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The Yellow Triangle



 
 
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  #11  
Old February 17th 21, 04:21 PM posted to rec.aviation.soaring
Eric Greenwell[_4_]
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Posts: 1,894
Default The Yellow Triangle

Hank Nixon wrote on 2/17/2021 6:08 AM:
On Tuesday, February 16, 2021 at 9:04:14 PM UTC-5, wrote:

....
T

In my experience, the minimum approach speeds given in the POH and labelled with the yellow triangle are pretty spot on where they need to be. My ASW-20B (48 kts) was perfect. My ASW-27 (54 kts) could be 50-52. Not really a big deal. These are recommended minimums. Like any other glider pilot I have had occasion to fly much faster approaches, appropriate to conditions. Best practices are scenario dependent.

I typically fly 65 in the pattern in a glass ship (unless I need to loiter), I choose whatever speed I need to for my approach. In light conditions, it's usually right on the yellow triangle. I fly in the land of small-ish agricultural fields. It just makes sense to be good at this.

If you want to assess your margin, put the ship in landing configuration at altitude and do a slow deceleration to full stall. You might be surprised.

T8

I'm with Evan on this.
The modern ships, with more powerful brakes than the old days, and many with flaps, allow adding some margin with the ability to shed
the excess energy fairly quickly when needed. Not so much on the older ships where speed control is important.
Going into a field, all things being equal, I will be at the yellow triangle coming over the border to the field.
It is important that this be a decision and not habit because we revert to habit in stress situations and that can lead to excess energy going into a tight space.
My observation is that more ships get broken due to too much energy in field landings than too little.
Flame suit on.
UH


A long time ago, the Brits had the rule "it's better to hit the far hedge slowly than the near
hedge quickly". I wonder if they still find that rule useful.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
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  #12  
Old February 17th 21, 05:47 PM posted to rec.aviation.soaring
[email protected]
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Posts: 225
Default The Yellow Triangle

On Wednesday, February 17, 2021 at 11:21:47 AM UTC-5, Eric Greenwell wrote:
Hank Nixon wrote on 2/17/2021 6:08 AM:
On Tuesday, February 16, 2021 at 9:04:14 PM UTC-5, wrote:

...
T
In my experience, the minimum approach speeds given in the POH and labelled with the yellow triangle are pretty spot on where they need to be. My ASW-20B (48 kts) was perfect. My ASW-27 (54 kts) could be 50-52. Not really a big deal. These are recommended minimums. Like any other glider pilot I have had occasion to fly much faster approaches, appropriate to conditions.. Best practices are scenario dependent.

I typically fly 65 in the pattern in a glass ship (unless I need to loiter), I choose whatever speed I need to for my approach. In light conditions, it's usually right on the yellow triangle. I fly in the land of small-ish agricultural fields. It just makes sense to be good at this.

If you want to assess your margin, put the ship in landing configuration at altitude and do a slow deceleration to full stall. You might be surprised.

T8

I'm with Evan on this.
The modern ships, with more powerful brakes than the old days, and many with flaps, allow adding some margin with the ability to shed
the excess energy fairly quickly when needed. Not so much on the older ships where speed control is important.
Going into a field, all things being equal, I will be at the yellow triangle coming over the border to the field.
It is important that this be a decision and not habit because we revert to habit in stress situations and that can lead to excess energy going into a tight space.
My observation is that more ships get broken due to too much energy in field landings than too little.
Flame suit on.
UH

A long time ago, the Brits had the rule "it's better to hit the far hedge slowly than the near
hedge quickly". I wonder if they still find that rule useful.

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

The problem that UH has identified is the lack of training for low energy landings. I often see pilots scorching down the runway bleeding off speed so that they can arrive at the desired point. If these same pilots were forced to make an off field landing with little or no margin for extra speed the would be in serious trouble. Practice does not make perfect, but prefect practice will result in near perfect results. There is no substitute for being prepared for what can and will at some point happen.
  #13  
Old February 17th 21, 11:49 PM posted to rec.aviation.soaring
6PK
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Posts: 241
Default The Yellow Triangle; Spot on

On Wednesday, February 17, 2021 at 7:32:39 AM UTC-8, Christoph Barniske wrote:
The yellow triangle marks is defined in CS 22.145 as the lowest approach speed (at maximum weight without water ballast) recommended by the manufacturer. So it should be treated as a minimum value without any margins.

Christoph

  #14  
Old February 17th 21, 11:51 PM posted to rec.aviation.soaring
6PK
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Posts: 241
Default The Yellow Triangle

Spot on On Wednesday, February 17, 2021 at 3:50:01 PM UTC-8, 6PK wrote:
On Wednesday, February 17, 2021 at 7:32:39 AM UTC-8, Christoph Barniske wrote:
The yellow triangle marks is defined in CS 22.145 as the lowest approach speed (at maximum weight without water ballast) recommended by the manufacturer. So it should be treated as a minimum value without any margins.

Christoph

  #15  
Old February 17th 21, 11:54 PM posted to rec.aviation.soaring
6PK
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Posts: 241
Default The Yellow Triangle

On Wednesday, February 17, 2021 at 3:51:33 PM UTC-8, 6PK wrote:
Spot on On Wednesday, February 17, 2021 at 3:50:01 PM UTC-8, 6PK wrote:
On Wednesday, February 17, 2021 at 7:32:39 AM UTC-8, Christoph Barniske wrote:
The yellow triangle marks is defined in CS 22.145 as the lowest approach speed (at maximum weight without water ballast) recommended by the manufacturer. So it should be treated as a minimum value without any margins.

Christoph

Spot on!
  #16  
Old February 18th 21, 04:01 AM posted to rec.aviation.soaring
Charlie M. (UH & 002 owner/pilot)
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Posts: 1,380
Default The Yellow Triangle

On Wednesday, February 17, 2021 at 12:47:03 PM UTC-5, wrote:
On Wednesday, February 17, 2021 at 11:21:47 AM UTC-5, Eric Greenwell wrote:
Hank Nixon wrote on 2/17/2021 6:08 AM:
On Tuesday, February 16, 2021 at 9:04:14 PM UTC-5, wrote:

...
T
In my experience, the minimum approach speeds given in the POH and labelled with the yellow triangle are pretty spot on where they need to be. My ASW-20B (48 kts) was perfect. My ASW-27 (54 kts) could be 50-52. Not really a big deal. These are recommended minimums. Like any other glider pilot I have had occasion to fly much faster approaches, appropriate to conditions. Best practices are scenario dependent.

I typically fly 65 in the pattern in a glass ship (unless I need to loiter), I choose whatever speed I need to for my approach. In light conditions, it's usually right on the yellow triangle. I fly in the land of small-ish agricultural fields. It just makes sense to be good at this.

If you want to assess your margin, put the ship in landing configuration at altitude and do a slow deceleration to full stall. You might be surprised.

T8
I'm with Evan on this.
The modern ships, with more powerful brakes than the old days, and many with flaps, allow adding some margin with the ability to shed
the excess energy fairly quickly when needed. Not so much on the older ships where speed control is important.
Going into a field, all things being equal, I will be at the yellow triangle coming over the border to the field.
It is important that this be a decision and not habit because we revert to habit in stress situations and that can lead to excess energy going into a tight space.
My observation is that more ships get broken due to too much energy in field landings than too little.
Flame suit on.
UH

A long time ago, the Brits had the rule "it's better to hit the far hedge slowly than the near
hedge quickly". I wonder if they still find that rule useful.

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

The problem that UH has identified is the lack of training for low energy landings. I often see pilots scorching down the runway bleeding off speed so that they can arrive at the desired point. If these same pilots were forced to make an off field landing with little or no margin for extra speed the would be in serious trouble. Practice does not make perfect, but prefect practice will result in near perfect results. There is no substitute for being prepared for what can and will at some point happen.

Part of the changes in the HHSC "Snowbird" contest over the last few decades....basically, if you do well at the contest, you have off airport skills....
  #17  
Old February 18th 21, 12:48 PM posted to rec.aviation.soaring
Tango Eight
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Posts: 957
Default The Yellow Triangle

There is margin at the yellow triangle.

ASW-20B, landing flaps + full spoilers on final, spoilers held open all the way to wheel stopped.

Touch down is tail first, landing roll 200', disk brake on hard but not rubbing nose in the dirt.

https://www.youtube.com/watch?v=oBexl9GfKK0

T8
  #18  
Old February 18th 21, 01:02 PM posted to rec.aviation.soaring
India November[_2_]
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Posts: 30
Default The Yellow Triangle

On Wednesday, February 17, 2021 at 10:32:39 AM UTC-5, Christoph Barniske wrote:
The yellow triangle marks is defined in CS 22.145 as the lowest approach speed (at maximum weight without water ballast) recommended by the manufacturer. So it should be treated as a minimum value without any margins.

Christoph


To be clear, my Discus 2b flight manual states the yellow triangle is the lowest approach speed at maximum mass without water ballast, with air brakes fully extended and landing gear down. For the D2B the triangle is marked at 54 kt IAS. That's over 20kts faster than the stall speed given in the flight manual for the same configuration.

In normal calm conditions where I fly near Ottawa, I try to be at, or just a few kts faster, than the bug speed on final approach but faster depending on wind and gust conditions.

Ian IN
  #19  
Old February 18th 21, 01:11 PM posted to rec.aviation.soaring
Eric Greenwell[_4_]
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Posts: 1,894
Default The Yellow Triangle

Nicholas Kennedy wrote on 2/16/2021 4:56 PM:
On many German gliders on the ASI is a yellow triangle.
This Yelloe Triangle on my ASw 20 and my LS3a is the factory recommended approach airspeed. This speed is 49 knots.
This has bothered me for a long time now, I think the factory did alot of pilots a disservice by putting this, to me anyway, very low number on there.
On both the above gliders, the max speed, normal landing flap flaps down, is 86 knots.
About 15 years ago my Gold Seal flight instructor Bob Faris, CX,indicated to me in his LS3 he planned on a much higher speed in the pattern, like 70-75 knots depending on conditions. I followed suit ever since.


Since so many gliders have 49 knots for the Yellow Triangle, I think this might be a regulatory
requirement, not a choice by the glider manufacturer. Perhaps gliders are required to have an
approach speed no higher than 49 knots at a certain weight with the regulation required control
authority.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
  #20  
Old February 18th 21, 02:37 PM posted to rec.aviation.soaring
India November[_2_]
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Posts: 30
Default The Yellow Triangle

On Thursday, February 18, 2021 at 8:11:35 AM UTC-5, Eric Greenwell wrote:
Nicholas Kennedy wrote on 2/16/2021 4:56 PM:
On many German gliders on the ASI is a yellow triangle.
This Yelloe Triangle on my ASw 20 and my LS3a is the factory recommended approach airspeed. This speed is 49 knots.
This has bothered me for a long time now, I think the factory did alot of pilots a disservice by putting this, to me anyway, very low number on there.
On both the above gliders, the max speed, normal landing flap flaps down, is 86 knots.
About 15 years ago my Gold Seal flight instructor Bob Faris, CX,indicated to me in his LS3 he planned on a much higher speed in the pattern, like 70-75 knots depending on conditions. I followed suit ever since.

Since so many gliders have 49 knots for the Yellow Triangle, I think this might be a regulatory
requirement, not a choice by the glider manufacturer. Perhaps gliders are required to have an
approach speed no higher than 49 knots at a certain weight with the regulation required control
authority.
--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1


My D2B says 54 kts. The standard does not fix a given speed.
IN
 




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