REFLECTOR: Vne Revisited

[Scott Derrick]

There is two separate limits to VNE.  Flutter and airframe distortion.

airframe distortion is cause by the force of the air against the 
airframe.  This is directly related to IAS.

Flutter on the other hand is related to the speed of the air molecules 
going over an airfoil,  which is related to TAS.

Scott

Alex Balic wrote:
> I would agree with John- just as a matter of principal- the indicated
> airspeed is the force exerted on the pitot tube ( and flight surfaces )
> irregardless of density, temp or humidity- it is the force of the fluid that
> will cause flutter - in a vacuum, the aircraft would never reach VNE even
> with Saturn 5 rocket propulsion since no matter how fast you were going, you
> would still have a 0 airspeed reading. (of course the G-forces of Saturn 5
> rocket propulsion would be another matter- might need to reinforce the seat
> mounting hard points)
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of Paula & John Schoorl
> Sent: Thursday, June 12, 2008 8:22 PM
> To: 'Velocity Aircraft Owners and Builders list'
> Subject: Re: REFLECTOR: Vne Revisited
>
> I disagree.  Vne is always given as indicated airspeed.  By hitting 256 kt
> TAS they are probably not exceeding their Vne recommendation of 200kt IAS.
>
> John Schoorl
>
> -----Original Message-----
> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
> Behalf Of LAURA WALKER
> Sent: Thursday, June 12, 2008 5:21 PM
> To: reflector at tvbf.org
> Subject: REFLECTOR: Vne Revisited
>
> I always get a kick when I read about those questioning Velocity's 200kt
> indicated Vne. For the uninitiated, Vne is ALWAYS based on true airspeed,
> not indicated airspeed. Velocity themselves grudgingly admit that the 200kt
> indicated rule is just a conservative figure to try and keep people from
> hurting themselves. Their own TurboCharlie demonstrator, when advertised at
> 256kts true is actually exceeding their own recommendation by 56kts!!. When
> asked about this, their answer is "well, we never actually go over 200kts
> indicated".  Enough said...for those who have the need for speed, and with
> careful attention to rudder fitment and elevator balancing, the actual Vne
> (true airspeed) of the XL airframe is probably closer to 280 kts.
>
> Bill Walker
>
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