final glide estimates

No, just calculate it by taking the square root of the mass/max gross
and multiply that by Va, in the cockpit, in rotor, while dropping below
glide to the nearest safe field.
Simple!

LOL!

Of course, you could also do it safely on the ground when you first get
the glider. Or simply subtract about 15 - 20 knots as a "rule of thumb".

Tony V.

The manufacturor would probably state the weight condition that Va
applies for, ballasted or dry. I would expect that the Va was stated
for dry.

The wing structure would not break at a lower Va due to lower weights.
It's structure like the pilot seat, that is stressed to 232 lbs X
4g's(for an example). If you pull 232 lbs X 5 g's, then it will break.
That's why Va decreases with weight.

Toad
'3S'

toad wrote:
The manufacturor would probably state the weight condition that Va
applies for, ballasted or dry. I would expect that the Va was stated
for dry.

The listing of all speeds at max gross weight is an aircraft industry
standard.

I just pulled out the POH for my LS6-b and page 2-2 lists 108 kts for
the rough air speed. There is no weight reference - your POH may vary.

Tony V. "6N"
http://home.comcast.net/~verhulst/SOARING

I have been watching this thread for a while now.

The term "rough air" seems somewhat subjective. Review of the various
aerodynamic manuals in my personal library does not give me a clue to what
gust load is used in rough air limit calculations or its' relationship to
the V-n diagram.

I am sure there is a precise definition which is used in to determine
performance limits. Could anyone provide the gust load definition of "rough
air?"

Respectfully,

Wayne
http://www.soaridaho.com/Schreder

You can be sure that it was calculated for dry, and then set as general
limit.
Aircraft industry standards are not necessarily applied when they don't make
sense...

"Tony Verhulst" wrote in message
. ..
toad wrote:
The manufacturor would probably state the weight condition that Va
applies for, ballasted or dry. I would expect that the Va was stated
for dry.

The listing of all speeds at max gross weight is an aircraft industry
standard.

I just pulled out the POH for my LS6-b and page 2-2 lists 108 kts for the
rough air speed. There is no weight reference - your POH may vary.

Tony V. "6N"
http://home.comcast.net/~verhulst/SOARING

On Sun, 12 Mar 2006 00:24:17 UTC, Bruce Hoult wrote:

: Rough air places lower loads on a structure than do extreme control
: deflections

Surely that depends entirely on just how rough the air is?

Ian
--

In article cCUlhtvFIYkV-pn2-g3gnB5bUeG9L@localhost,
"Ian Johnston" wrote:

On Sun, 12 Mar 2006 00:24:17 UTC, Bruce Hoult wrote:

: Rough air places lower loads on a structure than do extreme control
: deflections

Surely that depends entirely on just how rough the air is?

True.

The point of rough air speed is that below that speed the structure will
be protected from breaking under the load from vertical gusts by the
wing stalling, which dramatically decreases the constant factor of the
aerodynamic forces.

There is still of course the V^2 factor, so the total force will rise
again to structural breaking point if the gusts are sufficiently strong
-- 100 m/s, say.

But at that point the speed you are flying at is irrelevant, so this
situation has no bearing on the setting of rough air speed.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------

Wayne,

Thanks for the link.

Toad

Maneuvering speed and rough air speed are different
animals. For the curious, refer to JAR-22.341, which
begins with 'in the absence of a more rational analysis..'
and continues with an equation. The equation involves
a number of parameters, including the slope of the
wing lift curve and the wing chord - so it will vary
with sailplane model. There is no obvious relationship
between the rough air and maneuvering speeds, but JAR-22
also requires that the rough air speed must not be
less than the maneuvering speed. Of course, not all
sailplanes are subject to JAR-22.

http://www.tux.org/~milgram/temp/jar22.pdf

Ian

There is a common misconception of maneuvering speed among pilots that
somehow has been interpreted to be the maximum speed that will not
cause airframe damage with full and abrupt control deflections. THIS
IS WRONG! The November 2001 crash of the AA Airbus in New York was
determined to be from abrupt rudder deflections below maneuvering speed
resulting in the loss of the vertical fin.
http://www.flyingmag.com/article.asp...article_id=527
Maneuvering speed only relates to a limiting speed for wing protection
in a positive mode. Therefore, any full deflection of controls, other
than the elevator in a stick back mode, could result in failure of the
airframe. Also, since the wing is the only surface defined under
maneuvering speed, there could be a possible failure of elevator,
ailerons, fuselage, etc. with abrupt deflections.
http://www.x-plane.com/myths.html
In the USA, aircraft certification standards for maneuvering speed are
typically determined at gross weight in a clean configuration. As
mentioned in other posts, flying at weights below gross, or with flaps,
will cause a lower stall speed and a corresponding reduction in
maneuvering speed. The maximum positive g load subjected by the wing
before a stall will occur in any given configuration is calculated by
squaring the ratio of the aircraft speed divided by the unaccelerated
stall speed in the current configuration.

Bob Faris

W.J. (Bill) Dean (U.K.). wrote:
I used to own an ASW20, Schleicher built early version with tip extensions.

From memory the handbook explained what was meant by "rough air", it was
described as a 15 m/s (30kt.) vertical gust. This might be running from
still air into 30kt. up, or into 30kt. down, or from say 10kt. down into
20kt. up. The handbook also said that it was possible to find air rougher
than that, for instance when running close to mountain ridges, in rotor, or
in thunderstorms; and that if there was a risk of this lower speeds should
be used.

I think the possibility and danger of rougher air is obvious, after all what
would happen if you tried soaring a big twister? I think that for a while
you would go up very fast, but in bits.

I have been looking at the book "Exploring the Monster". On 25th April
1955 Larry Edgar flying solo in the Pratt-Read was unable to keep out of the
rotor, and the glider broke up, being subjected to at least 15G. He had
entered the cloud at about 65 knots and had encountered a gust of about 85
knots horizontal speed and a very large change in vertical speed. I
suggest that no glider ever built could withstand this sort of thing, and if
the glider could the pilot could not.

As for manoeuvring speed, this is the limit speed for full deflection of any
one control. Use another control as well and you are outside limits.

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


"Wayne Paul" wrote in message
...

I have been watching this thread for a while now.

The term "rough air" seems somewhat subjective. Review of the various
aerodynamic manuals in my personal library does not give me a clue to what
gust load is used in rough air limit calculations or its' relationship to
the V-n diagram.

I am sure there is a precise definition which is used in to determine
performance limits. Could anyone provide the gust load definition of
"rough air?"

Respectfully,

Wayne
http://www.soaridaho.com/Schreder