Gents,

As far as the pilot is concerned, VNE is always read directly as an IAS
limit, that's why it's painted on the ASI as a radial line.
I've never seen any remarks about VNE as "VNE is XXX at Sea Level at ISA".
There is no such thing.

VNE is always good as an Indicated figure, except at altitudes and airspeeds
where compressibility comes into play, in which case MMO (Maximum Mach
Operating speed) becomes the limiting factor, usually well above our speeds.
That happens at a certain altitude, up to which the pilot uses the Indicated
VNE as a limit, then after that the MMO.


Exception :
Certain models of sailplanes have limitations in IAS with altitude for
various reasons,
(Flutter is not the only factor in determining VNE).
When a sailplane does have this limitation, it will be expressed so in their
manuals, and there will be a table of limiting IAS x Altitude.

Tha Jantar Std 2 is not one of these, so, VNE is good as an IAS as high as
it will go.

The bottom-line is that it dependent on each design, but VNE is not a TAS
figure, whoever told you so, doesn't know what he/she is talking about.

AP



"Mark James Boyd" wrote in message
news:3fd4e4e4$1@darkstar...
In article ,
Marc Till wrote:
Just remind how VNE varies with altitude !

Mark James Boyd a écrit:

Snip
Isn't Vne for this glider 255 kph?
Snip


Yep, I guess if you use the 2% per 1000 feet rule for TAS,
and you assume the Vne is a limitation based on flutter,
7000 feet is the absolute max altitude for this flight.

But I must say I don't entirely understand WHY flutter
is based on TAS. I also don't know if the IGC cares
if Vne is exceeded during a world record. It would
also be very hard to "prove" since GPS log only shows
groundspeed and never airspeed.

So part of my post was to say that I suspect he came close
to or exceeded Vne during the record attempt. This takes
some real confidence in the equipment and finesse about
its limits. Good for him, seriously. It's great to see
a new world record...