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Date: Sun, 24 Apr 2005 23:34:34 -0500
From: Jim Sower <canarder@frontiernet.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Upper Airspeed Data on Rotary-Powered Van's RV
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Flutter is intuitively an IAS issue, but TAS influences the harmonic 
aspects of the thing.

kenpowell@comcast.net wrote:

> Hi Dave (and welcome John),
> I agree that this (TAS) is really strange and not intuitive. But 
> consider the source - Van himself!!! When I read this in RVator I had 
> doubts but I gotta go with John on this unless we hear from another 
> impeccable source to the contray. TAS it is!!!! Call Van if you need 
> more info; I doubt any of us (do we have any aeronautical engineers on 
> the list? I know we have every other flavor of engineer here!) have 
> the knowledge to debate this with Van.
> --
> Ken Powell
> Bryant, Arkansas
> 501-847-4721
>
>     -------------- Original message --------------
>
>
>     rv-7a wrote:
>
>>     However, my bubble was busted by the Van's RVAtor article on
>>     flutter (6th issue 2004). Van’s engineers instructed their
>>     readership on flutter – that Vne is really a TAS limit, not an
>>     IAS limit. A US Air Force pilot and RV commuter corroborated the
>>     Van’s article by telling his disturbing TAS flutter story (first
>>     2005 RVAtor issue). If you haven’t read this, I recommend it for
>>     all pilots, no matter what they fly.
>>
>>     I’ve decided to follow Van’s advice and restrict my upper
>>     airspeed to limit to 200 KTS TAS in smooth air. I don’t want to
>>     be a test pilot. Therefore, I’m reconsidering my plan to
>>     supercharge the Renesis/RD-1C installation. The weight penalty
>>     may not be worth climb performance increase if 200 KTS TAS cruise
>>     can be easily achieved with a normally aspirated installation. If
>>     I can collect empirical data from RV Rotary flyers, it would sure
>>     help my decision.
>>
>>     Thanks,
>>
>>     John Burns
>>
>>     rv-7a@comcast.net <mailto:rv-7a@comcast.net>
>>
>>     http://mywebpages.comcast.net/jgburns/Engine/Engine.html for my
>>     engine webpage.
>>
>     Intuitively it does not make sense that flutter is a TAS issue. I
>     would be interested in reviewing the engineering/hypothesis on
>     which this is based. The plane "feels" IAS.. not TAS... you can
>     have a TAS of 400 and still have only an IAS of 200 (if you are
>     high enough).. IAS is the dynamic pressure and state that the
>     aircraft experiences. So.. I would be greatly interested in
>     knowing why the engineers are making this claim and what its basis is.
>
>     Dave
>
>>>  Homepage:  http://www.flyrotary.com/
>
>>>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>
>    
>