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HelicopterGasser Model RC HelicoptersOther › Essential gasser equipment
11-20-2009 08:51 AM  7 years agoPost 1
shawmcky

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Isle of Wight,United​Kingdom

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Has anyone made a cheap vibratometer yet so we can measure peak vibes and run the heli at the best(maybe compromise) settings through a governor.Must be some stress engineers out there somewhere.There are plenty of stressed gasser owners

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11-20-2009 11:06 AM  7 years agoPost 2
Fixit

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UK

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Has anyone made a cheap vibratometer yet
Yes but she’s always booked up for some reason

I only like to fly gassed up

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11-20-2009 01:33 PM  7 years agoPost 3
kogibankole

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albuquerque/ibadan

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Running the engine at a lower rpm under load I have discovered helps with the vibration issues. In the zenoah manual it states to gear the headspeed for heli engine rpm to be between 9000 - 10,000 at full throttle. Al over at Hanson also recommends to run his modified engine at 10,500 for lease vibes ( AP) I think this is very critical.

if im not blade bogging youll find me pack puffing

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11-20-2009 01:54 PM  7 years agoPost 4
AceBird

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Utica, NY USA

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Has anyone made a cheap vibratometer yet so we can measure peak vibes
Anything long and light that you hang off the frame will give you a visual of the vibrations present. Most people use the vert and horz stab as an indicator. The stiffer the member the higher the resonate frequency. Lower frequencies can be indicated with a dowel and a small weight on the end that you can change to look for different frequencies.

Ace
What could be more fun?

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11-20-2009 01:54 PM  7 years agoPost 5
shawmcky

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Isle of Wight,United​Kingdom

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On a quick search

under hand held vibration testers came up with one of many examples

i could think of many uses for this on a helicopter,no prices found but doesnt look expensive.

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11-20-2009 02:03 PM  7 years agoPost 6
shawmcky

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Isle of Wight,United​Kingdom

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Vibration tester

this equipment is apparently common place in industrial applications to warn of impending failures for example on production line equipment to isolate component failures before they happen.

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11-20-2009 05:15 PM  7 years agoPost 7
smallplanes

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S.C. ,SSA

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I think that would just be a good maintenance man.


Spectra G 26cc
Jewel
Bat 27cc
Trex 700<br

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11-20-2009 05:30 PM  7 years agoPost 8
BeltFedBrowning

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Kansas City

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I use a vibratometer on car engines and drivelines to find the frequency of the vibration. With a little math I can find the rotational speed of the part that is causing the vibration. It could be used on RC helis I guess. The problem is that the meter must be in contact with the heli as you turn the dial to find the frequency.

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11-20-2009 05:31 PM  7 years agoPost 9
FloridaHeli

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jacksonville,​florida

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I don't see how you could use the vibration instruments shown above. Think about it, you want to check for vibration when the rotor is up to speed. That is no place and time to be using a hand held sensor. You might get caught up in those spinning blades. A 600 mm blade at 2000 rpm has a tip speed of 300 mph. That is a lot of energy to tangle with.

Think about it.

This hobby is WAY too expensive!!

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11-20-2009 05:32 PM  7 years agoPost 10
BeltFedBrowning

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Kansas City

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I agree!
I have never used it on my helis and I never will.

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11-20-2009 05:56 PM  7 years agoPost 11
Dr. Fibinotchi

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Sioux Falls SD

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hmm

I went down this path a while back. I am in maintenance and sched vibration anylisis for the ovens we have. It has saved time in the past and we have found motors with bearings going out as well as pillow block bearings near end of life.

I have not found anything usefull for us to use either. A eagle tree that records vibration in flight would be nice with a probe. I remmeber reading somewhere that each shaft has a frequency for it when it fails like torque tube bearings etc.

Nothing concrete that anyone can use though. It would be nice.

-C

If you want others to be happy, practice compassion. If you want to be happy, practice compassion.

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11-20-2009 06:49 PM  7 years agoPost 12
pgkevet

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Wales

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I use a vibratometer on car engines and drivelines to find the frequency of the vibration. With a little math I can find the rotational speed of the part that is causing the vibration.
In a heli are there more than 4 rotational speeds? engine system, mainshaft system, TT system and tail rotor?

If that is the case and one could govern the engine to a set rpm then the above quote implies at at any given rpm one just needs 4 frequency indicators?

My physics is way too rusty to work this all out.. but I'd guess that 4 prongs sticking out somewhere could do it?

Aftre that it's a combination of reducng that cause and attention to why it's being magnified - as in loose/worn bits?

pgk

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11-20-2009 08:35 PM  7 years agoPost 13
AceBird

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Utica, NY USA

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If that is the case and one could govern the engine to a set rpm then the above quote implies at at any given rpm one just needs 4 frequency indicators?
These four frequencies would be the norm so seeing them means nothing. It is all the other frequencies that would mean trouble.

To tell you the truth I think we already do have a vibration detection device on our helies. It is called a gyro. If you took the output of the gyro and recorded it or sent it down to a scope I think you would see all the problem frequencies or vibrations that shouldn't be there. This would confirm that you have vibration problems but not necessary tell you where they are coming from.

Because the helicopter is such a complicated mechanism it will always be difficult to tell where the problems are coming from. A good PM is probably the best answer for trouble free flights in the long run.

Ace
What could be more fun?

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