S-turns on final

On Friday, February 17, 2017 at 9:15:13 AM UTC-7, Don Johnstone wrote:
Time was when we used to teach S turns, both for final approach and
launch failures, and this was fine in slow, wooden open cockpit gliders.
We also taught slipping. Pitching nose down 10 or even 20 degrees in
a T21 when side slipping was not a problem, doing the same in a
modern glass glider certainly is, especially when you stop the slip, the
glider will accelerate rapidly, unlike the T21 which did not understand
acceleration.
The difference is between what we teach, which has very little do do
with what is possible to do. Modern teaching tends towards getting the
circuit right so that the "emergency" procedures are not needed.
Modern airbrakes tend to be so good that even if you get it wrong they
are all that is needed.
S turns and sideslips are perfectly valid solutions, just not something
you want to teach a low hours pilot, concentrating on getting the
circuit right and effective use of airbrake is much safer.
I still fly a T21 and sideslip a lot. I sideslip very little in glass ships
as
proper use of airbrake, at the correct speed, is much more effective.

Last time I slipped in a T21 my hat and sunglasses blew off. S turns are more comfortable in an open-cockpit!

Mike

On Sunday, 19 February 2017 06:35:49 UTC+2, Eric Greenwell wrote:
The technique is simple and easy to learn. Just don't start out with the
extreme version John related! Basically, you are just increasing the
rate of energy/altitude loss by 2 or 3 times normal by using full
spoiler at high speeds. Try this for starters:

-enter the pattern at least 1000' AGL
-fly the pattern all the way until after you've turned final...NO
spoilers or sideslip
-continue down final without spoilers or side slip until it seems you
are almost too high to get down to your aim point with full spoilers
-open the spoilers fully, point the nose down until you are going 80-90
knots (but NO MORE than the max allowed speed for your landing
configuration - flap setting is the usual thing limiting the allowed speed)
-When the angle to your aim point looks about right for a half-spoiler
approach, pull the nose up gradually to maintain that angle
-when your speed drops to the desired speed on final, retract the
spoilers to one-half
-proceed with a normal landing

Use the technique a few times, and it won't seem very extreme at all.
The altitude loss is very rapid with full spoiler, gear down, and high
speeds, and it's very effective at dumping excess altitude.

--
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
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf


The irony of reading this, and then discovering link to something called "soaringsafety" below.

On Sun, 19 Feb 2017 02:11:37 -0800, krasw wrote:

The irony of reading this, and then discovering link to something called
"soaringsafety" below.

No irony: there's nothing dangerous about using brakes to scrub off
excess height - its easy-peasy in a Discus 1 or K21: just follow Eric's
excellent directions if you haven't done it before. Just make sure that
you're not trying it for the first time on a short runway. You shouldn't
need the extra length but it makes a nice comfort blanket.

I haven't tried it yet in my Libelle because I haven't needed to:
slipping one brings it down like a sack of anvils what with all the extra
drag from pushing its razor-back tail boom sideways.


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

For what is worth the the technique works in Condor. Application to meat world may vary.

On Sunday, 19 February 2017 13:33:25 UTC+2, Martin Gregorie wrote:
On Sun, 19 Feb 2017 02:11:37 -0800, krasw wrote:

The irony of reading this, and then discovering link to something called
"soaringsafety" below.

No irony: there's nothing dangerous about using brakes to scrub off
excess height - its easy-peasy in a Discus 1 or K21: just follow Eric's
excellent directions if you haven't done it before. Just make sure that
you're not trying it for the first time on a short runway. You shouldn't
need the extra length but it makes a nice comfort blanket.

I haven't tried it yet in my Libelle because I haven't needed to:
slipping one brings it down like a sack of anvils what with all the extra
drag from pushing its razor-back tail boom sideways.


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

Sorry, speed control in approach has been ironed to my skull. Sure you can do anything you want, land inverted if you like, but what is the point? We have brakes and slip which both get you you down with safe approach speed.

I look at S-turns on final as a way to increase your time aloft (at
minimum sink speed), perhaps to wait for an obstruction to be cleared
off the runway (like a takeoff or a short landing). To lose altitude on
final, I'll do a slip (almost) every time. And yes, I can fly at
minimum sink and below without stalling...

But what about a gust or gradient or blah, blah... Training and practice.

On 2/19/2017 1:53 PM, krasw wrote:
On Sunday, 19 February 2017 13:33:25 UTC+2, Martin Gregorie wrote:
On Sun, 19 Feb 2017 02:11:37 -0800, krasw wrote:

The irony of reading this, and then discovering link to something called
"soaringsafety" below.

No irony: there's nothing dangerous about using brakes to scrub off
excess height - its easy-peasy in a Discus 1 or K21: just follow Eric's
excellent directions if you haven't done it before. Just make sure that
you're not trying it for the first time on a short runway. You shouldn't
need the extra length but it makes a nice comfort blanket.

I haven't tried it yet in my Libelle because I haven't needed to:
slipping one brings it down like a sack of anvils what with all the extra
drag from pushing its razor-back tail boom sideways.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |
Sorry, speed control in approach has been ironed to my skull. Sure you can do anything you want, land inverted if you like, but what is the point? We have brakes and slip which both get you you down with safe approach speed.

--
Dan, 5J

On Saturday, February 18, 2017 at 8:35:49 PM UTC-8, Eric Greenwell wrote:
wrote on 2/17/2017 11:16 AM:
Then there is always the Marty Eiler special: Full spoiler, point the nose at the ground, go VNE to 5 feet off the deck. Even accounting for the float in ground effect, it uses up gobs of altitude.

John Cochrane.

Any video links to this technique? Heard of it before, don't doubt it works, just like to see it. No, I'm not going to teach it to myself.

The technique is simple and easy to learn. Just don't start out with the
extreme version John related! Basically, you are just increasing the
rate of energy/altitude loss by 2 or 3 times normal by using full
spoiler at high speeds. Try this for starters:

-enter the pattern at least 1000' AGL
-fly the pattern all the way until after you've turned final...NO
spoilers or sideslip
-continue down final without spoilers or side slip until it seems you
are almost too high to get down to your aim point with full spoilers
-open the spoilers fully, point the nose down until you are going 80-90
knots (but NO MORE than the max allowed speed for your landing
configuration - flap setting is the usual thing limiting the allowed speed)
-When the angle to your aim point looks about right for a half-spoiler
approach, pull the nose up gradually to maintain that angle
-when your speed drops to the desired speed on final, retract the
spoilers to one-half
-proceed with a normal landing

Use the technique a few times, and it won't seem very extreme at all.
The altitude loss is very rapid with full spoiler, gear down, and high
speeds, and it's very effective at dumping excess altitude.

--
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
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf

The "fast and dirty" approach works better, the dirtier you can get. On a flapped glider, full landing flaps and spoilers, point the nose down and you pick up some speed, but you lose energy much faster.

There are landing sites where this makes a lot of sense (including the one at which I fly). One reason is you are flying through the gradient and boundary layer turbulence at well over stall speed and can withstand a 40 knot gradient without stalling.

On my ASH26, this works really well. On the Duo Discus I owned and flew at the same site, not so well - wasn't dirty enough in landing configuration to lose the energy.

krasw wrote on 2/19/2017 12:53 PM:
On Sunday, 19 February 2017 13:33:25 UTC+2, Martin Gregorie wrote:
On Sun, 19 Feb 2017 02:11:37 -0800, krasw wrote:

The irony of reading this, and then discovering link to something called
"soaringsafety" below.

No irony: there's nothing dangerous about using brakes to scrub off
excess height - its easy-peasy in a Discus 1 or K21: just follow Eric's
excellent directions if you haven't done it before. Just make sure that
you're not trying it for the first time on a short runway. You shouldn't
need the extra length but it makes a nice comfort blanket.

I haven't tried it yet in my Libelle because I haven't needed to:
slipping one brings it down like a sack of anvils what with all the extra
drag from pushing its razor-back tail boom sideways.

Sorry, speed control in approach has been ironed to my skull. Sure you can do anything you want, land inverted if you like, but what is the point? We have brakes and slip which both get you you down with safe approach speed.

I didn't recommend you keep the high speed all the way to ground - just long
enough to get on a good glide path. I have used slips many times, but find the
"dirty dive" is a quick, easy, and safe way to get rid of a lot of altitude. No
turns required, no uncoordinated flight, no airspeed instrument inaccuracies.

I suggest you try it enough times to have some competence and confidence in it
before you make any judgement about it. Or go up with someone that can demonstrate
it for you.

--
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
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/...anes-2014A.pdf