RIHNOSAUR
Topic Author
Posts: 336
Joined: Sat Mar 11, 2006 5:05 pm

Obtaining Vibration Spectrum From X Aircraft.

Wed Sep 03, 2008 2:51 pm

hello every one,

Currently I am working on this project where it would be extremely useful to have the mechanical vibration spectra of particular aircraft. (specifically, coast guard helicopters/crafts)
Before I get into more detail, I would just like to ask if any one knows where I would go to find this type information. Or, if some one has first had expertise with this. I guess the first question I have is if this kind of information is under a general spec characteristics for aircraft/Helicopters.

I understand that I can try to contact the manufacturers, but I figured this might be a great place to start.

thanks in advance.

[Edited 2008-09-03 07:52:16]
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RIHNOSAUR
Topic Author
Posts: 336
Joined: Sat Mar 11, 2006 5:05 pm

RE: Obtaining Vibration Spectrum From X Aircraft.

Wed Sep 03, 2008 3:01 pm

I realized I should have added the fact that I am interested in the vibration spectra near the cockpit, front turret area of the aircraft, during flight.
particles and waves are the same thing, but who knows what that thing is...
 
777den
Posts: 50
Joined: Sun Dec 24, 2006 10:52 am

RE: Obtaining Vibration Spectrum From X Aircraft.

Thu Sep 04, 2008 7:19 am

typically vibration info is collected to support advanced flight simulation requirements. a FAA Level D aircraft simulator needs vibration data for all phases of flight. I'm not sure what the requirements are for helicopters. The data is proprietary and licensed on a per device basis and usually is only available as a part of the full simulator data package which is very expensive ( 100K-1M USD or more )
 
RIHNOSAUR
Topic Author
Posts: 336
Joined: Sat Mar 11, 2006 5:05 pm

RE: Obtaining Vibration Spectrum From X Aircraft.

Thu Sep 04, 2008 2:34 pm

777DEN

thank you for responding, its an awkward/unusual question (that I'm asking), but nevertheless I am doing some research about it. To be more specific (unfortunately I cannot write about all the details that I am working on) I work for a technology development company and we are embarking on the possibility of adding enhanced features to infra-red-imagers that are mounted on the turret of coast guard helicopters.

To this end we are finding out that having the mechanical vibration spectra of the helicopter(s) at the turret region where the gimbaled systems are mounted would be extremely useful.

But I am afraid that the information we want is probably proprietary (like you very well mention) to the aircraft/helicopter manufacturer. Any ideas on how to get an answer for or something similar to the info we want ?

Does any one know how the vibration tests are performed??maybe we could rent a helicopter (and a pilot) and measure the spectrum ourselves??? (we have a limited budget...but it isn't small either)
particles and waves are the same thing, but who knows what that thing is...
 
777den
Posts: 50
Joined: Sun Dec 24, 2006 10:52 am

RE: Obtaining Vibration Spectrum From X Aircraft.

Thu Sep 04, 2008 5:40 pm

vibration data is recorded using a 3 axis accelerometer and instrumenting a plane is the easiest way to get it. Recording 3 axis acceleration data makes it easy to feed a 3 axis shaker with the recorded data to simulate the vibration environment. if you have a target customer you could probably work a deal to trade test flight time for a reduced cost for your system to that customer. You could easily record multiple accelerometers to get vibration data from different areas of the aircraft.
 
RIHNOSAUR
Topic Author
Posts: 336
Joined: Sat Mar 11, 2006 5:05 pm

RE: Obtaining Vibration Spectrum From X Aircraft.

Thu Sep 04, 2008 10:51 pm

Hi again and thanks for your reply

Quoting 777DEN (Reply 4):
instrumenting a plane is the easiest way to get it.


however what do you mean by "instrumenting a plane".....not sure I follow this

what you mention makes sense, that is what I was envisioning: using like 3 accelerometers/ geo-phones with the appropriate sensitivity (or as you mention a 3 axis accelerometer), hooking up a digital scope or what the heck maybe even directly to a spectrum analyzer and just record the measurements over the flight conditions that we need.

The idea of then re-using the data to feed to shakers is very enticing ...!!!!...I will have to bring this up to my boss.

The best part of this is that we could then scale this however we like in the lab...as ultimately what we need is just to simulate the portion of the aircraft where the camera will be mounted.

By the way, is there an-mail where I can reach you directly if you don't mind (you can send me a private message)???

cheers.
particles and waves are the same thing, but who knows what that thing is...

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