Final glide

[s6]

I can use my Oudie or my Clearnav vario for final glide.
Lately my CNv final glide is 400 feet lower than my Oudie.
The Oudie is right. All the setting are the same.
I cant correct the CNv.
Any idea from other CNv user?
Gilles

[[email protected][_2_]]

Glad nobody died....’final glide’.
Have you checked/compared all the adjustable parameters?
Polars, ballast, bugs, units, winds, QNH, etc.

R

[JS[_5_]]

On Sunday, September 22, 2019 at 5:18:47 AM UTC-7, wrote:
> Glad nobody died....’final glide’.
> Have you checked/compared all the adjustable parameters?
> Polars, ballast, bugs, units, winds, QNH, etc.
>
> R

Also could be margin height, and if the CNv is set up for total energy arrival height (including a pull-up from cruise).
Jim

[s6]

Le dimanche 22 septembre 2019 07:48:02 UTC-4, s6 a écritÂ*:
> I can use my Oudie or my Clearnav vario for final glide.
> Lately my CNv final glide is 400 feet lower than my Oudie.
> The Oudie is right. All the setting are the same.
> I cant correct the CNv.
> Any idea from other CNv user?
> Gilles

Thank you
Margin height is set at 1000 feet.
Vario behave as if set at 600 feet.
Check all setting, nothing change????
Gilles

[waremark]

Have you confirmed for each whether or not they are using total energy arrival height, ie including the expected height recovery from pull up to best glide height? That could easily account for a difference of 400 feet.

Is the difference a fixed value regardless of distance to go, rather than a percentage?

Have you checked whether the elevation of your arrival airfield is set the same in both devices?

[Tango Eight]

On Monday, September 23, 2019 at 6:55:24 PM UTC-4, waremark wrote:
> Have you confirmed for each whether or not they are using total energy arrival height, ie including the expected height recovery from pull up to best glide height? That could easily account for a difference of 400 feet.
>
> Is the difference a fixed value regardless of distance to go, rather than a percentage?
>
> Have you checked whether the elevation of your arrival airfield is set the same in both devices?

It's either a user set up or database problem. There's no other likely possibility.

OT... but using a preset margin is sooooo 1986. Set the margin to zero and let the device tell you your predicted arrival height. If you don't like the numbers you see, do that PIC thing....

T8

[6PK]

On Monday, September 23, 2019 at 4:46:00 PM UTC-7, Tango Eight wrote:
> On Monday, September 23, 2019 at 6:55:24 PM UTC-4, waremark wrote:
> > Have you confirmed for each whether or not they are using total energy arrival height, ie including the expected height recovery from pull up to best glide height? That could easily account for a difference of 400 feet.
> >
> > Is the difference a fixed value regardless of distance to go, rather than a percentage?
> >
> > Have you checked whether the elevation of your arrival airfield is set the same in both devices?
>
> It's either a user set up or database problem. There's no other likely possibility.
>
> OT... but using a preset margin is sooooo 1986. Set the margin to zero and let the device tell you your predicted arrival height. If you don't like the numbers you see, do that PIC thing....
>
> T8
snip
"OT... but using a preset margin is sooooo 1986"

I beg to disagree with you sir. This is YOUR preference and opinion and maybe other's too and that is ok... but, using a safety margin is strictly a personal preference of others and no it does not go out of style like you so imply above..

[Tango Eight]

On Monday, September 23, 2019 at 8:54:25 PM UTC-4, 6PK wrote:
> On Monday, September 23, 2019 at 4:46:00 PM UTC-7, Tango Eight wrote:
> > On Monday, September 23, 2019 at 6:55:24 PM UTC-4, waremark wrote:
> > > Have you confirmed for each whether or not they are using total energy arrival height, ie including the expected height recovery from pull up to best glide height? That could easily account for a difference of 400 feet.
> > >
> > > Is the difference a fixed value regardless of distance to go, rather than a percentage?
> > >
> > > Have you checked whether the elevation of your arrival airfield is set the same in both devices?
> >
> > It's either a user set up or database problem. There's no other likely possibility.
> >
> > OT... but using a preset margin is sooooo 1986. Set the margin to zero and let the device tell you your predicted arrival height. If you don't like the numbers you see, do that PIC thing....
> >
> > T8
> snip
> "OT... but using a preset margin is sooooo 1986"
>
> I beg to disagree with you sir. This is YOUR preference and opinion and maybe other's too and that is ok... but, using a safety margin is strictly a personal preference of others and no it does not go out of style like you so imply above..

It was dumb in 1986 too :-).

No one arrival height covers all situations.

T8

[6PK]

On Monday, September 23, 2019 at 6:13:12 PM UTC-7, Tango Eight wrote:
> On Monday, September 23, 2019 at 8:54:25 PM UTC-4, 6PK wrote:
> > On Monday, September 23, 2019 at 4:46:00 PM UTC-7, Tango Eight wrote:
> > > On Monday, September 23, 2019 at 6:55:24 PM UTC-4, waremark wrote:
> > > > Have you confirmed for each whether or not they are using total energy arrival height, ie including the expected height recovery from pull up to best glide height? That could easily account for a difference of 400 feet.
> > > >
> > > > Is the difference a fixed value regardless of distance to go, rather than a percentage?
> > > >
> > > > Have you checked whether the elevation of your arrival airfield is set the same in both devices?
> > >
> > > It's either a user set up or database problem. There's no other likely possibility.
> > >
> > > OT... but using a preset margin is sooooo 1986. Set the margin to zero and let the device tell you your predicted arrival height. If you don't like the numbers you see, do that PIC thing....
> > >
> > > T8
> > snip
> > "OT... but using a preset margin is sooooo 1986"
> >
> > I beg to disagree with you sir. This is YOUR preference and opinion and maybe other's too and that is ok... but, using a safety margin is strictly a personal preference of others and no it does not go out of style like you so imply above..
>
> It was dumb in 1986 too :-).
>
> No one arrival height covers all situations.
>
> T8

Of course not but it is still personal a personal preference, no need to be opiniated, there is always more than one way to skin a cat.

[Tango Eight]

On Monday, September 23, 2019 at 9:30:25 PM UTC-4, 6PK wrote:
> On Monday, September 23, 2019 at 6:13:12 PM UTC-7, Tango Eight wrote:
> > On Monday, September 23, 2019 at 8:54:25 PM UTC-4, 6PK wrote:
> > > On Monday, September 23, 2019 at 4:46:00 PM UTC-7, Tango Eight wrote:
> > > > On Monday, September 23, 2019 at 6:55:24 PM UTC-4, waremark wrote:
> > > > > Have you confirmed for each whether or not they are using total energy arrival height, ie including the expected height recovery from pull up to best glide height? That could easily account for a difference of 400 feet.
> > > > >
> > > > > Is the difference a fixed value regardless of distance to go, rather than a percentage?
> > > > >
> > > > > Have you checked whether the elevation of your arrival airfield is set the same in both devices?
> > > >
> > > > It's either a user set up or database problem. There's no other likely possibility.
> > > >
> > > > OT... but using a preset margin is sooooo 1986. Set the margin to zero and let the device tell you your predicted arrival height. If you don't like the numbers you see, do that PIC thing....
> > > >
> > > > T8
> > > snip
> > > "OT... but using a preset margin is sooooo 1986"
> > >
> > > I beg to disagree with you sir. This is YOUR preference and opinion and maybe other's too and that is ok... but, using a safety margin is strictly a personal preference of others and no it does not go out of style like you so imply above..
> >
> > It was dumb in 1986 too :-).
> >
> > No one arrival height covers all situations.
> >
> > T8
>
> Of course not but it is still personal a personal preference, no need to be opiniated, there is always more than one way to skin a cat.

Try it the other way, you'll see.

Happy landings,
T8

[Eric Greenwell[_4_]]

Tango Eight wrote on 9/23/2019 7:01 PM:
>>> No one arrival height covers all situations.
>>>
>>> T8
>> Of course not but it is still personal a personal preference, no need to be opiniated, there is always more than one way to skin a cat.
> Try it the other way, you'll see.

After 40 years of using a 1000' arrival height as my "aim point", I probably
shouldn't be changing it now :^)

But, I have always added a few hundred (or more) feet if I thought there were
going to be difficulties at the landing area, or (rarely) subtracted a few hundred
when close to a landing place that had no problems, and the extra search time
might find me thermal.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Steve Thompson[_2_]]

At 03:27 24 September 2019, Eric Greenwell wrote:
>Tango Eight wrote on 9/23/2019 7:01 PM:
>>>> No one arrival height covers all situations.
>>>>
>>>> T8
>>> Of course not but it is still personal a personal
preference, no need to
>be opiniated, there is always more than one way to skin
a cat.
>> Try it the other way, you'll see.
>
>After 40 years of using a 1000' arrival height as my
"aim point", I
>probably
>shouldn't be changing it now :^)
>
>But, I have always added a few hundred (or more) feet
if I thought there
>were
>going to be difficulties at the landing area, or (rarely)
subtracted a few
>hundred
>when close to a landing place that had no problems,
and the extra search
>time
>might find me thermal.
>
>--
>Eric Greenwell - Washington State, USA (change
".netto" to ".us" to email
>me)
>- "A Guide to Self-Launching Sailplane Operation"
>
>https://sites.google.com/site/motorgliders/publications
/download-the-guide-1
>
Probably shouldn't comment but anyway..

Setting a fixed margin and then doing airborne sums
based on the current situation and that (remembered)
margin, is more difficult for me than just setting Zero
and seeing what AH is predicted on screen.

When I look at others' LXXXX devices I often find they
have 628feet (aka 200m), which suggests they may not
know what margin is set and indeed may never have
looked at the page.

Zander ZS-1 had the answer - AH welded at zero.
wysiwyg.

[RR]

Steve has mentioned the key here. If you are about to head home, and find yourself saying somthing like the following, "I am 1000 over, my 1000ft reserve" then your reserve is doing you a disservice. It is somewhat of catch 22. You need to be aware of your reserve in case things go south and you fall below it, but the purpose is to keep you from needing to think about it (always have 1000 ft in reserve).

The biggest problem is when things go south. If you are close in, you fall below 0, now you need to subtract from your reserve to figure out your true arrival height. If you use somthing other than 1000 ft it gets harder. So right when you most need clear information you are doing mental math. Bad timing to insert a math problem before you need to make a critical decision. Some (in the admiralty), if not most, know how I know this.

It has been described as setting your watch ahead so you are not late.

I too had flown with a reserve for years, and was worried about switching, but just a few flights and you adjust. And a few more and you realy start to appreciate the fact that you are, for the first time, realy getting the number you want out of your flight computer.

How high will I be when I get there...

RR
Commodore

[[email protected]]

On Tuesday, September 24, 2019 at 12:32:32 PM UTC+1, RR wrote:
> Steve has mentioned the key here. If you are about to head home, and find yourself saying somthing like the following, "I am 1000 over, my 1000ft reserve" then your reserve is doing you a disservice. It is somewhat of catch 22. You need to be aware of your reserve in case things go south and you fall below it, but the purpose is to keep you from needing to think about it (always have 1000 ft in reserve).
>
> The biggest problem is when things go south. If you are close in, you fall below 0, now you need to subtract from your reserve to figure out your true arrival height. If you use somthing other than 1000 ft it gets harder. So right when you most need clear information you are doing mental math. Bad timing to insert a math problem before you need to make a critical decision. Some (in the admiralty), if not most, know how I know this.
>
> It has been described as setting your watch ahead so you are not late.
>
> I too had flown with a reserve for years, and was worried about switching, but just a few flights and you adjust. And a few more and you realy start to appreciate the fact that you are, for the first time, realy getting the number you want out of your flight computer.
>
> How high will I be when I get there...
>
> RR
> Commodore

I think there is merit in having a small reserve of, say, 200 feet to allow for pressure altitude changes during flight, obstructions on the approach etc but to regard that as if it were a zero arrival altitude.

The biggest downside I find of a large reserve height isn't the mental arithmetic. With LXNav or Naviter glide computers it is to remember that it is added to the FAI or record "task arrival height" (1000m below start height). One day I struggled for a climb to make task arrival only to find I was getting there 1000 feet higher than necessary and way above ground.

[waremark]

I use an arrival height reserve. When flying to a destination airfield I readily and easily make mental adjustments up and down from it depending on conditions and distance to go. For me the benefit of setting the arrival height reserve is that if I see a green blob on my moving map when I am away from base I know that I have a fighting chance of reaching an alternate airfield. If you use a zero reserve then a green blob on the moving map is meaningless and you have to read the arrival height beside it.

By the way, at startup (after the gps has acquired) I check to see that the arrival height at the airfield I am sitting on is approximately minus my arrival height reserve. If the OP does this it might help him diagnose his problem. OP, please do report back to us on any further findings.

[waremark]

I am not convinced by the argument for a 200 foot reserve to allow for pressure changes or obstructions. That almost implies that you would be ready to arrive at an arrival height of 200 foot. If you have zero set but plan to arrive at 800 foot then you will be able to cope with pressure changes or obstructions. If you plan to arrive well below circuit height I hope you are using visual judgement before you get too low.

I am interested by the point about the reserve being added to your finish height where your finish height is different from your arrival height at an airfield. How does this work? I don't have 'Finish is 1,000m below start set' as it doesn't normally affect me - if I start above 1,000 m on a flight for which the scoring will be affected that is another adjustment which I make mentally. In the UK the rule does not affect competition scoring but does affect our BGA Ladder. I have never flown with a finish other than at an airfield - is there a way to set the minimum height at a finish ring?

[6PK]

On Tuesday, September 24, 2019 at 7:29:21 AM UTC-7, waremark wrote:
> I use an arrival height reserve. When flying to a destination airfield I readily and easily make mental adjustments up and down from it depending on conditions and distance to go. For me the benefit of setting the arrival height reserve is that if I see a green blob on my moving map when I am away from base I know that I have a fighting chance of reaching an alternate airfield. If you use a zero reserve then a green blob on the moving map is meaningless and you have to read the arrival height beside it.
>
> By the way, at startup (after the gps has acquired) I check to see that the arrival height at the airfield I am sitting on is approximately minus my arrival height reserve. If the OP does this it might help him diagnose his problem. OP, please do report back to us on any further findings.

Ditto..

[Tango Eight]

On Tuesday, September 24, 2019 at 10:29:21 AM UTC-4, waremark wrote:
> OP, please do report back to us on any further findings.

As mentioned before, CNv uses TE altitude for final glide purposes. The normal circumstance with correct setup and database is that it will show about -200 feet arrival with the glider at rest, on the ground, very close to the selected waypoint. So in the OP's case, with 1000' reserve altitude, it should indicate about -1200.

T8

[RR]

I do agree about the desire to have a "reserve" for graphical purposes. I believe clear nav can show the landing amobia both with and without reserve.. I wish the Lx would do this as well. I could cheat this in XCSoar with a terrain clearance. So the marginally reachable did not appear to be reachable with a 1000ft terrain clearance. But the best solution is a reserve that is only applied to the map view. This becomes a quick visual filter, only show me landing spots where I have the altitude for a decent approach. For me, the advantage of having an accurate arrival height is better than the inconvenience of checking if a candidate field has the margin I want. You only really get that after you have pick to go there anyway.

Rick

[[email protected]]

On Tuesday, September 24, 2019 at 11:41:33 AM UTC-4, RR wrote:
> I do agree about the desire to have a "reserve" for graphical purposes. I believe clear nav can show the landing amobia both with and without reserve. I wish the Lx would do this as well. I could cheat this in XCSoar with a terrain clearance. So the marginally reachable did not appear to be reachable with a 1000ft terrain clearance. But the best solution is a reserve that is only applied to the map view. This becomes a quick visual filter, only show me landing spots where I have the altitude for a decent approach. For me, the advantage of having an accurate arrival height is better than the inconvenience of checking if a candidate field has the margin I want.. You only really get that after you have pick to go there anyway.
>
> Rick

In Tophat the moving map shows the arrival altitude next to each landable waypoint that is within glide range. I use that instead of the color to identify the ones within range. (No colors on the Nook anyway :-)
And since, like Evan, I set the reserve altitude to zero, I do see some arrival altitudes on the map that are really too low to be safe, e.g., 300 feet. That's still good for planning, though, since it tells me that if I were to get a little higher, or closer, that landing spot will become a safer bet.

[Martin Gregorie[_6_]]

On Tue, 24 Sep 2019 07:44:48 -0700, waremark wrote:

> I am interested by the point about the reserve being added to your
> finish height where your finish height is different from your arrival
> height at an airfield. How does this work? I don't have 'Finish is
> 1,000m below start set' as it doesn't normally affect me - if I start
> above 1,000 m on a flight for which the scoring will be affected that is
> another adjustment which I make mentally. In the UK the rule does not
> affect competition scoring but does affect our BGA Ladder. I have never
> flown with a finish other than at an airfield - is there a way to set
> the minimum height at a finish ring?
>
I use LK8000 as my main navigation tool. It displays arrival heights as a
signed value, which is difference from your configured arrival height. So
with 1000 configured as your target arrival height, if it displays +200
its predicting you'll arrive 200 ft above target and if it shows -400 its
predicting arrival 400 ft below target.

That works for me.


--
Martin | martin at
Gregorie | gregorie dot org

[Dan Marotta]

I'm stuck back in 1986 (87, actually).Â* I set my CNII to arrive at
1,000' AGL over mid field and it never works out for me.Â* I get lower
and lower and, as I get nervous, I arrive well above where I want to be.

I can set the XCSoar unit to Automatic McCready and it directs scary
fast speeds with MC 9.0 or more.

So, Evan, precisely how do you read your expected arrival height after
setting your safety factor to zero?Â* I'd like to give it a try.

On 9/23/2019 8:01 PM, Tango Eight wrote:
> O
> It was dumb in 1986 too :-).
>
> No one arrival height covers all situations.
>
> T8
>> Of course not but it is still personal a personal preference, no need to be opiniated, there is always more than one way to skin a cat.
> Try it the other way, you'll see.
>
> Happy landings,
> T8

--
Dan, 5J

[Dan Marotta]

Now I get it!Â* My glide slope indication is what I'm interested in.
Since I maintain a 1,000' AGL arrival height in my settings, I look at
the glide slope indication as, "At what altitude will arrive over the
field?".Â* The only difference is, then, with my arrival height I know
that, as the glide slope approaches zero, I should arrive over the field
at 1,000', which is what I want.Â* If I set zero as my arrival height, I
must remember to think that this is the altitude that I'll arrive and
then think, "Will I have enough altitude to fly a proper pattern?"Â*
Neither method is very difficult, just a matter of preference.Â* On my
last flight, from 5 miles out, I said I'd be making a right base entry
to the runway whereas the normal pattern is to the left.Â* It was more
like a 45 degree base leg.

On 9/24/2019 5:32 AM, RR wrote:
> Steve has mentioned the key here. If you are about to head home, and find yourself saying somthing like the following, "I am 1000 over, my 1000ft reserve" then your reserve is doing you a disservice. It is somewhat of catch 22. You need to be aware of your reserve in case things go south and you fall below it, but the purpose is to keep you from needing to think about it (always have 1000 ft in reserve).
>
> The biggest problem is when things go south. If you are close in, you fall below 0, now you need to subtract from your reserve to figure out your true arrival height. If you use somthing other than 1000 ft it gets harder. So right when you most need clear information you are doing mental math. Bad timing to insert a math problem before you need to make a critical decision. Some (in the admiralty), if not most, know how I know this.
>
> It has been described as setting your watch ahead so you are not late.
>
> I too had flown with a reserve for years, and was worried about switching, but just a few flights and you adjust. And a few more and you realy start to appreciate the fact that you are, for the first time, realy getting the number you want out of your flight computer.
>
> How high will I be when I get there...
>
> RR
> Commodore

--
Dan, 5J

[Mike Clarke]

At 14:44 24 September 2019, waremark wrote:
In the UK the rule does not affect competition scoring but
>do=
>es affect our BGA Ladder. I have never flown with a finish other than
at
>an=
> airfield - is there a way to set the minimum height at a finish ring?

With LXxxxx, just set the finish ring radius and a "safety height" of
500ft or whatever on the QNH page. The LX will then show the arrival
height margin at the ring, not the airfield. 0ft on the LX means you are
at the set ring-crossing height.

MC

[waremark]

And then you land out before arriving at the airfield! I cannot understand why people ever set finish rings at a height which isn't sufficient to ensure a comfortable arrival at the airfield.

[Martin Gregorie[_6_]]

On Tue, 24 Sep 2019 15:30:42 -0700, waremark wrote:

> And then you land out before arriving at the airfield! I cannot
> understand why people ever set finish rings at a height which isn't
> sufficient to ensure a comfortable arrival at the airfield.

Looks reasonable to me: just set a small finish ring, say with a radius
equal to the distance from the airfield TP to the high key point for the
run being used on that day and ring height to what the destructors like
as high key height. That should be pretty close to putting you at the
start of what amounts to a text-book approach.

I'd try it myself, provided there's another flying day hiding amidst the
current rain and wind. However, although LK8000 7.0 allows a finish ring
to be specified, it doesn't allow a finish height to be input.

I feel a change request coming on....


--
Martin | martin at
Gregorie | gregorie dot org

[[email protected]]

Now who ever said making the perfect final glide was suppossed to be "comfortable" lol. If it is too comfortable you just left points on the table.

[2G]

On Tuesday, September 24, 2019 at 4:36:30 PM UTC-7, wrote:
> Now who ever said making the perfect final glide was suppossed to be "comfortable" lol. If it is too comfortable you just left points on the table.

I would be extremely nervous about making a final glide that would have me doing a straight-in final at max L/D. Under this scenario, if your glide computer is very accurate, half of the time you would be landing short. And anywhere I fly, landing short is not an option. I am with Mike: I don't regard it as a reserve, that IS the altitude that I want to arrive at. My real reserve is the altitude I have over that. Too many times I have seen that reserve evaporate along the way. You may encounter unexpected areas of sink or stronger headwinds than expected.

Tom

[[email protected]]

Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.

[2G]

On Tuesday, September 24, 2019 at 5:14:29 PM UTC-7, wrote:
> Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.

Yeah, RIGHT! How often do you get the "perfect" final glide? You, sir, are the one that's screwed up!

Tom

[[email protected]]

Since I do not fly competition, making the "perfect" final glide to avoid leaving "points on the table" is not much of a concern. What does concern me is arriving below pattern altitude and suddenly being out of options with other traffic in the pattern. Sometimes there are other aircraft doing touch and goes, the glider operation has tow planes and students without proper radio skill, or worse, no radio at all. I don't feel I should annoy other airport users by just charging in and demanding priority because my final glide got me home with no margin to integrate my arrival with other pilots' intentions. Therefore, I leave myself with a safety margin. I enjoy the worm burner low passes, but I always initiate them after arriving high enough to assess the airport usage, making sure I will not conflict with other traffic. It's just being polite.

[[email protected]]

lol once again you just don't seem to be able to read what someone says without "reinterpreting" the words.

I DID NOT say that I perform the "perfect" final glide. I have never performed the perfect final glide but there are those who have. And they are carrying energy AND hitting the exact altitude they were aiming at arriving at.

[s6]

Le dimanche 22 septembre 2019 07:48:02 UTC-4, s6 a écritÂ*:
> I can use my Oudie or my Clearnav vario for final glide.
> Lately my CNv final glide is 400 feet lower than my Oudie.
> The Oudie is right. All the setting are the same.
> I cant correct the CNv.
> Any idea from other CNv user?
> Gilles

I fly at a busy and some time very busy airfield, so 1000 feet is my arrival height. Still stuck with a faulty CNv!!!
Gilles

[Eric Greenwell[_4_]]

wrote on 9/24/2019 7:07 PM:
> lol once again you just don't seem to be able to read what someone says without "reinterpreting" the words.
>
> I DID NOT say that I perform the "perfect" final glide. I have never performed the perfect final glide but there are those who have. And they are carrying energy AND hitting the exact altitude they were aiming at arriving at.

I rarely did perfect final glide when I was flying contests; mostly, I flew too
slowly at the beginning of the glide, and too fast at the end it, trying to get
down. But it was fun trying.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[[email protected]]

I hear ya there Eric. Flying a low performance bird, I end up many times at the opposite end of the specrum where I start out great-guns, pretending I am Wally Scott in his asw12 at Marfa and then end up saying..."Oh ****...I better slow down". LOLo

[Mike Clarke]

At 23:02 24 September 2019, Martin Gregorie wrote:
>On Tue, 24 Sep 2019 15:30:42 -0700, waremark wrote:
>
>> And then you land out before arriving at the airfield! I cannot
>> understand why people ever set finish rings at a height which
isn't sufficient to ensure a comfortable arrival at the airfield.

>Looks reasonable to me: just set a small finish ring, say with a
radius equal to the distance from the airfield TP to the high key point
for the run being used on that day and ring height to what the
destructors like as high key height. That should be pretty close to
putting you at the start of what amounts to a text-book approach.


Mark,

If a Competition Director is setting a finish ring too low, have a word
with them. And also remember that you are PIC, not the CD. If you
need more height to land safely because of a stronger head wind,
weaker tail wind, pressure drop, bugs, rain or general nervousness,
the finish ring does not constrain you from crossing it above the
height set by the CD. For a given ring size, the CD will re-assess the
minimum height daily based on the minimum performance of gliders
competing and the conditions.

Martin,

See the BGA and IGC competition rules to understand properly what
a finish ring is about.

BGA:

A ring of specified radius (normally, but not exceeding, 3km) around
the finish point encompassing the contest site and the landing
circuits.

When a Finish Ring is specified, a minimum altitude related to glider
performance of the lowest performance glider in task group, terrain
and obstructions should be set. Unless there are specific
obstructions, the minimum altitude should be set to allow gliders to
just pass over the ring on a normal final for direct landing in the
expected prevailing wind.

For both the finish Line and Finish Ring, a viable direct landing
option must be available to allow finishers to land ahead without
turning after crossing the line or ring. A Control point should be
utilised as necessary to ensure compliance.

IGC:

A circle of specified radius (minimum 3 km) around the Finish Point
encompassing the contest site and the landing circuits.

Finish Ring is to be regarded as the preferred finish procedure as it
allows each pilot to slow down and concentrate on the landing
procedures and other sailplanes prior to landing.

Organisers are encouraged to use a Final Turn Point to align the
sailplanes with the desired direction of finishing.


You can download some logger files from the competitions at
Lasham to see how it works in practice.

MC

[Tango Eight]

On Tuesday, September 24, 2019 at 10:07:43 PM UTC-4, s6 wrote:
> Le dimanche 22 septembre 2019 07:48:02 UTC-4, s6 a écritÂ*:
> > I can use my Oudie or my Clearnav vario for final glide.
> > Lately my CNv final glide is 400 feet lower than my Oudie.
> > The Oudie is right. All the setting are the same.
> > I cant correct the CNv.
> > Any idea from other CNv user?
> > Gilles
>
> I fly at a busy and some time very busy airfield, so 1000 feet is my arrival height. Still stuck with a faulty CNv!!!
> Gilles

If/when you get serious about figuring this out, you will be doing one of calling Rex, emailing me or providing more information on the ClearNav forum (which I monitor).

Evan Ludeman

[[email protected]]

On Tuesday, September 24, 2019 at 8:14:29 PM UTC-4, wrote:
> Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.

The "perfect" final glide has the pilot crossing the finish at his selected height and at at the same speed as the average for the flight.
UH

[Martin Gregorie[_6_]]

On Wed, 25 Sep 2019 10:49:26 +0000, Mike Clarke wrote:

> Martin,
>
> See the BGA and IGC competition rules to understand properly what a
> finish ring is about.
>
My suggestion was for a way to use a finishing circle as the minimum
arrival height for a non-competition, e.g. BGA Ladder, xc flight, NOT
anything to do with a competition task.


--
Martin | martin at
Gregorie | gregorie dot org

[[email protected]]

Uncl, that is absolutely correct and what I was trying to express. The "perfect" flight would be one of relatively constant avg speed with little difference between normal task cruise avg speed and the final glide speed.

We all know however that that does'nt happen. Most of us do the best we can till we think we have our final glide in hand then modify our speed as we head on in depending on whats happening with our altitude.

On a related question, I wonder how many folks here could calculate and perform a successful/efficient final glide without their handy dandy flight computers?

[Tango Eight]

On Wednesday, September 25, 2019 at 9:55:44 AM UTC-4, wrote:
> Uncl, that is absolutely correct and what I was trying to express. The "perfect" flight would be one of relatively constant avg speed with little difference between normal task cruise avg speed and the final glide speed.
>
> We all know however that that does'nt happen. Most of us do the best we can till we think we have our final glide in hand then modify our speed as we head on in depending on whats happening with our altitude.
>
> On a related question, I wonder how many folks here could calculate and perform a successful/efficient final glide without their handy dandy flight computers?

200' per mile plus 1000', and you get home, even in an HP-18 :-). Back in the day an LNav was 20% of the cost of my glider and GPS wasn't even a thing yet. I had circles drawn on a map and eyeballs to check position. Worked every time, wasn't so hard.

T8

[Dan Marotta]

To add to what Mark said (and drift a little), I try to arrive in the
same fashion as he does.Â* I'm sometimes surprised by those with super
"radio discipline", who never say a word until someone arrives and
announces the pattern.Â* Then there's a frantic "I'm here, too!" call.Â*
Please don't forget to use the radio when you're near the field.

On 9/24/2019 7:14 PM, wrote:
> Since I do not fly competition, making the "perfect" final glide to avoid leaving "points on the table" is not much of a concern. What does concern me is arriving below pattern altitude and suddenly being out of options with other traffic in the pattern. Sometimes there are other aircraft doing touch and goes, the glider operation has tow planes and students without proper radio skill, or worse, no radio at all. I don't feel I should annoy other airport users by just charging in and demanding priority because my final glide got me home with no margin to integrate my arrival with other pilots' intentions. Therefore, I leave myself with a safety margin. I enjoy the worm burner low passes, but I always initiate them after arriving high enough to assess the airport usage, making sure I will not conflict with other traffic. It's just being polite.

--
Dan, 5J

[Dan Marotta]

200'/mile works out to 30:1 since we all use nautical miles, don't we?Â*
That may work just fine back east, but out west not so much. It's
disconcerting to see on the CNII that I need 20:1 to get home but I
can't seem to do better than 15:1.Â* Yes, we have strong thermals, but we
also have some very impressive sink!

On 9/25/2019 8:11 AM, Tango Eight wrote:
> On Wednesday, September 25, 2019 at 9:55:44 AM UTC-4, wrote:
>> Uncl, that is absolutely correct and what I was trying to express. The "perfect" flight would be one of relatively constant avg speed with little difference between normal task cruise avg speed and the final glide speed.
>>
>> We all know however that that does'nt happen. Most of us do the best we can till we think we have our final glide in hand then modify our speed as we head on in depending on whats happening with our altitude.
>>
>> On a related question, I wonder how many folks here could calculate and perform a successful/efficient final glide without their handy dandy flight computers?
> 200' per mile plus 1000', and you get home, even in an HP-18 :-). Back in the day an LNav was 20% of the cost of my glider and GPS wasn't even a thing yet. I had circles drawn on a map and eyeballs to check position. Worked every time, wasn't so hard.
>
> T8

--
Dan, 5J

[[email protected]]

On Wednesday, September 25, 2019 at 10:27:12 AM UTC-4, Dan Marotta wrote:
> 200'/mile works out to 30:1 since we all use nautical miles, don't we?Â*
> That may work just fine back east, but out west not so much. It's
> disconcerting to see on the CNII that I need 20:1 to get home but I
> can't seem to do better than 15:1.Â* Yes, we have strong thermals, but we
> also have some very impressive sink!
>
> On 9/25/2019 8:11 AM, Tango Eight wrote:
> > On Wednesday, September 25, 2019 at 9:55:44 AM UTC-4, wrote:
> >> Uncl, that is absolutely correct and what I was trying to express. The "perfect" flight would be one of relatively constant avg speed with little difference between normal task cruise avg speed and the final glide speed.
> >>
> >> We all know however that that does'nt happen. Most of us do the best we can till we think we have our final glide in hand then modify our speed as we head on in depending on whats happening with our altitude.
> >>
> >> On a related question, I wonder how many folks here could calculate and perform a successful/efficient final glide without their handy dandy flight computers?
> > 200' per mile plus 1000', and you get home, even in an HP-18 :-). Back in the day an LNav was 20% of the cost of my glider and GPS wasn't even a thing yet. I had circles drawn on a map and eyeballs to check position. Worked every time, wasn't so hard.
> >
> > T8
>
> --
> Dan, 5J

Most people I know use statute miles. I teach using 5 miles/1000 ft as a good final glide reference for Std or 15M ships. Easy to calculate. Adjust for conditions. Pretty much what Evan described but easier to calculate with GPS distance and altimeter.
UH

[[email protected]]

Yep, me too, did it old school for years and even this year flying the 1-26 championships in Moriarty where my flight.computer was inop. No big deal. Except with my bird its more like 350 ft/mile lol I usually ballpark 4mi/1,000ft with the sink and the ever present headwinds lol.

[Charlie M. (UH & 002 owner/pilot)]

OK....sorta "tongue in cheek".....for fun.....a couple of YOUR recent contests had winning task speeds BELOW what I could do (stall speed) in 002 at my weight.....yes....being a PITA.....
Yes, ideal is minimum speed (task average speed) at legal finish height....some peeps have lost a first in a worlds due to 2 many circles across more than a week....

I remember a regionals at Dansville where I got stuck for over an hour.
Spratt man called my finish from the hanger while drinking beer with the rest of the fleet.
Back then, first landout points was based on last finisher.....I think I was maybe 18mph....in a -20?.

[[email protected]]

LOL truth Charlie, we are surely not speed demons. But I'll tell ya we have had a few guys, namely Ron Schwarttz, Mark Keene and Daniel Sazhin who have won days at speeds in the high 50mph range. Thats doing something in a 1-26! lol.

This last weekend while racing in a local xc series down here, I had, I think it was, a ventus 2 come blasting past me on final glide. He called to me to look to my right and I saw him blast past me at least 70 mph faster than I was going lol.

I got the last laugh on the glass boys in my division however, by winning the day with my handicap lol.

[Eric Greenwell[_4_]]

wrote on 9/25/2019 5:41 AM:
> On Tuesday, September 24, 2019 at 8:14:29 PM UTC-4, wrote:
>> Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.
>
> The "perfect" final glide has the pilot crossing the finish at his selected height and at at the same speed as the average for the flight.

You don't really do that, do you? I'll bet you fly the final glide rather slowly
if your final thermal is weak, and rather fast if that thermal is strong, and
don't pay any attention to how fast the flight was before the final thermal.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Dan Marotta]

The Classic 1-26 - never more than 2 minutes from landing!

On 9/25/2019 10:02 AM, wrote:
> Yep, me too, did it old school for years and even this year flying the 1-26 championships in Moriarty where my flight.computer was inop. No big deal. Except with my bird its more like 350 ft/mile lol I usually ballpark 4mi/1,000ft with the sink and the ever present headwinds lol.

--
Dan, 5J

[[email protected]]

On Wednesday, September 25, 2019 at 2:14:48 PM UTC-4, Eric Greenwell wrote:
> unclhank... wrote on 9/25/2019 5:41 AM:
> > On Tuesday, September 24, 2019 at 8:14:29 PM UTC-4, wrote:
> >> Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.
> >
> > The "perfect" final glide has the pilot crossing the finish at his selected height and at at the same speed as the average for the flight.
>
> You don't really do that, do you? I'll bet you fly the final glide rather slowly
> if your final thermal is weak, and rather fast if that thermal is strong, and
> don't pay any attention to how fast the flight was before the final thermal.

That depends on the task. The MacCready theory for final glide speed that depends only on the climb rate in the last thermal applies to assigned tasks. AATs (TATs) are different, *if* your decision (last thermal) happens before the last turn, so that you can then choose, e.g., to fly farther into the last turn area but do the whole final glide (from the last thermal to the turn to the finish) slower. In that case, the optimal speed is the MC STF that corresponds to the average climb rate over the whole task. Yeah I know it sounds weird. Reference: the Brigliadoris' book.

[[email protected]]

On Wednesday, September 25, 2019 at 2:31:32 PM UTC-4, wrote:
> On Wednesday, September 25, 2019 at 2:14:48 PM UTC-4, Eric Greenwell wrote:
> > unclhank... wrote on 9/25/2019 5:41 AM:
> > > On Tuesday, September 24, 2019 at 8:14:29 PM UTC-4, wrote:
> > >> Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.
> > >
> > > The "perfect" final glide has the pilot crossing the finish at his selected height and at at the same speed as the average for the flight.
> >
> > You don't really do that, do you? I'll bet you fly the final glide rather slowly
> > if your final thermal is weak, and rather fast if that thermal is strong, and
> > don't pay any attention to how fast the flight was before the final thermal.
>
> That depends on the task. The MacCready theory for final glide speed that depends only on the climb rate in the last thermal applies to assigned tasks. AATs (TATs) are different, *if* your decision (last thermal) happens before the last turn, so that you can then choose, e.g., to fly farther into the last turn area but do the whole final glide (from the last thermal to the turn to the finish) slower. In that case, the optimal speed is the MC STF that corresponds to the average climb rate over the whole task. Yeah I know it sounds weird. Reference: the Brigliadoris' book.

I was commenting related to a preceding post that mentioned being very fast at the line. To have enough energy to be very fast one usually will have flown too slowly earlier in the final glide (assumes that one did not encounter surprise of very good air along the way). We used to do that so we had enough energy to pull up to fly a pattern. We pretty much don't do that any more.
UH

[Jonathan St. Cloud]

On Wednesday, September 25, 2019 at 8:16:19 AM UTC-7, wrote:
> On Wednesday, September 25, 2019 at 10:27:12 AM UTC-4, Dan Marotta wrote:
> > 200'/mile works out to 30:1 since we all use nautical miles, don't we?Â*
> > That may work just fine back east, but out west not so much. It's
> > disconcerting to see on the CNII that I need 20:1 to get home but I
> > can't seem to do better than 15:1.Â* Yes, we have strong thermals, but we
> > also have some very impressive sink!
> >
> > On 9/25/2019 8:11 AM, Tango Eight wrote:
> > > On Wednesday, September 25, 2019 at 9:55:44 AM UTC-4, wrote:
> > >> Uncl, that is absolutely correct and what I was trying to express. The "perfect" flight would be one of relatively constant avg speed with little difference between normal task cruise avg speed and the final glide speed.
> > >>
> > >> We all know however that that does'nt happen. Most of us do the best we can till we think we have our final glide in hand then modify our speed as we head on in depending on whats happening with our altitude.
> > >>
> > >> On a related question, I wonder how many folks here could calculate and perform a successful/efficient final glide without their handy dandy flight computers?
> > > 200' per mile plus 1000', and you get home, even in an HP-18 :-). Back in the day an LNav was 20% of the cost of my glider and GPS wasn't even a thing yet. I had circles drawn on a map and eyeballs to check position. Worked every time, wasn't so hard.
> > >
> > > T8
> >
> > --
> > Dan, 5J
>
> Most people I know use statute miles. I teach using 5 miles/1000 ft as a good final glide reference for Std or 15M ships. Easy to calculate. Adjust for conditions. Pretty much what Evan described but easier to calculate with GPS distance and altimeter.
> UH

I have been having a fun summer teaching a Dou XL owner to fly XC. His GPS nor mine was not working for several months and I know the LX9XXX pretty well but didn't know his CNII so we have been using the method I first learnt, 5 statute miles per 1000 ft. We also worked hard on judging distances and estimating what our glide (altitude we would lose enroute) to any cloud, ridge, airport, all glides must be estimated and told out loud. For longer final glides, rather than use something other than 5 miles per thousand, we would add 5, 10 or 15 miles to our estimated distance as a safety factor. We also visually judged and evaluated each glide by the target moving up or down on canopy so we could quickly ascertain how our glide was going. I so much enjoyed the first part of the summer without the computer than we still are not using, at least in the back seat I am not.

[Eric Greenwell[_4_]]

wrote on 9/25/2019 11:31 AM:
> On Wednesday, September 25, 2019 at 2:14:48 PM UTC-4, Eric Greenwell wrote:
>> unclhank... wrote on 9/25/2019 5:41 AM:
>>> On Tuesday, September 24, 2019 at 8:14:29 PM UTC-4, wrote:
>>>> Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.
>>>
>>> The "perfect" final glide has the pilot crossing the finish at his selected height and at at the same speed as the average for the flight.
>>
>> You don't really do that, do you? I'll bet you fly the final glide rather slowly
>> if your final thermal is weak, and rather fast if that thermal is strong, and
>> don't pay any attention to how fast the flight was before the final thermal.
>
> That depends on the task. The MacCready theory for final glide speed that depends only on the climb rate in the last thermal applies to assigned tasks. AATs (TATs) are different, *if* your decision (last thermal) happens before the last turn, so that you can then choose, e.g., to fly farther into the last turn area but do the whole final glide (from the last thermal to the turn to the finish) slower. In that case, the optimal speed is the MC STF that corresponds to the average climb rate over the whole task. Yeah I know it sounds weird. Reference: the Brigliadoris' book.

That does sound weird, but I stopped flying contests before the turn areas offered
a large range of choices. Does going farther in that situation add more points,
compared to going faster?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[Eric Greenwell[_4_]]

Jonathan St. Cloud wrote on 9/25/2019 12:27 PM:
>>>>> On a related question, I wonder how many folks here could calculate and perform a successful/efficient final glide without their handy dandy flight computers?
>>>> 200' per mile plus 1000', and you get home, even in an HP-18 :-). Back in the day an LNav was 20% of the cost of my glider and GPS wasn't even a thing yet. I had circles drawn on a map and eyeballs to check position. Worked every time, wasn't so hard.
>> Most people I know use statute miles. I teach using 5 miles/1000 ft as a good final glide reference for Std or 15M ships. Easy to calculate. Adjust for conditions. Pretty much what Evan described but easier to calculate with GPS distance and altimeter.
>> UH
>
> I have been having a fun summer teaching a Dou XL owner to fly XC. His GPS nor mine was not working for several months and I know the LX9XXX pretty well but didn't know his CNII so we have been using the method I first learnt, 5 statute miles per 1000 ft. We also worked hard on judging distances and estimating what our glide (altitude we would lose enroute) to any cloud, ridge, airport, all glides must be estimated and told out loud. For longer final glides, rather than use something other than 5 miles per thousand, we would add 5, 10 or 15 miles to our estimated distance as a safety factor. We also visually judged and evaluated each glide by the target moving up or down on canopy so we could quickly ascertain how our glide was going. I so much enjoyed the first part of the summer without the computer than we still are not using, at least in the back seat I am not.

How do you account for wind? That's a real value of the GPS base flight computers,
I think.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorgliders/publications/download-the-guide-1

[[email protected]]

"Back in the day" I used a homemade cardboard circular-slide-rule-type final glide calculator. It had distance and altitude scales, an airspeed scale, and curves for different winds. You set the distance and altitude and flew the speed according to the estimated wind. As the checkpoints went by, you adjusted the alt/dist to actuals and rapidly homed in on the approximate actual wind (conceptually similar to a pre-GPS LNAV, I believe). The finish margin was whatever you wanted it to be mentally. This was how REAL pilots flew: i.e., using a Sectional chart and compass. :)

I still keep it tucked away in my cockpit for sanity checks when my moving map shows me multiple altitude margins, including margin to gliding to the home airport, margin over the edge of the finish cylinder at finish height, margin to the center of the finish cylinder at ground level, etc. And then my CN vario shows its own altitude, which, as T8 helpfully explained, is always different, apparently based on total energy conserved in a pull up.

I can trust cardboard. It only offers one version of the truth, although it, too, can be fooled by sink, as happened twice this year on final glides at the CCSC Std. Nats that should have been straightforward but were anything but.

Chip Bearden
JB

[[email protected]]

On Wednesday, September 25, 2019 at 3:45:29 PM UTC-4, Eric Greenwell wrote:
> moshe... wrote on 9/25/2019 11:31 AM:
> > On Wednesday, September 25, 2019 at 2:14:48 PM UTC-4, Eric Greenwell wrote:
> >> unclhank... wrote on 9/25/2019 5:41 AM:
> >>> On Tuesday, September 24, 2019 at 8:14:29 PM UTC-4, wrote:
> >>>> Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.
> >>>
> >>> The "perfect" final glide has the pilot crossing the finish at his selected height and at at the same speed as the average for the flight.
> >>
> >> You don't really do that, do you? I'll bet you fly the final glide rather slowly
> >> if your final thermal is weak, and rather fast if that thermal is strong, and
> >> don't pay any attention to how fast the flight was before the final thermal.
> >
> > That depends on the task. The MacCready theory for final glide speed that depends only on the climb rate in the last thermal applies to assigned tasks. AATs (TATs) are different, *if* your decision (last thermal) happens before the last turn, so that you can then choose, e.g., to fly farther into the last turn area but do the whole final glide (from the last thermal to the turn to the finish) slower. In that case, the optimal speed is the MC STF that corresponds to the average climb rate over the whole task. Yeah I know it sounds weird. Reference: the Brigliadoris' book.
>
> That does sound weird, but I stopped flying contests before the turn areas offered
> a large range of choices. Does going farther in that situation add more points,
> compared to going faster?
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Assuming you won't finish under-time either way, going farther (up to a point) gives you more points since it increases the overall task speed (total distance divided by total time). The conditions (average climb rate) determine the best XC speed you can get, along with the STF between climbs, and since the distance is flexible you can maintain that speed for the best score.

What is not clear to me is how do you then decide when to leave that last thermal? Perhaps when the climb rate falls below that average climb rate? Assuming you have enough altitude to reach into the last turn area by that point.

[[email protected]]

On Wednesday, September 25, 2019 at 4:42:56 PM UTC-4, wrote:
> On Wednesday, September 25, 2019 at 3:45:29 PM UTC-4, Eric Greenwell wrote:
> > moshe... wrote on 9/25/2019 11:31 AM:
> > > On Wednesday, September 25, 2019 at 2:14:48 PM UTC-4, Eric Greenwell wrote:
> > >> unclhank... wrote on 9/25/2019 5:41 AM:
> > >>> On Tuesday, September 24, 2019 at 8:14:29 PM UTC-4, wrote:
> > >>>> Truth, and a final glide made at max l/d tells me that the guy already screwed up. The perfect final glide is one that gets you home at the proper altitude and at the max speed. He just screwed up on both counts.
> > >>>
> > >>> The "perfect" final glide has the pilot crossing the finish at his selected height and at at the same speed as the average for the flight.
> > >>
> > >> You don't really do that, do you? I'll bet you fly the final glide rather slowly
> > >> if your final thermal is weak, and rather fast if that thermal is strong, and
> > >> don't pay any attention to how fast the flight was before the final thermal.
> > >
> > > That depends on the task. The MacCready theory for final glide speed that depends only on the climb rate in the last thermal applies to assigned tasks. AATs (TATs) are different, *if* your decision (last thermal) happens before the last turn, so that you can then choose, e.g., to fly farther into the last turn area but do the whole final glide (from the last thermal to the turn to the finish) slower. In that case, the optimal speed is the MC STF that corresponds to the average climb rate over the whole task. Yeah I know it sounds weird. Reference: the Brigliadoris' book.
> >
> > That does sound weird, but I stopped flying contests before the turn areas offered
> > a large range of choices. Does going farther in that situation add more points,
> > compared to going faster?
> >
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "A Guide to Self-Launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> Assuming you won't finish under-time either way, going farther (up to a point) gives you more points since it increases the overall task speed (total distance divided by total time). The conditions (average climb rate) determine the best XC speed you can get, along with the STF between climbs, and since the distance is flexible you can maintain that speed for the best score.
>
> What is not clear to me is how do you then decide when to leave that last thermal? Perhaps when the climb rate falls below that average climb rate? Assuming you have enough altitude to reach into the last turn area by that point.

For final glide:Based upon current climb rate, with MC set for that, the computer tells you when you are high enough to get back at the selected finish height. One also should adjust for what the sky looks like ahead, what the climb rate trend has been, how tight a margin can be accepted, and then adjusted by a gut factor.
Easy Peasy
UH

[Jonathan St. Cloud]

On Wednesday, September 25, 2019 at 12:49:22 PM UTC-7, Eric Greenwell wrote:
> Jonathan St. Cloud wrote on 9/25/2019 12:27 PM:
> >>>>> On a related question, I wonder how many folks here could calculate and perform a successful/efficient final glide without their handy dandy flight computers?
> >>>> 200' per mile plus 1000', and you get home, even in an HP-18 :-). Back in the day an LNav was 20% of the cost of my glider and GPS wasn't even a thing yet. I had circles drawn on a map and eyeballs to check position. Worked every time, wasn't so hard.
> >> Most people I know use statute miles. I teach using 5 miles/1000 ft as a good final glide reference for Std or 15M ships. Easy to calculate. Adjust for conditions. Pretty much what Evan described but easier to calculate with GPS distance and altimeter.
> >> UH
> >
> > I have been having a fun summer teaching a Dou XL owner to fly XC. His GPS nor mine was not working for several months and I know the LX9XXX pretty well but didn't know his CNII so we have been using the method I first learnt, 5 statute miles per 1000 ft. We also worked hard on judging distances and estimating what our glide (altitude we would lose enroute) to any cloud, ridge, airport, all glides must be estimated and told out loud. For longer final glides, rather than use something other than 5 miles per thousand, we would add 5, 10 or 15 miles to our estimated distance as a safety factor. We also visually judged and evaluated each glide by the target moving up or down on canopy so we could quickly ascertain how our glide was going. I so much enjoyed the first part of the summer without the computer than we still are not using, at least in the back seat I am not.
>
> How do you account for wind? That's a real value of the GPS base flight computers,
> I think.
>
> --
> Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> - "A Guide to Self-Launching Sailplane Operation"
> https://sites.google.com/site/motorgliders/publications/download-the-guide-1

Computers are nice and when flying the 29 I certainly use the LX9XXX. We guesstimate wind and add distance to target for headwind. But we are constantly visually checking glide. These are early xc skills that we all learned before GPS and computers. I thought it was very important to teach. I fly with wiz wheel in cockpit for backup but frankly would visually judge glides over using the wheel. I also want my student to develop the habit of mentally checking his computer. I have on two occasions with marginal glide been given faulting computer data. The other thing we work very hard on is judging glides and glide angles and how we are doing on glide.

[Craig Funston[_3_]]

On Wednesday, September 25, 2019 at 2:54:10 PM UTC-7, Jonathan St. Cloud wrote:
> On Wednesday, September 25, 2019 at 12:49:22 PM UTC-7, Eric Greenwell wrote:
> > Jonathan St. Cloud wrote on 9/25/2019 12:27 PM:
> > >>>>> On a related question, I wonder how many folks here could calculate and perform a successful/efficient final glide without their handy dandy flight computers?
> > >>>> 200' per mile plus 1000', and you get home, even in an HP-18 :-). Back in the day an LNav was 20% of the cost of my glider and GPS wasn't even a thing yet. I had circles drawn on a map and eyeballs to check position. Worked every time, wasn't so hard.
> > >> Most people I know use statute miles. I teach using 5 miles/1000 ft as a good final glide reference for Std or 15M ships. Easy to calculate. Adjust for conditions. Pretty much what Evan described but easier to calculate with GPS distance and altimeter.
> > >> UH
> > >
> > > I have been having a fun summer teaching a Dou XL owner to fly XC. His GPS nor mine was not working for several months and I know the LX9XXX pretty well but didn't know his CNII so we have been using the method I first learnt, 5 statute miles per 1000 ft. We also worked hard on judging distances and estimating what our glide (altitude we would lose enroute) to any cloud, ridge, airport, all glides must be estimated and told out loud. For longer final glides, rather than use something other than 5 miles per thousand, we would add 5, 10 or 15 miles to our estimated distance as a safety factor. We also visually judged and evaluated each glide by the target moving up or down on canopy so we could quickly ascertain how our glide was going. I so much enjoyed the first part of the summer without the computer than we still are not using, at least in the back seat I am not.
> >
> > How do you account for wind? That's a real value of the GPS base flight computers,
> > I think.
> >
> > --
> > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > - "A Guide to Self-Launching Sailplane Operation"
> > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
>
> Computers are nice and when flying the 29 I certainly use the LX9XXX. We guesstimate wind and add distance to target for headwind. But we are constantly visually checking glide. These are early xc skills that we all learned before GPS and computers. I thought it was very important to teach. I fly with wiz wheel in cockpit for backup but frankly would visually judge glides over using the wheel. I also want my student to develop the habit of mentally checking his computer. I have on two occasions with marginal glide been given faulting computer data. The other thing we work very hard on is judging glides and glide angles and how we are doing on glide.

Lots of good analytical information from John Cochrane. Definitely worth the read.

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=2ahUKEwjar8u2j-3kAhVSvJ4KHZ91DS0QFjABegQIAhAC&url=https%3A%2F%2Ffaculty.chicagobooth.edu%2Fjohn. cochrane%2Fsoaring%2Fdocs%2Fsafety_glides.pdf&usg=AOvVaw2DlLAr6TzsYoqkBwBcDCSY

[Craig Funston[_3_]]

On Wednesday, September 25, 2019 at 4:26:19 PM UTC-7, Craig Funston wrote:
> On Wednesday, September 25, 2019 at 2:54:10 PM UTC-7, Jonathan St. Cloud wrote:
> > On Wednesday, September 25, 2019 at 12:49:22 PM UTC-7, Eric Greenwell wrote:
> > > Jonathan St. Cloud wrote on 9/25/2019 12:27 PM:
> > > >>>>> On a related question, I wonder how many folks here could calculate and perform a successful/efficient final glide without their handy dandy flight computers?
> > > >>>> 200' per mile plus 1000', and you get home, even in an HP-18 :-).. Back in the day an LNav was 20% of the cost of my glider and GPS wasn't even a thing yet. I had circles drawn on a map and eyeballs to check position. Worked every time, wasn't so hard.
> > > >> Most people I know use statute miles. I teach using 5 miles/1000 ft as a good final glide reference for Std or 15M ships. Easy to calculate. Adjust for conditions. Pretty much what Evan described but easier to calculate with GPS distance and altimeter.
> > > >> UH
> > > >
> > > > I have been having a fun summer teaching a Dou XL owner to fly XC. His GPS nor mine was not working for several months and I know the LX9XXX pretty well but didn't know his CNII so we have been using the method I first learnt, 5 statute miles per 1000 ft. We also worked hard on judging distances and estimating what our glide (altitude we would lose enroute) to any cloud, ridge, airport, all glides must be estimated and told out loud. For longer final glides, rather than use something other than 5 miles per thousand, we would add 5, 10 or 15 miles to our estimated distance as a safety factor. We also visually judged and evaluated each glide by the target moving up or down on canopy so we could quickly ascertain how our glide was going. I so much enjoyed the first part of the summer without the computer than we still are not using, at least in the back seat I am not.
> > >
> > > How do you account for wind? That's a real value of the GPS base flight computers,
> > > I think.
> > >
> > > --
> > > Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
> > > - "A Guide to Self-Launching Sailplane Operation"
> > > https://sites.google.com/site/motorgliders/publications/download-the-guide-1
> >
> > Computers are nice and when flying the 29 I certainly use the LX9XXX. We guesstimate wind and add distance to target for headwind. But we are constantly visually checking glide. These are early xc skills that we all learned before GPS and computers. I thought it was very important to teach. I fly with wiz wheel in cockpit for backup but frankly would visually judge glides over using the wheel. I also want my student to develop the habit of mentally checking his computer. I have on two occasions with marginal glide been given faulting computer data. The other thing we work very hard on is judging glides and glide angles and how we are doing on glide.
>
> Lots of good analytical information from John Cochrane. Definitely worth the read.
>
> https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=2ahUKEwjar8u2j-3kAhVSvJ4KHZ91DS0QFjABegQIAhAC&url=https%3A%2F%2Ffaculty.chicagobooth.edu%2Fjohn. cochrane%2Fsoaring%2Fdocs%2Fsafety_glides..pdf&usg=AOvVaw2DlLAr6TzsYoqkBwBcDCSY

Or for a deeper dive, Daniel Saznin, et. al. excellent paper on probability in soaring is available here.
https://engrxiv.org/yqgkc/