required LD versus required MC to make it home ??

[akiley]

Hi All,

I'm aware of and use the math formula to get my rental Cirrus back to
home base, but I like to back it up with SeeYou mobile. I know it's
recommended to use required LD to target making sure you have entered
a correct polar and safety altitude. But this doesn't account for
winds does it? If you are flying away from your target wondering how
far you can safely fly, you can't depend on required LD because big
headwinds can make this number useless. As an example, I notice I've
got 25LD required to my home base. I turn around and because of the
headwinds, I can only make 18LC. Outlanding anyone.

I'm curious about MC required to target. Wouldn't that be better to
use if you make sure all data is correct such as polar, winds, safety
altitude and make sure the correct target is activated. This way, I
can wander away from my home field and I know if my MC doesn't fall
below about say 7 (which plays out to about 20 LD in no wind) I am
fairly assured of making it and that this MC will be wind aware. Of
course it can't know about hitting lots of sink, but it seems a better
way for my type of non task, local soaring.

Before I finish, I would like to note that the MC to target NavBox in
SeeYouM doesn't always update very quickly if you change the winds
aloft manually. For this problem, I scroll the MC value untill the
little glide slope type indicater on the left side of SeeYou centers,
then compare that MC to the required MC NavBox.

akiley

[Darryl Ramm]

On Aug 22, 7:10*pm, akiley > wrote:
> Hi All,
>
> I'm aware of and use the math formula to get my rental Cirrus back to
> home base, but I like to back it up with SeeYou mobile. *I know it's
> recommended to use required LD to target making sure you have entered
> a correct polar and safety altitude. *But this doesn't account for
> winds does it? *If you are flying away from your target wondering how
> far you can safely fly, you can't depend on required LD because big
> headwinds can make this number useless. *As an example, I notice I've
> got 25LD required to my home base. *I turn around and because of the
> headwinds, I can only make 18LC. *Outlanding anyone.
>
> I'm curious about MC required to target. *Wouldn't that be better to
> use if you make sure all data is correct such as polar, winds, safety
> altitude and make sure the correct target is activated. *This way, I
> can wander away from my home field and I know if my MC doesn't fall
> below about say 7 (which plays out to about 20 LD in no wind) I am
> fairly assured of making it and that this MC will be wind aware. *Of
> course it can't know about hitting lots of sink, but it seems a better
> way for my type of non task, local soaring.
>
> Before I finish, I would like to note that the MC to target NavBox in
> SeeYouM doesn't always update very quickly if you change the winds
> aloft manually. *For this problem, I scroll the MC value untill the
> little glide slope type indicater on the left side of SeeYou centers,
> then compare that MC to the required MC NavBox.
>
> akiley

What is "the math formula". I am aware of many different math
formulas, including many for calculating/estimating glider performance/
navigation. But what are you using?

Required Mc is a kind of noisy number, especially if you think the
difference between two large numbers helps you much. It is sensitive
to high speed polar data and if you tried to fly it in a rental glider
with an unknown actual polar without a lot of experience at pushing it
is likely meaningless.

For recreational flying, unless you are racing with lots of
experience, I would focus less on twiddling Mc (or virtually twiddling
with SeeYou Mobile telling you its Mc estimate to goal) and more on L/
D achieved and L/D required as one data pair and on arrival height as
another. Arrival height factors in wind, uses the polar, bugs, Mc. Set
some sane low Mc near what you actually fly at. Pad the polar with
%bugs (start with max of 30% if new to XC) and have an arrival safety
height (at least your usual pattern height, more when starting). You
can try adjusting it at times and see what it does to your arrival
height but if you are at the stage it sounds like mostly leave it set
and don't go chasing large Mc numbers. Hide the navbox, there are
better things to look at. In fact hide almost everything, except the
two L/D boxes and arrival height and use the wind indicator on the
main map to check it looks sane. And forget the rest, including the
silly glideslope display, I cannot think of anybody who really uses
that thing (oops now we'll hear from them...).

Required L/D to target tells you what you need to achieve. It makes no
sense to fold wind into that, its just the distance divided by the
difference in height. Achieved L/D tells you what you are getting
obviously with wind affects as well, all without any assumptions about
polars, mass, bugs, or wind. That is the beauty of working with L/D
required and achieved.

But even better than asking on r.a.s. can you find a local
accomplished XC pilot(s) who can mentor you on all this stuff?

Darryl

[kirk.stant]

>
> Required L/D to target tells you what you need to achieve. It makes no
> sense to fold wind into that, its just the distance divided by the
> difference in height. Achieved L/D tells you what you are getting
> obviously with wind affects as well, all without any assumptions about
> polars, mass, bugs, or wind. That is the beauty of working with L/D
> required and achieved.
>
> But even better than asking on r.a.s. can you find a local
> accomplished XC pilot(s) who can mentor you on all this stuff?
>
> Darryl-

Darry is spot on. I would go a little further and dispense with the
Achieved L/D - I just use L/D required and watch for the trend: if it
is getting better (lower L/D required) then you are gaining on the
glide and can either speed up or relax more. If it's getting worse,
or not changing and looks a bit high (say more than half your
published L/D), then you need to stop and get some altitude. That
takes care of the wind, bugs, etc.

Totally agree with getting rid of all the navboxes that are "info
only" - unless your PDA is hooked up to a 302 and getting air data,
using GPS for fancy speed to fly info is a distraction. Use it as a
digital sectional, with your task, airspace, and landable fields (with
L/D required) on it, and in most cases turn off the terrain (exception
is in ridge country where the terrain can be really useful). Less is
more!

Cheers,

Kirk
66

[John Cochrane]

Well, just for a contrary opinion, I disagree with Darryl and Kirk. Mc
setting is the right set of units for everything in soaring.

If you must think about glide angles, the right units are D/L not L/
D. L/D goes through infinity when you run in to lift. D/L (feet per
mile, meters per kilometer) does not. If you gain 200 feet in lift vs.
lose 200 feet in lift, L/D shows radically different changes, D/L does
not.

The "safety profile" for making it to a goal with constant (say 99%)
probability follows a roughly square root function of distance.
(Square root follows if lift/sink are independent over distance) Most
of us approximate this with a relatively high Mc setting (3-4) plus a
reserve altitude.

Smoother conditions -- less lift or sink -- means less uncertainty
about your glide. So, paradoxically, you can use more aggressive
safety settings if there is no lift around, because then there is no
sink around. Strong lift mans strong sink; half chance of escaping in
10 knots, half chance of hitting the dirt in 10 knot sink. Therefore,
use a higher Mc setting and higher reserve altitude with stronger lift/
sink or general uncertainty.

To fly a safety glide you want to have the glide computer at a high Mc
setting, but fly slowly and accept weaker lift. Many pilots disconnect
the glide computer from the vario for this reason. Well, I do.
Instrument makers should recognize this difference and make it easier
to have a different Mc for glide than vario.

Wind is irrelevant here, with one exception. As you lower the Mc
setting heading upwind, you will discover a point at which lower Mc
setttings seem to make it worse. This is a featuer not a bug. The best
glide in wind occurs at a higher Mc setting. don't fly slower than
that, don't take weaker thermals than that, or you wont get home

John Cochrane

[Andy[_10_]]

On Aug 23, 6:40*am, "kirk.stant" > wrote:
> > Required L/D to target tells you what you need to achieve. It makes no
> > sense to fold wind into that, its just the distance divided by the
> > difference in height. Achieved L/D tells you what you are getting
> > obviously with wind affects as well, all without any assumptions about
> > polars, mass, bugs, or wind. That is the beauty of working with L/D
> > required and achieved.
>
> > But even better than asking on r.a.s. can you find a local
> > accomplished XC pilot(s) who can mentor you on all this stuff?
>
> > Darryl-
>
> Darry is spot on. *I would go a little further and dispense with the
> Achieved L/D - I just use L/D required and watch for the trend: if it
> is getting better (lower L/D required) then you are gaining on the
> glide and can either speed up or relax more. *If it's getting worse,
> or not changing and looks a bit high (say more than half your
> published L/D), then *you need to stop and get some altitude. *That
> takes care of the wind, bugs, etc.
>
> Totally agree with getting rid of all the navboxes that are "info
> only" - unless your PDA is hooked up to a 302 and getting air data,
> using GPS for fancy speed to fly info is a distraction. *Use it as a
> digital sectional, with your task, airspace, and landable fields (with
> L/D required) on it, and in most cases turn off the terrain (exception
> is in ridge country where the terrain can be really useful). *Less is
> more!
>
> Cheers,
>
> Kirk
> 66

I generally use arrival altitude for everything, especially final
glide. That way I know how much I need to climb to get to my goal and
wind is accounted for automatically in the computer. I typically
program in 1,000' for arrival altitude and speed up/slow down
depending on whether the arrival height is building or declining.
Typically I dial in 4 knots for the computation because it corresponds
to a typical cruise speed. I try not to set below 3 knots unless it's
a last resort. Except on very long glides low Mc settings just don't
yield enough glide angle margin - a little sink and you're at best L/D
or can't make it at all.

9B

[Mike the Strike]

On Aug 23, 7:02*am, Andy > wrote:
> On Aug 23, 6:40*am, "kirk.stant" > wrote:
>
>
>
> > > Required L/D to target tells you what you need to achieve. It makes no
> > > sense to fold wind into that, its just the distance divided by the
> > > difference in height. Achieved L/D tells you what you are getting
> > > obviously with wind affects as well, all without any assumptions about
> > > polars, mass, bugs, or wind. That is the beauty of working with L/D
> > > required and achieved.
>
> > > But even better than asking on r.a.s. can you find a local
> > > accomplished XC pilot(s) who can mentor you on all this stuff?
>
> > > Darryl-
>
> > Darry is spot on. *I would go a little further and dispense with the
> > Achieved L/D - I just use L/D required and watch for the trend: if it
> > is getting better (lower L/D required) then you are gaining on the
> > glide and can either speed up or relax more. *If it's getting worse,
> > or not changing and looks a bit high (say more than half your
> > published L/D), then *you need to stop and get some altitude. *That
> > takes care of the wind, bugs, etc.
>
> > Totally agree with getting rid of all the navboxes that are "info
> > only" - unless your PDA is hooked up to a 302 and getting air data,
> > using GPS for fancy speed to fly info is a distraction. *Use it as a
> > digital sectional, with your task, airspace, and landable fields (with
> > L/D required) on it, and in most cases turn off the terrain (exception
> > is in ridge country where the terrain can be really useful). *Less is
> > more!
>
> > Cheers,
>
> > Kirk
> > 66
>
> I generally use arrival altitude for everything, especially final
> glide. *That way I know how much I need to climb to get to my goal and
> wind is accounted for automatically in the computer. I typically
> program in 1,000' for arrival altitude and speed up/slow down
> depending on whether the arrival height is building or declining.
> Typically I dial in 4 knots for the computation because it corresponds
> to a typical cruise speed. I try not to set below 3 knots unless it's
> a last resort. Except on very long glides low Mc settings just don't
> yield enough glide angle margin - a little sink and you're at best L/D
> or can't make it at all.
>
> 9B

I do the same with arrival altitude, only am more conservative than
Andy. I increase or decrease MacCready accordingly. It seems the
only rational piece of data you need - arrival altitudes of less than
zero are likely to be less than useful.

Mike

[akiley]

On Aug 23, 12:32*am, Darryl Ramm > wrote:
> On Aug 22, 7:10*pm, akiley > wrote:
>
>
>
> > Hi All,
>
> > I'm aware of and use the math formula to get my rental Cirrus back to
> > home base, but I like to back it up with SeeYou mobile. *I know it's
> > recommended to use required LD to target making sure you have entered
> > a correct polar and safety altitude. *But this doesn't account for
> > winds does it? *If you are flying away from your target wondering how
> > far you can safely fly, you can't depend on required LD because big
> > headwinds can make this number useless. *As an example, I notice I've
> > got 25LD required to my home base. *I turn around and because of the
> > headwinds, I can only make 18LC. *Outlanding anyone.
>
> > I'm curious about MC required to target. *Wouldn't that be better to
> > use if you make sure all data is correct such as polar, winds, safety
> > altitude and make sure the correct target is activated. *This way, I
> > can wander away from my home field and I know if my MC doesn't fall
> > below about say 7 (which plays out to about 20 LD in no wind) I am
> > fairly assured of making it and that this MC will be wind aware. *Of
> > course it can't know about hitting lots of sink, but it seems a better
> > way for my type of non task, local soaring.
>
> > Before I finish, I would like to note that the MC to target NavBox in
> > SeeYouM doesn't always update very quickly if you change the winds
> > aloft manually. *For this problem, I scroll the MC value untill the
> > little glide slope type indicater on the left side of SeeYou centers,
> > then compare that MC to the required MC NavBox.
>
> > akiley
>
> What is "the math formula". I am aware of many different math
> formulas, including many for calculating/estimating glider performance/
> navigation. But what are you using?

Thanks for the good advice Darryl,

My personal math formula is that, without winds, I want to be 15:1 L/D
from my home airport, (not a cross country pilot yet) with a 1000
foot safety buffer. So this is 400 feet per NM. So for 5 miles, it's
just 400x5=2000 feet AGL plus 1000 safety = 3000AGL. If there is a 5
knot headwind on the return home, I would divide the Cirrus 46kt best
LD speed by 41 to get 0.9. That .9 can be divided by my 400 feet per
NM to get 445 feet per NM for my new calculated L/D to target. I
guess there are other factors, but this is ballpark for me. When I
start to get 20 L/D from home I start to get nervous. But my formula
is roughly based on one half my best LD plus a bit. I can't remember
which book I got my math from, but it's airspeed plus or minus winds
divided by airspeed which gives you a number to modify your L/D. Then
divide 6000 by the modified L/D to get feet per NM required to reach
your target, then add any safety altitude you desire to that agl
altitude.
>
> Required Mc is a kind of noisy number, especially if you think the
> difference between two large numbers helps you much. It is sensitive
> to high speed polar data and if you tried to fly it in a rental glider
> with an unknown actual polar without a lot of experience at pushing it
> is likely meaningless.
>
> For recreational flying, unless you are racing with lots of
> experience, I would focus less on twiddling Mc (or virtually twiddling
> with SeeYou Mobile telling you its Mc estimate to goal) and more on L/
> D achieved and L/D required as one data pair and on arrival height as
> another. Arrival height factors in wind, uses the polar, bugs, Mc. Set
> some sane low Mc near what you actually fly at. Pad the polar with
> %bugs (start with max of 30% if new to XC) and have an arrival safety
> height (at least your usual pattern height, more when starting). You
> can try adjusting it at times and see what it does to your arrival
> height but if you are at the stage it sounds like mostly leave it set
> and don't go chasing large Mc numbers. Hide the navbox, there are
> better things to look at. In fact hide almost everything, except the
> two L/D boxes and arrival height and use the wind indicator on the
> main map to check it looks sane. And forget the rest, including the
> silly glideslope display, I cannot think of anybody who really uses
> that thing (oops now we'll hear from them...).

Well, I've flown long enough to know not to trust electronics. I have
600 power hours using all sorts of navigators. Funny, when you use a
Garmin 396 on a computer, it sets magnetic variation to user set
instead of auto. SeeYou has quite a few bugs and gochas too. So my
primary is look at the down angle back to the airport.

I do monitor arrival height, but it's really just another way of
looking at MC as far as I can tell. The little glide slope indicator
is also sort of another way of looking at your MC to target. I figure
if I keep an eye on all of those, I'm less likely to trip over a bug
in SeeYou which I've found several of.
>
> Required L/D to target tells you what you need to achieve. It makes no
> sense to fold wind into that, its just the distance divided by the
> difference in height. Achieved L/D tells you what you are getting
> obviously with wind affects as well, all without any assumptions about
> polars, mass, bugs, or wind. That is the beauty of working with L/D
> required and achieved.

This is a good point, but since wind isn't factored into required L/D,
you don't know what your achieved L/D is unless you turn around and
head back to the airport. But it does seem to be safer and more
straight forward. And I suppose since you are always aware of the
winds, you can make a fairly accurate guess as to what you achieved L/
D is likely to be. If it's a straight headwind home at 5 knots, I
could just mentally modify what I expect to achieve.
>
> But even better than asking on r.a.s. can you find a local
> accomplished XC pilot(s) who can mentor you on all this stuff?

Yes, my club has several and I'm talking to them too. It's also funny
about gadgets in aircraft. My feeling is learn to use the autopilot
and whenever you can, learn navigators using simulators. Half
learning electronics is the most dangerous in my opinion. I enjoy
navigators, but I'm strict as to when and how to use them.
>
> Darryl

[T8]

On Aug 22, 10:10*pm, akiley > wrote:
> Hi All,
>
> I'm aware of and use the math formula to get my rental Cirrus back to
> home base, but I like to back it up with SeeYou mobile. *I know it's
> recommended to use required LD to target making sure you have entered
> a correct polar and safety altitude. *But this doesn't account for
> winds does it? *If you are flying away from your target wondering how
> far you can safely fly, you can't depend on required LD because big
> headwinds can make this number useless. *As an example, I notice I've
> got 25LD required to my home base. *I turn around and because of the
> headwinds, I can only make 18LC. *Outlanding anyone.
>
> I'm curious about MC required to target. *Wouldn't that be better to
> use if you make sure all data is correct such as polar, winds, safety
> altitude and make sure the correct target is activated. *This way, I
> can wander away from my home field and I know if my MC doesn't fall
> below about say 7 (which plays out to about 20 LD in no wind) I am
> fairly assured of making it and that this MC will be wind aware. *Of
> course it can't know about hitting lots of sink, but it seems a better
> way for my type of non task, local soaring.
>
> Before I finish, I would like to note that the MC to target NavBox in
> SeeYouM doesn't always update very quickly if you change the winds
> aloft manually. *For this problem, I scroll the MC value untill the
> little glide slope type indicater on the left side of SeeYou centers,
> then compare that MC to the required MC NavBox.
>
> akiley

It's probably also worth noting here that the Std Cirrus had some of
the least accurate static sources (under the wing) ever put on a
glider, so the accuracy of the ASI and any computer attempting to
calculate wind info using ASI will be compromised. Symptoms would be
significant changes in reported wind when you change heading or ground
track. At cruise speeds, Std Cirrus system reads higher than
calibrated airspeed, this should show as a headwind component that's
always there. There's a technical solution (tailcone statics), but it
will be at odds with your certification paperwork. I'll leave the
teaching of final glides via r.a.s. to the others :-).

-T8

[akiley]

On Aug 23, 10:00*am, John Cochrane >
wrote:
> Well, just for a contrary opinion, I disagree with Darryl and Kirk. Mc
> setting is the right set of units for everything in soaring.
>
> If you must think about glide angles, the right units are D/L not L/
> D. *L/D goes through infinity when you run in to lift. D/L (feet per
> mile, meters per kilometer) does not. If you gain 200 feet in lift vs.
> lose 200 feet in lift, L/D shows radically different changes, D/L does
> not.
>
> The "safety profile" for making it to a goal with constant (say 99%)
> probability follows a roughly square root function of distance.
> (Square root follows if lift/sink are independent over distance) *Most
> of us approximate this with a relatively high Mc setting (3-4) plus a
> reserve altitude.
>
> Smoother conditions -- less lift or sink -- means less uncertainty
> about your glide. So, paradoxically, you can use more aggressive
> safety settings if there is no lift around, because then there is no
> sink around. Strong lift mans strong sink; half chance of escaping in
> 10 knots, half chance of hitting the dirt in 10 knot sink. Therefore,
> use a higher Mc setting and higher reserve altitude with stronger lift/
> sink or general uncertainty.
>
> To fly a safety glide you want to have the glide computer at a high Mc
> setting, but fly slowly and accept weaker lift. Many pilots disconnect
> the glide computer from the vario for this reason. Well, I do.
> Instrument makers should recognize this difference and make it easier
> to have a different Mc for glide than vario.
>
> Wind is irrelevant here, with one exception. As you lower the Mc
> setting heading upwind, you will discover a point at which lower Mc
> setttings seem to make it worse. This is a featuer not a bug. The best
> glide in wind occurs at a higher Mc setting. don't fly slower than
> that, don't take weaker thermals than that, or you wont get home
>
> John Cochrane

I did a little calculation for a standard Cirrus with no wind. I did
this by using SeeYou mobile in simulator mode. I did manual math for
angle and feet per NM. Here are a few numbers. They might not format
correctly.

Required L/D 38, 28, 20, 15, 10
Required MC 0, 3.5, 7.4, 12, 22
glide angle deg 1.7, 2.2, 2.9, 3.8, 5.7
feet per NM 158, 215, 300, 400, 600

Then I added a big headwind. Required L/D stays the same, but MC
corrects for winds. ... akiley

[Andy[_1_]]

On Aug 23, 7:00*am, John Cochrane >
wrote:

> If you must think about glide angles, the right units are D/L not L/
> D. *L/D goes through infinity when you run in to lift. D/L (feet per
> mile, meters per kilometer) does not.

No expression using the terms lift and drag is appropriate for
defining a ground referenced flight path angle.

The proper term is, surprise, flight path angle. It has been used in
the aerospace industry for many, many, years. It has a range +/- 90
degrees. Required FPA describes the required geometry to reach the
goal and instantaneous FPA will descibe the current glider flight path
accurately whether climbing or descending.

Required and instantaneous FPA are just as easily calculated as the
incorrect term L/D or the misleadingly named term "efficiency".

Where did the use of L/D (the ratio of lift to drag) to describe a
ground referenced flight path angle originate? I know it has been
perpetuated by SeeYou, but did they start it?

Andy (GY)

[T8]

On Aug 23, 12:20*pm, Andy > wrote:

> Where did the use of L/D (the ratio of lift to drag) to describe a
> ground referenced flight path angle originate? *I know it has been
> perpetuated by SeeYou, but did they start it?

That goes back to the 50s, very likely. Certainly, it was used on
circular slide rule calculators of the 60s (referenced in Sunship Game
and articles of the era). L/D *is* a little easier to say than "the
inverse of the tangent of the flight path angle", even if it *is*
extremely sloppy shorthand.

-T8

[Andy[_1_]]

On Aug 23, 9:38*am, T8 > wrote:

> That goes back to the 50s, very likely. *Certainly, it was used on
> circular slide rule calculators of the 60s (referenced in Sunship Game
> and articles of the era). *L/D *is* a little easier to say than "the
> inverse of the tangent of the flight path angle", even if it *is*
> extremely sloppy shorthand.

I've been flying gliders long enough to have used prayer wheels as my
only flight computer. I never used one to compute my required L/D, and
don't know any way to use one to compute achieved L/D. Then, and now,
I considered arrival altitude and computed how high I had to climb to
achieve that arrival altitude.

L over D is no easier to say than FPA. In fact it's one syllable
longer.

Andy (GY)

[Darryl Ramm]

On Aug 23, 8:17*am, akiley > wrote:
> On Aug 23, 12:32*am, Darryl Ramm > wrote:
>
>
>
> > On Aug 22, 7:10*pm, akiley > wrote:
[snip]
> > Required L/D to target tells you what you need to achieve. It makes no
> > sense to fold wind into that, its just the distance divided by the
> > difference in height. Achieved L/D tells you what you are getting
> > obviously with wind affects as well, all without any assumptions about
> > polars, mass, bugs, or wind. That is the beauty of working with L/D
> > required and achieved.
>
> This is a good point, but since wind isn't factored into required L/D,
> you don't know what your achieved L/D is unless you turn around and
> head back to the airport. *But it does seem to be safer and more
> straight forward. *And I suppose since you are always aware of the
> winds, you can make a fairly accurate guess as to what you achieved L/
> D is likely to be. *If it's a straight headwind home at 5 knots, I
> could just mentally modify what I expect to achieve.

Again the L/D required is a statement of fact (as long as your
altitude and the destination elevation are accurate. It's beautiful
for it's simplicity. It also relates directly to the glide angle (OK
Andy) and you should develop eyeball skill for that over time.

Now its clearer where you are at, I would recommend at this stage of
your flying, where you are just taking steps away from the home
gliderport, to use the PDA calculated arrival height (above a safety
margin, with bugs factored -- in SeeYou Mobile if you want higher bugs
than 30% then you will need to modify the polar parameters). And that
arrival height will give you a safety margin that you can probalby
best relate to.

I suspect what John is talking about with Mc is too much for a new,
pre-XC pilot, it is probalby easier to work with what is likely to be
a more intuitive understanding of arrival height to start with. Then
I'd add the L/D metrics to get a feel for those (esp. as a sanity
check since they don't rely on computations) then maybe move up to
thinking more about the Mc stuff as you worry about XC performance and
develop a feel for what a Mc margin means.

How you are getting the wind calculation? As mentioned by others if
you don't have reliable wind data then worrying about factoring in
wind data may be irrelevant or worse. If you are hand entering wind
data that you trust that is great (all soaring software users knew how
to do that or at least how to reset suspect overly optimistic winds).

What Mc do you actually fly at? And how do you do this? For starting
off I would leave the Mc you actually fly at (i.e. your average
airspeed) low and don't try chasing the speed to fly (STF). Even if
you have a real STF computer that can calculate a reasonable STF there
are technical arguments about why its not as efficient as it might be,
but for a newer XC pilot overly chasing the STF is just a distraction
and especially may make it hard to find lift, estimate whether to take
a thermal, find blue convergence/energy lines etc. And don't try to
closely follow the STF Navbox on SeeYou Mobile, it just cannot
calculate that anything that useful from altitude (GPS or pressure)
data.

---

The PDA software is just a help, like other say, its a moving
sectional chart and a way to reduce calculations you would otherwise
do in your head, with a glide ruler or on a prayer wheel. Often a good
exercise to construct a glide ruler and hand draw some glide circles
on a sectional with different winds factored in. Doing that by hand
for where you fly should gives you a good feel for wind effects -- see
the ruler template at http://www.gliderbooks.com/downloads.html and
instructions in his Glider Pilot's Handbook of Aeronautical Knowledge
book. Just like getting a sectional and marking down landing options
also helps, "flying" to those in Google Earth or visiting them in a
power aircraft really help but there is something beautifully simple
and very tactile about pen and paper that seems to help people really
get a fell for things. GlidePlan (http://www.glideplan.com) can also
do this for you on a Mac or PC but doing by hand at least once is
probably a good idea.

> > But even better than asking on r.a.s. can you find a local
> > accomplished XC pilot(s) who can mentor you on all this stuff?
>
> Yes, my club has several and I'm talking to them too. *It's also funny
> about gadgets in aircraft. *My feeling is learn to use the autopilot
> and whenever you can, learn navigators using simulators. *Half
> learning electronics is the most dangerous in my opinion. *I enjoy
> navigators, but I'm strict as to when and how to use them.

Compared to power XC flying you are much more dependent on all the
subtleties happening outside the glider, so try to get the PDA into
the background and focus on finding lift, working thermals, finding
energy lines, flying smoothly and efficiently. You can learn a lot
just flying triangles around a local gliderport and just keep stepping
up what you do. There are lots of ways to skin a cat, but if somebody
skilled is willing to mentor you it is worth following the way they do
things so you can more easily learn from them.

If you know of any bugs in SeeYou Mobile, please report then to
Naviter.

Darryl

[T8]

On Aug 23, 12:54*pm, Andy > wrote:
> On Aug 23, 9:38*am, T8 > wrote:
>
> > That goes back to the 50s, very likely. *Certainly, it was used on
> > circular slide rule calculators of the 60s (referenced in Sunship Game
> > and articles of the era). *L/D *is* a little easier to say than "the
> > inverse of the tangent of the flight path angle", even if it *is*
> > extremely sloppy shorthand.
>
> *I've been flying gliders long enough to have used prayer wheels as my
> only flight computer. I never used one to compute my required L/D, and
> don't know any way to use one to compute achieved L/D. *Then, and now,
> I considered arrival altitude and computed how high I had to climb to
> achieve that arrival altitude.
>
> L over D is no easier to say than FPA. *In fact it's one syllable
> longer.
>
> Andy (GY)

40:1 seems more intuitive to me than 1.432 degrees, even if it isn't
strictly speaking an angle. I do prefer the term "glide angle" to L/
D.

I've never used a slide rule calculator in the cockpit. I started XC
soaring in the "early electronic" era, but before I could afford such
exotica, I simply used circles on the map, 5 statute miles per 1000'
plus pattern allowance. I always got home. Of course, if the weather
was in any way bizarre, I stayed above my final glide numbers by a
comfortable margin.

IIRC, George Moffatt had a design that incorporated various "glide
angles", expressed as 40:1, 35:1, 30:1 etc. I am uncertain of the
details.

-T8

[kirk.stant]

On Aug 23, 9:00*am, John Cochrane >
wrote:
> Well, just for a contrary opinion, I disagree with Darryl and Kirk. Mc
> setting is the right set of units for everything in soaring.
>
> If you must think about glide angles, the right units are D/L not L/
> D. *L/D goes through infinity when you run in to lift. D/L (feet per
> mile, meters per kilometer) does not. If you gain 200 feet in lift vs.
> lose 200 feet in lift, L/D shows radically different changes, D/L does
> not.
>
> The "safety profile" for making it to a goal with constant (say 99%)
> probability follows a roughly square root function of distance.
> (Square root follows if lift/sink are independent over distance) *Most
> of us approximate this with a relatively high Mc setting (3-4) plus a
> reserve altitude.
>
> Smoother conditions -- less lift or sink -- means less uncertainty
> about your glide. So, paradoxically, you can use more aggressive
> safety settings if there is no lift around, because then there is no
> sink around. Strong lift mans strong sink; half chance of escaping in
> 10 knots, half chance of hitting the dirt in 10 knot sink. Therefore,
> use a higher Mc setting and higher reserve altitude with stronger lift/
> sink or general uncertainty.
>
> To fly a safety glide you want to have the glide computer at a high Mc
> setting, but fly slowly and accept weaker lift. Many pilots disconnect
> the glide computer from the vario for this reason. Well, I do.
> Instrument makers should recognize this difference and make it easier
> to have a different Mc for glide than vario.
>
> Wind is irrelevant here, with one exception. As you lower the Mc
> setting heading upwind, you will discover a point at which lower Mc
> setttings seem to make it worse. This is a featuer not a bug. The best
> glide in wind occurs at a higher Mc setting. don't fly slower than
> that, don't take weaker thermals than that, or you wont get home
>
> John Cochrane

John, as usual, is correct, but in this case it's a bit of apples and
oranges. Darryl and I use "L/D" as a shorthand for a quick analysis
of the flight path angle required to make a destination. It's totally
Mc independent, and is easy to interpret at a glance on a moving map.
For accurate final glides in competition mode, where more accuracy is
desired, using Mc based on the last climb plus winds is the way to go
(and why I use my SN10 and not SeeYouM for final glides), but I also
crosscheck the two for a sanity check.

Always nice to have two opinions in the cockpit - the trick is to
decide which one is right!

Cheers,

Kirk

[Joseph Kiley]

Thanks Darryl,

> How you are getting the wind calculation? As mentioned by others if
> you don't have reliable wind data then worrying about factoring in
> wind data may be irrelevant or worse. If you are hand entering wind
> data that you trust that is great (all soaring software users knew how
> to do that or at least how to reset suspect overly optimistic winds).

I don't think SeeYou does very well with winds. This is what I've
experienced and read in other posts. I get winds aloft from several
sources/stations during my home briefing. I enter those directly into
SeeYou and always check them before I do my MC required to target.

> What Mc do you actually fly at? And how do you do this? For starting
> off I would leave the Mc you actually fly at (i.e. your average
> airspeed) low and don't try chasing the speed to fly (STF). Even if
> you have a real STF computer that can calculate a reasonable STF there
> are technical arguments about why its not as efficient as it might be,
> but for a newer XC pilot overly chasing the STF is just a distraction
> and especially may make it hard to find lift, estimate whether to take
> a thermal, find blue convergence/energy lines etc. And don't try to
> closely follow the STF Navbox on SeeYou Mobile, it just cannot
> calculate that anything that useful from altitude (GPS or pressure)
> data.

My SeeYou is not plugged into anything so it's all GPS. To be honest,
I use it mostly to analyze me flight when I get home. I look at it in
flight to backup a possible creepy feeling because I look a bit low
for my liking. I fly MC zero generally because I'm flying local
working on my thermal technique. If I encounter sink I speed up maybe
10 or 15 knots depending on how large the sink area is. If I have a
headwind I'm trying to penetrate, I will speed up somewhat as well. I
guess what I really want to be sure of is NOT landing out.
>
> The PDA software is just a help, like other say, its a moving
> sectional chart and a way to reduce calculations you would otherwise
> do in your head, with a glide ruler or on a prayer wheel. Often a good
> exercise to construct a glide ruler and hand draw some glide circles
> on a sectional with different winds factored in. Doing that by hand
> for where you fly should gives you a good feel for wind effects -- see
> the ruler template athttp://www.gliderbooks.com/downloads.htmland
> instructions in his Glider Pilot's Handbook of Aeronautical Knowledge
> book. Just like getting a sectional and marking down landing options
> also helps, "flying" to those in Google Earth or visiting them in a
> power aircraft really help but there is something beautifully simple
> and very tactile about pen and paper that seems to help people really
> get a fell for things. GlidePlan (http://www.glideplan.com) can also
> do this for you on a Mac or PC but doing by hand at least once is
> probably a good idea.

Great ideas. I'm a photographer and made a "Stocker" whizz wheel
using notes from Reichmann's cross country book. Put it together by
scanning a sectional and layering it in Photoshop. That thing turns
heads at the glider club. I've also computed range rings and put
layered them over a sectional offset for winds. That's a time
consuming math project for me anyway, especially if you have a safety
altitude figured in. Anyway, I love the old fashioned approaches and
used them as often as the electronics. I also flew a little Cessna
152 into all the local fields that I might land with gliders.
>
> > > But even better than asking on r.a.s. can you find a local
> > > accomplished XC pilot(s) who can mentor you on all this stuff?
>
> > Yes, my club has several and I'm talking to them too. *It's also funny
> > about gadgets in aircraft. *My feeling is learn to use the autopilot
> > and whenever you can, learn navigators using simulators. *Half
> > learning electronics is the most dangerous in my opinion. *I enjoy
> > navigators, but I'm strict as to when and how to use them.
>
> Compared to power XC flying you are much more dependent on all the
> subtleties happening outside the glider, so try to get the PDA into
> the background and focus on finding lift, working thermals, finding
> energy lines, flying smoothly and efficiently. You can learn a lot
> just flying triangles around a local gliderport and just keep stepping
> up what you do. There are lots of ways to skin a cat, but if somebody
> skilled is willing to mentor you it is worth following the way they do
> things so you can more easily learn from them.

I'm lucky, I have a friend that talked me into soaring last spring.
He has a Ventus 2CX and on any reasonable day, he and his buddies do
250 mile round trips landing at dinner time. Then our club has
several instructors that seem to be very good.
>
> If you know of any bugs in SeeYou Mobile, please report then to
> Naviter.

Have done that.

>
> Darryl

[Andy[_10_]]

On Aug 23, 8:40*am, akiley > wrote:
> On Aug 23, 10:00*am, John Cochrane >
> wrote:
>
>
>
>
>
> > Well, just for a contrary opinion, I disagree with Darryl and Kirk. Mc
> > setting is the right set of units for everything in soaring.
>
> > If you must think about glide angles, the right units are D/L not L/
> > D. *L/D goes through infinity when you run in to lift. D/L (feet per
> > mile, meters per kilometer) does not. If you gain 200 feet in lift vs.
> > lose 200 feet in lift, L/D shows radically different changes, D/L does
> > not.
>
> > The "safety profile" for making it to a goal with constant (say 99%)
> > probability follows a roughly square root function of distance.
> > (Square root follows if lift/sink are independent over distance) *Most
> > of us approximate this with a relatively high Mc setting (3-4) plus a
> > reserve altitude.
>
> > Smoother conditions -- less lift or sink -- means less uncertainty
> > about your glide. So, paradoxically, you can use more aggressive
> > safety settings if there is no lift around, because then there is no
> > sink around. Strong lift mans strong sink; half chance of escaping in
> > 10 knots, half chance of hitting the dirt in 10 knot sink. Therefore,
> > use a higher Mc setting and higher reserve altitude with stronger lift/
> > sink or general uncertainty.
>
> > To fly a safety glide you want to have the glide computer at a high Mc
> > setting, but fly slowly and accept weaker lift. Many pilots disconnect
> > the glide computer from the vario for this reason. Well, I do.
> > Instrument makers should recognize this difference and make it easier
> > to have a different Mc for glide than vario.
>
> > Wind is irrelevant here, with one exception. As you lower the Mc
> > setting heading upwind, you will discover a point at which lower Mc
> > setttings seem to make it worse. This is a featuer not a bug. The best
> > glide in wind occurs at a higher Mc setting. don't fly slower than
> > that, don't take weaker thermals than that, or you wont get home
>
> > John Cochrane
>
> I did a little calculation for a standard Cirrus with no wind. *I did
> this by using SeeYou mobile in simulator mode. *I did manual math for
> angle and feet per NM. *Here are a few numbers. *They might not format
> correctly.
>
> Required L/D * * 38, * *28, * 20, * *15, * 10
> Required MC * * * 0, * *3.5, *7.4, * 12, * 22
> glide angle deg *1.7, * 2.2, *2.9, * *3.8, *5.7
> feet per NM * * * *158, *215, 300, *400, *600
>
> Then I added a big headwind. *Required L/D stays the same, but MC
> corrects for winds. *... akiley

Okay, for eyeball calculations this makes sense. I normally use miles
per thousand plus 1000' arrival (plus field elevation) to estimate if
I'm high or low. I printed a table that showed how many miles I could
get per 1,000' as a function of Mc (0, 2, 4, 6, 8, 10) and wind (-25
to +25 mph).

If you are just starting to venture out from home and you are in the
US, consider getting a copy of GlidePlan software. It will allow you
to print minimum altitude contours directly onto a sectional chart
(you can even print alternate maps for different wind conditions).
Then all you need to do is figure out where you are on the chart and
it will tell you how high you need to be. Pretty cool. www.glideplan.com

Andy
9B

[Darryl Ramm]

On Aug 23, 11:56*am, Joseph Kiley > wrote:
> Thanks Darryl,
>
> > How you are getting the wind calculation? As mentioned by others if
> > you don't have reliable wind data then worrying about factoring in
> > wind data may be irrelevant or worse. If you are hand entering wind
> > data that you trust that is great (all soaring software users knew how
> > to do that or at least how to reset suspect overly optimistic winds).
>
> I don't think SeeYou does very well with winds. *This is what I've
> experienced and read in other posts. * I get winds aloft from several
> sources/stations during my home briefing. *I enter those directly into
> SeeYou and always check them before I do my MC required to target.

SeeYou Mobile does *very* well with wind if it has the data to work
from. With just a GPS input all SeeYou can do is effectively look at
thermal circle drift, that depends on how well you thermal, how long/
far since the last thermal, and lots of other things. When connected
to an external flight computer (like a C302) SeeYou Mobile will use
TAS data from the flight computer and relatively small change in
heading to also calculate winds and it tends to a much better job
overall. This is not just a SeeYou Mobile thing, other devices limited
to just GPS input will often show the same problems. However if you
are in doubt, clobber the wind settings and take a few good clean
circles with any of these devices they should produce a reasonable
idea of the wind. Search r.a.s. on Google for past discussion on
SeeYou Mobile wind calculations by myself and other authors.

> > What Mc do you actually fly at? And how do you do this? For starting
> > off I would leave the Mc you actually fly at (i.e. your average
> > airspeed) low and don't try chasing the speed to fly (STF). Even if
> > you have a real STF computer that can calculate a reasonable STF there
> > are technical arguments about why its not as efficient as it might be,
> > but for a newer XC pilot overly chasing the STF is just a distraction
> > and especially may make it hard to find lift, estimate whether to take
> > a thermal, find blue convergence/energy lines etc. And don't try to
> > closely follow the STF Navbox on SeeYou Mobile, it just cannot
> > calculate that anything that useful from altitude (GPS or pressure)
> > data.
>
> My SeeYou is not plugged into anything so it's all GPS. *To be honest,
> I use it mostly to analyze me flight when I get home. *I look at it in
> flight to backup a possible creepy feeling because I look a bit low
> for my liking. *I fly MC zero generally because I'm flying local
> working on my thermal technique. *If I encounter sink I speed up maybe
> 10 or 15 knots depending on how large the sink area is. *If I have a
> headwind I'm trying to penetrate, I will speed up somewhat as well. *I
> guess what I really want to be sure of is NOT landing out.

For typical days where there is lift available and as you become more
comfortable with thermaling I would encourage you to try to start with
Mc near 1. Mc == 0 means you really are in desperation mode and don't
really plan to go anywhere. See the discussion in Reichman about this.
Mc=0 quickly becomes a kind of boat anchor dragging on you. If you are
dialing the Mc into a flight computer (or STF ring on a winter vario)
it also starts giving you a feel for how excess Mc helps you if you
run into worse conditions than you expect. You can increase the Mc
setting you fly at up from there as you gain confidence, but dont' go
crazy with it. A rule of thumb often used especially for new XC folks
it to set the Mc conservatively at 1/2 to 1/3 of what you think your
next average climb will be - and even then its just to give you an
idea of average speed to fly, don't go chasing it. Sounds like you
have a good approach as is. The last thermal average climb stats in
SeeYou Mobile can be interesting to check, it will often be much less
than you think, and even then it often misses time wasted mucking
around trying to find lift.

BTW details of wind effects and Mc may not be obvious, search for past
r.a.s. postings by John Cochrane and others on this.

[snip]

Darryl

[johngalloway[_2_]]

How I use SeeYou mobile for final glides (when I get a chance to do
them):

With my chosen arrival altitude and my/or the computer's best
estimates of the wind set, then in the likely last thermal I use the
usual McCready/Cochrane considerations plus my personal wimp factor
to decide when to leave the thermal and to judge an appropriate
starting McCready setting. This is just to get in the ballpark of
when to start the glide.

Next, as I start the glide I take note of the required LD (SYM
calculates this to the arrival altitude) and as long as this number
stays the same or gets smaller then I am on glide or can speed up
respectively. If the number gets bigger I have to slow down or
climb. The required LD is wrongly named in SYM - it is actually the
glide angle with respect to the ground. All glide angles converge at
the destination so any glide angle that I can keep constant will
bring me to home at my arrival reserve altitude. This is independent
of any errors in wind/polar/bugs. I never have understood why most
glide calculators seem to work on altitude difference displays
resulting glides vertically parallel to the starting glide angle when
proportionately less altitude difference is required as one gets
closer to the destination.

(I don't find that the method recommended in the SYM manual of
comparing Achieved LD with Required LD is any good because the
Achieved LD varies so much in a much shorter time scale.)

John Galloway

[mike]

On Aug 22, 8:10*pm, akiley > wrote:
> Hi All,
>
> I'm aware of and use the math formula to get my rental Cirrus back to
> home base, but I like to back it up with SeeYou mobile. *I know it's
> recommended to use required LD to target making sure you have entered
> a correct polar and safety altitude. *But this doesn't account for
> winds does it? *If you are flying away from your target wondering how
> far you can safely fly, you can't depend on required LD because big
> headwinds can make this number useless. *As an example, I notice I've
> got 25LD required to my home base. *I turn around and because of the
> headwinds, I can only make 18LC. *Outlanding anyone.
>
> I'm curious about MC required to target. *Wouldn't that be better to
> use if you make sure all data is correct such as polar, winds, safety
> altitude and make sure the correct target is activated. *This way, I
> can wander away from my home field and I know if my MC doesn't fall
> below about say 7 (which plays out to about 20 LD in no wind) I am
> fairly assured of making it and that this MC will be wind aware. *Of
> course it can't know about hitting lots of sink, but it seems a better
> way for my type of non task, local soaring.
>
> Before I finish, I would like to note that the MC to target NavBox in
> SeeYouM doesn't always update very quickly if you change the winds
> aloft manually. *For this problem, I scroll the MC value untill the
> little glide slope type indicater on the left side of SeeYou centers,
> then compare that MC to the required MC NavBox.
>
> akiley

I look at "altitude required", with either an auto or manually set MC,
depending on the time of day. For a final glide, I climb to the
altitude I feel is appropriate for the glide home and then adjust my
speed, depending on the air mass I am gliding through.

[akiley]

snip
>
> For typical days where there is lift available and as you become more
> comfortable with thermaling I would encourage you to try to start with
> Mc near 1. Mc == 0 means you really are in desperation mode and don't
> really plan to go anywhere. See the discussion in Reichman about this.
> Mc=0 quickly becomes a kind of boat anchor dragging on you. If you are
> dialing the Mc into a flight computer (or STF ring on a winter vario)
> it also starts giving you a feel for how excess Mc helps you if you
> run into worse conditions than you expect. You can increase the Mc
> setting you fly at up from there as you gain confidence, but dont' go
> crazy with it. A rule of thumb often used especially for new XC folks
> it to set the Mc conservatively at 1/2 to 1/3 of what you think your
> next average climb will be - and even then its just to give you an
> idea of average speed to fly, don't go chasing it. Sounds like you
> have a good approach as is. The last thermal average climb stats in
> SeeYou Mobile can be interesting to check, it will often be much less
> than you think, and even then it often misses time wasted mucking
> around trying to find lift.

This brings up something I may have overlooked as I described how I
get home safely. I use MC more as a way to judge my wiggle room to my
home airport rather than STF. If my SeeYou is showing 10mc to get
home based on winds and safety altitude, I generally don't fly that MC
unless I'm very close and can see I have it made. Instead I fly
conservatively within 10kts of best L/D and use that high required MC
as my safety margin. Sort of like always being within half your best
L/D to your target airport. akiley
>
> BTW details of wind effects and Mc may not be obvious, search for past
> r.a.s. postings by John Cochrane and others on this.
>
> [snip]
>
> Darryl

[Andy[_1_]]

On Aug 23, 1:14*pm, johngalloway > wrote:
>All glide angles converge at
>the destination so any glide angle that I can keep constant will
>bring me to home at my arrival reserve altitude.

With the very, very, big caveat that there is no intervening terrain.

There is actually significant potential for advancement in gliding
computers. That is the display of a vertical profile view of the final
glide, complete with terrain. This display is known as the VSD
(Vertical Situation Display) in some non gliding display
applications. This type of display can clearly depict a multi-angle
final glide path when that is required to clear terrain and also make
the goal at the required finish altitude.

I suspect that this type of display would also be very useful for
understanding the effect on glide path and optimum MC when there is a
significant wind change when rounding the final turnpoint.

Andy (GY)

[Eric Greenwell]

On 8/23/2010 8:17 AM, akiley wrote:
> Well, I've flown long enough to know not to trust electronics. I have
> 600 power hours using all sorts of navigators. Funny, when you use a
> Garmin 396 on a computer, it sets magnetic variation to user set
> instead of auto. SeeYou has quite a few bugs and gochas too. So my
> primary is look at the down angle back to the airport.
>
I've used SeeYou Mobile for 1000+ hours all over the USA, and I'm not
aware of any bugs or gotchas. I would never go back to paper charts,
whiz wheels, or just looking out the window. For example, most of my
final glides begin 30 to 50 miles from the airport, where I can't even
see it, yet they work out well most of the time.

Your statement "So my primary is look at the down angle back to the
airport" suggests to me it's not SeeYou, but more likely your setup or
interpretation of what Mobile is telling you. If you are that close, the
computer should be working with no problems.

Flight computers can be a real aid to efficient, enjoyable soaring, so I
hate to see someone having problems with them. What version of mobile
are you using? Can you describe the two biggest bugs and gotchas?

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

[Westbender]

I'm with Mike. You can't get any simpler than using the "Arrival
Altitude" navbox. It takes into account all available parameters
(distance, Mc, bugs, ballast, wind), and is corrected for reserve
altitude. This requires you have reasonable polar info entered for the
ship you're flying. This feature is perfect for first forays into xc
flying. You can use this to "hop" from one airfield to the next. A
quick glance at the navbox will show whether you can make the current
waypoint from your current position. Negative value = climb, 0 or
higher = good to go.

[akiley]

On Aug 23, 11:11*pm, Andy > wrote:
> On Aug 23, 1:14*pm, johngalloway > wrote:
>
> >All glide angles converge at
> >the destination *so any glide angle that I can keep constant will
> >bring me to home at my arrival reserve altitude.
>
> With the very, very, big caveat that there is no intervening terrain.
>
> There is actually significant potential for advancement in gliding
> computers. That is the display of a vertical profile view of the final
> glide, complete with terrain. *This display is known as the VSD
> (Vertical Situation Display) in some non gliding display
> applications. *This type of display can clearly depict a multi-angle
> final glide path when that is required to clear terrain and also make
> the goal at the required finish altitude.
>
> I suspect that this type of display would also be very useful for
> understanding the effect on glide path and optimum MC when there is a
> significant wind change when rounding the final turnpoint.
>
> Andy (GY)

I use Condor soaring simulator with my iPaq running from the serial
port. It's a great way to test if/then situations and to get familiar
with your navigator. One interesting way of looking at terrain is
also the program XC-Soar. It draws a dotted, terrain aware, wind
aware, polar aware circle around your current position that indicates
the terrain strike point at your current MC. For terrain, this dotted
line spills into other valley's through lower gaps and valleys. Also
SeeYou has a red box on the course line indicating any ridge you will
hit before reaching you destination. You can run somewhat parallel to
this ridge way before you get to it and if SeeYou finds a gap, the red
box disappears and you can proceed direct. akiley

[Andreas Maurer]

On Mon, 23 Aug 2010 11:56:48 -0700 (PDT), Joseph Kiley
> wrote:


>I don't think SeeYou does very well with winds. This is what I've
>experienced and read in other posts. I get winds aloft from several
>sources/stations during my home briefing. I enter those directly into
>SeeYou and always check them before I do my MC required to target.

Well, actually SeeYou's wind calculations are actually very good, even
if its only data source is GPS. But you have to remember that the wind
is only calculated while you are circling, and that it might take a
couple of minutes to get accurate data.


>My SeeYou is not plugged into anything so it's all GPS. To be honest,
>I use it mostly to analyze me flight when I get home. I look at it in
>flight to backup a possible creepy feeling because I look a bit low
>for my liking. I fly MC zero generally because I'm flying local
>working on my thermal technique. If I encounter sink I speed up maybe
>10 or 15 knots depending on how large the sink area is. If I have a
>headwind I'm trying to penetrate, I will speed up somewhat as well. I
>guess what I really want to be sure of is NOT landing out.

Try this for your Cirrus:
- set MC on your PDA to 2 meters/second (do the maths for the units
you use)
- set bug factor to 30 percent
- set arrival altitude to a value of your liking, say, 600 to 900 ft

With these settings you can be nearly 100% sure that you are going to
reach the chosen airport with the desired arrival altitude.

>> If you know of any bugs in SeeYou Mobile, please report then to
>> Naviter.
>
>Have done that.

Which bugs did you observe?
I've been flying with the relatively old SeeYou 2.71 for the last
15.000 kilometers and found no bugs worth mentioning.


Greetings from germany
Andreas

[mattm[_2_]]

On Aug 23, 11:11*pm, Andy > wrote:
> On Aug 23, 1:14*pm, johngalloway > wrote:
>
> >All glide angles converge at
> >the destination *so any glide angle that I can keep constant will
> >bring me to home at my arrival reserve altitude.
>
> With the very, very, big caveat that there is no intervening terrain.
>
> There is actually significant potential for advancement in gliding
> computers. That is the display of a vertical profile view of the final
> glide, complete with terrain. *This display is known as the VSD
> (Vertical Situation Display) in some non gliding display
> applications. *This type of display can clearly depict a multi-angle
> final glide path when that is required to clear terrain and also make
> the goal at the required finish altitude.
>
> I suspect that this type of display would also be very useful for
> understanding the effect on glide path and optimum MC when there is a
> significant wind change when rounding the final turnpoint.
>
> Andy (GY)

Personally I love the SoarPilot final glide table. There's a picture
of it at
http://www.soaringpilot.org/dokuwiki/doku.php/soarpilot/final_glide_screen
It displays a table of MC settings (values 0-5, or 0-10 by 2) along
with
the speed to fly and a choice of arrival altitude, required altitude,
or
difference from glide slope. I find it very easy to follow on final
glide --
if I'm picking up energy I can see how fast I can fly and still
arrive,
or if I'm losing energy I can see how much I need to slow up and still
make it back.

The only problem with SoarPilot is that it runs on PalmOS,
which goes on outdated hardware these days. There's a version of
StyleTap that runs on the iPhone, but there's no serial port or
bluetooth
to connect it to any other devices in your plane. I don't know if
anyone
has gotten it to work on the PNDs that are being used nowadays.

-- Matt

[Ramy]

On Aug 24, 6:39*am, Westbender > wrote:
> I'm with Mike. You can't get any simpler than using the "Arrival
> Altitude" navbox. It takes into account all available parameters
> (distance, Mc, bugs, ballast, wind), and is corrected for reserve
> altitude. This requires you have reasonable polar info entered for the
> ship you're flying. This feature is perfect for first forays into xc
> flying. You can use this to "hop" from one airfield to the next. A
> quick glance at the navbox will show whether you can make the current
> waypoint from your current position. Negative value = climb, 0 or
> higher = good to go.

Seems like many pilots are using multiple complicated methods to
determine their final glides. Most are using MC settings for that
purpose. Is it just me who never use MC setting to determine arrival,
but using bug factor instead? Following the KISS principal, this is
the simplest way. No need to compare L/D, guesstimate MC, disconnect
the vario or ignore the MC speed to fly, etc. Just set your bug factor
to degrade your polar to something you are comfortable with (I found
70-75% to work fine most of the time), set your MC to zero and watch
your arrival altitude. Once you are comfortable with the arrival
altitude just keep maintain the same number by either speeding up or
slowing down. Works perfect for me.

Ramy

[Andreas Maurer]

On Tue, 24 Aug 2010 11:09:01 -0700 (PDT), Ramy >
wrote:


>Seems like many pilots are using multiple complicated methods to
>determine their final glides. Most are using MC settings for that
>purpose. Is it just me who never use MC setting to determine arrival,
>but using bug factor instead? Following the KISS principal, this is
>the simplest way. No need to compare L/D, guesstimate MC, disconnect
>the vario or ignore the MC speed to fly, etc. Just set your bug factor
>to degrade your polar to something you are comfortable with (I found
>70-75% to work fine most of the time), set your MC to zero and watch
>your arrival altitude. Once you are comfortable with the arrival
>altitude just keep maintain the same number by either speeding up or
>slowing down. Works perfect for me.

.... but is neither accurate, nor fast, not safer. :)

Most pilots don't want to waste time (or simply don't have the
weather) to climb extremely high in the last thermal, hence they
follow McCready's advice that has been proven for the last 50 years:
Set the average climb rate of the last thermal as MC setting, add the
bug factor, and leave the thermal once the arrival altitude is to your
liking. Works like a charm, and is extremely easy to use.
To be honest, I have difficulties to find an explanation why something
different (your settings, for example) should be less complicated.

What you are doing is simply to abandon the performance of your 56:1
ship and fly it like a 30:1 Ka-6. Works, but is far, far away from the
optimum. :)

Cheers
Andreas

[Ramy]

On Aug 24, 11:33*am, Andreas Maurer > wrote:
> On Tue, 24 Aug 2010 11:09:01 -0700 (PDT), Ramy >
> wrote:
>
> >Seems like many pilots are using multiple complicated methods to
> >determine their final glides. Most are using MC settings for that
> >purpose. Is it just me who never use MC setting to determine arrival,
> >but using bug factor instead? Following the KISS principal, this is
> >the simplest way. No need to compare L/D, guesstimate MC, disconnect
> >the vario or ignore the MC speed to fly, etc. Just set your bug factor
> >to degrade your polar to something you are comfortable with (I found
> >70-75% to work fine most of the time), set your MC to zero and watch
> >your arrival altitude. Once you are comfortable with the arrival
> >altitude just keep maintain the same number by either speeding up or
> >slowing down. Works perfect for me.
>
> ... but is neither accurate, nor fast, not safer. :)
>
> Most pilots don't want to waste time (or simply don't have the
> weather) to climb extremely high in the last thermal, hence they
> follow McCready's advice that has been proven for the last 50 years:
> Set the average climb rate of the last thermal as MC setting, add the
> bug factor, and leave the thermal once the arrival altitude is to your
> liking. Works like a charm, and is extremely easy to use.
> To be honest, I have difficulties to find an explanation why something
> different (your settings, for example) should be less complicated.
>
> What you are doing is simply to abandon the performance of your 56:1
> ship and fly it like a 30:1 Ka-6. Works, but is far, far away from the
> optimum. :)
>
> Cheers
> Andreas

Nope. We both are going to leave the thermal at the same time and
glide at the same speed.
In my case the MC will be zero and the bug factor 75%, in your case
MC=3 and bug factor = 95-100%.
However you will need to ignore the speed to fly as John suggested
unless you are willing to risk landout to save couple of minutes
(which may make sense only in contest).
Using the last average climb in the thermal is often meaningless in my
opinion. In many places I fly (Truckee, Hollister, Byron), the last
average thermal is maybe 5 knots but the next is zero since this was
the last thermal. This is true for many soaring sites which are in the
valley and not on the top of the montain range you just left, as well
as long XC flight where the likelyhood to find another thermal late in
the day is small. So using the method of dialing MC = last average
climb and then follow STF is guaranty landout, and a very silly one...
So my recomendation to all non contest XC pilots will be to degrade
your performance using bug factor 70-75%, which will give you enough
buffer for unexpected sink or head wind (which can also be very
different from the wind measured in your last turn) and fly MC=0 until
you are comfrtable with your arrival altitude and then speed up if
your arrival altitude start increasing. This will usually result in
slower glide speed at the beginning of the final glide, gradually
increasing as you get closer, much safer than the other way around.

Ramy

[John Cochrane[_2_]]

You guys need to distinguish two separate uses of the flight
computer.

1. How to use it to maximize speed on the final glide, with an
acceptable small risk of landing out in friendly terrain short of the
airport, costing you only contest points and a few beers for your crew

2. How to use it to gauge safety glides, where speed is not so much an
issue, but making really really sure you make it to the destination is
important.

For 1, Andreas has it exactly right, even at Minden. If you're in a 5
knot thermal, yes, you will do better climbing to the correct height
and blasting home at the 5 knot Mc speed -- if you dare. Try it some
time. It's a lot of fun to let your buddy leave, fly home at 80 knots,
while you climb high, blast home at about 115 and catch him a few
miles from the airport.


For 2, thermal strength is not really an issue. If there were a
thermal of decent strength, you'd take it! The issue is proceeding or
turning back. Here is where you evaluate the wisdom of gliding on with
substantially higher Mc values than the weakest thermal you'd take
(anything!) and substantially higher values than correspond to the
speed you're going to glide back at. Just how much higher should that
MC value (or bugs if you like) be? That depends on just how bad the
terrain is below, and also on the chance of finding significant sink
on the way. Again, smoother air means less risk.

John Cochrane

[mattm[_2_]]

On Aug 24, 3:44*pm, Ramy > wrote:
> On Aug 24, 11:33*am, Andreas Maurer > wrote:
>
>
>
> > On Tue, 24 Aug 2010 11:09:01 -0700 (PDT), Ramy >
> > wrote:
>
> > >Seems like many pilots are using multiple complicated methods to
> > >determine their final glides. Most are using MC settings for that
> > >purpose. Is it just me who never use MC setting to determine arrival,
> > >but using bug factor instead? Following the KISS principal, this is
> > >the simplest way. No need to compare L/D, guesstimate MC, disconnect
> > >the vario or ignore the MC speed to fly, etc. Just set your bug factor
> > >to degrade your polar to something you are comfortable with (I found
> > >70-75% to work fine most of the time), set your MC to zero and watch
> > >your arrival altitude. Once you are comfortable with the arrival
> > >altitude just keep maintain the same number by either speeding up or
> > >slowing down. Works perfect for me.
>
> > ... but is neither accurate, nor fast, not safer. :)
>
> > Most pilots don't want to waste time (or simply don't have the
> > weather) to climb extremely high in the last thermal, hence they
> > follow McCready's advice that has been proven for the last 50 years:
> > Set the average climb rate of the last thermal as MC setting, add the
> > bug factor, and leave the thermal once the arrival altitude is to your
> > liking. Works like a charm, and is extremely easy to use.
> > To be honest, I have difficulties to find an explanation why something
> > different (your settings, for example) should be less complicated.
>
> > What you are doing is simply to abandon the performance of your 56:1
> > ship and fly it like a 30:1 Ka-6. Works, but is far, far away from the
> > optimum. :)
>
> > Cheers
> > Andreas
>
> Nope. We both are going to leave the thermal at the same time and
> glide at the same speed.
> In my case the MC will be zero and the bug factor 75%, in your case
> MC=3 and bug factor = 95-100%.
> However you will need to ignore the speed to fly as John suggested
> unless you are willing to risk landout to save couple of minutes
> (which may make sense only in contest).
> Using the last average climb in the thermal is often meaningless in my
> opinion. In many places I fly (Truckee, Hollister, Byron), the last
> average thermal is maybe 5 knots but the next is zero since this was
> the last thermal. This is true for many soaring sites which are in the
> valley and not on the top of the montain range you just left, as well
> as long XC flight where the likelyhood to find another thermal late in
> the day is small. So using the method of dialing MC = last average
> climb and then follow STF is guaranty landout, and a very silly one...
> So my recomendation to all non contest XC pilots will be to degrade
> your performance using bug factor 70-75%, which will give you enough
> buffer for unexpected sink or head wind (which can also be very
> different from the wind measured in your last turn) and fly MC=0 until
> you are comfrtable with your arrival altitude and then speed up if
> your arrival altitude start increasing. This will usually result in
> slower glide speed at the beginning of the final glide, gradually
> increasing as you get closer, much safer than the other way around.
>
> Ramy

Only a smallish fraction of my flying is in contests, but whenever I'm
on cross country I aim to go fast. MC 0 is almost always a poor speed
to fly, unless you're positive you won't see any more lift and you
want
to go as far as absolutely possible (to pick up a few points in a
contest
or for an easier retrieve, e.g., which aren't really very good
reasons).
Reichmann points out that MC 1 is a better setting if you are in
desparation mode, because you give up only a little glide distance
but you get to sample more air in a given time.

As far as flying final glide, the correct speed to fly is the ultimate
strength of your last thermal. If you were climbing at 5 knots (20s
avg)
in a thermal that had averaged 2.5 knots from when you started (e.g.
it
was narrow down low and it took a while to get going), and you could
make it home with MC 2.5, you will finish quicker if you continue to
climb until you can get home at MC 5.

As far as safety in final glides, John Cochrane has a good paper on
that.
I ensure safety by flying to a safety altitude at finish. If I'm not
going to
make that I stop and climb or land out when I still have time to do it
safely.
When I do go to a contest I'm safer for having practiced how to do
that.

Now, for a beginner at cross country, it's great to be conservative.
You've
never landed out, so worrying about being too far away is a stress
factor.
Reduce that by practicing your off field landing skills at home on
every
landing so you're confident when it happens for real. Sooner or later
that
will happen, even if you're on a "local" flight. I had a friend do
that while
taking his wife on a sightseeing flight! You won't make enemies if
you
exercise good judgment on the day you're caught away from the field
and put it down safely someplace.

-- Matt

[Ramy]

On Aug 24, 1:11*pm, mattm > wrote:

> Reichmann points out that MC 1 is a better setting if you are in
> desparation mode, because you give up only a little glide distance
> but you get to sample more air in a given time.

Are you sure about that? MC=0 will give you more time and more air to
sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
switch to survival mode unless I am also battling significant head
wind.

Ramy

[mattm[_2_]]

On Aug 24, 4:44*pm, Ramy > wrote:
> On Aug 24, 1:11*pm, mattm > wrote:
>
> > Reichmann points out that MC 1 is a better setting if you are in
> > desparation mode, because you give up only a little glide distance
> > but you get to sample more air in a given time.
>
> Are you sure about that? MC=0 will give you more time and more air to
> sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
> switch to survival mode unless I am also battling significant head
> wind.
>
> Ramy

Yes, it's true. It's on the last page of this paper:
http://www.dragonnorth.com/djpresentations/Reichmann%20training_for_cross_country.pdf

"A lot of pilots flew and fly unnecessarily low average
speeds when they get low, because they are anxious
and fly with a zero setting. They don’t know that with a
setting at 1 knot they have almost the same glide angle
and lose much less average speed in case they recover
and complete the task."

In my plane (ASW-19) MC=0 speed is 53kts, and L/D is 38:1.
MC=1 speed is 61kts, and L/D is 35:1. Granted my sink rate
is about 30fpm faster, but I'll have almost 20% greater range to find
that thermal I need to get back up again.

-- Matt

[Andy[_10_]]

On Aug 24, 1:44*pm, Ramy > wrote:
> On Aug 24, 1:11*pm, mattm > wrote:
>
> > Reichmann points out that MC 1 is a better setting if you are in
> > desparation mode, because you give up only a little glide distance
> > but you get to sample more air in a given time.
>
> Are you sure about that? MC=0 will give you more time and more air to
> sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
> switch to survival mode unless I am also battling significant head
> wind.
>
> Ramy

Depends on your objective. If you want to absolutely minimize chance
of landout and are certain you are not going to run out of time before
the lift dies, Mc = 0 is a better bet. If you care about speed around
the course or are worried about the end of useful lift at the end of
the day you should be willing to give up a little search range to gain
speed towards the goal (this presumes you search in direction of the
goal when you get desperate - also important if you are speed or time
constrained)

9B

[Ramy]

On Aug 24, 2:54*pm, mattm > wrote:
> On Aug 24, 4:44*pm, Ramy > wrote:
>
> > On Aug 24, 1:11*pm, mattm > wrote:
>
> > > Reichmann points out that MC 1 is a better setting if you are in
> > > desparation mode, because you give up only a little glide distance
> > > but you get to sample more air in a given time.
>
> > Are you sure about that? MC=0 will give you more time and more air to
> > sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
> > switch to survival mode unless I am also battling significant head
> > wind.
>
> > Ramy
>
> Yes, it's true. *It's on the last page of this paper:http://www.dragonnorth.com/djpresentations/Reichmann%20training_for_c...
>
> "A lot of pilots flew and fly unnecessarily low average
> speeds when they get low, because they are anxious
> and fly with a zero setting. They don’t know that with a
> setting at 1 knot they have almost the same glide angle
> and lose much less average speed in case they recover
> and complete the task."
>
> In my plane (ASW-19) MC=0 speed is 53kts, and L/D is 38:1.
> MC=1 speed is 61kts, and L/D is 35:1. *Granted my sink rate
> is about 30fpm faster, but I'll have almost 20% greater range to find
> that thermal I need to get back up again.
>
> -- Matt

Matt I'm afraid you missunderstood Reichmann comment. He claimed that
you will lose less average speed with MC1 which is true. But you will
not gain 20% greater range. On the contrary, Your search range will
always be less if you fly faster than MC=0 (unless you have
significant head wind which requires flying faster than best L/D).
Bottom line, as other pointed out, it all depends on your goal. If you
are flying contest, in which every second counts, then flying correct
MC is important. If you fly for OLC or distance, like I believe the
majority of XC flights are, and your main objection is to make it back
home at the end of the day (as the subject lline says), than fly MC 0
when you are in survival mode or starting your final glide.

Ramy

[Darryl Ramm]

On Aug 24, 5:06*pm, Ramy > wrote:
> On Aug 24, 2:54*pm, mattm > wrote:
>
>
>
> > On Aug 24, 4:44*pm, Ramy > wrote:
>
> > > On Aug 24, 1:11*pm, mattm > wrote:
>
> > > > Reichmann points out that MC 1 is a better setting if you are in
> > > > desparation mode, because you give up only a little glide distance
> > > > but you get to sample more air in a given time.
>
> > > Are you sure about that? MC=0 will give you more time and more air to
> > > sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
> > > switch to survival mode unless I am also battling significant head
> > > wind.
>
> > > Ramy
>
> > Yes, it's true. *It's on the last page of this paper:http://www.dragonnorth.com/djpresentations/Reichmann%20training_for_c...
>
> > "A lot of pilots flew and fly unnecessarily low average
> > speeds when they get low, because they are anxious
> > and fly with a zero setting. They don’t know that with a
> > setting at 1 knot they have almost the same glide angle
> > and lose much less average speed in case they recover
> > and complete the task."
>
> > In my plane (ASW-19) MC=0 speed is 53kts, and L/D is 38:1.
> > MC=1 speed is 61kts, and L/D is 35:1. *Granted my sink rate
> > is about 30fpm faster, but I'll have almost 20% greater range to find
> > that thermal I need to get back up again.
>
> > -- Matt
>
> Matt I'm afraid you missunderstood Reichmann comment. He claimed that
> you will lose less average speed with MC1 which is true. But you will
> not gain 20% greater range. On the contrary, Your search range will
> always be less if you fly faster than MC=0 (unless you have
> significant head wind which requires flying faster than best L/D).
> Bottom line, as other pointed out, it all depends on your goal. If you
> are flying contest, in which every second counts, then flying correct
> MC is important. If you fly for OLC or distance, like I believe the
> majority of XC flights are, and your main objection is to make it back
> home at the end of the day (as the subject lline says), than fly *MC 0
> when you are in survival mode or starting your final glide.
>
> Ramy

But, but, but, (and I think I can hear John Cochrane pounding his head
on his desk in Chicago...) when about to go on final glide and you are
in that last thermal you know what the theoretical final glide Mc
should be. And by all means factor in safety margins but if you have a
climb significantly over your Mc="0" value then keep climbing and bump
the Mc appropriately to match that climb. I mean why not? I know
sometimes pilots like to float past the home airport and stretch a few
more OLC miles then turn back. Personally the call of that cold beer
makes me want to fly that final glide as fast as possible.

What is really annoying about arguing with Ramy on this point (which I
think I've done before) is no matter what I can argue on paper I have
no hope of keeping up with him in practice.

Sigh

Darryl

[Andreas Maurer]

On Tue, 24 Aug 2010 17:06:17 -0700 (PDT), Ramy >
wrote:

>Matt I'm afraid you missunderstood Reichmann comment. He claimed that
>you will lose less average speed with MC1 which is true. But you will
>not gain 20% greater range. On the contrary, Your search range will
>always be less if you fly faster than MC=0 (unless you have
>significant head wind which requires flying faster than best L/D).

What Matt wanted to say (and what Reichmann said) is that the loss of
L/D is negligible if you fly MC1 (compared to MC0), therefore your
chances to catch a thermal are hardly affected, but IF you catch a
thermal, you will have lost lots of time if you flew MC0 instead of
MC1.



>Bottom line, as other pointed out, it all depends on your goal. If you
>are flying contest, in which every second counts, then flying correct
>MC is important. If you fly for OLC or distance, like I believe the
>majority of XC flights are, and your main objection is to make it back
>home at the end of the day (as the subject lline says), than fly MC 0
>when you are in survival mode or starting your final glide.

In one word:
No. :)
Even on a normal XC flight average speed counts - you want to be back
before the thermals die.

There's one basic rule in XC flying:
Use MC0 only if you are very, very, very desperate.
For me this starts at 1000 ft above the ground with no thermal in
sight.


Cheers
Andreas

[Andreas Maurer]

On Tue, 24 Aug 2010 12:44:22 -0700 (PDT), Ramy >
wrote:


>Nope. We both are going to leave the thermal at the same time and
>glide at the same speed.

Not at all.
You leave the thermal at a height that is dictated by a relatively
crude estimation of your glider's performance.
I leave the thermal at an altitude that is the optimum for a given
climb rate, wind vector and glider performance.

Guess what's more effective. :)


>However you will need to ignore the speed to fly as John suggested
>unless you are willing to risk landout to save couple of minutes
>(which may make sense only in contest).

Not at all.
Flying my STF will always get me to the airfield as long as there is
no significant air mass sink. It's as safe as your proposed MC0
approach in any way. Usually even safer because an MC2 or higher
setting for the final approach usually dictates a higher climb in the
last thermal and higher STF than your MC0, resulting in more energy
reserves. And yet it's faster, too.


>Using the last average climb in the thermal is often meaningless in my
>opinion.
>So using the method of dialing MC = last average
>climb and then follow STF is guaranty landout, and a very silly one...

Nope.. it's not. These rules have been proven over and over again, and
with a little experience in XC gliding (say, ten years), you'll find
that these rules really work as advertized. :)


>So my recomendation to all non contest XC pilots will be to degrade
>your performance using bug factor 70-75%, which will give you enough
>buffer for unexpected sink or head wind (which can also be very
>different from the wind measured in your last turn) and fly MC=0 until
>you are comfrtable with your arrival altitude and then speed up if
>your arrival altitude start increasing. This will usually result in
>slower glide speed at the beginning of the final glide, gradually
>increasing as you get closer, much safer than the other way around.

Well... safety-wise both methods are identical.
How do you fly on a long XC flight? Which MC do you use?


Cheers
Andreas

[akiley]

On Aug 24, 12:08*am, Eric Greenwell > wrote:
> On 8/23/2010 8:17 AM, akiley wrote:> Well, I've flown long enough to know not to trust electronics. *I have
> > 600 power hours using all sorts of navigators. *Funny, when you use a
> > Garmin 396 on a computer, it sets magnetic variation to user set
> > instead of auto. *SeeYou has quite a few bugs and gochas too. *So my
> > primary is look at the down angle back to the airport.
>
> I've used SeeYou Mobile for 1000+ hours all over the USA, and I'm not
> aware of any bugs or gotchas. I would never go back to paper charts,
> whiz wheels, or just looking out the window. For example, most of my
> final glides begin 30 to 50 miles from the airport, where I can't even
> see it, yet they work out well most of the time.
Eric,
What happens if your electronics fry? Hope you have a backup
something. Just happened to a friend of mine, he found a 5 year old
WAC chart under his seat. I'm not going back to paper charts either,
I'm just saying for me, I'm going to back it up with something, even
if it's a quick math in the head thing. There are plenty of gochas I
can think of is SeeYouM. All you have to do is not double check what
your goto waypoint is, forget to add winds, polar, safety altitude.
Maybe they aren't gochas, but they sort of are for new users. It
takes a lot of thinking to make sure you know what you are doing.

I have the latest version of SeeYouM that I bought last fall. One
known bug is that the wing loading changes when you leave the polar
screen then come back. Try it. I think they fixed the one with Oudie
that didn't allow the user to set NM in units. You would have to
reset it every time you loaded SeeYouM. I haven't gotten an answer on
my Magnetic Track NavBox yet. It's off by 12 degrees. Maybe it's
party to do with old PDA hardware but I've had a lot of problems with
logging not starting, and NavBoxes showing no data, and lockups.
Other have had these problem too. Some days my statistic page that is
supposed to show thermal graphs doesn't.

I'm slowly replacing components of my iPaq to see if that's the
problem. I just replaced the CF card adapter back, I've tried a
different CF card. We'll see.

I'm definitely a navigator user. I have a Garmin 395, I've put quite
a lot of hours on Garmin G1000's in IFR flight. My point is one has
to be careful throwing full trust into these things. My SeeYou
experience has had a bad start, but I'll get it nailed down
eventually. I really enjoy analyzing my IGC file on my PC after the
day is done. In playback mode on the iPaq too, that is a learning
experience too. ... akiley
>
> Your statement "So my primary is look at the down angle back to the
> airport" suggests to me it's not SeeYou, but more likely your setup or
> interpretation of what Mobile is telling you. If you are that close, the
> computer should be working with no problems.
>
> Flight computers can be a real aid to efficient, enjoyable soaring, so I
> hate to see someone having problems with them. What version of mobile
> are you using? Can you describe the two biggest bugs and gotchas?
>
> --
> Eric Greenwell - Washington State, USA (netto to net to email me)
>
> - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarmhttp://tinyurl.com/yb3xywl
>
> - "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

[Ramy]

On Aug 24, 5:16*pm, Darryl Ramm > wrote:
> On Aug 24, 5:06*pm, Ramy > wrote:
>
>
>
>
>
> > On Aug 24, 2:54*pm, mattm > wrote:
>
> > > On Aug 24, 4:44*pm, Ramy > wrote:
>
> > > > On Aug 24, 1:11*pm, mattm > wrote:
>
> > > > > Reichmann points out that MC 1 is a better setting if you are in
> > > > > desparation mode, because you give up only a little glide distance
> > > > > but you get to sample more air in a given time.
>
> > > > Are you sure about that? MC=0 will give you more time and more air to
> > > > sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
> > > > switch to survival mode unless I am also battling significant head
> > > > wind.
>
> > > > Ramy
>
> > > Yes, it's true. *It's on the last page of this paper:http://www.dragonnorth.com/djpresentations/Reichmann%20training_for_c...
>
> > > "A lot of pilots flew and fly unnecessarily low average
> > > speeds when they get low, because they are anxious
> > > and fly with a zero setting. They don’t know that with a
> > > setting at 1 knot they have almost the same glide angle
> > > and lose much less average speed in case they recover
> > > and complete the task."
>
> > > In my plane (ASW-19) MC=0 speed is 53kts, and L/D is 38:1.
> > > MC=1 speed is 61kts, and L/D is 35:1. *Granted my sink rate
> > > is about 30fpm faster, but I'll have almost 20% greater range to find
> > > that thermal I need to get back up again.
>
> > > -- Matt
>
> > Matt I'm afraid you missunderstood Reichmann comment. He claimed that
> > you will lose less average speed with MC1 which is true. But you will
> > not gain 20% greater range. On the contrary, Your search range will
> > always be less if you fly faster than MC=0 (unless you have
> > significant head wind which requires flying faster than best L/D).
> > Bottom line, as other pointed out, it all depends on your goal. If you
> > are flying contest, in which every second counts, then flying correct
> > MC is important. If you fly for OLC or distance, like I believe the
> > majority of XC flights are, and your main objection is to make it back
> > home at the end of the day (as the subject lline says), than fly *MC 0
> > when you are in survival mode or starting your final glide.
>
> > Ramy
>
> But, but, but, (and I think I can hear John Cochrane pounding his head
> on his desk in Chicago...) when about to go on final glide and you are
> in that last thermal you know what the theoretical final glide Mc
> should be. And by all means factor in safety margins but if you have a
> climb significantly over your Mc="0" value then keep climbing and bump
> the Mc appropriately to match that climb. I mean why not? I know
> sometimes pilots like to float past the home airport and stretch a few
> more OLC miles then turn back. Personally the call of that cold beer
> makes me want to fly that final glide as fast as possible.
>
> What is really annoying about arguing with Ramy on this point (which I
> think I've done before) is no matter what I can argue on paper I have
> no hope of keeping up with him in practice.
>
> Sigh
>
> Darryl- Hide quoted text -
>
> - Show quoted text -

Funny, I guess I can fly better than I can explain myself :-)
All I am trying to say about the final glide is that if you are not
competing (or competing against the sun as in my case sometimes) the
exact speed you fly on your final glide wouldn't matter much. And
instead of dialing MC according to your last climb to determine when
to leave the thermal and then ignore this MC on your glide if you want
to ensure you get back home even with no lift, just degrade your polar
instead, climb as high as you feel comfortable, then fly as fast as
you can without loosing glide. Simple. Of course while on course and
high crank up the MC as high as you dare, just make sure you stay in
the desired lift band.
But honestly, I don't understand how many of you fly XC safely if you
don't degrade your polar. How do you determine you are within safe
glide from airports at any point in time? using your published polar
and a safety altitude margin? Good luck if you hit any sink or head
wind on the way unless you use a big altitude margin which will
significantly hurt your decision down lower. The suggestion to use bug
factor to degrade your polar is basically an implementation of the
common rule of thumb to use 50%-75% of your published polar to
determine arrival altitude.

Ramy

[Darryl Ramm]

On Aug 24, 9:32*pm, Ramy > wrote:
> On Aug 24, 5:16*pm, Darryl Ramm > wrote:
>
>
>
> > On Aug 24, 5:06*pm, Ramy > wrote:
>
> > > On Aug 24, 2:54*pm, mattm > wrote:
>
> > > > On Aug 24, 4:44*pm, Ramy > wrote:
>
> > > > > On Aug 24, 1:11*pm, mattm > wrote:
>
> > > > > > Reichmann points out that MC 1 is a better setting if you are in
> > > > > > desparation mode, because you give up only a little glide distance
> > > > > > but you get to sample more air in a given time.
>
> > > > > Are you sure about that? MC=0 will give you more time and more air to
> > > > > sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
> > > > > switch to survival mode unless I am also battling significant head
> > > > > wind.
>
> > > > > Ramy
>
> > > > Yes, it's true. *It's on the last page of this paper:http://www.dragonnorth.com/djpresentations/Reichmann%20training_for_c...
>
> > > > "A lot of pilots flew and fly unnecessarily low average
> > > > speeds when they get low, because they are anxious
> > > > and fly with a zero setting. They don’t know that with a
> > > > setting at 1 knot they have almost the same glide angle
> > > > and lose much less average speed in case they recover
> > > > and complete the task."
>
> > > > In my plane (ASW-19) MC=0 speed is 53kts, and L/D is 38:1.
> > > > MC=1 speed is 61kts, and L/D is 35:1. *Granted my sink rate
> > > > is about 30fpm faster, but I'll have almost 20% greater range to find
> > > > that thermal I need to get back up again.
>
> > > > -- Matt
>
> > > Matt I'm afraid you missunderstood Reichmann comment. He claimed that
> > > you will lose less average speed with MC1 which is true. But you will
> > > not gain 20% greater range. On the contrary, Your search range will
> > > always be less if you fly faster than MC=0 (unless you have
> > > significant head wind which requires flying faster than best L/D).
> > > Bottom line, as other pointed out, it all depends on your goal. If you
> > > are flying contest, in which every second counts, then flying correct
> > > MC is important. If you fly for OLC or distance, like I believe the
> > > majority of XC flights are, and your main objection is to make it back
> > > home at the end of the day (as the subject lline says), than fly *MC 0
> > > when you are in survival mode or starting your final glide.
>
> > > Ramy
>
> > But, but, but, (and I think I can hear John Cochrane pounding his head
> > on his desk in Chicago...) when about to go on final glide and you are
> > in that last thermal you know what the theoretical final glide Mc
> > should be. And by all means factor in safety margins but if you have a
> > climb significantly over your Mc="0" value then keep climbing and bump
> > the Mc appropriately to match that climb. I mean why not? I know
> > sometimes pilots like to float past the home airport and stretch a few
> > more OLC miles then turn back. Personally the call of that cold beer
> > makes me want to fly that final glide as fast as possible.
>
> > What is really annoying about arguing with Ramy on this point (which I
> > think I've done before) is no matter what I can argue on paper I have
> > no hope of keeping up with him in practice.
>
> > Sigh
>
> > Darryl- Hide quoted text -
>
> > - Show quoted text -
>
> Funny, I guess I can fly better than I can explain myself :-)
> All I am trying to say about the final glide is that if you are not
> competing (or competing against the sun as in my case sometimes) the
> exact speed you fly on your final glide wouldn't matter much. And
> instead of dialing MC according to your last climb to determine when
> to leave the thermal and then ignore this MC on your glide if you want
> to ensure you get back home even with no lift, just degrade your polar
> instead, climb as high as you feel comfortable, then fly as fast as
> you can without loosing glide. Simple. Of course while on course and
> high crank up the MC as high as you dare, just make sure you stay in
> the desired lift band.
> But honestly, I don't understand how many of you fly XC safely if you
> don't degrade your polar. How do you determine you are within safe
> glide from airports at any point in time? using your published polar
> and a safety altitude margin? Good luck if you hit any sink or head
> wind on the way unless you use a big altitude margin which will
> significantly hurt your decision down lower. The suggestion to use bug
> factor to degrade your polar is basically an implementation of the
> common rule of thumb to use 50%-75% of your published polar to
> determine arrival altitude.
>
> Ramy

Now you are going to start another argument. Oh well, here goes... I
degrade my ASH-26E book polar by 5% bugs if the wings are clean, just
want to take the edge off and it seems to match pretty close to what I
can get. I want the computer to tell me what I can really do and I'll
factor safety margins (including using arrival height padding, Mc
etc.) depending on how I assess the risk. And that is not just because
I flying a motorglider, I'll use similar low bugs when flying the Duo
etc.

I payed all that money for that 50:1 L/D -- I'm not going to just
throw it away :-)

(yes for new XC pilots, padding with bugs is entirely different).

Darryl

[Mike[_8_]]

On Aug 24, 10:32*pm, Ramy > wrote:
> On Aug 24, 5:16*pm, Darryl Ramm > wrote:
>
>
>
> > On Aug 24, 5:06*pm, Ramy > wrote:
>
> > > On Aug 24, 2:54*pm, mattm > wrote:
>
> > > > On Aug 24, 4:44*pm, Ramy > wrote:
>
> > > > > On Aug 24, 1:11*pm, mattm > wrote:
>
> > > > > > Reichmann points out that MC 1 is a better setting if you are in
> > > > > > desparation mode, because you give up only a little glide distance
> > > > > > but you get to sample more air in a given time.
>
> > > > > Are you sure about that? MC=0 will give you more time and more air to
> > > > > sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
> > > > > switch to survival mode unless I am also battling significant head
> > > > > wind.
>
> > > > > Ramy
>
> > > > Yes, it's true. *It's on the last page of this paper:http://www.dragonnorth.com/djpresentations/Reichmann%20training_for_c...
>
> > > > "A lot of pilots flew and fly unnecessarily low average
> > > > speeds when they get low, because they are anxious
> > > > and fly with a zero setting. They don’t know that with a
> > > > setting at 1 knot they have almost the same glide angle
> > > > and lose much less average speed in case they recover
> > > > and complete the task."
>
> > > > In my plane (ASW-19) MC=0 speed is 53kts, and L/D is 38:1.
> > > > MC=1 speed is 61kts, and L/D is 35:1. *Granted my sink rate
> > > > is about 30fpm faster, but I'll have almost 20% greater range to find
> > > > that thermal I need to get back up again.
>
> > > > -- Matt
>
> > > Matt I'm afraid you missunderstood Reichmann comment. He claimed that
> > > you will lose less average speed with MC1 which is true. But you will
> > > not gain 20% greater range. On the contrary, Your search range will
> > > always be less if you fly faster than MC=0 (unless you have
> > > significant head wind which requires flying faster than best L/D).
> > > Bottom line, as other pointed out, it all depends on your goal. If you
> > > are flying contest, in which every second counts, then flying correct
> > > MC is important. If you fly for OLC or distance, like I believe the
> > > majority of XC flights are, and your main objection is to make it back
> > > home at the end of the day (as the subject lline says), than fly *MC 0
> > > when you are in survival mode or starting your final glide.
>
> > > Ramy
>
> > But, but, but, (and I think I can hear John Cochrane pounding his head
> > on his desk in Chicago...) when about to go on final glide and you are
> > in that last thermal you know what the theoretical final glide Mc
> > should be. And by all means factor in safety margins but if you have a
> > climb significantly over your Mc="0" value then keep climbing and bump
> > the Mc appropriately to match that climb. I mean why not? I know
> > sometimes pilots like to float past the home airport and stretch a few
> > more OLC miles then turn back. Personally the call of that cold beer
> > makes me want to fly that final glide as fast as possible.
>
> > What is really annoying about arguing with Ramy on this point (which I
> > think I've done before) is no matter what I can argue on paper I have
> > no hope of keeping up with him in practice.
>
> > Sigh
>
> > Darryl- Hide quoted text -
>
> > - Show quoted text -
>
> Funny, I guess I can fly better than I can explain myself :-)
> All I am trying to say about the final glide is that if you are not
> competing (or competing against the sun as in my case sometimes) the
> exact speed you fly on your final glide wouldn't matter much. And
> instead of dialing MC according to your last climb to determine when
> to leave the thermal and then ignore this MC on your glide if you want
> to ensure you get back home even with no lift, just degrade your polar
> instead, climb as high as you feel comfortable, then fly as fast as
> you can without loosing glide. Simple. Of course while on course and
> high crank up the MC as high as you dare, just make sure you stay in
> the desired lift band.
> But honestly, I don't understand how many of you fly XC safely if you
> don't degrade your polar. How do you determine you are within safe
> glide from airports at any point in time? using your published polar
> and a safety altitude margin? Good luck if you hit any sink or head
> wind on the way unless you use a big altitude margin which will
> significantly hurt your decision down lower. The suggestion to use bug
> factor to degrade your polar is basically an implementation of the
> common rule of thumb to use 50%-75% of your published polar to
> determine arrival altitude.
>
> Ramy

Within safe glide to an airport at any one time?

What a concept!

[Andy[_10_]]

On Aug 24, 9:32*pm, Ramy > wrote:
> On Aug 24, 5:16*pm, Darryl Ramm > wrote:
>
>
>
>
>
> > On Aug 24, 5:06*pm, Ramy > wrote:
>
> > > On Aug 24, 2:54*pm, mattm > wrote:
>
> > > > On Aug 24, 4:44*pm, Ramy > wrote:
>
> > > > > On Aug 24, 1:11*pm, mattm > wrote:
>
> > > > > > Reichmann points out that MC 1 is a better setting if you are in
> > > > > > desparation mode, because you give up only a little glide distance
> > > > > > but you get to sample more air in a given time.
>
> > > > > Are you sure about that? MC=0 will give you more time and more air to
> > > > > sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
> > > > > switch to survival mode unless I am also battling significant head
> > > > > wind.
>
> > > > > Ramy
>
> > > > Yes, it's true. *It's on the last page of this paper:http://www.dragonnorth.com/djpresentations/Reichmann%20training_for_c...
>
> > > > "A lot of pilots flew and fly unnecessarily low average
> > > > speeds when they get low, because they are anxious
> > > > and fly with a zero setting. They don’t know that with a
> > > > setting at 1 knot they have almost the same glide angle
> > > > and lose much less average speed in case they recover
> > > > and complete the task."
>
> > > > In my plane (ASW-19) MC=0 speed is 53kts, and L/D is 38:1.
> > > > MC=1 speed is 61kts, and L/D is 35:1. *Granted my sink rate
> > > > is about 30fpm faster, but I'll have almost 20% greater range to find
> > > > that thermal I need to get back up again.
>
> > > > -- Matt
>
> > > Matt I'm afraid you missunderstood Reichmann comment. He claimed that
> > > you will lose less average speed with MC1 which is true. But you will
> > > not gain 20% greater range. On the contrary, Your search range will
> > > always be less if you fly faster than MC=0 (unless you have
> > > significant head wind which requires flying faster than best L/D).
> > > Bottom line, as other pointed out, it all depends on your goal. If you
> > > are flying contest, in which every second counts, then flying correct
> > > MC is important. If you fly for OLC or distance, like I believe the
> > > majority of XC flights are, and your main objection is to make it back
> > > home at the end of the day (as the subject lline says), than fly *MC 0
> > > when you are in survival mode or starting your final glide.
>
> > > Ramy
>
> > But, but, but, (and I think I can hear John Cochrane pounding his head
> > on his desk in Chicago...) when about to go on final glide and you are
> > in that last thermal you know what the theoretical final glide Mc
> > should be. And by all means factor in safety margins but if you have a
> > climb significantly over your Mc="0" value then keep climbing and bump
> > the Mc appropriately to match that climb. I mean why not? I know
> > sometimes pilots like to float past the home airport and stretch a few
> > more OLC miles then turn back. Personally the call of that cold beer
> > makes me want to fly that final glide as fast as possible.
>
> > What is really annoying about arguing with Ramy on this point (which I
> > think I've done before) is no matter what I can argue on paper I have
> > no hope of keeping up with him in practice.
>
> > Sigh
>
> > Darryl- Hide quoted text -
>
> > - Show quoted text -
>
> Funny, I guess I can fly better than I can explain myself :-)
> All I am trying to say about the final glide is that if you are not
> competing (or competing against the sun as in my case sometimes) the
> exact speed you fly on your final glide wouldn't matter much. And
> instead of dialing MC according to your last climb to determine when
> to leave the thermal and then ignore this MC on your glide if you want
> to ensure you get back home even with no lift, just degrade your polar
> instead, climb as high as you feel comfortable, then fly as fast as
> you can without loosing glide. Simple. Of course while on course and
> high crank up the MC as high as you dare, just make sure you stay in
> the desired lift band.
> But honestly, I don't understand how many of you fly XC safely if you
> don't degrade your polar. How do you determine you are within safe
> glide from airports at any point in time? using your published polar
> and a safety altitude margin? Good luck if you hit any sink or head
> wind on the way unless you use a big altitude margin which will
> significantly hurt your decision down lower. The suggestion to use bug
> factor to degrade your polar is basically an implementation of the
> common rule of thumb to use 50%-75% of your published polar to
> determine arrival altitude.
>
> Ramy

Hi Ramy,

I know you are an OLC stud. Nevertheless I will take a crack at
spanning the gap between you and Mr. Cochrane - who is a competition
strategy stud.

There are two potential objectives in calculating how to look for and
manage the last climb leading to final glide: 1) maximize the
probability of getting home when time is not a factor, and 2)
maximizing expected speed (and hence expected contest points) adjusted
for probability of landing out. In the first case, if you are low and
desperate you pull back to best L/D and fly in the direction of the
most likely lift, even if it means backtracking on course. In the
second case you are trading off your best estimate of probability of
landing out against speed, with the tradeoff in contests dictated by
the ratio of speed points to distance points. Reichmann's point here
is quite relevant - a 1.0 McCready keeps up progress toward the goal
and dilutes your total speed less quickly than Mc = 0, which trades
landout probability for speed at a suboptimal rate - that is, you gain
expected finish points less quickly than you lose speed points - all
probability adjusted. The stronger the lift the more you want to fly a
little faster while searching to make sure that you don't give up
speed points.

As to the final glide itself (and I understand the unique issues
associated with returning to an elevated airport like Truckee, where
you need to set up the final glide quite far out with little chance to
recover if you miss low). The basic issue here is how to balance the
glide margin - how much should be based on glide angle margin and how
much should be based on finish height margin? There are two potential
estimation errors you need to deal with: 1) error associated with mis-
estimating the actual glide angle you can achieve at any given glide
speed and 2) errors associated with short-term losses in altitude from
sink enroute. Ideally you can account for 1) by managing your glide
speed to make sure your achieved glide angle is shallower than needed.
You can do this in one of two ways. First you can artificially steepen
up the glide angle at any given speed through manipulating the polar,
or you can set the Mc for higher than the speed you actually fly (or
some combination of the two). The basic objective under both
approaches is to ensure you gain a bit on the glide rather than losing
a bit. The problem with using bugs and flying with a zero Mc is that
you fly too slow to optimize speed and you tend to leave strong final
thermals too soon.

As to issue 2), the issue to keep in mind is the risk of hitting a
line of sink and losing your glide. As John points out, this risk
goes up as you get closer to home because you get progressively lower
and have a declining chance of being able to find a saving climb after
a sink street. This is why the better strategy when there is a lot of
uncertainty about lift/sink on the way home is to add finish altitude
rather than steepen the glide - steepening the glide give you a margin
that decrements to zero feet as you approach the finish whereas
altitude margin doesn't. This says that you are better off adding
finish height than steepening the glide angle as a glide angle margin
goes away as you get closer to home. It also argues for leaving the
final thermal at with a Mc setting that is a bit higher than you
actual climb rate, then setting speed-to-fly a bit slower so yo gain
on the glide going home.

I will observe that in my experience the first glider to leave the
thermal gets home first. I have left thermals before getting to the
the height indicated by the Mc setting and won by a couple of minutes
and have stuck with 10-knot thermals only to be unable to catch
gliders leaving before me. It has never worked any other way. This
must mean that either pilots are able to "bump up' the final glide on
the way home, or that final thermal isn't as strong as I think. In
either case it means I generally stay with my final climb too long.

9B

Hope that helps,

9B

[David[_13_]]

On Aug 24, 9:32*pm, Ramy > wrote:
> On Aug 24, 5:16*pm, Darryl Ramm > wrote:
>
>
>
>
>
> > On Aug 24, 5:06*pm, Ramy > wrote:
>
> > > On Aug 24, 2:54*pm, mattm > wrote:
>
> > > > On Aug 24, 4:44*pm, Ramy > wrote:
>
> > > > > On Aug 24, 1:11*pm, mattm > wrote:
>
> > > > > > Reichmann points out that MC 1 is a better setting if you are in
> > > > > > desparation mode, because you give up only a little glide distance
> > > > > > but you get to sample more air in a given time.
>
> > > > > Are you sure about that? MC=0 will give you more time and more air to
> > > > > sample (beeing the best L/D speed) than MC=1. I always use MC=0 when I
> > > > > switch to survival mode unless I am also battling significant head
> > > > > wind.
>
> > > > > Ramy
>
> > > > Yes, it's true. *It's on the last page of this paper:http://www.dragonnorth.com/djpresentations/Reichmann%20training_for_c...
>
> > > > "A lot of pilots flew and fly unnecessarily low average
> > > > speeds when they get low, because they are anxious
> > > > and fly with a zero setting. They don’t know that with a
> > > > setting at 1 knot they have almost the same glide angle
> > > > and lose much less average speed in case they recover
> > > > and complete the task."
>
> > > > In my plane (ASW-19) MC=0 speed is 53kts, and L/D is 38:1.
> > > > MC=1 speed is 61kts, and L/D is 35:1. *Granted my sink rate
> > > > is about 30fpm faster, but I'll have almost 20% greater range to find
> > > > that thermal I need to get back up again.
>
> > > > -- Matt
>
> > > Matt I'm afraid you missunderstood Reichmann comment. He claimed that
> > > you will lose less average speed with MC1 which is true. But you will
> > > not gain 20% greater range. On the contrary, Your search range will
> > > always be less if you fly faster than MC=0 (unless you have
> > > significant head wind which requires flying faster than best L/D).
> > > Bottom line, as other pointed out, it all depends on your goal. If you
> > > are flying contest, in which every second counts, then flying correct
> > > MC is important. If you fly for OLC or distance, like I believe the
> > > majority of XC flights are, and your main objection is to make it back
> > > home at the end of the day (as the subject lline says), than fly *MC 0
> > > when you are in survival mode or starting your final glide.
>
> > > Ramy
>
> > But, but, but, (and I think I can hear John Cochrane pounding his head
> > on his desk in Chicago...) when about to go on final glide and you are
> > in that last thermal you know what the theoretical final glide Mc
> > should be. And by all means factor in safety margins but if you have a
> > climb significantly over your Mc="0" value then keep climbing and bump
> > the Mc appropriately to match that climb. I mean why not? I know
> > sometimes pilots like to float past the home airport and stretch a few
> > more OLC miles then turn back. Personally the call of that cold beer
> > makes me want to fly that final glide as fast as possible.
>
> > What is really annoying about arguing with Ramy on this point (which I
> > think I've done before) is no matter what I can argue on paper I have
> > no hope of keeping up with him in practice.
>
> > Sigh
>
> > Darryl- Hide quoted text -
>
> > - Show quoted text -
>
> Funny, I guess I can fly better than I can explain myself :-)
> All I am trying to say about the final glide is that if you are not
> competing (or competing against the sun as in my case sometimes) the
> exact speed you fly on your final glide wouldn't matter much. And
> instead of dialing MC according to your last climb to determine when
> to leave the thermal and then ignore this MC on your glide if you want
> to ensure you get back home even with no lift, just degrade your polar
> instead, climb as high as you feel comfortable, then fly as fast as
> you can without loosing glide. Simple. Of course while on course and
> high crank up the MC as high as you dare, just make sure you stay in
> the desired lift band.
> But honestly, I don't understand how many of you fly XC safely if you
> don't degrade your polar. How do you determine you are within safe
> glide from airports at any point in time? using your published polar
> and a safety altitude margin? Good luck if you hit any sink or head
> wind on the way unless you use a big altitude margin which will
> significantly hurt your decision down lower. The suggestion to use bug
> factor to degrade your polar is basically an implementation of the
> common rule of thumb to use 50%-75% of your published polar to
> determine arrival altitude.
>
> Ramy

Ramy et al,

Part of the different views in this discussion is the different kinds
of final
glides people are talking about.

For example, in Ramy's case (and mine as well), a typical "final
glide" means:
it is is around 6:30 pm or even later, lift is dying, you are 40 to 50
nautical
miles away from home, you are in the last obvious lift which could be
very well
be a 5 knot thermal, but still the last one. A westerly wind is
pushing everything
east, the nature of the airmass ahead is unknown with a potential
strong headwind
component (funny how winds play havoc on the PDA's estimate of your
situation
when you are 40~50 miles from home).

And to make things even more interesting, "home" means you also need
to cross
Lake Tahoe to get there.

Under this situation it is not unusual to climb to the top of the
thermal or even
bump up against class A airspace, and you barely have it at MC 0. The
bug factor
Ramy talks about is to account for the significant uncertainty in the
airmass/wind
on the 40 nm leg (which can easily span a couple of airmasses).

Waiting for an MC 5 altitude under those conditions, not going to
happen.

David

[Eric Greenwell]

On 8/24/2010 7:53 PM, akiley wrote:
> On Aug 24, 12:08 am, Eric > wrote:
>
>>
>> I've used SeeYou Mobile for 1000+ hours all over the USA, and I'm not
>> aware of any bugs or gotchas. I would never go back to paper charts,
>> whiz wheels, or just looking out the window. For example, most of my
>> final glides begin 30 to 50 miles from the airport, where I can't even
>> see it, yet they work out well most of the time.
>>
> Eric,
> What happens if your electronics fry? Hope you have a backup
> something.
I've used 4 PDAs over 10 years, 2000 hours total, with no failures, so I
haven't had to pull out the charts and ruler I always carry with me
(mostly out of habit). But, a PDA going bad isn't a SeeYou Mobile problem.
> There are plenty of gochas I
> can think of is SeeYouM. All you have to do is not double check what
> your goto waypoint is, forget to add winds, polar, safety altitude.
> Maybe they aren't gochas, but they sort of are for new users.
These aren't SeeYou Mobile gotchas either, they are part of using a
"soaring computer", whether it's a map with circles, paper sheets with
tables of glide distances, or an electronic computer.

The polar and safety altitude (I assume you mean the "arrival altitude",
are settings you should do at home; i.e. "set and forget".

I'm not sure what you mean by "add winds", as SYM automatically uses the
winds in it's computations. Perhaps you mean "adjusting the winds"?
Sometimes you have to do that when you realize the winds ahead of you
are different from the winds SYM has calculated.
> It
> takes a lot of thinking to make sure you know what you are doing.
>
Yep, the cockpit is a busy place in a glider if you are going
cross-country, and it takes a while to get accustomed to a flight
computer. I had the advantage of 20 years of soaring before using PDA
flight computers, so the transition was much easier for me.
> I have the latest version of SeeYouM that I bought last fall. One
> known bug is that the wing loading changes when you leave the polar
> screen then come back. Try it.
It doesn't change on my setup (Ipaq 3835 with ver 3.11). Maybe it's a
3.12 issue.
> I think they fixed the one with Oudie
> that didn't allow the user to set NM in units. You would have to
> reset it every time you loaded SeeYouM. I haven't gotten an answer on
> my Magnetic Track NavBox yet. It's off by 12 degrees.
I have to admit I've never used any kind of track bearing. I just put
the two different track bearing boxes on my PDA (simulator mode), and
they both read correctly (Washington state area); however, I get the
same error you do when I try to "fly" in Michigan.
> Maybe it's
> party to do with old PDA hardware but I've had a lot of problems with
> logging not starting, and NavBoxes showing no data, and lockups.
> Other have had these problem too. Some days my statistic page that is
> supposed to show thermal graphs doesn't.
>
There is a quirk in the older Ipaqs that can cause symptoms like this.
The fix is to disable the IR port, which is sensitive to sunlight, and
slows down the system. Make sure the beam is off on your Ipaq. Do
something like this: Start, Settings, Connections, Beam, uncheck box.

It also might be your hardware, as I've had none of those problems on my
fairly old 3835. What PDA are you using? Do you have GPS problems (you
might be able to determine that by looking at the flight trace in
SeeYou)? What GPS do you use?
> I'm slowly replacing components of my iPaq to see if that's the
> problem. I just replaced the CF card adapter back, I've tried a
> different CF card. We'll see.
>
> I'm definitely a navigator user. I have a Garmin 395, I've put quite
> a lot of hours on Garmin G1000's in IFR flight. My point is one has
> to be careful throwing full trust into these things.
Agreed. Start out conservatively, get comfortable with it, and then you
can reduce the margins bit by bit to make cross-country flying easier
and more enjoyable.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

[Eric Greenwell]

On 8/24/2010 9:32 PM, Ramy wrote:
> On Aug 24, 5:16 pm, Darryl R
> But honestly, I don't understand how many of you fly XC safely if you
> don't degrade your polar. How do you determine you are within safe
> glide from airports at any point in time? using your published polar
> and a safety altitude margin? Good luck if you hit any sink or head
> wind on the way unless you use a big altitude margin which will
> significantly hurt your decision down lower. The suggestion to use bug
> factor to degrade your polar is basically an implementation of the
> common rule of thumb to use 50%-75% of your published polar to
> determine arrival altitude.
>

Point #1: I think what you are doing is essentially the same as keeping
the bugs at "no bugs", but using a high MC setting to figure the "safety
glide". A high MC means a steep glide angle compared to 0 MC - there's
the "degradation" in the polar you are wondering about. I normally use a
4 MC for my "safety glide" computation, which gives an L/D of 70% of my
max L/D.

Point #2: In addition to the 4 MC setting, I usually carry excess
altitude above the 4 MC glide slope to absorb strong sink and
unexpectedly strong headwinds. Over friendly ground in moderate
conditions, 500' excess has proven adequate; in strong conditions over
unfriendly ground, it might be as much as 2000' excess. These numbers
are trimmed as the distance to the airport decreases, starting about
10-20 miles out, because my 1000' AGL arrival height begins to provide
the "sink absorption" buffer.

Of course, I don't use the 4 MC setting as my speed to fly if I have to
head towards my safety airport; instead, I use a 1 MC setting (or zero
MC if I'm truly desperate). My MC setting for the "safety glide" is
separate from my "speed to fly" setting on my Cambridge 302, which is
usually set at 1 (moderate conditions) or 2 (strong conditions).

The above MC and excess altitude settings have proved satisfactory for
all my gliders, from a Ka-6e to an ASH 26 E. Of course, the speeds flown
were quite different for each glider.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

[Andy[_10_]]

On Aug 25, 2:41*pm, Eric Greenwell > wrote:
> On 8/24/2010 9:32 PM, Ramy wrote:
>
> > On Aug 24, 5:16 pm, Darryl R
> > But honestly, I don't understand how many of you fly XC safely if you
> > don't degrade your polar. How do you determine you are within safe
> > glide from airports at any point in time? using your published polar
> > and a safety altitude margin? Good luck if you hit any sink or head
> > wind on the way unless you use a big altitude margin which will
> > significantly hurt your decision down lower. The suggestion to use bug
> > factor to degrade your polar is basically an implementation of the
> > common rule of thumb to use 50%-75% of your published polar to
> > determine arrival altitude.
>
> Point #1: I think what you are doing is essentially the same as keeping
> the bugs at "no bugs", but using a high MC setting to figure the "safety
> glide". A high MC means a steep glide angle compared to 0 MC - there's
> the "degradation" in the polar you are wondering about. I normally use a
> 4 MC for my "safety glide" computation, which gives an L/D of 70% of my
> max L/D.
>
> Point #2: In addition to the 4 MC setting, I usually carry excess
> altitude above the 4 MC glide slope to absorb strong sink and
> unexpectedly strong headwinds. Over friendly ground in moderate
> conditions, 500' excess has proven adequate; in strong conditions over
> unfriendly ground, it might be as much as 2000' excess. These numbers
> are trimmed as the distance to the airport decreases, starting about
> 10-20 miles out, because my 1000' AGL arrival height begins to provide
> the "sink absorption" buffer.
>
> Of course, I don't use the 4 MC setting as my speed to fly if I have to
> head towards my safety airport; instead, I use a 1 MC setting (or zero
> MC if I'm truly desperate). My MC setting for the "safety glide" is
> separate from my "speed to fly" setting on my Cambridge 302, which is
> usually set at 1 (moderate conditions) or 2 (strong conditions).
>
> The above MC and excess altitude settings have proved satisfactory for
> all my gliders, from a Ka-6e to an ASH 26 E. Of course, the speeds flown
> were quite different for each glider.
>
> --
> Eric Greenwell - Washington State, USA (netto to net to email me)
>
> - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarmhttp://tinyurl.com/yb3xywl
>
> - "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

I generally do something similar to what Eric describes. In my
computer setup it's a lot easier to fiddle with the Mc setting than
adjust the bugs setting. The basic idea is to have a steeper glide
dialed and fly slightly slower until you establish that you are on
glidepath or better, but also to keep a constant arrival altitude
margin to account for the "2 miles of 10 kts down" scenario - for that
you need an arrival altitude buffer, not a glide angle buffer. If you
are way out on final glide you might start with a negative arrival
margin in an attempt to bump it up over time, but you need to get up
to glidepath by the time you are about 20 mile out or you will be out
of search range to find some lift to get up to glidepath.

9B

[akiley]

On Aug 25, 2:35*pm, Eric Greenwell > wrote:
> On 8/24/2010 7:53 PM, akiley wrote:> On Aug 24, 12:08 am, Eric > *wrote:
>
> >> I've used SeeYou Mobile for 1000+ hours all over the USA, and I'm not
> >> aware of any bugs or gotchas. I would never go back to paper charts,
> >> whiz wheels, or just looking out the window. For example, most of my
> >> final glides begin 30 to 50 miles from the airport, where I can't even
> >> see it, yet they work out well most of the time.
>
> > Eric,
> > What happens if your electronics fry? *Hope you have a backup
> > something.
>
> I've used 4 PDAs over 10 years, 2000 hours total, with no failures, so I
> haven't had to pull out the charts and ruler I always carry with me
> (mostly out of habit). But, a PDA going bad isn't a SeeYou Mobile problem..> There are plenty of gochas I
> > can think of is SeeYouM. *All you have to do is not double check what
> > your goto waypoint is, forget to add winds, polar, safety altitude.
> > Maybe they aren't gochas, but they sort of are for new users.
>
> These aren't SeeYou Mobile gotchas either, they are part of using a
> "soaring computer", whether it's a map with circles, paper sheets with
> tables of glide distances, or an electronic computer.
>
> The polar and safety altitude (I assume you mean the "arrival altitude",
> are settings you should do at home; i.e. "set and forget".
>
> I'm not sure what you mean by "add winds", as SYM automatically uses the
> winds in it's computations. Perhaps you mean "adjusting the winds"?
> Sometimes you have to do that when you realize the winds ahead of you
> are different from the winds SYM has calculated.> * *It
> > takes a lot of thinking to make sure you know what you are doing.

I mean clear the winds totally in SeeYou then enter the official winds
aloft forecast. Maybe SeeYou does a better job, I haven't really
tested this. I just look at my IGC file from this Wednesday and the
winds were supposed to be 320 at 12kts in the 3000 to 6000 range. At
a few points spanning several minutes, SeeYou came back with winds
from 160 at 2 kts. But maybe this happens and is to be believed. Or
I'm really bad a drawing circles with a glider. Probably the later.

>
> Yep, the cockpit is a busy place in a glider if you are going
> cross-country, and it takes a while to get accustomed to a flight
> computer. I had the advantage of 20 years of soaring before using PDA
> flight computers, so the transition was much easier for me.> I have the latest version of SeeYouM that I bought last fall. *One
> > known bug is that the wing loading changes when you leave the polar
> > screen then come back. *Try it.
>
> It doesn't change on my setup (Ipaq 3835 with ver 3.11). Maybe it's a
> 3.12 issue.> * *I think they fixed the one with Oudie
> > that didn't allow the user to set NM in units. *You would have to
> > reset it every time you loaded SeeYouM. *I haven't gotten an answer on
> > my Magnetic Track NavBox yet. *It's off by 12 degrees.

I bought this used iPaq which was listed as a 3700 on the reciept from
Wings and Wheels. Just out of warrantee. The label is worn and
unreadable on the back. Don't know of a software way to positively ID
the unit. It uses the CF cards and an add-on sleeve adapter to hold
the CF card. I have the slightly newer SeeYou Mobil ver 3.12. I have
had lots of IGC files with broken track or perfectly straight lines or
both. Also, I have to reboot my iPaq on a daily basis. Not sure if I
replace the iPaq next or the GPS. I did get an uninterrupted file
this wednesday on a 2.5 hr flight in the Cirrus.
>
> I have to admit I've never used any kind of track bearing. I just put
> the two different track bearing boxes on my PDA (simulator mode), and
> they both read correctly (Washington state area); however, I get the
> same error you do when I try to "fly" in Michigan.> * *Maybe it's
> > party to do with old PDA hardware but I've had a lot of problems with
> > logging not starting, and NavBoxes showing no data, and lockups.
> > Other have had these problem too. *Some days my statistic page that is
> > supposed to show thermal graphs doesn't.

I just have the navBox called "Magnetic track over ground" at the top
center used as a heading indicator, even though it really is'nt.
>
> There is a quirk in the older Ipaqs that can cause symptoms like this.
> The fix is to disable the IR port, which is sensitive to sunlight, and
> slows down the system. Make sure the beam is off on your Ipaq. Do
> something like this: Start, Settings, Connections, Beam, uncheck box.

I just checked, this box is unchecked. But thanks for the heads up.

>
> It also might be your hardware, as I've had none of those problems on my
> fairly old 3835. What PDA are you using? Do you have GPS problems (you
> might be able to determine that by looking at the flight trace in
> SeeYou)? What GPS do you use?> I'm slowly replacing components of my iPaq to see if that's the
> > problem. *I just replaced the CF card adapter back, I've tried a
> > different CF card. *We'll see.

I had the guys on the Navitar forum looking at these IGC files and
trying to help me with all my issues. They never came to any
conclusion on the broken flight tracks.

.... akiley
>
> > I'm definitely a navigator user. *I have a Garmin 395, I've put quite
> > a lot of hours on Garmin G1000's in IFR flight. *My point is one has
> > to be careful throwing full trust into these things.
>
> Agreed. Start out conservatively, get comfortable with it, and then you
> can reduce the margins bit by bit to make cross-country flying easier
> and more enjoyable.
>
> --
> Eric Greenwell - Washington State, USA (netto to net to email me)

[Eric Greenwell]

On 8/26/2010 7:16 PM, akiley wrote:
>
> I mean clear the winds totally in SeeYou then enter the official winds
> aloft forecast. Maybe SeeYou does a better job, I haven't really
> tested this. I just look at my IGC file from this Wednesday and the
> winds were supposed to be 320 at 12kts in the 3000 to 6000 range. At
> a few points spanning several minutes, SeeYou came back with winds
> from 160 at 2 kts. But maybe this happens and is to be believed. Or
> I'm really bad a drawing circles with a glider. Probably the later.
>
I always let Mobile fill in the blanks. It does a good job of measuring
the wind while circling, so I think it's better to use the actual wind
instead of a forecast wind; less trouble, too. I will sometimes change
the wind settings when I know I am flying into an area where the wind is
different from what Mobile has measured. This is usually the final glide
to the home airport, and since I haven't flown near home for the last
few hours, the wind it measured after the takeoff and the first couple
of thermals as I headed out on course may no longer be correct.
> I bought this used iPaq which was listed as a 3700 on the reciept from
> Wings and Wheels. Just out of warrantee. The label is worn and
> unreadable on the back. Don't know of a software way to positively ID
> the unit. It uses the CF cards and an add-on sleeve adapter to hold
> the CF card. I have the slightly newer SeeYou Mobil ver 3.12. I have
> had lots of IGC files with broken track or perfectly straight lines or
> both. Also, I have to reboot my iPaq on a daily basis. Not sure if I
> replace the iPaq next or the GPS. I did get an uninterrupted file
> this wednesday on a 2.5 hr flight in the Cirrus.
>
Mobile for PDAs is a mature, stable program. These problems are almost
certainly hardware related. Can you borrow another Ipaq for a flight or
two?
> I just have the navBox called "Magnetic track over ground" at the top
> center used as a heading indicator, even though it really is'nt.
>
Unless you are really in love with magnetic bearings, I suggest you
switch to "track over ground" to use True bearings instead.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl

- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

[mattm[_2_]]

On Aug 27, 1:36*am, Eric Greenwell > wrote:
> On 8/26/2010 7:16 PM, akiley wrote:
>
> > I mean clear the winds totally in SeeYou then enter the official winds
> > aloft forecast. *Maybe SeeYou does a better job, I haven't really
> > tested this. *I just look at my IGC file from this Wednesday and the
> > winds were supposed to be 320 at 12kts in the 3000 to 6000 range. *At
> > a few points spanning several minutes, SeeYou came back with winds
> > from 160 at 2 kts. * But maybe this happens and is to be believed. *Or
> > I'm really bad a drawing circles with a glider. *Probably the later.
>
> I always let Mobile fill in the blanks. It does a good job of measuring
> the wind while circling, so I think it's better to use the actual wind
> instead of a forecast wind; less trouble, too. I will sometimes change
> the wind settings when I know I am flying into an area where the wind is
> different from what Mobile has measured. This is usually the final glide
> to the home airport, and since I haven't flown near home for the last
> few hours, the wind it measured after the takeoff and the first couple
> of thermals as I headed out on course may no longer be correct.> I bought this used iPaq which was listed as a 3700 on the reciept from
> > Wings and Wheels. *Just out of warrantee. *The label is worn and
> > unreadable on the back. *Don't know of a software way to positively ID
> > the unit. *It uses the CF cards and an add-on sleeve adapter to hold
> > the CF card. *I have the slightly newer SeeYou Mobil ver 3.12. *I have
> > had lots of IGC files with broken track or perfectly straight lines or
> > both. *Also, I have to reboot my iPaq on a daily basis. *Not sure if I
> > replace the iPaq next or the GPS. *I did get an uninterrupted file
> > this wednesday on a 2.5 hr flight in the Cirrus.
>
> Mobile for PDAs is a mature, stable program. These problems are almost
> certainly hardware related. Can you borrow another Ipaq for a flight or
> two?> I just have the navBox called "Magnetic track over ground" at the top
> > center used as a heading indicator, even though it really is'nt.
>
> Unless you are really in love with magnetic bearings, I suggest you
> switch to "track over ground" to use True bearings instead.
>
> --
> Eric Greenwell - Washington State, USA (netto to net to email me)
>
> - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarmhttp://tinyurl.com/yb3xywl
>
> - "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

I agree this may be a hardware problem. What are you using for a GPS
source?
It may be losing lock periodically when you bank.

-- Matt

[akiley]

On Aug 27, 10:25*am, mattm > wrote:
> On Aug 27, 1:36*am, Eric Greenwell > wrote:
>
>
>
> > On 8/26/2010 7:16 PM, akiley wrote:
>
> > > I mean clear the winds totally in SeeYou then enter the official winds
> > > aloft forecast. *Maybe SeeYou does a better job, I haven't really
> > > tested this. *I just look at my IGC file from this Wednesday and the
> > > winds were supposed to be 320 at 12kts in the 3000 to 6000 range. *At
> > > a few points spanning several minutes, SeeYou came back with winds
> > > from 160 at 2 kts. * But maybe this happens and is to be believed. *Or
> > > I'm really bad a drawing circles with a glider. *Probably the later..
>
> > I always let Mobile fill in the blanks. It does a good job of measuring
> > the wind while circling, so I think it's better to use the actual wind
> > instead of a forecast wind; less trouble, too. I will sometimes change
> > the wind settings when I know I am flying into an area where the wind is
> > different from what Mobile has measured. This is usually the final glide
> > to the home airport, and since I haven't flown near home for the last
> > few hours, the wind it measured after the takeoff and the first couple
> > of thermals as I headed out on course may no longer be correct.> I bought this used iPaq which was listed as a 3700 on the reciept from
> > > Wings and Wheels. *Just out of warrantee. *The label is worn and
> > > unreadable on the back. *Don't know of a software way to positively ID
> > > the unit. *It uses the CF cards and an add-on sleeve adapter to hold
> > > the CF card. *I have the slightly newer SeeYou Mobil ver 3.12. *I have
> > > had lots of IGC files with broken track or perfectly straight lines or
> > > both. *Also, I have to reboot my iPaq on a daily basis. *Not sure if I
> > > replace the iPaq next or the GPS. *I did get an uninterrupted file
> > > this wednesday on a 2.5 hr flight in the Cirrus.
>
> > Mobile for PDAs is a mature, stable program. These problems are almost
> > certainly hardware related. Can you borrow another Ipaq for a flight or
> > two?> I just have the navBox called "Magnetic track over ground" at the top
> > > center used as a heading indicator, even though it really is'nt.
>
> > Unless you are really in love with magnetic bearings, I suggest you
> > switch to "track over ground" to use True bearings instead.
>
> > --
> > Eric Greenwell - Washington State, USA (netto to net to email me)
>
> > - "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarmhttp://tinyurl.com/yb3xywl
>
> > - "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz
>
> I agree this may be a hardware problem. *What are you using for a GPS
> source?
> It may be losing lock periodically when you bank.
>
> -- Matt

It's a GlobalSat BR-355 which I think is referred to as a mouse style
GPS that plus into the bottom of my iPaq 3700. If it was always
loosing a signal I would suspect that, but I don't have a really
concrete set of errors that point to any one thing. Intermittent and
varied issues I would describe it as. These have included the iPaq
suddenly wanting to reformat my CF card, intermittant NavBox problems,
usually showing data not available. Log file not stopping after
landing, log file not starting at all. Daily reboots usually required
when SeeYouM does not load. Some of these problems could have been
the CF card sleeve which I replaced a few weeks back because I seems
to be getting good uninterrupted IGC files now. Today, I'm borrowing
a friends iPaq, trouble it I have to order an adapter cord so my mouse
GPS can plug into it. I think iPaq changed the plug in the bottom at
some point. ... akiley

[Eric Greenwell]

On 8/28/2010 7:06 AM, akiley wrote:
> It's a GlobalSat BR-355 which I think is referred to as a mouse style
> GPS that plus into the bottom of my iPaq 3700. If it was always
> loosing a signal I would suspect that, but I don't have a really
> concrete set of errors that point to any one thing. Intermittent and
> varied issues I would describe it as. These have included the iPaq
> suddenly wanting to reformat my CF card, intermittant NavBox problems,
> usually showing data not available. Log file not stopping after
> landing, log file not starting at all. Daily reboots usually required
> when SeeYouM does not load. Some of these problems could have been
> the CF card sleeve which I replaced a few weeks back because I seems
> to be getting good uninterrupted IGC files now. Today, I'm borrowing
> a friends iPaq, trouble it I have to order an adapter cord so my mouse
> GPS can plug into it. I think iPaq changed the plug in the bottom at
> some point. ... akiley
>
I suspect an Ipaq with a built-in slot would be inherently more
reliable. The two I've used - 3830 and 2210 - had slots, and both worked
without problems. Let us know how the new iPaq works out.

--
Eric Greenwell - Washington State, USA (netto to net to email me)

[Martin Gregorie[_5_]]

On Sat, 28 Aug 2010 07:06:45 -0700, akiley wrote:



--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[akiley]

Thank you everyone for all the input on this subject. It's been very
interesting to read these posts! I'm still digesting.

To recap, I'm a fairly new glider pilot with only 30 hours. But I
have spent a LOT of time with SeeYou Mobile in sim mode and with
flight sims, testing, reading trying to take it all in. It really
helps understanding the theory.

In real world, I'm currently staying within range of my primary
airport at all times. With a club Cirrus and not having formal cross
country training (yet), this is what I must do for now.

For the most part, I understand what everyone is talking about. To
me, looking at required MC as a way of seeing how much reserve energy
I have to make it home seems fairly straight forward and takes
everything into account as long as I make sure all parameters are
correct including safety altitude, bugs, winds aloft, polar and such.
I like it because I can be flying away from home base and it will work
without having to test by actually starting the final glide. For
example, if I'm 10 miles out and I see a value of 10MC required, I
know I can fly a substantially lower MC final glide and be sure of
making it home. For a cross check it's easy to also look at required
L/D versus achieved L/D especially as the final glide is in progress.
It's also easy to look at arrival height.

But I also like MC because it plays out in thermals, speed to fly and
is seems to be the theoretical basis of making forward progress in
soaring. Something I plan to use more and more as I progress.

akiley Adrian, Michigan

[Surfer![_2_]]

"akiley" > wrote in message
...
>
>
> Thank you everyone for all the input on this subject. It's been very
> interesting to read these posts! I'm still digesting.
>
> To recap, I'm a fairly new glider pilot with only 30 hours. But I
> have spent a LOT of time with SeeYou Mobile in sim mode and with
> flight sims, testing, reading trying to take it all in. It really
> helps understanding the theory.
>
> In real world, I'm currently staying within range of my primary
> airport at all times. With a club Cirrus and not having formal cross
> country training (yet), this is what I must do for now.

<snip>

Thank goodness you are staying in glide range. Does the SeeYou simulator
teach field landings?

[PCool]

(Garmin is using GR Glide Ratio, not LD. The confusion comes to the fact
that a "glide ratio" relative to the air is not the same to glide ratio
relative to ground.
LD should be used for indicating glide ratio relative to air, and GR or Eff
for ground. But since most pilots don't care at all about the LD (air
relative efficiency) because when we are gliding we are flying toward a
ground point, then we all use either LD GR or EFF.
Old instrument with no GPS are using LD and this is not accounting for wind.
Even bigger confusion)

Months ago I did experiment using current efficiency averaged in last 90
seconds for calculating altitude arrivals (using lk8000, not seeyou).
During long glides it was very accurate.
Currently arrival altitudes are calculated using your MC setting, but if you
fall in sinking air and follow the glider's speed to fly indicator then you
will speed up and use a different MC at all effects.
So now I am experimenting what paraglider's are already using since time:
the "equivalent MC", which is based on your airspeed and polar.
In the end it is like using average efficiency.

Personally I think that it's all a matter of guessing, and the good old GR
or Eff is still the most simple and valuable parameter.

paolo