So What Helos did they use in the Bin Laden Raid?

[russ_watters]

Something interesting popped-up in the Bin Laden raid photos: a previously unknown stealth helicopter!
http://abcnews.go.com/Blotter/top-s...-program-revealed-osama-bin/story?id=13530693
http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=defense&id=news/awx/2011/05/03/awx_05_03_2011_p0-318248.xml&headline=Bin%20Laden%20Raid%20May%20Have%20Exposed%20Stealth%20Helicopter
http://en.wikipedia.org/wiki/Death_of_Osama_bin_Laden#Execution_of_the_operation

That's pretty extrordinary since the only known stealth helicopter, the Commanche, was publicly known and in development for 13 years before being canceled in 2004.

Speculation is that it is a modified version of the [S/C/M]H-60 [Black/Sea]hawk. Note the angular (stealthy) features in the tail boom and the plate on the rotor (to reduce noise). There's still a significant issue with the story, though: how many helicopters of what type were actually involved? It was first said that there were 79 soldiers and a dog in the raid, carried by 2 Army (!?) CH-60 Blackhawks. If only the Army has the stealth version, that would explain why they weren't Navy, but there is still the capacity issue: the H-60 a medium-sized helicopter and has a capacity of 16. It's nowhere close to big enough for he task if there really were 79 troops on the ground. However, I'm also seeing 24 SEALS and a total of 79, which included intelligence and other support personnel. Perhaps that's just a mis-report or they included everyone who was airborne at the time (which makes the number seem small to me) or they used more or different helicopters.

I had somehow gotten it into my head they used CH-53 Sea Stallions, which have a capacity of 38 troops, two pilots and a crew cheif, which gets us pretty close to the 79. It's also been reported they had CH-47 Chinooks on standby. Perhaps there were back-up troops in them, to get us to the 79. They are big too, with a capcity of up to 55. Regardless of all this, the tail configuration in the attached photo is closest to the H-60, so that theory seems most reasonable to me.

Thoughts?

 

[boneh3ad]

Everything I had heard said there were 24 DEVGRU operators on the ground. That 79 figure seems high to me for boots on the ground. I would imagine that figure was including the guys who were flying just across the border or flying support missions. It may also include the CIA spotters that were reportedly on the ground in the area to observe, but I suppose we will never know how many of them there were.

As for the chopper, I guess I am inclined to believe it was a modified Blackhawk rather than a modified Sea/Super Stallion. If you have ever bean around the Stallions when they fly, they are incredibly loud and I don't have any idea how they could sneak something of that size and noise level past so many people without drawing more attention than they did.

I don't know where the quote about the choppers being Army came from, but that could be a typo I suppose. It could also make sense since the DEVGRU team, unlike normal SEALs, are under the command of JSOC rather than the Navy, which has elements from all the major service branches if I am not mistaken. That was one of the things they implemented after Eagle Claw to streamline JSOC operations.

The important thing is, I don't think we will ever know with any level of certainty. Personally, I am inclined to believe it was a 24-member strike team on the ground flying in modified Blackhawks.

My only question is this: once the first chopper went down, how did they get the guys from that bird out since the second couldn't have handled them all? I suppose either a third chopper would have to have been involved or the guys who wouldn't fit had to discreetly hike across the border. I would bet on the extra helo.

 

[Mech_Engineer]

Pretty incredible stuff, I'll bet those seals are kicking themselves for not putting a block of C4 on the tail

It's interesting because the first news reports stated that the Pakinstani Air Force was scrambled after news of the attack started getting around, but the Seals were able to slip away before being intercepted by jets. I guess this helps explain why they were able to infiltrate and slip away: stealth tech!

 

[Mech_Engineer]

Do you think these stealth choppers utilized stealth/silent blade technology as well? Something similar to this new rotor from Eurocopter:

http://www.popsci.com/technology/ar...ntroduces-silent-rotor-blade-stealth-choppers
[PLAIN]http://www.popsci.com/files/imagecache/article_image_large/articles/500x_main-660x440.jpg

 

[russ_watters]

Good stuff, guys. See, this is why I posted in AE instead of P&WA. Less traffic, but better analysis.

Everything I had heard said there were 24 DEVGRU operators on the ground. That 79 figure seems high to me for boots on the ground.

Yeah, it's possible it was just plain wrong. I heard it from more than one source, but there was plenty of "official" wrong information floating around.

I would imagine that figure was including the guys who were flying just across the border or flying support missions. It may also include the CIA spotters that were reportedly on the ground in the area to observe, but I suppose we will never know how many of them there were.

Very possible.

My only question is this: once the first chopper went down, how did they get the guys from that bird out since the second couldn't have handled them all? I suppose either a third chopper would have to have been involved or the guys who wouldn't fit had to discreetly hike across the border. I would bet on the extra helo.

I'm assuming one of the first two had to take off before the 3rd could land. I'm not sure if the third was a '46 or a '60, but I'm less interested in that one than I am in the stealth.

 

[russ_watters]

Pretty incredible stuff, I'll bet those seals are kicking themselves for not putting a block of C4 on the tail

Particularly if it's a modified H-60 and the main rotor and tail were the largest modifications! But I wonder if they were even briefed on that or knew what was important to destroy. And if the chopper hadn't crash-landed, we still wouldn't know it existed.

Regardless, it's a pretty substantial loss: keeping stealth a secret, much less out of enemy hands, was as important as having it. Though conversely, if you want to keep it secret it is best not to use it. They had the same dilema with the F-117.

 

[Mech_Engineer]

My guess is their primary objective was destruction of the radio equipment and avionics in the helicopter, the tail was probably a low priority for destruction (even if it had obvious "stealth tech")...

I heard on a talk radio show that it has been said that the crashed chopper's tail actually collided with the outer wall during landing, wonder if that's what caused the tail to end up outside the wall rather than the destruction by the seals?

 

[boneh3ad]

I heard the same about the tail hitting the wall. My guess is they either just botched the landing or had something go wrong that kept them from maintaining control on their descent so they clipped the wall. I am sure they were well aware of the importance of destroying the chopper, but I would imagine the tail section wasn't high priority enough to risk going outside the compound and into the neighborhood to do it, especially since a brick of C4 on the tail would have potentially damaged surrounding buildings leading to more collateral damage.

Maybe this is just me talking out the wazoo, but I would imagine that it would be tough to get too much insight into the stealth characteristics based solely on the tail section. It would give hints about how to make that area stealthy, but most people familiar at all with stealth could probably guess a lot of those anyway. The real tricks would have been in hiding engine heat and anything done around the main rotor, and those seem to have been pretty well destroyed.

All things considered, these DEVGRU guys did one hell of a job, I'd say. I wish I could buy them a round of beers.

 

[russ_watters]

I also thought maybe they just botched the landing and clipped the wall. I'm wondering how much time the pilot had in this helicopter and if the stealth features (different rotor and stabilizer) affected the handling enough to help cause the pilot to misjudge the landing and come in just short. In a situation like this, you come in as fast as you can, at the edge of what the helicopter can handle. There isn't much room for error.

All that said, my new issue of Time says the SEALs were fast-roping from the helo when it lost lift and went down. That seems unlikely to me as it would create a likelihood of dropping and hurting a SEAL.

 

[boneh3ad]

That seems unlikely to me as it would create a likelihood of dropping and hurting a SEAL.

Fact: SEALs can't be hurt.

In all seriousness, it may have been a loss of lift or it may have been pilot error on account of the new, barely-tested stealth helicopter and the government made up a lift loss story to cover the fact that it was actually a stealth helicopter. Either way, I would buy each and every one of them a beer if I met them, including the pilot of the crashed chopper.

 

[Mech_Engineer]

So nobody commented on my link for the "whisper quiet" rotors from Eurocopter, but in the article they mention that rotor noise is due to interaction of blades and the vortices caused by the preceding blade. The noise reduction they present is very significant- down to something like under 10 dB.

It seems unlikely that the helicopters used by the Seals had a technology like this since people were able to hears the choppers hovering over the compound. Still, it seems that the most important features of a truly "stealth" helicopter would be masking infrared signature, and sound...

 

[turbo]

Sound is an important one, IMO. Going from an even number of tail-rotor-blades to an odd one (5, as it appears from the photo) would be a good start. That would cut down on the harmonics in the sound-signature.

 

[russ_watters]

Now they're saying a Chinook or two might have been stealthy too: http://www.wired.com/dangerroom/2011/05/another-stealth-chopper-in-the-osama-raid/?hpt=Sbin