Posted on 05/12/2011 7:58:29 AM PDT by BwanaNdege
How about coaxial rotors? that would cure the close ground vortex and eliminate the need for a tail rotor system.
If you ever come across a photo of a breaching hole, please let me know because I still haven't seen one.
Thanks for the info, and for other things as well, both of you.
“Hot air close to the ground and the aircraft’s proximity to the high walls of the compound could have caused that thin, hot air to be driven by propwash up the walls and then down through the rotor, causing the vortex ring state. With those conditions, the helicopter would have lost lift and settled with power, which is what officials say happened.”
A close friend who does know, and is in a position to know something about all this, says that the size of the opening of the compound and its high walls (& the altitude and air temperature) could have by themselves caused loss of lift, without the vortex ring state - simply collectively restricting how much air could be sucked how quickly under the main rotors, to provide, or to continue to provide the lift. He does not discount the vortex ring theory; he just thinks it is not the only possibility.
I know someone who KNOWS the Blackhawks; intimately. He says the tail rotor size and shape was "non-standard" for a "production" Blackhawk.
If the changes were actually stealth related, the tragedy is not the mere fact that it was left in the compound, but that in all likelihood it has left Pakistan, for China.
Make your own comparisons:
A tour from the maker of the Blackhawks (it's an Adobe Flash video and it starts slow). What is nice is it lets you alter the view of an operating Blackhawk, to see it from either side or either end; at:
http://www.sikorsky.com/Products/Helicopter+Tour
versus
http://cencio4.wordpress.com/2011/05/03/mysterious-helicopter/
which includes the comment:
"However, the depicted horizontal stabiliser and tail rotor of the wreckage dont seem to be a any form of H-60. Both the shape and position are not common to either Black Hawks or Apaches helicopters. Noteworthy, the tail rotor has a weird cover that could be anything from a stealth cover, to an armour plate to a noise reduction device."
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