REFLECTOR: Reflector Digest, Vol 49, Issue 25

Chuck Jensen cjensen at dts9000.com
Fri Jun 13 07:55:27 CDT 2008


Laura is point-on.  If you go high enough, the VNE and stall speed can become one and the same.  IAS is not the measure--as counter intuitive as that may seem.

Chuck Jensen


-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of LAURA WALKER
Sent: Friday, June 13, 2008 8:10 AM
To: reflector at tvbf.org
Subject: Re: REFLECTOR: Reflector Digest, Vol 49, Issue 25


I know this sounds funky, but my information is reliable. The airspeed indicator is truly "The Gauge that Lies". These gauges, with a fixed redline or what most people assume is the aircraft's Vne come from two necessities, cost and weight. They were developed years ago when light planes had simple needs and relatively slow speeds. Manfacturers did the math with respect to the aircraft's true Never Exceed Speed at altitudes at which they were likely to operate, factored out the differrence in indicated speed versus true airspeed and likely did a coin toss about where to put the redline. 
Sophisticated aircraft have almost always had "sliding" barber poles that reflected the change in maximum allowable airspeed with respect to altitude, and frankly I am dismayed that the current crop of air-data wizardry available to home builders does not show Vne on a sliding scale. 
I have personally asked at least 20 seasoned flight instructors about this common misperception, and almost all reply that Vne is based on indicated airspeed. The ones who reply correctly are the ones who have done the research because they have truly scared the crap out of themselves by mistrusting the airspeed indicator on a fast, high-flying airplane.
Read this article and let us know what you think:     http://www.vansaircraft.com/pdf/hp_limts.pdf

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To: reflector at tvbf.org
Sent: Thursday, June 12, 2008 9:28:44 PM
Subject: Reflector Digest, Vol 49, Issue 25

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Today's Topics:

  1. Re:  AirVenture Cup 2008 (Al Gietzen)
  2. Re:  AirVenture Cup 2008 (TimRhod at aol.com)
  3. Re:  AirVenture Cup 2008 (Jon Bachman)
  4.  Vne Revisited (LAURA WALKER)
  5. Re:  Vne Revisited (Paula & John Schoorl)


----------------------------------------------------------------------

Message: 1
Date: Thu, 12 Jun 2008 10:21:26 -0800
From: "Al Gietzen" <ALVentures at cox.net>
Subject: Re: REFLECTOR: AirVenture Cup 2008
To: "'Velocity Aircraft Owners and Builders list'"
    <reflector at tvbf.org>
Message-ID: <000001c8ccb9$20693140$6401a8c0 at BigAl>
Content-Type: text/plain; charset="us-ascii"

Jon;



I don't think the 200 kts is a hard number; more like a suggested limit. I
have had my SE RG to 208 KTAS more than once, for short periods, and it was
steady as a rock.  Any flutter would be felt, but you can also look back and
see the control surfaces. "Flutter" would be defined as a resonant
condition, and gets serious quickly. A vibration is something else - I noted
some of that when my aileron torque tube bearing was loose. I could look
back and see that the ailerons were vibrating at some small amplitude.  It
only happened at a specific rpm in climb.



Al



-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Jon Bachman
Sent: Thursday, June 12, 2008 8:58 AM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: AirVenture Cup 2008



That's great!  I assumed the 200 factory limit was for flutter.  How did you
expand the envelope?  Did you use cameras to verify you did not have flutter
in the wings/controls/winglets or some other means?



Jon

N956DR

Std RG

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of TimRhod at aol.com
Sent: Thursday, June 12, 2008 10:27 AM
To: reflector at tvbf.org
Subject: Re: REFLECTOR: AirVenture Cup 2008



Jon  Yes that is correct.  I can get about 218Kts indicated at 2000AGL.
I have a stock XLRG  with a modified  370 HP continental IO550. MT prop with
1/4 inch shaved off the tips: not by choice.  Tim 



  _____  

Vote for your city's best dining and nightlife. City's Best 2008
<http://citysbest.aol.com?ncid=aolacg00050000000102> .

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Message: 2
Date: Thu, 12 Jun 2008 16:39:52 EDT
From: TimRhod at aol.com
Subject: Re: REFLECTOR: AirVenture Cup 2008
To: reflector at tvbf.org
Message-ID: <d21.2e57bdbe.3582e398 at aol.com>
Content-Type: text/plain; charset="us-ascii"

Jon  My understanding is that the factory VNE was based on the fact  that 
that's as fast as they had tested it.  At that time smaller engines  were the 
norm and about 180KTS was the fastest the plane would go straight and  level.  
Mine can go about 218 straight and level and I have tested it to  230 KTS in a 
full power dive.  I did experience flutter on my left rudder  and had to 
quickly pull up and pull power.  The flutter was violent and  shook me up quite a 
bit.  I was anxious to get on the ground because at the  time I didn't know what 
it was and didn't want to be in the air when something  came off.  A very 
hard landing with to much nose up allowed my prop to hit  the runway thus 
removing about a 1/2 inch.  I have since fixed the prop and  changed the incidence of 
my rudder with factory advice and have again tested it  to 230 KTS with no 
problem but now at about 215 to 230 kts my engine starts  running rough.  I have 
sought out lots of experts and no conclusions to  date.  I need to install a 
recordable engine monitor to diagnose the  problem but haven't had the time 
yet plus I'm a little gun shy about going that  fast .  Tim 



**************Vote for your city's best dining and nightlife. City's Best 
2008.      (http://citysbest.aol.com?ncid=aolacg00050000000102)
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Message: 3
Date: Thu, 12 Jun 2008 15:36:14 -0600
From: "Jon Bachman" <jbachman at zianet.com>
Subject: Re: REFLECTOR: AirVenture Cup 2008
To: "'Velocity Aircraft Owners and Builders list'"
    <reflector at tvbf.org>
Message-ID: <9B3CFBD955A9413BBD67766D5FD5A311 at jons>
Content-Type: text/plain; charset="us-ascii"

Thanks.I really appreciate you sharing your experiences.



Jon

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of TimRhod at aol.com
Sent: Thursday, June 12, 2008 2:40 PM
To: reflector at tvbf.org
Subject: Re: REFLECTOR: AirVenture Cup 2008



Jon  My understanding is that the factory VNE was based on the fact that
that's as fast as they had tested it.  At that time smaller engines were the
norm and about 180KTS was the fastest the plane would go straight and level.
Mine can go about 218 straight and level and I have tested it to 230 KTS in
a full power dive.  I did experience flutter on my left rudder and had to
quickly pull up and pull power.  The flutter was violent and shook me up
quite a bit.  I was anxious to get on the ground because at the time I
didn't know what it was and didn't want to be in the air when something came
off.  A very hard landing with to much nose up allowed my prop to hit the
runway thus removing about a 1/2 inch.  I have since fixed the prop and
changed the incidence of my rudder with factory advice and have again tested
it to 230 KTS with no problem but now at about 215 to 230 kts my engine
starts running rough.  I have sought out lots of experts and no conclusions
to date.  I need to install a recordable engine monitor to diagnose the
problem but haven't had the time yet plus I'm a little gun shy about going
that fast .  Tim 





  _____  

Vote for your city's best dining and nightlife. City's Best 2008
<http://citysbest.aol.com?ncid=aolacg00050000000102> .

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Message: 4
Date: Thu, 12 Jun 2008 17:21:22 -0700 (PDT)
From: LAURA WALKER <blwalker105 at sbcglobal.net>
Subject: REFLECTOR: Vne Revisited
To: reflector at tvbf.org
Message-ID: <749400.46538.qm at web81802.mail.mud.yahoo.com>
Content-Type: text/plain; charset=us-ascii

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



------------------------------

Message: 5
Date: Thu, 12 Jun 2008 18:21:50 -0700
From: "Paula & John Schoorl" <pjschoorl at sbcglobal.net>
Subject: Re: REFLECTOR: Vne Revisited
To: "'Velocity Aircraft Owners and Builders list'"
    <reflector at tvbf.org>
Message-ID: <6968723537E346058BC9214F98A6A235 at Office>
Content-Type: text/plain;    charset="us-ascii"

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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