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aileron flutter

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jaybannist(at)cs.com
Guest

Posted: Wed Apr 15, 2009 2:39 pm Post subject: aileron flutter

First off, I'm not convinced that aileron flutter is responsible for any of the accidents cited by the NTSB letter.  There has been absolutely no proof of such a connection, only conjecture. In fact, flutter was ruled out as a cause in one of the accidents cited in that letter - by the NTSB's own accident report.  In other NTSB accident reports probable causes other than flutter have been given, that the NTSB letter now says were "probably" caused by flutter. What changed in the time between those official accident reports and the NTSB warning letter?

 

 Second, I don't believe that hinged or  hingless has anything to do with flutter.  If anything, I believe that the weight of an aileron trim tab and servo would have more effect since it would add to the total weight of the aileron; and that additional weight would be further from the hinge point.  Does anyone know FOR A FACT how many of the accident airplanes had aileron trim?

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Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Wed Apr 15, 2009 6:58 pm Post subject: Re: aileron flutter

I have just re-read the NTSB request letter to the FAA and counted several citations from the ZBAG community.  The same group who went off to determine if there was a problem with the design seem to have convinced several government authorities of the designs weakness without proving anything.  If they (ZBAG) have proved anything it needs to be published so we all are signing out of the same book.



We all have a stake in this now. I can't think of to many things to stop this other than full physical testing to destruction of several of the airplanes that have been built by different methods, Factory built, Kit Built, Quick Built and Scratch Built.  That would be quite expensive.  Maybe it will just go away, but if we keep fanning the flames it certainly won't go away.



It's not like these airplanes are all falling out of the sky.  I have flown in three CH 601 XL's and they all functioned as expected.  I know that does not make me an expert but the point about those flights is they were non events because they were conducted responsibly.  That is the pilots real job, managing risk.



off the soap box

do not archive

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_________________
Ron Lendon
WW Corvair with Roy's Garage 5th bearing
CH 601 XLB
N601LT - Flying
http://www.mykitlog.com/rlendon
Corvair Engine Prints:
https://sites.google.com/site/corvairenginedata/

psm(at)att.net
Guest

Posted: Wed Apr 15, 2009 7:24 pm Post subject: aileron flutter

Hi Ron,



Sorry if I am getting into the argument, but there are a few things 

you said that got me going.



First, I don't think it matters what information the NTSB might have 

heard or considered in their decision making process.  For my money, 

they are the top of the food chain when it comes to determining 

causes for accidents.  If I can't accept their judgement, then I must 

put myself above the whole world in the judgement and reasoning 

arena.  I might have a big ego, but not that big.



Second, I don't agree with you that lots of planes need to be tested 

to destruction.  The NTSB laid out a series of actions meant to 

resolve this issue.  I personally feel the vibration testing is the 

most important part of the analysis they demanded.  Since the 

beginning of this problem I have felt it is based on some sort of 

mechanical oscillation that causes the low frequency noise cited by 

surviving pilots.  If this oscillation tendency can be isolated then 

it can be removed from the structure.  This is similar to the history 

of the Lockheed Electra.  If found, this would indeed constitute a 

valid explanation for all the troubles and amount to a proof.



On a more mundane level, I have to respect the NTSB's judgement that 

aileron mass balancing will correct all this trouble.  I agree that 

nothing has been proven, but as I mentioned above the NTSB is the 

best source for this kind of judgement.  For me, that means my plane 

is grounded until a satisfactory aileron mass balance design is 

installed.  I hope this can be done in just a few days or weeks, but 

I doubt a truly satisfying design will surface by then.  The way 

Zenith is dragging their feet and making comments about their doubts 

I don't think we will get anything from Chris or one of the other 

really qualified engineers for a long time.  My take on all this is 

Sebastian will get in the way of a speedy resolution and there is 

nothing any of us can do to change that.



Paul

XL grounded

do not archive



At 07:58 PM 4/15/2009, you wrote:

 	  Quote: 	
		  It's not like these airplanes are all falling out of the sky.

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Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Thu Apr 16, 2009 5:03 pm Post subject: Re: aileron flutter

Paul,



No apology necessary, I like a good debate.  I do agree the design could be made better and as an experimental product we should just do that and not wait for the government to push for us.



I had a conversation one day with a friend and he asked me who gave me permission to build the plane, I replied if he meant my wife.  His response floored me, he thought I actually needed the government permission just to go out to my garage and build an airplane.  He really doesn't understand freedom and I do think that is what is happening here.  Here  we are free people and we wait for some government body to guide us on decisions we can and should be making for ourselves.



The whole purpose of this forum is to solve problems.  I see waiting for NTSB, FAA to be counter productive and a bad influence.  I guess I could say I Love my Country, But I fear my government.

 	  psm(at)att.net wrote: 	
		  Hi Ron,



Sorry if I am getting into the argument, but there are a few things 

you said that got me going.



	




Be well, I'm going to SnF

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