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Article on flutter, now attached

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willie.harrison(at)tinyon
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Posted: Mon Jun 25, 2007 6:25 am Post subject: Article on flutter, now attached

Dear All



Many thanks to Martin Le Poidevin at Flyer Magazine for letting us  

distribute the article on flutter, which is now attached. It is PDF  

and may be easier to read if you print it.



The link to their website incidentally is: www.flyer.co.uk



Willie Harrison





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Gilles.Thesee(at)ac-greno
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Posted: Mon Jun 25, 2007 8:11 am Post subject: Article on flutter, now attached

William Harrison a écrit :

 	  Quote: 	
		   Many thanks to Martin Le Poidevin at Flyer Magazine for letting us 

 distribute the article on flutter, which is now attached. It is PDF 

 and may be easier to read if you print it.


	


William and all,



Thanks for this very knowledgeable article.

By the way, balancing control surfaces directly instead of using a bob 

weight on a balance arm is considered safer when practicable, especially 

if the weight is evenly distributed spanwise.

I'm aware of at least two aerobatics airplanes that went down due to 

aileron balance arm attachment failure followed by explosive flutter. In 

one case the crew was able to bail out.



Has anyone mentioned balancing each tailplane directly with lead in the 

leading edge? This would eliminate any possible slop on the balance arm 

attachment points and reduce wear an tear on the torque tube.



FWIW,

Best regards,

-- 

Gilles,

http://contrails.free.fr

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ami(at)mcfadyean.freeserv
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Posted: Mon Jun 25, 2007 12:40 pm Post subject: Article on flutter, now attached

So, does the Liberty use the same system as the Europa?



Duncan McF.

---

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ami(at)mcfadyean.freeserv
Guest

Posted: Mon Jun 25, 2007 1:09 pm Post subject: Article on flutter, now attached

Not forgetting that I=mr2, counterbalance weights in the tailplane leadng 

edge, apart from being much heavier would have much less inertia, offering a 

lower amount of resistance to flutter and/or its initiation.



Duncan Mcf.



---

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topglock(at)cox.net
Guest

Posted: Mon Jun 25, 2007 1:25 pm Post subject: Article on flutter, now attached

It would be interesting to know just how much lead would be needed to 

balance the tailplanes in this way...

Jeff - Baby Blue

299 hours

Gilles Thesee wrote:

 	  Quote: 	

 <Gilles.Thesee(at)ac-grenoble.fr>

 William Harrison a écrit :

> Many thanks to Martin Le Poidevin at Flyer Magazine for letting us 

> distribute the article on flutter, which is now attached. It is PDF 

> and may be easier to read if you print it.

 William and all,

 Thanks for this very knowledgeable article.

 By the way, balancing control surfaces directly instead of using a bob 

 weight on a balance arm is considered safer when practicable, 

 especially if the weight is evenly distributed spanwise.

 I'm aware of at least two aerobatics airplanes that went down due to 

 aileron balance arm attachment failure followed by explosive flutter. 

 In one case the crew was able to bail out.

 Has anyone mentioned balancing each tailplane directly with lead in 

 the leading edge? This would eliminate any possible slop on the 

 balance arm attachment points and reduce wear an tear on the torque tube.

 FWIW,

 Best regards,

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Gilles.Thesee(at)ac-greno
Guest

Posted: Mon Jun 25, 2007 1:37 pm Post subject: Article on flutter, now attached

Duncan & Ami McFadyean a écrit :

 	  Quote: 	
		   

 <ami(at)mcfadyean.freeserve.co.uk>



 Not forgetting that I=mr2, counterbalance weights in the tailplane 

 leadng edge, apart from being much heavier would have much less 

 inertia, offering a lower amount of resistance to flutter and/or its 

 initiation. 


	


Duncan,



The leading edge balance weight is something widespread in aviation. 

Concerning weight, some messages seem to state that some Europas do 

carry weight in the tail.

Defeating flutter necessitates a complex study, but mass balancing has 

something to do with the POSITION of the CG of the control surface. It 

is considered that one should aim at a forward or at least neutral CG 

position with regard to the control hinge.

A lightweight construction aft of the hinge point is key, and painting 

and hardware are best carefully studied to avoid adding weight aft of 

the hinge.

The problem with mass balance arms (which are also used), is localized 

wear and tear allowing slop to develop. Any slop encourages flutter.

Of course flutter also has to do with torsional and flexural(?) 

properties of the structure.

Darrol Stinton's Design of the aeroplane could be a good starting point 

for further insight.



FWIW,

Best regards,

-- 

Gilles

http://contrails.free.fr

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DuaneFamly(at)aol.com
Guest

Posted: Mon Jun 25, 2007 8:20 pm Post subject: Article on flutter, now attached

Thoughts and questions for those that know,

  

 I have been reading with great interest.....and concern......this flutter thread. Please correct me if I'm wrong, but isn't the flutter the result of the total slop anywhere in between the mass balance weight and the tailplane? The more slop the more up and down travel distance the tailplane will be able to move. I doubt if the mass balance weight is fluttering during this event.

  

 Now if the weight was an integral part of the tailplane, then one could not flutter without the other. And since the weight would be further back, the fuselage CofG could be maintained with less total weight.

  

 Question: Does the frequency of the flutter of a particular plane increase and decrease with a change of airspeed? What is the failure mechanism caused by flutter? Does the part that flutters destroy itself? 

  

  

 Mike Duane A207A

Redding, California

XS Conventional Gear

Jabiru 3300 

Sensenich R64Z N

Ground Adjustable Prop



See what's free at AOL.com. 

  [quote][b]

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