Stealth Helicopter used in Osama Raid

[csv8]

Well, now we know why all of us had trouble ID'ing the helicopter that crashed, or was brought down, in the Osama raid.



It was a secretly developed stealth helicopter, probably a highly modified version of an H-60 Blackhawk. Photos published in the Daily Mail and on the Secret Projects board show that the helicopter's tail features stealth-configured shapes on the boom and tip fairings, swept stabilizers and a "dishpan" cover over a non-standard five-or-six-blade tail rotor. It has a silver-loaded infra-red suppression finish similar to that seen on some V-22s.

No wonder the team tried to destroy it. The photos show that they did a thorough job - except for the end of the tailboom, which ended up outside the compound wall. (It almost looks as if the helo's tail hit the wall on landing.)

Stealth helicopter technology in itself is not new and was applied extensively to the RAH-66 Comanche. Priorities are usually different versus fixed-wing aircraft. Reducing noise and making it less conspicuous is the first job (more main and tail blades reduce the classic whop-whop signature). Listen here.

Noise can also be reduced by aerodynamic modifications and flight control changes that make it possible to slow the rotor down, particularly in forward flight below maximum speed. Infra-red reduction measures are crucial -- the Comanche had an elaborate system of exhaust ducts and fresh-air mixers in its tailboom.



Radar cross-section reduction is also possible - you can't make a helo as radar-stealthy as a fixed-wing airplane, because of all its moving parts, but on the other hand it is generally operating at low altitude in ground clutter, and is not an easy target. Reducing RCS also makes jamming more effective, whether from the aircraft itself or from a standoff jammer.

The willingness to compromise this technology shows the importance of the mission in the eyes of US commanders -- and what we're seeing here also explains why Pakistani defenses didn't see the first wave (at least) coming in.

Update: Quellish at Secret Projects mentions an ancestor system.

Read the Aviation Week article: Bin Laden Raid May Have Exposed Stealth Helicopter.

[PHANTMXR6]

Originally Posted by csv8

Listen here.

Sorry mate, can't hear a thing.

[csv8]

Originally Posted by PHANTMXR6

Sorry mate, can't hear a thing.

http://rotored.arc.nasa.gov/activity...cheListen.html

[Road_Warrior]

Here are some pics of the tailboom:







Definitely not Pave Hawk, and definitely not Pave Low III or IV because they were decommissioned in 2008. The popular opinion on the net is that it is some sort of evolved UH-60 Blackhawk design.

The RAH-66 Comanche was cancelled in 2004. There is a chance that US Army chiefs were a bit butthurt about that and allowed some of the tech to carry over to a new 'black' helicopter and to save money (and keep it off the radar of Congressmen) basing it on the UH-60 airframe makes sense.

[Polyal]

That is cool...this scene would make a sweet Call of Duty mission..LOL

[divine_afg]

Originally Posted by Polyal

That is cool...this scene would make a sweet Call of Duty mission..LOL

COD is Probably working on it

[Road_Warrior]

Originally Posted by Polyal

That is cool...this scene would make a sweet Call of Duty mission..LOL

OH GOD YES

[XR6_661]

After watching and reading heaps of stuff about how special forces do these kind of ops...It would have been unreal, they don't stuff around.

[Polyal]

^^And thats only the stuff we end up hearing about, usually because they stuff something..LOL

[csv8]

Originally Posted by Polyal

That is cool...this scene would make a sweet Call of Duty mission..LOL

Or Die Hard 5!!!!!

[fmc351]

yeah yeah I know its stealth, but taking the "wop wop" sound as the article puts it, out of a chopper is like running a V8 with a quiet cam and too many mufflers.

Sad panda, I love the sound of some choppers.

[XR6_661]

Originally Posted by fmc351

yeah yeah I know its stealth, but taking the "wop wop" sound as the article puts it, out of a chopper is like running a V8 with a quiet cam and too many mufflers.

Sad panda, I love the sound of some choppers.

How good do chinhooks sound!

[Jim Goose]

Originally Posted by fmc351

yeah yeah I know its stealth, but taking the "wop wop" sound as the article puts it, out of a chopper is like running a V8 with a quiet cam and too many mufflers.

Sad panda, I love the sound of some choppers.

Well yes true, but being quiet means a bit more time before your exposed.
An eyewitness reports that a helicopter could be heard when far away, but was quieter as it approached the compound.

Years ago there was apparently a project where a trial was run, where a drone flew with a helicopter and used noise cancelling (large speakers) to hide the noise of the chopper.

The other issue is where did the funding for this modified Blackhawk come from?
Interestingly the project to replace the Presidential Helicopter has spent hundreds of millions on just 4 or 6 Helicopters. A huge cost over run can mean it was hidden inside someone elses budget.

Some one eagle eyed spotted that the rotor head is the same...


Kinked and swept tips to reduce noise...




One possible idea of what it looks like?

[Jim Goose]

NASA SELECTS ACTIVE SENSORS RVDT’S FOR LATEST BLACKHAWK STEALTH PROJECT
1st April 2010

A team of NASA engineers are looking into methods of increasing the militery stealth of the UH-60 Blackhawk helicopter through noise reduction tests being carried out this year (2010) at the National Full-Scale Aerodynamics Complex (NFAC), Moffet Field, California. To reduce noise from the rotor blades, engineers are developing motion-control technology by inputing low-frequency variations of rotor blade pitch-angle into the control system.

From an old article

[WMD351]

In the Herald-Sun they reported that the first time the guys in the compound would of heard it was when it was already directly overhead and at that point while it hovered stationary it would have then sounded like it was moving away.

[Road_Warrior]

I don't think they could have made it that silent when it is hovering over the target. That would (almost) be a physical impossibility. The whole point of this bird is to penetrate enemy airspace undetected, bust up someone else's shee-it and then GTFO before the bad guys can get their act together.

And now the Pakis are saying "we didn't have our western region radars switched on that night" yeah whatever

[Jim Goose]

Yes but on a still night a helicopter can be heard from miles away.
This doesnt give it any advantage if it has to land close to its target.

Noise reduction would be as important as reducing IR and radar signature in helicopter.
Even a reduction of 50% of blade noise means it can get closer.

[Gomez]

Remember the Pakistani local who famously tweeted about the damn noisy chopper outside his house in Abbottabad on the night of the Bin Laden raid?

They weren't that quiet.

[nstg8a]

Originally Posted by Road_Warrior

And now the Pakis are saying "we didn't have our western region radars switched on that night" yeah whatever

they probably got a call saying 'switch it off or we will do it for you....'

[Jim Goose]

Pakistans air defence radar system is very old and they have (the military) wanted to replace it for a while now. They apparently leave it switched off a lot.
I can see now money will be found for upgraded system...

[Road_Warrior]

Originally Posted by Gomez

Remember the Pakistani local who famously tweeted about the damn noisy chopper outside his house in Abbottabad on the night of the Bin Laden raid?

They weren't that quiet.

Highly likely there were 'normal' helos as part of the 'package' as well, most likely MH-47's which would have been the noisy bastards. You wouldn't conduct an operation like this without support and redundancy.

[XR Martin]

Yeah apparently there was a second batch of choppers a few miles away in case things got messy.

[gtfpv]

mission control , geronimo is down , just like that frarking peice of crap we flew in with , taking a taxi to the airport , pick us up there , and hurry .

[wrongwaynorris]

Originally Posted by Polyal

^^And thats only the stuff we end up hearing about, usually because they stuff something..LOL

Quite true , noone knew of the F 117's existence until Gulf war 1 . And I am absolutely certain they still have stuff we dont know about .

[DBourne]

Originally Posted by PHANTMXR6

Sorry mate, can't hear a thing.

exactly!

[csv8]

Area 51 must have some interesting experimental aircraft..

[SteveJH]

Originally Posted by csv8

Area 51 must have some interesting experimental aircraft..

Doubtful, its too well known.

[Road_Warrior]

Originally Posted by SteveJH

Doubtful, its too well known.

Well known, and completely inaccessible to anyone apart from military personnel and even then you need special clearance to work there. They would still be using it widely for testing top secret aircraft.

[Keepleft]

Well, the yanks failed to get PAK to allow them to eliminate the remaining bits of the chopper then.

[vxssm6]

Very interesting read csv8, thanks. Love all the stealth military stuff.

You would have to think there would still be a fair amount of down-wash once it was overhead, regardless of how 'quiet' it was. Too late by that stage I guess.