required LD versus required MC to make it home ??

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)

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

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.

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

"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?