Go Back  PPRuNe Forums > Aircrew Forums > Rotorheads
Reload this Page >

Anyone for Ground Resonance?

Rotorheads A haven for helicopter professionals to discuss the things that affect them

Anyone for Ground Resonance?

Old 13th Jul 2021, 06:25
  #1 (permalink)  
Thread Starter
 
Join Date: Aug 1999
Location: Gold Coast, Australia
Age: 73
Posts: 4,307
Anyone for Ground Resonance?

Shame about the shakycam video, but talk about resonating to destruction

John Eacott is offline  
Old 13th Jul 2021, 07:07
  #2 (permalink)  
 
Join Date: Sep 2002
Location: Great South East, tired and retired
Posts: 3,496
**Sigh** when will the Facebook generation learn to hold the phone horizontal to include a heck of a lot more picture.

That must have been an exciting ride for the pilot!
Ascend Charlie is offline  
Old 13th Jul 2021, 07:58
  #3 (permalink)  
 
Join Date: Feb 2006
Location: At home
Posts: 445
Originally Posted by John Eacott View Post
Shame about the shakycam video, but talk about resonating to destruction

https://youtu.be/BwYcAwv-m3w
Well, when you land so hard that the tailboom shear off, you really can’t blame ground resonance for the damage.

Accident info
Nubian is offline  
Old 13th Jul 2021, 11:03
  #4 (permalink)  
 
Join Date: Sep 2002
Location: Great South East, tired and retired
Posts: 3,496
Could be crappy reporting, like in Oz, and the tailboom was shaken off by the resonance? The rattling around didn't do anything for the landing gear either.
Ascend Charlie is offline  
Old 13th Jul 2021, 13:43
  #5 (permalink)  
 
Join Date: Sep 2018
Location: California
Posts: 450
That chopper was just trying to shake off that third blade he didn't really need.
Robbiee is offline  
Old 13th Jul 2021, 21:47
  #6 (permalink)  
 
Join Date: Jul 1999
Location: Warrington, UK
Posts: 3,589
Call that ground resonance? This is ground resonance.

MightyGem is offline  
Old 13th Jul 2021, 22:02
  #7 (permalink)  
 
Join Date: May 2002
Location: "Deplorable but happy as a drunken Monkey!
Age: 73
Posts: 17,053
The Chinook in the video was the victim of some Army Aeronautical Engineers who were test running the aircraft by remote control prior to shooting at it for ballistic tolerance testingl

Sadly...they chained the aircraft firmly to the ground which did not allow for the Oleo's to work as designed....and as there was no Rotor Brake on the A Model Chinooks.....there was no quick way to shut it down....thus the sad results.

The thing that stands out about the AStar coming to bits is how quickly the cabin roof and forward section of the aircraft separates....confirming how weak that thing is built.
SASless is offline  
Old 13th Jul 2021, 23:56
  #8 (permalink)  
 
Join Date: Sep 2002
Location: Great South East, tired and retired
Posts: 3,496
Sassy, the story I read was that the gearboxes had been emptied of oil and this was a test to destruction to see how long they could go.

Who knows the real story? Nick? John Dixson? The Sultan??
Ascend Charlie is offline  
Old 14th Jul 2021, 02:11
  #9 (permalink)  
 
Join Date: May 2002
Location: "Deplorable but happy as a drunken Monkey!
Age: 73
Posts: 17,053
AC,

You better check your sources for your information.

Trust me on this this....it was a ballistics tolerance test program.


http://www.chinook-helicopter.com/hi.../84-24156.html

Last edited by SASless; 14th Jul 2021 at 02:21.
SASless is offline  
Old 14th Jul 2021, 08:50
  #10 (permalink)  
 
Join Date: Oct 1999
Location: Nigeria
Age: 54
Posts: 5,029
and as there was no Rotor Brake on the A Model Chinooks.....there was no quick way to shut it down....thus the sad results.
Pretty sure there is nobody in the cockpit anyway - both from the video showing screens covered, plus the purpose of the testing!
212man is offline  
Old 14th Jul 2021, 08:53
  #11 (permalink)  
 
Join Date: Feb 2006
Location: At home
Posts: 445
Originally Posted by Ascend Charlie View Post
Could be crappy reporting, like in Oz, and the tailboom was shaken off by the resonance? The rattling around didn't do anything for the landing gear either.
The pictures suggest the tail boom being cut off by the blades as it is cut mid-section with a clean cut and associated dents on the right side of the boom.
The “spread eagle” landing gear, don’t support ground resonance either, but a hell of a hard landing… Damage of the lower vertical fin also suggest it has hit the ground hard.

Have a look at the Brazilian BA that shook itself to pieces and compare.

Nubian is offline  
Old 14th Jul 2021, 11:50
  #12 (permalink)  
 
Join Date: May 2002
Location: "Deplorable but happy as a drunken Monkey!
Age: 73
Posts: 17,053
212man is correct.....the aircraft was being controlled remotely.....simple automation re engine controls.

Notice the rather large and high berms all round the aircraft.....and note that Aberdeen Proving Grounds is focused upon things that go bang.....Fort Eustis in Virginia is the maintenance training base....and Fort Rucker is the home to the Aviation....and now days the military facility in Huntsville, Alabama does some aviation related testing.

From the Aberdeen Proving Grounds historical data.....During the period of conflict in Southeast Asia, APG reentered a period of intense growth and new direction.

The recreation of the Ordnance Officer Candidate School (OCS) took place and the unusual contributions of the Land Warfare Laboratory increased.

The intensive developmental efforts and scientific contributions of the Ballistic Research Laboratory, the Army Materiel Systems Analysis Activity and the Human Engineering Laboratory made the decade of the 1960s and 1970s an extraordinary time in APG's history.

The Ordnance Center and School's contributions included three-shifts-a-day training at the height of the conflict.

A significant change was made on July 1, 1971, when Edgewood Arsenal, the former chemical center and current chemical research and engineering center for the U.S. Army, was merged into APG. Although the mission functions remained separate entities, the real estate and base operations functions were operated as one post. From this point on, APG was the common identifier for both areas.
SASless is offline  
Old 14th Jul 2021, 12:50
  #13 (permalink)  
 
Join Date: Mar 2007
Location: Hobe Sound, Florida
Posts: 809
SAS, your information is all I have seen re the video clip. It certainly looks like the classic 2/3P mechanical instability as it starts. Easy to criticize when ignorant of the details as to what they were doing, but taking away the wheels and gear struts, key parts of the dynamics involved, and replacing with a cable system that, just looking at the video, still allowed for aircraft motion, most likely didn’t help.
JohnDixson is offline  
Old 14th Jul 2021, 21:30
  #14 (permalink)  
 
Join Date: Nov 2006
Location: After all, what’s more important than proving to someone on the internet that they’re wrong? - Manson
Posts: 1,594
B3 incident not ground resonance at all. Technical issue on maintenance flight and happened just North of the airport.

Post may be a little disparaging when you can see the pilot is still in the aircraft and incapacitated.

Maybe it’s just a plastic Ozzy thing.

Just as well the internet is a recent thing and older skeletons remain in the closet?
RVDT is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.