Are 'Single 180 Turn From Downwind to Final' and 'Stall-spin on Turnfrom Base to Final' mutually exclusive?

Evan,
Flying a pattern with the intention of 50% spoilers is to provide the safety buffer in both directions (high and low), rather than needing to adjust your ground track and preserve the sacred rectangular pattern. While you are completely correct that most spoilers can cure your excessive altitude problems in the pattern, if you fly a pattern that is sized to not need any spoilers/airbrakes and you are too low, you must now change your pattern rather than closing the airbrakes a bit. It is mostly about making the size of your pattern halfway between what would be required for a no-spoilers pattern and a full spoilers pattern.

Chris

On Sunday, July 31, 2016 at 8:08:51 AM UTC-4, Giaco wrote:
Evan,
Flying a pattern with the intention of 50% spoilers is to provide the safety buffer in both directions (high and low), rather than needing to adjust your ground track and preserve the sacred rectangular pattern. While you are completely correct that most spoilers can cure your excessive altitude problems in the pattern, if you fly a pattern that is sized to not need any spoilers/airbrakes and you are too low, you must now change your pattern rather than closing the airbrakes a bit. It is mostly about making the size of your pattern halfway between what would be required for a no-spoilers pattern and a full spoilers pattern.

Chris

Hi Chris,

In a word -- baloney! Read it again:

On Saturday, July 30, 2016 at 12:51:25 AM UTC-4, son_of_flubber wrote:
My default procedure is to set spoilers to 50% open, then adjust pattern shape to make my aim point.

That is a very different SOP / not something I ever do / not something I plan to teach / something I would likely intercept and work on correcting if a pilot brought it to my club.

I like Tom's emphasis on best practices.

See ya,

Evan

Maybe I misunderstood, but Flub’s description of his approach technique seems very mechanical and/or contrived. To me it seems very similar to how I was taught in a 2-33 using Joy of Soaring, except instead of “being at 500 feet over the red barn� he keeps 50% spoiler and moves his ground track toward and away from the airport.

Tom Knauff transitioned me into my ASW-19 at Ridge Soaring, and of course he taught me to use TLAR. What I took away from him was to “always look and judge how the approach is going�, and to do what you had to do with the controls to put the glider into the proper position. Those of you who’ve flown at Ridge Soaring know that the approach to 25 is never amenable to recipe flying...

Tom’s TLAR has served me well during both routine and very tricky approaches. Honestly I couldn’t tell you where my spoilers are, unless I hit either the forward or aft limit while reacting to extreme sink or lift. But I can always tell you if I’m too high or too low! And during every approach I always hear my instructor Jack chanting “airspeed, yaw string�, over and over.

-John, Q3

I may have mentioned this before, but the series of my articles and tests currently being printed in Soaring magazine will continue for a few more months. As a result of this discussion, I am submitting a rather lengthy article about landing procedures / technique. My guess is it will not be published until early next year.

If I send in two pages of my popular Glider Flight Training Manual each month, it will take 15 years to publish all the information it contains.

You might consider upgrading to this new version rather than waiting.

Tom Knauff

On Sunday, July 31, 2016 at 11:46:23 AM UTC-7, wrote:
I may have mentioned this before, but the series of my articles and tests currently being printed in Soaring magazine will continue for a few more months. As a result of this discussion, I am submitting a rather lengthy article about landing procedures / technique. My guess is it will not be published until early next year.

If I send in two pages of my popular Glider Flight Training Manual each month, it will take 15 years to publish all the information it contains.

You might consider upgrading to this new version rather than waiting.

Tom Knauff

I thought of four situations when this "military",or button hook, landing pattern MIGHT be appropriate:

1. Terrain/buildings forced a tight base leg, such as an airstrip in a canyon.
2. Remaining altitude is at an absolute minimum for landing.
3. Unusual local weather conditions, like microbursts, are occurring.
4. The pilot wanted to impress his/her girl/boyfriend (just JOKING!).

In all other situations a square pattern (or a modified square pattern) is far safer. Flying a button hook pattern puts the runway out of sight to the pilot, so it is hard to judge how far you have flown, making it much more likely that an overshoot or undershoot landing will occur.

An important aspect of the square pattern, in addition to the visibility part, is to assess the winds aloft by the amount of crab required. I have been flying lately in conditions of high cross winds (10-20 kt) and even higher gusts (20-30 kt). Having a stabilized base leg is essential to judge this (the AWOS is just to old to be relied upon). If I were to fly a button hook pattern I would have a ground speed of 110-130 kt, given the high density altitudes we are flying and an 80 kt IAS (100 kt TAS + 10-30 kt tail wind)! This translates to up to 220 ft/sec (a 180 deg turn takes 10-20 sec and complicates the design point on when to start the turn). If you hit unexpected sinking air during this turn you could be in a real pickle! You may not experience these conditions where you fly, but a lot of accidents occur when flatlanders venture into high density altitude airports.

I also like to have A LOT of altitude when entering the pattern (2,000 ft). It is easy to burn off that altitude in modern gliders and it gives me options if something unexpected happens (like a plane pulling out onto the runway unannounced). Altitude lost is like runway behind you - it doesn't do you any good.

Tom

Hi Chris,

In a word -- baloney! Read it again:

On Saturday, July 30, 2016 at 12:51:25 AM UTC-4, son_of_flubber wrote:
My default procedure is to set spoilers to 50% open, then adjust pattern shape to make my aim point.

That is a very different SOP / not something I ever do / not something I plan to teach / something I would likely intercept and work on correcting if a pilot brought it to my club.

I like Tom's emphasis on best practices.

See ya,

Evan

Sorry, i totally misread that... That pattern makes no sense to me then if you are just setting an arbitrary airbrake setting and building a pattern around it.

One consideration I don't think was mentioned; A straight base leg gives the pilot a chance to really look hard for head-on traffic in the opposite pattern. A situation that killed a friend of mine.

Matt

An AOPA article states that the AOPA Safety Institute and University of North Dakota are studying the "circular vs rectangular" pattern as a result of the NTSB "Most Wanted Safety Improvements. It'll be interesting to see what the study produces.

To reply to the subject question in a word: NO.

You can stall and spin from any attitude or airspeed. All you have to
do is plan and execute it correctly or simply f*ck up the turn.

On 11/18/2016 6:25 AM, wrote:
An AOPA article states that the AOPA Safety Institute and University of North Dakota are studying the "circular vs rectangular" pattern as a result of the NTSB "Most Wanted Safety Improvements. It'll be interesting to see what the study produces.

--
Dan, 5J

On Friday, November 18, 2016 at 8:06:21 AM UTC-8, Dan Marotta wrote:
To reply to the subject question in a word: NO.

You can stall and spin from any attitude or airspeed. All you have to
do is plan and execute it correctly or simply f*ck up the turn.

On 11/18/2016 6:25 AM, wrote:
An AOPA article states that the AOPA Safety Institute and University of North Dakota are studying the "circular vs rectangular" pattern as a result of the NTSB "Most Wanted Safety Improvements. It'll be interesting to see what the study produces.

--
Dan, 5J

It's REALLY hard to spin while flying coordinated - if you know of a way I would truly like to know. It is also tough to stall while flying coordinated because it takes a very high angle of attack and you would really have to work it keeping the glider coordinated as you approach stall. The FAA is emphasizing an angle of attack indicator to prevent spins; I think what is needed is an audible flight coordination indicator. In our gliders we have a heads-up flight coordination indicator which is even better - it's called a yaw string (but you have to look at it and react to it).

Tom