottom a dead giveaway to radars, anyway?

 

[Abraham Gubler]

No matter all the faceting and blade redesign... isn't the flat bottom a dead giveaway to radars, anyway?

No flat bottoms are very good for stealth. Because the radar is never exactly under the aircraft and if it is its only for a brief second as the plane flies by. Otherwise the geometric relationship is very acute, which is good.

 

[Stargazer]

No matter all the faceting and blade redesign... isn't the flat bottom a dead giveaway to radars, anyway?

No flat bottoms are very good for stealth. Because the radar is never exactly under the aircraft and if it is its only for a brief second as the plane flies by. Otherwise the geometric relationship is very acute, which is good.

Thanks for the reminder. Of course I should have remembered the F-117... :

 

[quellish]

No matter all the faceting and blade redesign... isn't the flat bottom a dead giveaway to radars, anyway?

This aircraft flies at low level, so it should be optimized differently than something like an F-117 or F-22.
"For air vehicles, the most critical region for low RCS is the front angular sector, typically +-45 in azimuth and +-15 in elevation"
Radar Cross Section, pg 279 (http://books.google.com/books?id=j7hdXhgwws4C&lpg=PA279&pg=PA279#v=onepage&q&f=false)

That is true of fighters, bombers, etc but not necessarily true for vehicles flying nap of the earth (NOE). This is also a special operations helicopter, which may not often be flying directly at a threat radar, but is more likely to be flying around it and using terrain masking. The RAND study I cited earlier in this thread brought up some other interesting points, like when a NOE helicopter was visible to a threat radar in their study, it was already well inside the engagement range for the AAA site.

Regardless, modeling the tail from photos and performing a radar cross section analysis of the tail revealed something interesting - the tail appears to be optimized to reduce reflections in certain bands from the rear and overhead aspects. The AGM-129 was also designed to have a reduced RCS from those aspects, and also flew NOE. I was actually skeptical wether the SHHHH-60 was designed for a reduced RCS until I performed the analysis.

A flat bottom is unlikely to be directly visible to a threat radar system in this case as the helicopter would be too low.

 

[Gridlock]

It's a shame the aircraft needs landing gear, for FARPing I guess. Otherwise I'd leave it at the FOB upon takeoff, as the most elegant solution to its RCS (and weight) issues.

Can we offically propose SHHH-60 as the moniker now?

 

[Stargazer]

Can we offically propose SHHH-60 as the moniker now?

I don't think DoD people have THAT kind of humour... :

As for the name, I think "Hush Hawk", "Quiet Hawk" or "Silent Hawk" would be appropriate...

 

[Grey Havoc]

Can we offically propose SHHH-60 as the moniker now?

I don't think DoD people have THAT kind of humour... :

As for the name, I think "Hush Hawk", "Quiet Hawk" or "Silent Hawk" would be appropriate...

"Anasazi". ;D

 

[yasotay]

I think that folks are reading way to much into the modified CH-47. The SOAR "MH"-47 is indeed highly modified from the base CH-47 used by the Regular Army. Just can't see that big an investment.

I also agree that the idea that the "special" H-60 would have retracting landing gear is wrong. First it add a lot of weight to an already marginalized aircraft and it also, I suspect, decreases the crashworthiness of the aircraft.

Personally I think the artwork from Deviant Art is the closest estimation to what the "special" H-60 probably looks like.

 

[quellish]

There are a few photos out there of some of the Kiowas that were modified for reduced observables and fielded. Here you can see some photos of the distinctive nose (which is different from the one-off "OH-58X" mentioned earlier in this thread).

http://www.pinhaysfarm.co.uk/stealth%20nose.html

In addition to the changed nose and windscreen, rotor shrouds were added, RAM was added to several places, and some inlets and vents were given screens. The nose makes them easy to spot at a distance.

 

[Gridlock]

Can we offically propose SHHH-60 as the moniker now?

I don't think DoD people have THAT kind of humour... :

As for the name, I think "Hush Hawk", "Quiet Hawk" or "Silent Hawk" would be appropriate...

While I'm sure there's a form somewhere to propose a name for a new airframe (quellish can probably give us its ref number) I was thinking more just for SP - unless someone wants to file a FOI request so we can confirm it's a -60 derivative?

I'd imagine 'Night Hawk' is taken..

 

[Stargazer]

I'd imagine 'Night Hawk' is taken..

Although the F-117A was the "Nighthawk", it was in one word, not two. However, I believe this would be enough to discard the idea because, although it's no longer in the inventory, it was still operational not so long ago.

 

[Firefly 2]

Just pitching in an idea: Ghost Hawk?

 

[Rigid Rotor]

I'd imagine 'Night Hawk' is taken..

Yes...and no. In the early/mid-1980s, the Air Force was planning to order the HH-60D for dedicated rescue operations, and it was slated to be called "Night Hawk". It was planned to have basically the same night/adverse weather capabilities as the larger Pave Low, and it even included a proposed helmet-mounted display. When funding got tighter, they cut back on the number of HH-60Ds to be ordered, and also planned to order some less capable variants known as the HH-60E. However, none of it came to pass, as the program was eventually axed, with only a single HH-60D demonstrator tested at Edwards AFB. Later, the HH/MH-60G was developed, which of course became the Pave Hawk we know and love today.

In fact, if any of you out there have any photos or material on the HH-60D, please contact me. I'm planning to do an article on it for Vertiflite.

 

[Orionblamblam]

This didn't take very long:

http://www.dragonmodelsusa.com/dmlusa/prodd.asp?pid=DRA4628

1/144 Stealth Black Hawk "Operation Geronimo" (Twin Pack)

EAN-13 BARCODE: 0089195846280
SCALE: 1:144
ANNOUNCED ON: 5/23/2011
EST ARRIVAL: July 2011

 

[Demon Lord Razgriz]

I dunno about everyone else, but I'd have love to have seen a fleet of those with Comanches! ;D

 

[jstar]

It's a MH-60 'What Hawk"

 

[Deino]

... a bit larger !

 

[Grey Havoc]

Let the new round of model wars begin!

 

[Gridlock]

1/144 Stealth Black Hawk "Operation Geronimo" (Twin Pack)

I presume that's one complete one and one tail rotor + charred fuselage diorama?

 

[Mat Parry]

Taking the army times article posted previously by Quellish at face value, it is stated that the stealthy blackhawks have the typical blackhawk door gunner window / mini gun arrangement for self protection (fair enough, makes sense, possibly these sliding windows are modified to generate lower RADAR returns and presumably the windows are only opened & the miniguns deployed when hovering in harms way).

My question...... is the presence of windows in a helicopters cargo doors essential for the insertion of troops from a helicopter? (NB// cargo door windows, not the previously mentioned door gunners windows).

If it is not essential then I might expect that a stealthy blackhawk would have simple, single piece composite doors (without windows) for RCS reduction purposes. The provision of windows just so the Spec Ops troops can have a nice view would seem..... unlikely?

 

[bobbymike]

This didn't take very long:

http://www.dragonmodelsusa.com/dmlusa/prodd.asp?pid=DRA4628

1/144 Stealth Black Hawk "Operation Geronimo" (Twin Pack)

EAN-13 BARCODE: 0089195846280
SCALE: 1:144
ANNOUNCED ON: 5/23/2011
EST ARRIVAL: July 2011

OBB in your expert opinion what do you think of the model? Are the things like rotors, inlets and general body shape conducive to a possible stealth design?

 

[Nik]

Mentioned on news this morning that Pakistan have returned the debris to US control...

 

[InvisibleDefender]

Yeah heard on the news yesterday that it was "Returned to the US over the weekend"

Reuters
Tue May 24, 2011 12:17pm EDT

Pakistan returns US helicopter from bin Laden raid

Pakistan has returned the wreckage of a U.S. helicopter destroyed during the raid by U.S. special forces that killed al Qaeda leader Osama bin Laden, a Pentagon official told Reuters on Tuesday.
"It was returned over the weekend and is now back in the United States," Pentagon spokesman Colonel Dave Lapan said.


India Today
May 25, 2011 | Updated 17:23 IST

Pakistan returns crashed Abbottabad chopper to US

Pakistan has given back the wreckage of the American helicopter that was used in the raid in which al Qaeda chief Osama bin Laden had been killed in Abbottabad earlier this month to the United States.

Confirming the return of the chopper wreckage, Pentagon spokesman Colonel Dave Lapan said on Tuesday, "The wreckage of the special operations helicopter that was involved in the bin Laden raid was returned by the government of Pakistan to the United States and was flown back here to the US over the past weekend."

"Now US investigators will go over the wreckage for clues that may be able to determine about the cause of the crash," he added.

The helicopter was apparently damaged due to a hard landing inside Laden's compound following which the US special forces had deliberately blown it up.

Photographs of the wrecked helicopter had fuelled speculation that it was a secret aircraft model with features designed to reduce noise and foil radar detection. Aviation experts believe that it was most likely a modified Blackhawk aircraft.

Pakistan had earlier refuted reports that it would share the damaged helicopter with China, which has been accused of buying up wreckage of US military aircraft to get an insight into American defence technology.

 

[Orionblamblam]

OBB in your expert opinion what do you think of the model? Are the things like rotors, inlets and general body shape conducive to a possible stealth design?

It looks fairly reasonable. But accurate? hell, I dunno. Kinda like reconstructing a new dinosaur based on nothing but some tail vertebrae. Dragon must be fairly confident, since they would have to devote a fairly substantial chunk of change to building the molds.

 

[chuck4]

CNC molds are relatively cheap to make, and dragon restricted it to a tiny scale. This tells me they are guessing and trying to cash in quick just like everyone else.

 

[Orionblamblam]

Still, it's a bit of a gamble. The actual design could be shown at any moment (you never know) including five seconds after Dragon ships a bunch of models that turn out to be dead wrong.

 

[TomS]

Even if they're wrong, it might still sell pretty well. I don't recall; did Testors keep selling their "F-19" kit after the F-117 was unveiled?

 

[yasotay]

Taking the army times article posted previously by Quellish at face value, it is stated that the stealthy blackhawks have the typical blackhawk door gunner window / mini gun arrangement for self protection (fair enough, makes sense, possibly these sliding windows are modified to generate lower RADAR returns and presumably the windows are only opened & the miniguns deployed when hovering in harms way).

My question...... is the presence of windows in a helicopters cargo doors essential for the insertion of troops from a helicopter? (NB// cargo door windows, not the previously mentioned door gunners windows).

If it is not essential then I might expect that a stealthy blackhawk would have simple, single piece composite doors (without windows) for RCS reduction purposes. The provision of windows just so the Spec Ops troops can have a nice view would seem..... unlikely?

The widows have a multitude of reasons. First they are usually used to keep the troops in back from getting sick. Try a roller coaster with a blind fold to see the less than wonderous effects of not being able to visually equate the outside world with the inner ear. As those at the back of the bus are farther away from the center of gravity they tend to get more of the moment (pun intended yes). They also serve as emergency exits if the primary door is somehow jammed in a less than good landing (what we used to call a crash ... landing). Then there is the fact that like car windows in the back of the car the aircrew do used them to look outside the aircraft now and again. Especially on those cold nights when sticking your head out into the -20 degree hurricane is less than desireable. Sometimes the pilots (preferably the one not on the controls) will look over his/her shoulder to see if chalk 2 is still back there in formation.

I would expect that if they really needed to get rid of the windows it could be done, but I would not want to be the one sitting in back of the no window bus going into combat on a dark night.

As to the Stealthhawk stuff. I am still not convinced that retractable gear is worth the extra weight, and MH-60 are already heavy with all of the extra "special" kit; so adding even more complex gear seems a bit much. Besides I think you can make the wheels stealthy without retracting them if you have to (spats anyone?) for the mission. I also think that if you are going to go to all of the trouble to reduce the radar signature you are going to have to have some sort of cover over the dynamic components going to the rotor hub. Either an extension of the hydraulics access/cover or a separate element. Recall that most of Sikorsky's recent work has covers over those components if RCS is important.

 

[quellish]

My question...... is the presence of windows in a helicopters cargo doors essential for the insertion of troops from a helicopter? (NB// cargo door windows, not the previously mentioned door gunners windows).

Windows were treated, but not removed, from previous LO helicopter efforts like the "Special" OH-58.

As to the Stealthhawk stuff. I am still not convinced that retractable gear is worth the extra weight, and MH-60 are already heavy with all of the extra "special" kit; so adding even more complex gear seems a bit much. Besides I think you can make the wheels stealthy without retracting them if you have to (spats anyone?) for the mission. I also think that if you are going to go to all of the trouble to reduce the radar signature you are going to have to have some sort of cover over the dynamic components going to the rotor hub. Either an extension of the hydraulics access/cover or a separate element. Recall that most of Sikorsky's recent work has covers over those components if RCS is important.

I agreee, if you look at RAH-66, the LO OH-58 and LO -60, you'll see that efforts were made to mask certain parts of the rotor head assembly on all of them. In particular, the points where rotors attach to the hub are given sleeves/shrouds (I am drawing a blank on what this area is called). On the LO OH-58 these were developed and fielded, but were not actually used outside of testing.

The SSSSH-60 has some obvious RCS reduction measures in the tail. Curiously though, the rotor head doesn't show signs of having the kinds of shrouds/sleeves mentioned above. If they had been present there should be some sign in the debris. The rotor components such a shroud/sleeve would cover show no signs of scorching or unusual combustion byproducts in the wreckage photos. If the shroud melted or burned there should be some obvious signs, but there aren't any.

 

[Abraham Gubler]

If they had been present there should be some sign in the debris. The rotor components such a shroud/sleeve would cover show o signs of scorching or unusual combustion byproducts in the wreckage photos. If the shroud melted or burned there should be some obvious signs, but there aren't any.

It depends on what they are made of. The rotor head is usually steel and obviously doesn’t burn away. But a more flammable material like magnesium or a plastic could disappear in a puff of smoke in an intense thermite powered flame.

 

[Mat Parry]

The widows have a multitude of reasons. First they are usually used to keep the troops in back from getting sick. Try a roller coaster with a blind fold to see the less than wonderous effects of not being able to visually equate the outside world with the inner ear. As those at the back of the bus are farther away from the center of gravity they tend to get more of the moment (pun intended yes). They also serve as emergency exits if the primary door is somehow jammed in a less than good landing (what we used to call a crash ... landing). Then there is the fact that like car windows in the back of the car the aircrew do used them to look outside the aircraft now and again. Especially on those cold nights when sticking your head out into the -20 degree hurricane is less than desireable. Sometimes the pilots (preferably the one not on the controls) will look over his/her shoulder to see if chalk 2 is still back there in formation.

Thank you, all good points! I guess the determining factor would be wether the loss of functionality these windows provide is outweighed by the gains in stealth achieved (if any). I like the spats idea! seems more likely from an airframe modification point of view, retractable under carrage would require a large structural rebuild. The fun thing about this topic is in years to come we'll likely be able to see how accurate our speculation was (or wildly inaccurate in my case ).

I would expect that if they really needed to get rid of the windows it could be done, but I would not want to be the one sitting in back of the no window bus going into combat on a dark night.

Am I wrong in thinking that there is a kind of precedent for this? nap of the earth penetration in an MC -130H Combat Talon II would be neither a smooth ride, nor a sight-seeing tour?

Windows were treated, but not removed, from previous LO helicopter efforts like the "Special" OH-58.

Yeah that would seem to be damning to my attempts to imagine the SSSSH-60! although to my eyes the stealth treatments applied to the crashed helicopters empennage and tail rotor would appear to be more advanced than those applied anywhere on the "special" OH-58, is it fair to extrapolate that more advanced stealth technologies were also applied to the rest of the crashed stealth helicopter? or as you have suggested, is rear aspect stealth is the primary focus? Once again we'll probably see the answer at some point yay, love it!

EDIT
numerous typo's

 

[flateric]

go eBay, go!

 

[LowObservable]

&OBB...

It could turn into a collectible like this one:

http://www.fantastic-plastic.com/REVELL%20B-2%20HIGH%20TECHNOLOGY%20BOMBER%20PAGE.htm

From the site: "Working from known flying wing technology and the accepted requirements of Stealth designs, the engineers at Revell concocted this smooth, low-profile, tailless bat-wing design."

Snort. Revell engineers my a**e.

 

[quellish]

Yeah that would seem to be damning to my attempts to imagine the SSSSH-60! although to my eyes the stealth treatments applied to the crashed helicopters empennage and tail rotor would appear to be more advanced than those applied anywhere on the "special" OH-58, is it fair to extrapolate that more advanced stealth technologies were also applied to the rest of the crashed stealth helicopter? or as you have suggested, is rear aspect stealth is the primary focus? Once again we'll probably see the answer at some point yay, love it!

EDIT
numerous typo's

It's not so much different technology as different requirements. The OH-58D(I) LO was more than a "snap on kit", there were structural changes. Some components could be removed, and were. The LO Kiowa was optimized primarily for front aspect RCS reduction, which makes sense for an armed attack helicopter. The SSHHH-60 was clearly optimized for a different set of mission requirements. I couldn't tell you if the SSSHHH-60 is optimized only for rear aspect RCS reduction as I have not seen the rest of the aircraft, only the tail - which does seem to be designed to have a significantly reduced RCS from the rear aspects, for certain bands.
Advances in stealth technology are primarily things like simulation tools, testing tools, and manufacturing capabilities. Shaping is still (and always will be) the dominant method of controlling radar signature. Coatings have practical and physical limitations, as do absorbing and frequency selective structures. There is no magic coating that can make an F-15 have the signature of "an eagle's eyeball", and composite structures do not necessarily reduce the RCS of a shape (in many cases, they increase it, and limit your options for coatings). Composites *can* enable you to create a less observable shape that would be impractical (too heavy, too expensive, too difficult to manufacture to the correct tolerances) with other materials or construction techniques.

 

[Orionblamblam]

Walter Boyne: Why everyone misinterpreted Stealth Black Hawk story

http://www.flightglobal.com/blogs/the-dewline/2011/05/walter-boyne-why-everyone-misi.html

"I think it gave [the public] a sense of pride and self-sufficiency," Boyne said. "For me to think that the United States of America with 4.9% of [gross domestic product] devoted to defence can at best field four modified stealth helicopters when engaged in three wars is shameful."

In Boyne's view, the knowledge that US special operations still rely on bolt-on stealth kits reveals the US vertical lift aircraft industry is still mired in the aerodynamic and signature limitations of the Vietnam-era. The fact that one helicopter crashed during the operation allegedly due to power settling -- ironically, revealing the programme's existence -- should come as no surprise, Boyne said.

The Black Hawk "is still a 30-year old design," Boyne said. "When you put on aftermarket stealth it degrades your performance."