Jantars are back :)

H. Miranda World Record technique:

1. Fill wings with water

The Jantar that Horacio flight, DIDN'T HAVE WATER!!!!!

They flew using the 1 and 2 wave of cordillera del viento starting at
5000 meters (16666 ft) climb to 6000 m (20000 ft) and finish at 4400
meters (14666 ft). His maximum ground speed was 413 km/h (223 kts). I
have the IGC file for this record. I can e-mail you if you wish. The
jantar VNE is 275 kph (148 kts) at sea level.

Last year I flew with Horacio in the same triangle in a IS-28B2. Our
maximum ground speed was 330 kph (178kts) flying always at 160 kpn (86
kts) IAS, that is a little less that the IAS VNE for this altitude.
The VNE at sea level for the IS is 220 kph (118 kts)

Best regars,

Luis Briones

"Janusz Kesik" wrote in message ...
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,

What? In Eastern European manufactured junk? Impossible!

Woo-hoo! Let's hear it for the worlds fastest 63 statute mile glider flight!

It is not the distance, but the speed accomplished. I did a 100km attempt
on early spring day and finally got around at 19 mph, so his speed is really
great. I know it was crazy to attempt a speed task that early, but there
was no state record for that distance at the time so any time would be a
state record.


"Bob Kuykendall" wrote in message
om...
Woo-hoo! Let's hear it for the worlds fastest 63 statute mile glider
flight!

Bob,

I'm not sure if your comment is serious or not. Apologies if it is
serious.

The record is there to be beaten, no matter what length it is.

The fact it was done in an older design Jantar just makes it an even
better achievement.

The Jantars have proved to be very good gliders for their era, in
performance, ease of flying and strength. I flew one for many years
and found it to be be forgiving, reliable and as good as most at my
club.

Andy Henderson




(Bob Kuykendall) wrote in message . com...
Woo-hoo! Let's hear it for the worlds fastest 63 statute mile glider flight!

Ok,

Firstly VNE is very much limited by TAS not IAS. If
you understand the maths behind how an ASI works then
you will know that the ASI indicates a TAS based on
an assumed air density equivalent to sea level. TAS
is the speed that affects flutter, IAS is simply a
gash estimate of TAS which is reasonable at low altitudes.
Hence the rules of thumb for safe flight at altitude.

Secondly, ground speed at altitude is much higher than
TAS due to lower air density and can be greatly affected
by very high velocity winds at altitude. This is how
high average speeds can be achieved without exceeding
TAS VNE. Try looking at your GPS groundspeed when at
high altitude, it should be much higher than your IAS
even when the wind effect is removed.

"Jon Meyer" wrote in
message ...
| Ok,
|
| Firstly VNE is very much limited by TAS not IAS. If
| you understand the maths behind how an ASI works then
| you will know that the ASI indicates a TAS based on
| an assumed air density equivalent to sea level. TAS
| is the speed that affects flutter, IAS is simply a
| gash estimate of TAS which is reasonable at low altitudes.
| Hence the rules of thumb for safe flight at altitude.
|
| Secondly, ground speed at altitude is much higher than
| TAS due to lower air density and can be greatly affected
| by very high velocity winds at altitude. This is how
| high average speeds can be achieved without exceeding
| TAS VNE. Try looking at your GPS groundspeed when at
| high altitude, it should be much higher than your IAS
| even when the wind effect is removed.

I am confused !
How can the ground speed exceed TAS when measured in still
air ?
TAS means TRUE Air Speed. i.e. the actual speed of the
aircraft through the particular parcel of air around the
aircraft. If this parcel of air is stationary with respect
to the ground, the ground speed of the aircraft must equal
the TAS.
Cheers, John G.

Jon,

I don't like to come accross as arrogant, I'm sorry if I do, but you seem to
be confusing the issue.

IAS is what you see in your ASI.
TAS is the speed at which the aircraft is is moving trough the air (nothing
to do with groundspeed).

To obtain you TAS at any time during flight, you look at what your ASI is
indicating, then apply a correction based on altitude and oustide air
temperature. You can do that with an E-6B type computer.
If you don't have an OAT reading, you're out of luck, but the well-known 2%
per 1000ft will give you an approximation.

Groundspeed, on the other hand is the speed at which you move in relation to
the ground.
The Groundspeed is the result of your TAS plus (or minus) the wind
component.

When I say most Turboprops and Turbocharged airplanes fly at faster TAS than
their IAS VNEs,
that's exactly what I mean :
At altitudes of 20k plus, their TAS will be higher than their indicated VNE,
regardless of what the Groundspeed is.

The Twin commander will be reading Groundspeeds of 350Kt when eastbound
(tailwind) and it may read as little as 230Kt westbound.
But in both cases, with the same power setting, it will be doing 290Kt TAS,
which is more than the 255Kt VNE.

Meanwhile, their ASI will be showing 180Kt to 190Kt, depending on altitude
and powersetting, well below the VNE of 255Kt.

Same thing holds true for all these airplanes. Other examples :
TBM-700, cruises at 290Kt TAS (not groundspeed), while the VNE is 265Kt.
King Air 350, cruises at 300Kt TAS, VNE is 265Kt.





"Jon Meyer" wrote in message
...
Ok,

Firstly VNE is very much limited by TAS not IAS. If
you understand the maths behind how an ASI works then
you will know that the ASI indicates a TAS based on
an assumed air density equivalent to sea level. TAS
is the speed that affects flutter, IAS is simply a
gash estimate of TAS which is reasonable at low altitudes.
Hence the rules of thumb for safe flight at altitude.

Secondly, ground speed at altitude is much higher than
TAS due to lower air density and can be greatly affected
by very high velocity winds at altitude. This is how
high average speeds can be achieved without exceeding
TAS VNE. Try looking at your GPS groundspeed when at
high altitude, it should be much higher than your IAS
even when the wind effect is removed.

Jon Meyer wrote:

Secondly, ground speed at altitude is much higher than
TAS due to lower air density
^^^^^ ^^^ ^^^^^^^

Are you joking ?


--
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 suspect that the VNE of these aircraft will be calculated
based on IAS at cruising altitude, That is why TAS
is not mentioned. Sailplanes normally operate at a
low cruising altitude so VNE is calculated based on
IAS at (i think) 5000ft. That is why a factor has to
be applied for higher altitudes. (read Fundamentals
of Sailplane Design if you want to check)


At 19:54 09 December 2003, Arnold Pieper wrote:
This seems to me to be some arbitrary way of staying
conservative.
High altitude research is NOT an early 80s affair,
I don't even know about
any such research during the 80s.

The Sierra Wave project was done during the 50s in
the Owens Valley of Ca
with very old gliders that have been flown to 45000ft,
altitudes at which,
according to this calculation, they would barely be
able to fly.
However, curiously enough none of them flutter themselves
to pieces.

To make a long story short :
-Look at the ASI on any turboprop or even some turbocharged
aircraft, and
you will see that they fly at TAS much faster than
the VNE painted on their
ASI.

Example : Twin Commander, VNE=255Kt (it's on it's ASI),
Cruise TAS = 280Kt
to 300Kt.

The same holds true for all airplanes that fly up to
the 20s and higher,
which aviation has been doing since WWII.


Look at the manual of some gliders, that do have the
limitation on IAS with
Altitude.
You will see that the table of IAS is not correcting
the VNE as a TAS value.

Nowhere in aviation VNE is considered a TAS value.


'W.J. (Bill) Dean (U.K.).' wrote in message
...
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