TLAR help

[Slick]

Can someone elaborate on the formula GAG=GAA(airspeed +/- wind)/airspeed

I'm a little confused on what GAA is and if it's just a constant number. I
kind of derived it as being 30 degrees as a constant target of angle you
want to the touchdown point (?). it works for Tom Knauff's calculation in
his book with 50mph a/s and 30 mph headwind, and using 30 for GAA. but when
I reduce it to a 5 mph headwind the resultant doesn't come within the cone.
Am I missing something here?



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[5Z]

Formula??? TLAR == That Looks About Right; Don't need no steenkin'
formulas

Just be sure the approach always "looks right".

Though I think Tom teaches too flat an approach for my taste. FLew a
few approaches with a pilot claiming to make Tom happy and I really
wanted a bit more altitude or a closer base leg....

-Tom

[Tony Verhulst]

5Z wrote:
> Formula??? TLAR == That Looks About Right; Don't need no steenkin'
> formulas

Precisely!

> Just be sure the approach always "looks right".
> Though I think Tom teaches too flat an approach for my taste. FLew a
> few approaches with a pilot claiming to make Tom happy and I really
> wanted a bit more altitude or a closer base leg....

I really like this booklet By Stephen DuPont
http://home.comcast.net/~verhulst/GBSC/landings/SaferLandings.pdf

Tony V.

[Tony Verhulst]

> I really like this booklet By Stephen DuPont
> http://home.comcast.net/~verhulst/GBSC/landings/SaferLandings.pdf

Should you prefer to read it in html:
http://home.comcast.net/~verhulst/GBSC/landings/safer_landings.htm

Tony V. LS6-b "6N"

[flying_monkey]

Slick wrote:
> Can someone elaborate on the formula GAG=GAA(airspeed +/- wind)/airspeed
>
> I'm a little confused on what GAA is and if it's just a constant number. I
> kind of derived it as being 30 degrees as a constant target of angle you
> want to the touchdown point (?). it works for Tom Knauff's calculation in
> his book with 50mph a/s and 30 mph headwind, and using 30 for GAA. but when
> I reduce it to a 5 mph headwind the resultant doesn't come within the cone.
> Am I missing something here?
>
I think you're getting two things confused. TLAR is what the other
posters have already said - "That Looks About Right." It's about using
judgement to modify your planned approach depending on what you see
that conditions are doing to your glider.

The formula you quote has to do with the changes a headwind or tailwind
makes to your glide angle. GAG = Glide Angle Ground, GAA = Glide Angle
Air. GAA is a constant, the glide ratio or lift to drag ratio of your
glider.

Some examples. First, lets assume that you're flying a G103, L/D 36:1
at about 51kt. So your GAA = 36. The wind is 0, so the formula for
GAG is airspeed +- wind component, all divided by airspeed, then this
result times the glide angle in air. So, 51 plus zero = 51, divided by
51 = 1.0, times 36 (GAA), resulting in a GAG of 36:1.

Now, let's put in 10 kt of headwind component. That could either be a
10kt direct headwind, or a 20kt wind 60 degrees off the nose, it's the
component that counts. You can figure that with an E6B computer, or
with graph paper, or by multiplying the wind speed by the cosine of the
angle between a direct headwind and the wind angle. So we have 51-10 =
41, divided by 51 = about .8, times 36 = 28.9, your glide angle with
respect to the ground.

Same thing, except with a headwind: 51+ 10 = 61, divided by 51 = about
1.2, times 36 = 43, your glide angle with respect to the ground.

Does that help? You can read about this, put in better terms than I
can, in this book:
http://www.eglider.org/index.php?act=viewProd&productId=120

Ed

[Thomas Knauff]

Glide Angle on the Ground is equal to the Glide Angle in the Air (at a given
airspeed plus or minus the wind; divided by the airspeed.

For landing, the basic concept (you need to read the entire chapter) is to
fly the landing pattern in a manner so you are on final approach below the
steepest possible glide slope possible with full dive brakes, and above the
mid-range glide slope. (half way between maximum and minimum possible.)

At the same time, the turn onto final approach needs to be above any
possible low-level turbulence (generally above 200 feet AGL.)

The most common error in flying gliders is to turn onto the base leg too
low, resulting in an even lower turn onto final. Turning onto final further
out and higher results in the same glide path to touchdown, but is far
safer.



"Slick" > wrote in message
...
> Can someone elaborate on the formula GAG=GAA(airspeed +/- wind)/airspeed
>
> I'm a little confused on what GAA is and if it's just a constant number. I
> kind of derived it as being 30 degrees as a constant target of angle you
> want to the touchdown point (?). it works for Tom Knauff's calculation in
> his book with 50mph a/s and 30 mph headwind, and using 30 for GAA. but
when
> I reduce it to a 5 mph headwind the resultant doesn't come within the
cone.
> Am I missing something here?
>
>
>
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[Slick]

That's exactly what i wanted to know, it all makes sense now.
"flying_monkey" > wrote in message
oups.com...
> Slick wrote:
> > Can someone elaborate on the formula GAG=GAA(airspeed +/- wind)/airspeed
> >
> > I'm a little confused on what GAA is and if it's just a constant number.
I
> > kind of derived it as being 30 degrees as a constant target of angle you
> > want to the touchdown point (?). it works for Tom Knauff's calculation
in
> > his book with 50mph a/s and 30 mph headwind, and using 30 for GAA. but
when
> > I reduce it to a 5 mph headwind the resultant doesn't come within the
cone.
> > Am I missing something here?
> >
> I think you're getting two things confused. TLAR is what the other
> posters have already said - "That Looks About Right." It's about using
> judgement to modify your planned approach depending on what you see
> that conditions are doing to your glider.
>
> The formula you quote has to do with the changes a headwind or tailwind
> makes to your glide angle. GAG = Glide Angle Ground, GAA = Glide Angle
> Air. GAA is a constant, the glide ratio or lift to drag ratio of your
> glider.
>
> Some examples. First, lets assume that you're flying a G103, L/D 36:1
> at about 51kt. So your GAA = 36. The wind is 0, so the formula for
> GAG is airspeed +- wind component, all divided by airspeed, then this
> result times the glide angle in air. So, 51 plus zero = 51, divided by
> 51 = 1.0, times 36 (GAA), resulting in a GAG of 36:1.
>
> Now, let's put in 10 kt of headwind component. That could either be a
> 10kt direct headwind, or a 20kt wind 60 degrees off the nose, it's the
> component that counts. You can figure that with an E6B computer, or
> with graph paper, or by multiplying the wind speed by the cosine of the
> angle between a direct headwind and the wind angle. So we have 51-10 =
> 41, divided by 51 = about .8, times 36 = 28.9, your glide angle with
> respect to the ground.
>
> Same thing, except with a headwind: 51+ 10 = 61, divided by 51 = about
> 1.2, times 36 = 43, your glide angle with respect to the ground.
>
> Does that help? You can read about this, put in better terms than I
> can, in this book:
> http://www.eglider.org/index.php?act=viewProd&productId=120
>
> Ed
>
>



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[David Kinsell]

Slick wrote:
> Can someone elaborate on the formula GAG=GAA(airspeed +/- wind)/airspeed
>
> I'm a little confused on what GAA is and if it's just a constant number. I
> kind of derived it as being 30 degrees as a constant target of angle you
> want to the touchdown point (?). it works for Tom Knauff's calculation in
> his book with 50mph a/s and 30 mph headwind, and using 30 for GAA. but when
> I reduce it to a 5 mph headwind the resultant doesn't come within the cone.
> Am I missing something here?
>
>
>
> ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
> http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
> ----= East and West-Coast Server Farms - Total Privacy via Encryption =----

You're making it way too hard. Just set your flight computer to 0 altitude
at the threshold. "Call the ball" and follow the needles. There's no actual
need to look outside anymore.


















This being R.A.S., it's sad but true that it's necessary to point out the
above was sarcasm.

[fcnorton]

Check out the following link. It's a tutorial on TLAR that our Chief
CFIG put together for our pilots in an effort to get our heads out of
our "cockpits".

http://www.soarelsinore.org/tlar.htm

FC Norton
Lake Elsinore Soaring Club

David Kinsell wrote:
> Slick wrote:
> > Can someone elaborate on the formula GAG=GAA(airspeed +/- wind)/airspeed
> >
> > I'm a little confused on what GAA is and if it's just a constant number. I
> > kind of derived it as being 30 degrees as a constant target of angle you
> > want to the touchdown point (?). it works for Tom Knauff's calculation in
> > his book with 50mph a/s and 30 mph headwind, and using 30 for GAA. but when
> > I reduce it to a 5 mph headwind the resultant doesn't come within the cone.
> > Am I missing something here?
> >
> >
> >
> > ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
> > http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
> > ----= East and West-Coast Server Farms - Total Privacy via Encryption =----
>
> You're making it way too hard. Just set your flight computer to 0 altitude
> at the threshold. "Call the ball" and follow the needles. There's no actual
> need to look outside anymore.
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> This being R.A.S., it's sad but true that it's necessary to point out the
> above was sarcasm.