Chicken Wings Forum

Roost Air Lounge => Aviation related topics => Topic started by: Stef on February 24, 2012, 10:55:37 PM

Title: Helicopter falling apart...
Post by: Stef on February 24, 2012, 10:55:37 PM

Whoa! What happened here?!  :o

http://www.youtube.com/watch?v=3QgXQ39aL5I (http://www.youtube.com/watch?v=3QgXQ39aL5I)

Title: Re: Helicopter falling apart...
Post by: Mitchell99 on February 25, 2012, 12:44:47 AM

It looks like ground resonance.  Should have picked up the helicopter.
http://en.wikipedia.org/wiki/Ground_resonance

Title: Re: Helicopter falling apart...
Post by: Stef on February 25, 2012, 11:18:47 AM

Yeah, just had my brother explain the concept to me. Amazing how many things can go wrong in a helicopter...

Title: Re: Helicopter falling apart...
Post by: Mike on February 26, 2012, 10:49:59 AM

check out the test the Army did where they introduced it on purpose to see what would happen....

http://www.youtube.com/watch?v=-LFLV47VAbI (http://www.youtube.com/watch?v=-LFLV47VAbI)

Title: Re: Helicopter falling apart...
Post by: Mike on February 26, 2012, 10:52:39 AM

and here is how the fix looks like!

http://www.youtube.com/watch?v=6vICf8l-KV0&feature=related (http://www.youtube.com/watch?v=6vICf8l-KV0&feature=related)

Title: Re: Helicopter falling apart...
Post by: Oddball on February 26, 2012, 05:05:53 PM

This is the side view of the Chinook test Mike posted:

http://www.youtube.com/watch?v=vTRuWgoEFxo&feature=related

Title: Re: Helicopter falling apart...
Post by: Ragwing on February 27, 2012, 03:26:39 PM

From AV web on the AS350BA

Some observers speculate that a bad episode of ground resonance may be to blame for the violent self-destruction of a medevac helicopter as it landed in a field in Para, Brazil. Few details are available about the incident, which reportedly took place Wednesday -- the same day video of the accident began spreading, online. The helicopter appears to be a Eurocopter A-Star AS350BA. Some reports state that there were four aboard -- two pilots, a doctor, and a nurse -- and all escaped serious injury in spite of the helicopter engaging full-flail mode. Several accounts repeat that the aircraft suffered excessive vibration while airborne and that vibration developed into destructive ground resonance after the aircraft landed. Generally, ground resonance will resolve itself if the pilot is able to respond quickly by returning the aircraft to hover.