REFLECTOR::Re:Pure Jet Velocity XL
Jim Sower
reflector@tvbf.org
Wed, 11 Feb 2004 11:56:49 -0600
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<... According to your data there's only two ways to get down in a canard: A nice
slow descent, or straight down nose first in an unrecoverable canard stall ...>
Tongue firmly in cheek I presume??
A. The discussion was about transonic Velocity, and
B. You ignore the obvious third option: Reduce power to idle, reduce speed to well
under Vne and let down at that speed (say, 100-120 KIAS with belly board deployed as
needed.
Robin Ream wrote:
> Richard,
>
> I'm not an engineer, period. - BUT, it logically follows in your
> reasoning about the catastrophic results of exceeding Vne in level flight
> that we're talking about theVelocity and other similar canards being
> inherently dangerous; even in a moderate dive it's not that hard to exceed
> Vne in any type of aircraft. According to your data there's only two ways
> to get down in a canard: A nice slow descent, or straight down nose first
> in an unrecoverable canard stall... Hmmm. Something about those choices
> aren't particularly appealing. ------------------ Anybody want to buy a
> Velocity now?
>
> Robin
>
> ----- Original Message -----
> From: <richard@riley.net>
> To: <reflector@tvbf.org>
> Sent: Wednesday, February 11, 2004 12:38 AM
> Subject: REFLECTOR::Re:Pure Jet Velocity XL
>
> > Simply put, I believe an airplane that can exceed it's Vne in level flight
> > is extraordinarily dangerous.
> >
> > Your pilot may have the discipline to never open up the throttle while at
> > cruise speed and altitude. I believe most don't have that discipline, at
> > least, I wouldn't want to stake my life on it.
> >
> > At 08:13 PM 2/10/04 -0500, you wrote:
> > >At 07:55 PM 2/7/04, Richard Riley wrote:
> > >
> > >Richard,
> > >
> > >It is always disconcerting to read contributions like this, which raise
> > >fears based on very little factual information, and a great deal of
> > >speculation.
> > >
> > >It is also rather annoying that anyone reading your e-mail would be
> > >excused from assuming you are referring to the Velocity Jet as shown on
> > >the http://x-jets.com/ web site. I can't imagine you are, because you
> have
> > >not discussed this aircraft with me or my partner at any time, and I have
> > >no idea where you get the numbers and engine type that you quote.
> > >
> > >Let me say quite clearly to everyone on this list, that we do not feel
> > >compelled to operate outside of the envelope of a standard Velocity XL
> RG.
> > >
> > >Whether you choose turbojet power or a reciprocating engine, The VNE and
> > >Critical Mach Speed of the airframe remain the same. A jet engine is
> > >simply a very good power to weight ratio, not a license to exceed VNE or
> > >other airframe limits including Mcr.
> > >
> > >Those limits have been estimated for our airframe, and prudent placard
> > >limits have been set. All this was done at a very early stage, before an
> > >engine choice was finalized. We did not simply bolt a jet engine on the
> > >back end and cross our fingers. All the systems on our plane have been
> > >designed for routine flight above 20K. Our project represents a safety
> > >conscious and carefully engineered next step in Experimental aviation. If
> > >you are curious, just watch for more news on the web site.
> > >
> > >The engine, by the way, is a GE-T58-8F NOT a Honeywell T55. The Mcr of
> > >the Main wing airfoil is the lowest at M=.54, which equates
> approximately
> > >to 240 Kts IAS at 25K, 218 Kts IAS at 25K, and 199 Kts IAS at 29K. The
> > >reference you give is excellent. However, it would be better to read it
> > >from the start of the
> > >chapter http://142.26.194.131/aerodynamics1/High-Speed/default.htm with
> > >particular note of the way drag increases as Mcr is approached. Also note
> > >how Mcr may be increased.
> > >
> > >Best Regards,
> > >
> > >Andreas P Christou
> > >andreas@x-jets.com
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >_______________________________________________
> > >To change your email address, visit
> > >http://www.tvbf.org/mailman/listinfo/reflector
> > >
> > >Visit the gallery! www.tvbf.org/gallery
> > >user:pw = tvbf:jamaicangoose
> > >Check new archives: www.tvbf.org/pipermail
> > >Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >
> > _______________________________________________
> > To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
> >
> > Visit the gallery! www.tvbf.org/gallery
> > user:pw = tvbf:jamaicangoose
> > Check new archives: www.tvbf.org/pipermail
> > Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
> >
>
> _______________________________________________
> To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery! www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
--
Jim Sower ... Destiny's Plaything
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T
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<... According to your data there's only two ways to get down in a canard:
A nice slow descent, or straight down nose first in an unrecoverable canard
stall ...>
<br>Tongue firmly in cheek I presume??
<br>A. The discussion was about <b>transonic</b> Velocity, and
<br>B. You ignore the obvious third option: Reduce power to idle,
reduce speed to well under Vne and let down at that speed (say, 100-120
KIAS with belly board deployed as needed.
<br>
<p>Robin Ream wrote:
<blockquote TYPE=CITE>Richard,
<p> I'm not an engineer, period. - BUT, it
logically follows in your
<br>reasoning about the catastrophic results of exceeding Vne in level
flight
<br>that we're talking about theVelocity and other similar canards being
<br>inherently dangerous; even in a moderate dive it's not that hard to
exceed
<br>Vne in any type of aircraft. According to your data there's only
two ways
<br>to get down in a canard: A nice slow descent, or straight down
nose first
<br>in an unrecoverable canard stall... Hmmm. Something about
those choices
<br>aren't particularly appealing. ------------------ Anybody
want to buy a
<br>Velocity now?
<p>Robin
<p>----- Original Message -----
<br>From: <richard@riley.net>
<br>To: <reflector@tvbf.org>
<br>Sent: Wednesday, February 11, 2004 12:38 AM
<br>Subject: REFLECTOR::Re:Pure Jet Velocity XL
<p>> Simply put, I believe an airplane that can exceed it's Vne in level
flight
<br>> is extraordinarily dangerous.
<br>>
<br>> Your pilot may have the discipline to never open up the throttle
while at
<br>> cruise speed and altitude. I believe most don't have that discipline,
at
<br>> least, I wouldn't want to stake my life on it.
<br>>
<br>> At 08:13 PM 2/10/04 -0500, you wrote:
<br>> >At 07:55 PM 2/7/04, Richard Riley wrote:
<br>> >
<br>> >Richard,
<br>> >
<br>> >It is always disconcerting to read contributions like this, which
raise
<br>> >fears based on very little factual information, and a great deal
of
<br>> >speculation.
<br>> >
<br>> >It is also rather annoying that anyone reading your e-mail would
be
<br>> >excused from assuming you are referring to the Velocity Jet as shown
on
<br>> >the <a href="http://x-jets.com/">http://x-jets.com/</a> web site.
I can't imagine you are, because you
<br>have
<br>> >not discussed this aircraft with me or my partner at any time, and
I have
<br>> >no idea where you get the numbers and engine type that you quote.
<br>> >
<br>> >Let me say quite clearly to everyone on this list, that we do not
feel
<br>> >compelled to operate outside of the envelope of a standard Velocity
XL
<br>RG.
<br>> >
<br>> >Whether you choose turbojet power or a reciprocating engine, The
VNE and
<br>> >Critical Mach Speed of the airframe remain the same. A jet engine
is
<br>> >simply a very good power to weight ratio, not a license to exceed
VNE or
<br>> >other airframe limits including Mcr.
<br>> >
<br>> >Those limits have been estimated for our airframe, and prudent placard
<br>> >limits have been set. All this was done at a very early stage, before
an
<br>> >engine choice was finalized. We did not simply bolt a jet engine
on the
<br>> >back end and cross our fingers. All the systems on our plane have
been
<br>> >designed for routine flight above 20K. Our project represents a
safety
<br>> >conscious and carefully engineered next step in Experimental aviation.
If
<br>> >you are curious, just watch for more news on the web site.
<br>> >
<br>> >The engine, by the way, is a GE-T58-8F NOT a Honeywell T55.
The Mcr of
<br>> >the Main wing airfoil is the lowest at M=.54, which equates
<br>approximately
<br>> >to 240 Kts IAS at 25K, 218 Kts IAS at 25K, and 199 Kts IAS at 29K.
The
<br>> >reference you give is excellent. However, it would be better to
read it
<br>> >from the start of the
<br>> >chapter <a href="http://142.26.194.131/aerodynamics1/High-Speed/default.htm">http://142.26.194.131/aerodynamics1/High-Speed/default.htm</a>
with
<br>> >particular note of the way drag increases as Mcr is approached.
Also note
<br>> >how Mcr may be increased.
<br>> >
<br>> >Best Regards,
<br>> >
<br>> >Andreas P Christou
<br>> >andreas@x-jets.com
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >
<br>> >_______________________________________________
<br>> >To change your email address, visit
<br>> ><a href="http://www.tvbf.org/mailman/listinfo/reflector">http://www.tvbf.org/mailman/listinfo/reflector</a>
<br>> >
<br>> >Visit the gallery! www.tvbf.org/gallery
<br>> >user:pw = tvbf:jamaicangoose
<br>> >Check new archives: www.tvbf.org/pipermail
<br>> >Check old archives: <a href="http://www.tvbf.org/archives/velocity/maillist.html">http://www.tvbf.org/archives/velocity/maillist.html</a>
<br>>
<br>> _______________________________________________
<br>> To change your email address, visit
<br><a href="http://www.tvbf.org/mailman/listinfo/reflector">http://www.tvbf.org/mailman/listinfo/reflector</a>
<br>>
<br>> Visit the gallery! www.tvbf.org/gallery
<br>> user:pw = tvbf:jamaicangoose
<br>> Check new archives: www.tvbf.org/pipermail
<br>> Check old archives: <a href="http://www.tvbf.org/archives/velocity/maillist.html">http://www.tvbf.org/archives/velocity/maillist.html</a>
<br>>
<p>_______________________________________________
<br>To change your email address, visit <a href="http://www.tvbf.org/mailman/listinfo/reflector">http://www.tvbf.org/mailman/listinfo/reflector</a>
<p>Visit the gallery! www.tvbf.org/gallery
<br>user:pw = tvbf:jamaicangoose
<br>Check new archives: www.tvbf.org/pipermail
<br>Check old archives: <a href="http://www.tvbf.org/archives/velocity/maillist.html">http://www.tvbf.org/archives/velocity/maillist.html</a></blockquote>
<p>--
<br>Jim Sower ... Destiny's Plaything
<br>Crossville, TN; Chapter 5
<br>Long-EZ N83RT, Velocity N4095T
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