Jantars are back :)

On the 1st December 2003, H. Miranda (Argentina) flying Jantar Standard 2
has set a new World Record over the 100km triangular course in Open and
15-metre classes. The speed was 249.09 kph.

Regards,


--
Janusz Kêsik,
(the Eastern Bloc crap pilot)

In article ,
Janusz Kesik wrote:
On the 1st December 2003, H. Miranda (Argentina) flying Jantar Standard 2
has set a new World Record over the 100km triangular course in Open and
15-metre classes. The speed was 249.09 kph.

Janusz Kêsik,
(the Eastern Bloc crap pilot)


Isn't Vne for this glider 255 kph?


H. Miranda World Record technique:

1. Fill wings with water
2. Find wicked updraft
3. Point nose down a lot
4. Hope wings don't come off

:-]

5. Smile for the camera

I think VNE for this glider is actually much faster than that. 154 kts.

Nick.


"Mark James Boyd" wrote in message
news:3fd2360d$1@darkstar...
In article ,
Janusz Kesik wrote:
On the 1st December 2003, H. Miranda (Argentina) flying Jantar Standard 2
has set a new World Record over the 100km triangular course in Open and
15-metre classes. The speed was 249.09 kph.

Janusz Kêsik,
(the Eastern Bloc crap pilot)


Isn't Vne for this glider 255 kph?


H. Miranda World Record technique:

1. Fill wings with water
2. Find wicked updraft
3. Point nose down a lot
4. Hope wings don't come off

:-]

5. Smile for the camera

Just remind how VNE varies with altitude !

Mark James Boyd a écrit:

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

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...

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...

Arnold Pieper wrote:
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.

So what are these reasons? Can someone explain this a bit better?
At 25,000 feet with a 90 knot headwind I'd like to know if
pushing the nose down to redline is maybe a bad idea...
and I'm not so sure I'd be confident doing it just
because there are blank pages in the manual...

No.

The BGA have produced a book published 2002 by A & C Black, London titled
"Gliding - The British Gliding Association Manual", ISBN 0-7136-5947-5
(not to be confused with the book "Gliding" by Derek Piggott published in
about 1958 and now I think in its 6th edition).

This book covers the technical knowledge which the BGA thinks glider pilots
should have, and is required reading for BGA rated instructors. The main
author is Steve Longland, and he had input from many others.

In chapter 5 "The placard, structure and flight limitations" there is a
section starting on p.155 "The effects of changes in air density".
In this section an explanation is given as to why the Vne is related to True
Air Speed and not to Indicated Air Speed. I do not claim to fully
understand it myself, but I certainly intend always to obey.
The conclusion is:
"Avoiding flutter.
"The practical rule of thumb is that you should reduce the glider's Vne by
"1.5% for every 1,000ft above sea level. If your glider's Vne is 128kt,
"then at 20,000ft the ASI reading corresponding to TAS of 128kt is 90kt,
"and at 30,000ft it will be 70kt. ....."

If you read the earlier section in the same chapter about test flying, you
will see that the glider is not tested to Vd (Design dive speed) but only to
Vdf (Demonstration design speed) which is 95% of Vd and that the placard
speed Vne is 90% of Vd.
To quote from the book: "If the glider's Vne is 130kt, it has only ever been
6.5kt faster, once, when it was new, in ideal conditions, and flown by a
specially trained test pilot."

If anyone thinks this is wrong, could we please have a reasoned argument and
not just abuse.

W.J. (Bill) Dean (U.K.).
Remove "ic" to reply.


"Arnold Pieper" wrote in message
om...

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.

The 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:

But I must say I don't entirely understand WHY flutter
is based on TAS.

it's not. It is only because the IAS at which flutter happens is likely
to vary with altitude (it may be lower or higher !) that some
manufacturers and/or authorities limit the VNE at a constant TAS above
2000 or 3000 m (i.e. the altitude where tests have been conducted)


I also don't know if the IGC cares
if Vne is exceeded during a world record.

IGC don't care of exceeding any limit, with the exception of legal
day/night flight rules.

I think there is still a provision that the record may only be validated
if the glider lands back in one piece (that rule was set after some
altitude gains in CuNimbs where the pilot had jumped with the barogramm
after his glider broke ;-)

Only in championships you must have a valid permit-to-fly and respect
the limitations of your glider (weight, etc.)


--
Denis
Private replies: remove "moncourrielest" from my e-mail address
Pour me répondre utiliser l'adresse courriel figurant après
moncourrielest" dans mon adresse courriel...

I think there is still a provision that the record may only be validated
if the glider lands back in one piece (that rule was set after some
altitude gains in CuNimbs where the pilot had jumped with the barogramm
after his glider broke ;-)

Denis

C'mon, is that really true? How did he prove he was
still in the "aerodyne" when the barograph got its highest
altitude? Maybe he was just a big piece of hail.
My gosh, maybe he used the baro to tell his altitude
to make sure he didn't pull his chute too early...LOL