S-turns on final [Archive]

David Salmon[_3_]

February 14th 17, 09:45 AM

At 05:51 14 February 2017, bumper wrote:
>Admittedly, not used often, but I was taught S-turns on long final for
>spac=
>ing while flying power. This might be due to an aircraft delayed and not
>cl=
>earing the runway in a timely manner as expected, rather than execute a
>go-=
>around (which remains an option if all else fails), or to increase
spacing
>=
>between the aircraft ahead if requested by tower. I was once asked for
360
>=
>for spacing while on long final by the tower while flying a Stemme (in
>glid=
>er mode). I most always planned a steeper approach when landing glider at
>a=
>n often busy airport (Napa, CA) to allow for sequencing. And an engine
>star=
>t on roll out to taxi home!
>
>Stemmes do towered airports no problem - though I did visit the tower
>first=
> to explain that I'd normally be landing as a glider and why.
>
>bumper=20
>
>I seem to remember George Moffatt, in one of his books, saying that that
was what he was taught in France, when he started.

Dave

Tom BravoMike

February 14th 17, 03:24 PM

Due to the hills and runway profile, S-turns are a standard procedure for landing at the Zar Mountain Gliding Center, Sebastian Kawa's home place. Also, they are commonly taught in Poland as just ONE of the methods to lose height in a particular situation. The more methods you have at hand, the better. S-turns allow you to do both: descend and yet delay landing a little bit, if needed, e.g. to give time to clear the runway.

Tom BravoMike

kirk.stant

February 14th 17, 03:47 PM

On Monday, February 13, 2017 at 5:54:51 PM UTC-6, Matt Herron Jr. wrote:

> S turns on final seems like a great way to get uncoordinated and kill yourself. Count me out.
>
> Matt

Really? How are S-turns any different from normal turns in a pattern, especially if you have to setup for a crosswind on final?

Perhaps you are not comfortable with turns at low altitude? That in itself is pretty dangerous, more so than the actual turns.

Watch out on the ridge!

Kirk
66

Sean Fidler

February 14th 17, 04:17 PM

Ok, I'll bite.

I prefer S turns to slips, but that's more about the glider I am flying today. And, when I say S turns, I usually mean two easy turns (back and forth) in order to make the final approach as long as possible. This is usually in a land out situation, dealing with trees on the approach end of the field and only if very, very high (above a full spoiler descent). Basically S turns are the result of a fairly large miscalculation. That would be rare however as it's usually far easier (and safer) to do a circle at 75mph, if truly too high for a safe full spoiler approach. So doing S turns is very rare with the effectiveness of modern spoilers and the performance of even modest performance sailplanes.

All glider turns (at 'almost' all times) must be perfectly coordinated (or any aircraft for that matter). This must be natural for the pilot, effortless in fact. That's the key focus for the pilot during the execution of all turns, correct? Especially so when near that hard thing known as the ground. So, if you are proficient with the basic skill of coordinated flight and follow that key rule, you're fine with a couple S turns. If you don't have that natural skill developed, if your sloppy, your risk is immediately.. That's a far broader problem than S turns.

So S-turns are very safe if you are properly trained and therefore fly the glider properly at all times without stress or difficulty. The only exceptions would be 1) slip landings (which is not very effective (to nil) in a high performance sailplane, in my humble opinion) and therefore I never use slips when flying my personal glider. If attempted (I have tried them a few times), they are very scary as the slip angle must be quite extreme in order to create any meaningful drag. -or- 2) utilizing a slight top rudder configuration whilst thermalling.

Slips work great in a 2-33 or a 126. But even a Grob 103 is fairly poor at slipping. An ASG29 or Lak17a (my experience) gets virtually zero benefit from slipping (my opinion) even in an extreme slip. And with full spoilers, flying relatively slow (65 mph) and at extreme slip angle is not what I want to be doing in any modern sailplane at 200-300 ft (again, my opinion).

Bottom line, turn coordination must be job one for all pilots at all times, from student pilots to advanced pilots. It must be natural and without exception, especially when under stress. When that skill breaks down, the risk increases dramatically at all stages of flight.

So as with all things, and with the question of slips or S-turns (IMO) it depends on the many circumstances involved.

Sean Fidler

February 14th 17, 04:47 PM

Ok, I'll bite.

I prefer S turns to slips, but that's more about the glider I am flying today. When I say S turns, I mean two easy turns (back and forth) to make the final approach as long as possible. Not 5-10 sharp back and forth turns, for example. In my experience, an S turn is usually employed during a land out, and often when dealing with tall trees on the approach end of the field or a short field. S turns are an easy way to fine-tune the approach, without extreme glide angles, extreme changes in spoiler power or (low) airspeeds (hard slip, full spoiler). But S turns are very rare (for me) as it would be far easier (and safer) to do a simple circle at a consistent and higher airspeed, rather than a couple big, sharp S turns. So doing S turns (or slips) is very rare with the effectiveness of modern spoilers and the glide performance of even modest performance sailplanes.

All glider turns (at 'almost' all times) must be perfectly coordinated (any aircraft for that matter). Coordinated turns should be natural for the pilot, entirely effortless in fact. That's the key focus for the pilot during the execution of all turns, correct? Especially so when near that hard thing, otherwise known as the ground. So, if you are proficient with the basic skill of coordinated flight, you're fine with a mild couple S-turns on final. If you don't have the natural ability of proper turn coordination developed, risks are higher (especially when under pressure). That's a far broader problem than slips or S-turns.

So S-turns are very safe the pilot is properly trained and therefore flies the glider properly, at all times, without stress or difficulty. The only exceptions would be 1) slip landings - not very efficient (to nil) in a high-performance sailplane and therefore I never use slips when flying my personal glider. If attempted (I have tried slips a few times), they are very scary as the slip angle must be quite extreme to create any perceivable drag. -or- 2) utilizing a slight top rudder configuration while thermalling.

Slips work great in a 2-33 or a 126. But even a Grob 103 is fairly poor at slipping. An ASG29 or Lak17a (my experience) gets virtually zero benefits from slipping (my opinion) even in an extreme slip. And with full spoilers, flying relatively slow (60 mph) and at extreme slip angle is not what I want to be doing in any modern sailplane at 200-300 ft (again, my opinion). But in lower performance trainers, slips are perfectly practical and even fun.

Bottom line, turn coordination must be job one for all pilots at all times, from student pilots to advanced pilots. It must be natural and without exception, especially when under stress. When that skill breaks down, the risk increases dramatically at all stages of flight.

So as with all things, and with the question of slips or S-turns (IMO), it depends on the many circumstances involved.

Matt Herron Jr.

February 14th 17, 06:16 PM

On Tuesday, February 14, 2017 at 7:47:49 AM UTC-8, kirk.stant wrote:
> On Monday, February 13, 2017 at 5:54:51 PM UTC-6, Matt Herron Jr. wrote:
>
> > S turns on final seems like a great way to get uncoordinated and kill yourself. Count me out.
> >
> > Matt
>
> Really? How are S-turns any different from normal turns in a pattern, especially if you have to setup for a crosswind on final?
>
> Perhaps you are not comfortable with turns at low altitude? That in itself is pretty dangerous, more so than the actual turns.
>
> Watch out on the ridge!
>
> Kirk
> 66

What is the most dangerous turn in pattern? Base to final. S turns on final will be even lower. Shallow turns really aren't going to loose much altitude for you. If you are so high that spoilers are not going to do the trick, you will need substantial deviations in your S turns to get back on glide slope. In addition to a greater risk of stall/spin, this also makes you unpredictable to others in the pattern. Button hooks are also considered dangerous on the turn to final, and S turns really aren't much different in my mind. Add a 15 knot x-wind, wind gradient, and turbulence and the situation is not good for a bunch of turns at 200 ft

I am sure S turns would be appropriate in some instances, especially for traffic spacing, but I would personally pick a slip first to correct a glide slope problem if at all possible.

Jonathan St. Cloud

February 14th 17, 06:48 PM

On Tuesday, February 14, 2017 at 8:47:11 AM UTC-8, Sean Fidler wrote:
> Ok, I'll bite.
>
> I prefer S turns to slips, but that's more about the glider I am flying today. When I say S turns, I mean two easy turns (back and forth) to make the final approach as long as possible. Not 5-10 sharp back and forth turns, for example. In my experience, an S turn is usually employed during a land out, and often when dealing with tall trees on the approach end of the field or a short field. S turns are an easy way to fine-tune the approach, without extreme glide angles, extreme changes in spoiler power or (low) airspeeds (hard slip, full spoiler). But S turns are very rare (for me) as it would be far easier (and safer) to do a simple circle at a consistent and higher airspeed, rather than a couple big, sharp S turns. So doing S turns (or slips) is very rare with the effectiveness of modern spoilers and the glide performance of even modest performance sailplanes.
>

My 29 slips great, every effective, huge. From early training I have been taught that a 360 turn low while adjusting glide path for an out landing can get you into real trouble. You are turning away from intended landing site and losing sight of the touchdown area. I do regularly practice slips on downwind, base and final making all the turns while in a slip (but then one day a week I get to fly rides at the local glider port so I have many opportunities). Have I flown a 360 low while landing out, you bet I have, but in my humble opinion this should be discouraged. With the landing flaps (sorry std class), slips, spoilers and the ability to plan ahead we have lots of options rather than S-turns, but they should be in a quiver of skills as you never know what circumstances you might find yourself in and it helps to have a full bag of skills.

February 14th 17, 07:15 PM

On Tuesday, February 14, 2017 at 10:48:26 AM UTC-8, Jonathan St. Cloud wrote:
> On Tuesday, February 14, 2017 at 8:47:11 AM UTC-8, Sean Fidler wrote:
> > Ok, I'll bite.
> >
> > I prefer S turns to slips, but that's more about the glider I am flying today. When I say S turns, I mean two easy turns (back and forth) to make the final approach as long as possible. Not 5-10 sharp back and forth turns, for example. In my experience, an S turn is usually employed during a land out, and often when dealing with tall trees on the approach end of the field or a short field. S turns are an easy way to fine-tune the approach, without extreme glide angles, extreme changes in spoiler power or (low) airspeeds (hard slip, full spoiler). But S turns are very rare (for me) as it would be far easier (and safer) to do a simple circle at a consistent and higher airspeed, rather than a couple big, sharp S turns. So doing S turns (or slips) is very rare with the effectiveness of modern spoilers and the glide performance of even modest performance sailplanes.
> >
>
> My 29 slips great, every effective, huge. From early training I have been taught that a 360 turn low while adjusting glide path for an out landing can get you into real trouble. You are turning away from intended landing site and losing sight of the touchdown area. I do regularly practice slips on downwind, base and final making all the turns while in a slip (but then one day a week I get to fly rides at the local glider port so I have many opportunities). Have I flown a 360 low while landing out, you bet I have, but in my humble opinion this should be discouraged. With the landing flaps (sorry std class), slips, spoilers and the ability to plan ahead we have lots of options rather than S-turns, but they should be in a quiver of skills as you never know what circumstances you might find yourself in and it helps to have a full bag of skills.

On a scale of "ease to get rid of altitude on final", The ASG29 would be very near the easy end. Almost as much fun as ASW17 drag chute landings with full spoilers.
Jim

Jonathan St. Cloud

February 14th 17, 07:47 PM

My 29 slips great, every effective. From early training I have been taught that a 360 turn low while adjusting glide path for an out landing can get you into real trouble. You are turning away from intended landing site and losing sight of the touchdown area. I do regularly practice slips on downwind, base and final making all the turns while in a slip. Have I flown a 360 low while landing out, you bet I have, but in my humble opinion this should be discouraged. With the landing flaps (sorry std class), slips, spoilers and the ability to plan ahead we have lots of options rather than S-turns, but they should be in a quiver of skills as you never know what circumstances you might find yourself in and it helps to have a full bag of skills.

[email protected]

February 15th 17, 12:35 AM

I tend to turn high final. Slipping my ASW 24 with full dive brakes steepens the approach significantly with little drama. If it's a short final, a slipping turn lets me start sooner. I slipped my 201 Libelle with smaller dive brakes all the time. Hardly ever my LS-3 because the brakes were so effective. A slip also allows moving laterally using more or less aileron to slide into position when the runway approach is unobstructed but the approach to the parallel taxiway is not quite so clear, as is the case at several East Coast airports I've flown out of.

I use S turns when I want to do the opposite: i.e., I've turned high final and do NOT want to lose a lot of altitude quickly. For example, when allowing another, lower glider to turn in ahead of me and land long (not uncommon at a site like New Castle when multiple gliders are finishing at different altitudes all needing the same runway). I also use S turns occasionally to check out a field when I'm landing out. And to lose altitude in front of a hill blocking a normal approach. S turns--taught as part of the standard course when I learned how to fly in the 60s--means never losing sight of the landing spot and are much preferred/safer compared with a 360 on final. If a 90 degree turn base to final is safe, I'm not sure why one or more 180 degree S turns at a higher altitude aren't just as safe so long as they're coordinated and the speed is controlled. Actually it's usually slightly more than 180 degrees when the objective is to descend slowly while not getting closer to the landing spot. And I usually have short intervals of straight flight between the turns so it's not one continuous series of rolling back and forth.

Just my opinion.

Chip Bearden

[email protected]

February 15th 17, 04:35 AM

Gotta agree with Sean on this one. Sometimes you don't WANT to expedite the landing. Slips and spoilers decrease the time you are in the air. Sometimes delaying the touchdown while maintaining controlled coordinated flight is necessary if the runway is not clear, but might be safe few seconds later.

Remember that your "S-turns" should be MORE than 180 degrees to keep you from moving closer to the end of the runway. Really, your turns should resemble an elongated figure 8 with the crossing over a point aligned with the runway centerline. Round out of your final turn on to the final approach when the runway is clear, or your personal safety margin is reached. Remember that you are LOW, so SLOW turns are putting you in that nasty corner we are reminded of in every other article we read about in "Soaring" magazine. Keep your energy up!

If the runway is not clear yet, use full spoilers to minimize the runway length needed, touch down with as much margin as possible and get on the brakes. Steer off the runway at minimum speed to avoid the obstruction (aircraft, emergency vehicle, etc.)

Of course, if you have sufficient runway past the obstruction, overflying and landing long is a completely acceptable option. Better to be chastised and eventually forgiven than being carted away in an ambulance.

WAVEGURU

February 15th 17, 03:48 PM

S turns on final:

http://www.onlinecontest.org/olc-2.0/gliding/flightinfo.html?dsId=5523393

Boggs

[email protected]

February 15th 17, 07:51 PM

On Monday, February 13, 2017 at 2:45:27 PM UTC-5, Jonathan St. Cloud wrote:
> Came across a blast from the past on youtube. There was a video of teaching s-turns for glide path control. Looked to be from the 40's. Not sure why they would teach this when a slip would be safer and more effective.

If the pilot has the skills and judgement to use S turns on final without reducing safety margins, he or she most likely would have the skills and judgement to not need them.
UH

Casey[_2_]

February 15th 17, 11:44 PM

"S" turns were taught to me in early stages of hang glider training. It is used as inexperience to judging height when too high on final. Most I saw used on first few flights then used a more standard approach. From the ground it really looks like an inexperienced pilot, but the judgement for approach was right on for those that I saw using it. I think there were a lot of hang glider pilots that did/do not have any other type of flight training and so no good judgement of height, and I think the tendency of new hang glider solo would tend to be high on final.

I have never been taught "S" turns in glider training. I would much rather track slightly away on downwind, and or extend, than to have to "S" turn on final.

If that video is from the 40's, I wonder when this was stopped being taught..

Bruce Hoult

February 16th 17, 03:10 AM

On Thursday, February 16, 2017 at 2:44:26 AM UTC+3, Casey wrote:
> "S" turns were taught to me in early stages of hang glider training. It is used as inexperience to judging height when too high on final. Most I saw used on first few flights then used a more standard approach. From the ground it really looks like an inexperienced pilot, but the judgement for approach was right on for those that I saw using it. I think there were a lot of hang glider pilots that did/do not have any other type of flight training and so no good judgement of height, and I think the tendency of new hang glider solo would tend to be high on final.
>
> I have never been taught "S" turns in glider training. I would much rather track slightly away on downwind, and or extend, than to have to "S" turn on final.
>
> If that video is from the 40's, I wonder when this was stopped being taught.

It's good to have as many techniques in your arsenal as possible.

Even NASA does (did) S-turns in the circuit.

Jonathan St. Cloud

February 16th 17, 07:38 AM

On Wednesday, February 15, 2017 at 7:10:55 PM UTC-8, Bruce Hoult wrote:

> It's good to have as many techniques in your arsenal as possible.
>
> Even NASA does (did) S-turns in the circuit.

Gosh, I would hesitate to call the roll reversals "S-turns"

Read below article, very interesting.

https://www.nasa.gov/centers/johnson/pdf/584730main_Wings-ch4d-pgs226-241.pdf

Tango Whisky

February 16th 17, 09:16 AM

Le jeudi 16 fÃ©vrier 2017 08:38:18 UTC+1, Jonathan St. Cloud a Ã©critÂ*:
> On Wednesday, February 15, 2017 at 7:10:55 PM UTC-8, Bruce Hoult wrote:
>
> > It's good to have as many techniques in your arsenal as possible.
> >
> > Even NASA does (did) S-turns in the circuit.
>
>
> Gosh, I would hesitate to call the roll reversals "S-turns"
>
> Read below article, very interesting.
>
> https://www.nasa.gov/centers/johnson/pdf/584730main_Wings-ch4d-pgs226-241..pdf

Great article.

Martin Gregorie[_5_]

February 16th 17, 10:54 AM

On Wed, 15 Feb 2017 23:38:17 -0800, Jonathan St. Cloud wrote:

> On Wednesday, February 15, 2017 at 7:10:55 PM UTC-8, Bruce Hoult wrote:
>
>> It's good to have as many techniques in your arsenal as possible.
>>
>> Even NASA does (did) S-turns in the circuit.
>
>
> Gosh, I would hesitate to call the roll reversals "S-turns"
>
> Read below article, very interesting.
>
> https://www.nasa.gov/centers/johnson/pdf/584730main_Wings-ch4d-
pgs226-241.pdf

Thanks for posting that. However, whether you consider those S-turns or
not, they were certainly not in the circuit (the shuttle flew straight-in
patterns IIRC), rather they were en route to destination.

BTW, somewhere I have an ancient shuttle landing simulator (for Win 95)
that was interesting to experiment with. Does anybody know if a Linux
version is available? There should be a port - NASA's original version
ran on a Unix-based laptop that got sat on the Shuttle glare shield
during command pilot training. The PC sim started you at 350kts and
55,000ft and no matter what you did with it, you were on the ground after
2.5 - 3 minutes.

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

[email protected]

February 16th 17, 03:40 PM

Let us not forget that turns below 200 ft AGL potentially expose us to wind gradient having unequal and undesirable effects on the high vs low wing.

Sean Fidler

February 16th 17, 04:26 PM

With the very high degree of spoiler effectiveness on most gliders, if "said pilot" is regularly "forced" to slip or S-turn in order to make their intended touch down point, there is probably something else wrong "upstream" in said pilots landing pattern decision making process. Also, the majority of sailplane landing patterns appear to me to be rather high (again, IMO).

I commented here only to state (I'll say it again now) that slipping a high performance glider is almost useless (IMO). It requires such an aggressive slip angle (in order to result in any measurable increase in descent rate) that it is uncomfortable (and unnecessary) for me, personally (IMO). I'm surprised to hear otherwise, but that certainly doesn't change my opinion or practices. Perhaps their fuselages are the "slab sided" ASG29 version ;-). Perhaps I am a poor pilot. Perhaps this is a skill I need to work on. Oh well, for now, I don't slip unless absolutely necessary. I prefer docile S turns, but can only really recall one time I have done this. I have never needed a slip in my ASG29 or (ex) Lak17a (in the execution of many, many land-outs)

That said, slips are an important skill in glider pilot training. To need to use them on a regular basis (or even rare basis) is perhaps indicative of some other concerns or areas of potential landing pattern/planning skill improvement. The need to slip or S-turn means that to that point in the approach, the pilot has misjudged the approach extremely high in terms of altitude and/or total energy, requiring a last resort maneuver (slip or S-turn) in order to bleed it off. Desperate. Poor planning. Poor energy management. This is how people get hurt.

For those who have not yet flown higher performance glider, when you do, I would strongly suggest practicing slips at high altitude before trying (or being forced to exectute) a true, aggressive (full rudder) slip, with full spoilers (and perhaps 25-30% water remaining, simulating real world stress, for example) and at low (minimum possible) final approach speed while at very low altitude into a short land-out field (perhaps with tall trees on both ends and in some wind).

I strongly prefer striving to execute consistent, well managed, stable approaches without big transitions from slip to non slip (close to the ground, at the last moment), especially when flying in a high performance glider (in which I feel slips are ineffective). Gliders have outstanding glideslope control with spoilers (and perhaps flaps). My goal is to fly the entire approach (from midfield downwind to near touchdown) with a set pitch, set flap setting, set speed and set spoiler setting (33%, I have a mark I use). The exact same approach every time. This takes significant practice. I prefer focusing on precisely controlling my energy (not too fast, not too high, good base turn decision) as early as possible in every approach. That is the critical moment in the approach for me, not the final leg. Everything flows from this mindset of setting the approach up with great precision and getting stable early.. If necessary, I prefer managing my glideslope with spoilers (only) and in a very smooth, controlable manner. If I must use them, I try and minimize adjustments rather than making constant adjustments (unstable). If I ultimately need to S turn, or slip, it means I have really (enormously) misjudged the approach and/or the landing area (perhaps the height of the trees on the approach end, wires I didn't see, or the usable length of the field (perhaps identifying a rock or a post on final)). If I started experiencing gross errors in general landing pattern decisions regularly (landouts or normal landings at an airport), requiring slips or S-turns to make the touchdown point (and stress), I would schedule some meaningful time with a respected flight instructor and sort myself out.

Perhaps I'll be having a talk with one about slips in my 29 in fact. So, thanks for this discussion.

Sean
7T

Tango Whisky

February 16th 17, 06:17 PM

Sorry Sean,

if you think that slips are not effective in high performance ships, you should get some training.

Not that I think that they are much needed, but you should know how to comfortably perform them down to 30 ft off the ground.

In the lasr 35 years of flying all types of gliders, it never came to my mind to use S-turns. But I had to use slips some time.

Bert

Ventus cM
which slips nicely...

Matt Herron Jr.

February 16th 17, 08:24 PM

On Thursday, February 16, 2017 at 8:26:51 AM UTC-8, Sean Fidler wrote:
> With the very high degree of spoiler effectiveness on most gliders, if "said pilot" is regularly "forced" to slip or S-turn in order to make their intended touch down point, there is probably something else wrong "upstream" in said pilots landing pattern decision making process. Also, the majority of sailplane landing patterns appear to me to be rather high (again, IMO)..
>
> I commented here only to state (I'll say it again now) that slipping a high performance glider is almost useless (IMO). It requires such an aggressive slip angle (in order to result in any measurable increase in descent rate) that it is uncomfortable (and unnecessary) for me, personally (IMO). I'm surprised to hear otherwise, but that certainly doesn't change my opinion or practices. Perhaps their fuselages are the "slab sided" ASG29 version ;-). Perhaps I am a poor pilot. Perhaps this is a skill I need to work on. Oh well, for now, I don't slip unless absolutely necessary. I prefer docile S turns, but can only really recall one time I have done this. I have never needed a slip in my ASG29 or (ex) Lak17a (in the execution of many, many land-outs)
>
> That said, slips are an important skill in glider pilot training. To need to use them on a regular basis (or even rare basis) is perhaps indicative of some other concerns or areas of potential landing pattern/planning skill improvement. The need to slip or S-turn means that to that point in the approach, the pilot has misjudged the approach extremely high in terms of altitude and/or total energy, requiring a last resort maneuver (slip or S-turn) in order to bleed it off. Desperate. Poor planning. Poor energy management. This is how people get hurt.
>
> For those who have not yet flown higher performance glider, when you do, I would strongly suggest practicing slips at high altitude before trying (or being forced to exectute) a true, aggressive (full rudder) slip, with full spoilers (and perhaps 25-30% water remaining, simulating real world stress, for example) and at low (minimum possible) final approach speed while at very low altitude into a short land-out field (perhaps with tall trees on both ends and in some wind).
>
> I strongly prefer striving to execute consistent, well managed, stable approaches without big transitions from slip to non slip (close to the ground, at the last moment), especially when flying in a high performance glider (in which I feel slips are ineffective). Gliders have outstanding glideslope control with spoilers (and perhaps flaps). My goal is to fly the entire approach (from midfield downwind to near touchdown) with a set pitch, set flap setting, set speed and set spoiler setting (33%, I have a mark I use).. The exact same approach every time. This takes significant practice. I prefer focusing on precisely controlling my energy (not too fast, not too high, good base turn decision) as early as possible in every approach. That is the critical moment in the approach for me, not the final leg. Everything flows from this mindset of setting the approach up with great precision and getting stable early.. If necessary, I prefer managing my glideslope with spoilers (only) and in a very smooth, controlable manner. If I must use them, I try and minimize adjustments rather than making constant adjustments (unstable). If I ultimately need to S turn, or slip, it means I have really (enormously) misjudged the approach and/or the landing area (perhaps the height of the trees on the approach end, wires I didn't see, or the usable length of the field (perhaps identifying a rock or a post on final)). If I started experiencing gross errors in general landing pattern decisions regularly (landouts or normal landings at an airport), requiring slips or S-turns to make the touchdown point (and stress), I would schedule some meaningful time with a respected flight instructor and sort myself out.
>
> Perhaps I'll be having a talk with one about slips in my 29 in fact. So, thanks for this discussion.
>
> Sean
> 7T

How do people feel about aggressive slips with partial water? I had an experience where exiting the slip and leveling off on approach was more difficult than expected due to water shifting to the downhill portion of both wings.

Matt

Bruce Hoult

February 16th 17, 09:04 PM

On Thursday, February 16, 2017 at 7:26:51 PM UTC+3, Sean Fidler wrote:
> With the very high degree of spoiler effectiveness on most gliders, if "said pilot" is regularly "forced" to slip or S-turn in order to make their intended touch down point, there is probably something else wrong "upstream" in said pilots landing pattern decision making process. Also, the majority of sailplane landing patterns appear to me to be rather high (again, IMO)..
>
> I commented here only to state (I'll say it again now) that slipping a high performance glider is almost useless (IMO). It requires such an aggressive slip angle (in order to result in any measurable increase in descent rate) that it is uncomfortable (and unnecessary) for me, personally (IMO). I'm surprised to hear otherwise, but that certainly doesn't change my opinion or practices. Perhaps their fuselages are the "slab sided" ASG29 version ;-). Perhaps I am a poor pilot. Perhaps this is a skill I need to work on. Oh well, for now, I don't slip unless absolutely necessary. I prefer docile S turns, but can only really recall one time I have done this. I have never needed a slip in my ASG29 or (ex) Lak17a (in the execution of many, many land-outs)
>
> That said, slips are an important skill in glider pilot training. To need to use them on a regular basis (or even rare basis) is perhaps indicative of some other concerns or areas of potential landing pattern/planning skill improvement. The need to slip or S-turn means that to that point in the approach, the pilot has misjudged the approach extremely high in terms of altitude and/or total energy, requiring a last resort maneuver (slip or S-turn) in order to bleed it off. Desperate. Poor planning. Poor energy management. This is how people get hurt.
>
> For those who have not yet flown higher performance glider, when you do, I would strongly suggest practicing slips at high altitude before trying (or being forced to exectute) a true, aggressive (full rudder) slip, with full spoilers (and perhaps 25-30% water remaining, simulating real world stress, for example) and at low (minimum possible) final approach speed while at very low altitude into a short land-out field (perhaps with tall trees on both ends and in some wind).
>
> I strongly prefer striving to execute consistent, well managed, stable approaches without big transitions from slip to non slip (close to the ground, at the last moment), especially when flying in a high performance glider (in which I feel slips are ineffective). Gliders have outstanding glideslope control with spoilers (and perhaps flaps). My goal is to fly the entire approach (from midfield downwind to near touchdown) with a set pitch, set flap setting, set speed and set spoiler setting (33%, I have a mark I use).. The exact same approach every time. This takes significant practice. I prefer focusing on precisely controlling my energy (not too fast, not too high, good base turn decision) as early as possible in every approach. That is the critical moment in the approach for me, not the final leg. Everything flows from this mindset of setting the approach up with great precision and getting stable early.. If necessary, I prefer managing my glideslope with spoilers (only) and in a very smooth, controlable manner. If I must use them, I try and minimize adjustments rather than making constant adjustments (unstable). If I ultimately need to S turn, or slip, it means I have really (enormously) misjudged the approach and/or the landing area (perhaps the height of the trees on the approach end, wires I didn't see, or the usable length of the field (perhaps identifying a rock or a post on final)). If I started experiencing gross errors in general landing pattern decisions regularly (landouts or normal landings at an airport), requiring slips or S-turns to make the touchdown point (and stress), I would schedule some meaningful time with a respected flight instructor and sort myself out.
>
> Perhaps I'll be having a talk with one about slips in my 29 in fact. So, thanks for this discussion.

Of course you shouldn't find yourself unexpectedly needing a slip -- at least not more than once in a few hundred landings due to a headwind a circuit altitude turning into a tail wind on short final, or something like that (e.g. on an outlanding).

That doesn't mean you shouldn't practice it. I often fly approaches in the DG1000 (or Janus before it) with perfectly standard heights turning base and final, but using only slip and no brakes/flaps at all until at maybe 50 ft and in the normal place at the normal speed and height.

I don't know whether those count as "high performance" for you -- I don't fly single-seaters a lot and maybe they're different. A slip is relatively ineffective, but it's comparable to half brakes. If you add it to full brakes instead of using it instead of brakes then you can come down really quick..

Charlie M. (UH & 002 owner/pilot)

February 16th 17, 10:17 PM

Eh, I get twitchy getting uncoordinated anywhere low with partial water. While a slip is considered aerodynamically coordinated, not sure water in the wings would agree.

Andy Blackburn[_3_]

February 16th 17, 11:56 PM

On Wednesday, February 15, 2017 at 11:51:27 AM UTC-8, wrote:
>
> If the pilot has the skills and judgement to use S turns on final without reducing safety margins, he or she most likely would have the skills and judgement to not need them.
> UH

Heh, heh. Irony.

If I have a lot of room before touchdown (and even more than a lot of height in this scenario) and I need to make space I'll extend a leg or two in my pattern or make a circle. If I'm on short final I really want my velocity vector pointed at the runway and not a lot of bank on. I especially don't like the idea of a lot of maneuvering, reversing turns, etc when I'm close to the ground and needing to focus on a dozen other really important things. A stabilized approach makes a lot of other potential problems less problematic. It should be sufficient to use spoilers, landing flaps if you got 'em and an aggressive slip (which also guards against spin entry since it's the opposite of a skidding turn). Maybe there is a place for S-turns between turn to final and short final if you are ridiculously high and flying a really slippery glider with weak spoilers and no flaps. Fortunately, I don't fly one of those.

9B

Steve Leonard[_2_]

February 17th 17, 01:17 AM

On Thursday, February 16, 2017 at 4:17:08 PM UTC-6, Charlie M. (UH & 002 owner/pilot) wrote:
> Eh, I get twitchy getting uncoordinated anywhere low with partial water. While a slip is considered aerodynamically coordinated, not sure water in the wings would agree.

Crabbing is coordinated. Slipping is not. By any book, stretch of the imagination, or even alternate fact. It may be aerodynaimcally "balanced", as there is no steady state pitch, roll, or yaw RATE. But, not coordinated.

CindyB[_2_]

February 17th 17, 03:17 AM

On Thursday, February 16, 2017 at 5:17:58 PM UTC-8, Steve Leonard wrote:
> On Thursday, February 16, 2017 at 4:17:08 PM UTC-6, Charlie M. (UH & 002 owner/pilot) wrote:
> > While a slip is considered aerodynamically coordinated, not sure ...
>
> Crabbing is coordinated. Slipping is not. By any book, stretch of the imagination, or even alternate fact. It may be aerodynaimcally "balanced", as there is no steady state pitch, roll, or yaw RATE. But, not coordinated..

Thanks, Steve. I was getting twitchy on this one (but not pitchy). But hey,
Charlie M. wasn't the only one to say a slip was 'coordinated' in this thread.
Youch.

A fair range of opinions, and fewer with some slipping experience at altitude that then allows application at lower altitudes with familiarity and confidence.
I find it pretty common that pilots will lower their nose "a bunch" when slipping and then getting down to the chosen angle and unslipping to find they have ~ten more knots than they wanted.

Pretty soon it will be the "Silly Season". This sounds like a good topic for spring brush ups with a CFI - doing slips in > 32:1. Balanced slips ( on a track), turning slips, and doing either with no speed change on entry and recovery. Can you tell your CFI what descent rate you can manufacture with your slip in your ship in calm air? It's a helpful data point, rather than conjecture.

My alternative aerodynamics fact is to be happy with pilots who slip, crab, S-turn, buttonhook, angle in or out, min sink loiter, full-spoiler parasitic drag plummet or even make a perfectly coordinated circle to address spacing and slope to satisfy the situation in a pattern. If it is done well, there are lots of ways to 'approach'. Adaptability is a good thing.

Best,
Cindy B

Jonathan St. Cloud

February 17th 17, 06:43 AM

On Thursday, February 16, 2017 at 8:26:51 AM UTC-8, Sean Fidler wrote:
> With the very high degree of spoiler effectiveness on most gliders, if "said pilot" is regularly "forced" to slip or S-turn in order to make their intended touch down point, there is probably something else wrong "upstream" in said pilots landing pattern decision making process. Also, the majority of sailplane landing patterns appear to me to be rather high (again, IMO)..
>
> I commented here only to state (I'll say it again now) that slipping a high performance glider is almost useless (IMO). It requires such an aggressive slip angle (in order to result in any measurable increase in descent rate) that it is uncomfortable (and unnecessary) for me, personally (IMO). I'm surprised to hear otherwise, but that certainly doesn't change my opinion or practices. Perhaps their fuselages are the "slab sided" ASG29 version ;-). Perhaps I am a poor pilot. Perhaps this is a skill I need to work on. Oh well, for now, I don't slip unless absolutely necessary. I prefer docile S turns, but can only really recall one time I have done this. I have never needed a slip in my ASG29 or (ex) Lak17a (in the execution of many, many land-outs)
>
> That said, slips are an important skill in glider pilot training. To need to use them on a regular basis (or even rare basis) is perhaps indicative of some other concerns or areas of potential landing pattern/planning skill improvement. The need to slip or S-turn means that to that point in the approach, the pilot has misjudged the approach extremely high in terms of altitude and/or total energy, requiring a last resort maneuver (slip or S-turn) in order to bleed it off. Desperate. Poor planning. Poor energy management. This is how people get hurt.
>
> For those who have not yet flown higher performance glider, when you do, I would strongly suggest practicing slips at high altitude before trying (or being forced to exectute) a true, aggressive (full rudder) slip, with full spoilers (and perhaps 25-30% water remaining, simulating real world stress, for example) and at low (minimum possible) final approach speed while at very low altitude into a short land-out field (perhaps with tall trees on both ends and in some wind).
>
> I strongly prefer striving to execute consistent, well managed, stable approaches without big transitions from slip to non slip (close to the ground, at the last moment), especially when flying in a high performance glider (in which I feel slips are ineffective). Gliders have outstanding glideslope control with spoilers (and perhaps flaps). My goal is to fly the entire approach (from midfield downwind to near touchdown) with a set pitch, set flap setting, set speed and set spoiler setting (33%, I have a mark I use).. The exact same approach every time. This takes significant practice. I prefer focusing on precisely controlling my energy (not too fast, not too high, good base turn decision) as early as possible in every approach. That is the critical moment in the approach for me, not the final leg. Everything flows from this mindset of setting the approach up with great precision and getting stable early.. If necessary, I prefer managing my glideslope with spoilers (only) and in a very smooth, controlable manner. If I must use them, I try and minimize adjustments rather than making constant adjustments (unstable). If I ultimately need to S turn, or slip, it means I have really (enormously) misjudged the approach and/or the landing area (perhaps the height of the trees on the approach end, wires I didn't see, or the usable length of the field (perhaps identifying a rock or a post on final)). If I started experiencing gross errors in general landing pattern decisions regularly (landouts or normal landings at an airport), requiring slips or S-turns to make the touchdown point (and stress), I would schedule some meaningful time with a respected flight instructor and sort myself out.
>
> Perhaps I'll be having a talk with one about slips in my 29 in fact. So, thanks for this discussion.
>
> Sean
> 7T

Sean the 29actually slips well and really increases sink rate. Yes, it can be uncomfortable until you are comfortable flying them. A slip can be very valuable if you have a rope break at 100' and need to use an aggressive slip to put it on remaining runway. Slip is a maneuver that is essential to have in a quiver of mastered skills.

I have used slips in helicopters, war birds, gliders, never came across an aircraft that was not effective in a slip. Probably the only time I really needed the slip was one flight in a helicopter.

[email protected]

February 17th 17, 02:25 PM

On Wednesday, February 15, 2017 at 6:44:26 PM UTC-5, Casey wrote:
> "S" turns were taught to me in early stages of hang glider training. It is used as inexperience to judging height when too high on final. Most I saw used on first few flights then used a more standard approach. From the ground it really looks like an inexperienced pilot, but the judgement for approach was right on for those that I saw using it. I think there were a lot of hang glider pilots that did/do not have any other type of flight training and so no good judgement of height, and I think the tendency of new hang glider solo would tend to be high on final.
>
> I have never been taught "S" turns in glider training. I would much rather track slightly away on downwind, and or extend, than to have to "S" turn on final.
>
> If that video is from the 40's, I wonder when this was stopped being taught.

As a hang glider pilot for 38 years I agree Casey.... but we didn't have air brakes on Hang Gliders. I still used pattern approaches then but I landed in small fields surrounded by trees most of the time.

Dennis.... DC

Dan Marotta

February 17th 17, 03:17 PM

Dammit, Steve and Cindy! You should never interject knowledge,
experience, and logic into a discussion on RAS!

On 2/16/2017 8:17 PM, CindyB wrote:
> On Thursday, February 16, 2017 at 5:17:58 PM UTC-8, Steve Leonard wrote:
>> On Thursday, February 16, 2017 at 4:17:08 PM UTC-6, Charlie M. (UH & 002 owner/pilot) wrote:
>>> While a slip is considered aerodynamically coordinated, not sure ...
>> Crabbing is coordinated. Slipping is not. By any book, stretch of the imagination, or even alternate fact. It may be aerodynaimcally "balanced", as there is no steady state pitch, roll, or yaw RATE. But, not coordinated.
> Thanks, Steve. I was getting twitchy on this one (but not pitchy). But hey,
> Charlie M. wasn't the only one to say a slip was 'coordinated' in this thread.
> Youch.
>
> A fair range of opinions, and fewer with some slipping experience at altitude that then allows application at lower altitudes with familiarity and confidence.
> I find it pretty common that pilots will lower their nose "a bunch" when slipping and then getting down to the chosen angle and unslipping to find they have ~ten more knots than they wanted.
>
> Pretty soon it will be the "Silly Season". This sounds like a good topic for spring brush ups with a CFI - doing slips in > 32:1. Balanced slips ( on a track), turning slips, and doing either with no speed change on entry and recovery. Can you tell your CFI what descent rate you can manufacture with your slip in your ship in calm air? It's a helpful data point, rather than conjecture.
>
> My alternative aerodynamics fact is to be happy with pilots who slip, crab, S-turn, buttonhook, angle in or out, min sink loiter, full-spoiler parasitic drag plummet or even make a perfectly coordinated circle to address spacing and slope to satisfy the situation in a pattern. If it is done well, there are lots of ways to 'approach'. Adaptability is a good thing.
>
> Best,
> Cindy B

--
Dan, 5J

Don Johnstone[_4_]

February 17th 17, 04:12 PM

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.

John Cochrane[_3_]

February 17th 17, 06:42 PM

I think the main point against S turns is that they will not actually lose that much altitude -- unless you turn 90 degrees or more. If you are so high that full flap spoiler and slip are not going to work, then try to do S turns, but get nervous about it and don't head the nose more than 45 degrees away from the runway, you're just not going to get down that fast, and the runway will still slide along below you.

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.

[email protected]

February 17th 17, 07:16 PM

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.

Dave Walsh

February 17th 17, 09:39 PM

At 19:16 17 February 2017, wrote:
>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.

The Vne approach is an interesting idea that I won't be trying
without 6000 feet of runway available! How do you get rid of
all that speed 5 feet off the ground? It must produce an
incredibly long float?

Here in France "S" bends on approach are the standard
method taught for microlights, but they all tend to be a lot
dragger than even the poorest glider. Seems to me to be a
valid idea (like the side slip) assuming it's done correctly; any
method that doesn't involve flying through the far hedge/wall
must be good.

February 17th 17, 10:57 PM

On Friday, February 17, 2017 at 10:42:13 AM UTC-8, John Cochrane wrote:
> I think the main point against S turns is that they will not actually lose that much altitude -- unless you turn 90 degrees or more. If you are so high that full flap spoiler and slip are not going to work, then try to do S turns, but get nervous about it and don't head the nose more than 45 degrees away from the runway, you're just not going to get down that fast, and the runway will still slide along below you.
>
> 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.

I was running the line at Mountain Valley one day when Rich Benbrook wanted to demonstrate to a student that you could not be too high on final. I relayed to the tow pilot "2000' at the end of the runway behind you". They released, lined up with the runway, full airbrakes and PUSH.
Looked like a Space shuttle landing in a Twin Grob. Rolled casually to the start line.
But I wouldn't try that in a Nimbus 3 or even a Duo.
Jim

[email protected]

February 17th 17, 11:20 PM

> I think the main point against S turns is that they will not actually lose that much altitude

Agreed. I guess originally they were used to control descent but for me they're a way of "loitering" at the approach end. I was on a high downwind at New Castle landing to the north a few years ago when a guy called in much lower and behind me to ask if I could either turn in immediately or let him go first. I responded: "__, you go first, JB will hold." I'd always wanted to say that. :)

I didn't want to circle or extend the downwind leg much farther (IIRC, this was NC on a rough ridge day, one reason I was pretty high) so I turned onto a high base and just continued beyond the normal base-to-final point. Turned slightly more than 180 degrees and made a couple of figure eights with short straight segments, "parked" out there still on high base. I could see the glider behind me (plus any more traffic) as well as the gliderport at all times. When I saw him touch down, I turned onto a (still) high final, announced my intention, and made my normal final approach.

Yeah, there were alternatives. But because S turns were part of the curriculum when I learned how to fly back in the dark ages and because I've used them a few times to check out fields just ahead where I didn't have enough altitude to fly to them and still do a full pattern, I thought it was safe. When the pilot asked me later how I'd managed the "hold", I realized S turns weren't universally known.

I've tried the full-brakes-and-dive-for-the-earth technique, though not to VNE. :) Seems to work but everything happens pretty fast so I'll stay with the slips-and-dive-brakes-in-a-high-pattern approach I've been using for decades in Std. Class gliders. Do I NEED slips? Probably not, and I usually end up holding the slip and using partial dive brakes to get the desired angle. But I like having that skill just in case.

Of course, no one should be experimenting with slips or S turns down low the first time. I slipped my ASW 24 at altitude when I got it both to verify there weren't any odd issues as well as whether the sink rate was worth doing it (it was).

Just to stir the pot up, I might offer that not being skilled in slips because you shouldn't ever need them if you fly a correct pattern is sort of like saying you shouldn't need to know how to recover from a spin because if you fly correctly, you'll never enter one. But that analogy might be stretching things....

Since it was mentioned, I can offer that I have slipped down a long final approach with partial water and not noticed a bit of difference in the way the glider handled. It was unintentional. I didn't realize I'd forgotten to dump ballast (after a very busy, crowded finish) until the glider rolled and rolled and rolled. I wouldn't try it again, though.

I did unwittingly land my LS-3 one time with water in one wing but not the other (failed valve actuator) and didn't notice anything amiss until the last few knots when the wing went down hard.

Chip Bearden

[email protected]

February 17th 17, 11:40 PM

On Thursday, February 16, 2017 at 5:17:58 PM UTC-8, Steve Leonard wrote:
> On Thursday, February 16, 2017 at 4:17:08 PM UTC-6, Charlie M. (UH & 002 owner/pilot) wrote:
> > Eh, I get twitchy getting uncoordinated anywhere low with partial water. While a slip is considered aerodynamically coordinated, not sure water in the wings would agree.
>
> Crabbing is coordinated. Slipping is not. By any book, stretch of the imagination, or even alternate fact. It may be aerodynaimcally "balanced", as there is no steady state pitch, roll, or yaw RATE. But, not coordinated.

Well spoken buy the guy who owns an ASW-12!

Bruce Hoult

February 18th 17, 01:30 AM

On Saturday, February 18, 2017 at 1:57:34 AM UTC+3, JS wrote:
> On Friday, February 17, 2017 at 10:42:13 AM UTC-8, John Cochrane wrote:
> > I think the main point against S turns is that they will not actually lose that much altitude -- unless you turn 90 degrees or more. If you are so high that full flap spoiler and slip are not going to work, then try to do S turns, but get nervous about it and don't head the nose more than 45 degrees away from the runway, you're just not going to get down that fast, and the runway will still slide along below you.
> >
> > 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.
>
> I was running the line at Mountain Valley one day when Rich Benbrook wanted to demonstrate to a student that you could not be too high on final. I relayed to the tow pilot "2000' at the end of the runway behind you". They released, lined up with the runway, full airbrakes and PUSH.
> Looked like a Space shuttle landing in a Twin Grob. Rolled casually to the start line.
> But I wouldn't try that in a Nimbus 3 or even a Duo.
> Jim

At Foxton airfield (NZ) there are some very high pine trees exactly 100 metres before the boundary fence. Most people approach around the end of the trees and then make a 30 degree turn at 50 ft -- including the guys with the Pitts. I decided to try approaching over the trees one day in the DG1000. I started my final from well back at 1000 ft. When I could just see the fence over the top of the trees I opened full brakes. That wasn't enough, so I also nosed down. It turned out to need 95-100 knots to maintain the visual picture and just clear both the trees and the fence (standard farm cattle fence). I whizzed past the folks and gliders assembled at the launch point and took about 400 metres to slow down to landing speed, plus of course another 100 to stop without the wheel brake.

That was still before the official displaced threshold for landing over the trees.

A slip (with brakes) would probably have let me achieve the same descent angle at a lower speed, but I haven't had a chance to try it.

kirk.stant

February 18th 17, 02:24 AM

On Friday, February 17, 2017 at 3:45:08 PM UTC-6, Dave Walsh wrote:
> At 19:16 17 February 2017, wrote:
> >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.
>
> The Vne approach is an interesting idea that I won't be trying
> without 6000 feet of runway available! How do you get rid of
> all that speed 5 feet off the ground? It must produce an
> incredibly long float?

When I took the glider acro course at Estrella back in the early 90s, one of the "party tricks" was to dive at Vne to the deck on entry to downwind, then fly the whole pattern in ground effect - you had to climb to turn base and final - aiming to be near the approach end of the runway, 10 ft over the desert, at about 60 knots. Then you just cracked the spoilers and landed.. Interesting, to say the least!

It did teach you that once in ground effect, a little speed would take you a LONG WAY.

Helps to have an airport out in the middle of nowhere (then); at my local field there would be too much dodging of houses, water tower, trucks on the interstate, etc..! (although I have tried it in Condor and it still works).

Kirk
66

Dave Walsh

February 18th 17, 10:26 PM

And then there are gliders where side slipping with full air
brakes makes the glide angle better! Apparently.

Bob Whelan[_3_]

February 19th 17, 12:21 AM

On 2/18/2017 3:26 PM, Dave Walsh wrote:
> And then there are gliders where side slipping with full air
> brakes makes the glide angle better! Apparently.
>

Definitely true in my S/N 3 Zuni with full flaps on...

Bob W.

P.S. And a hearty "I second those sentiments!" found in the posts of Dave L.
and Cindy B. earlier in this thread. Always good to have Plans B, C, & D
ready-to-go...and the skills to implement 'em, too.

Jonathan St. Cloud

February 19th 17, 12:34 AM

On Saturday, February 18, 2017 at 4:21:21 PM UTC-8, Bob Whelan wrote:
> Always good to have Plans B, C, & D
> ready-to-go...and the skills to implement 'em, too.

This thread on s-turns or slipping is all about airman skills that we should all posses or should learn enough to be comfortable with these skills. S-turns may be used in another application unforeseen, same for slips. You never know which skills or experiences you might have to apply to another situation to bring you home save. It is part of being a good airman. Often we fly precise, but that does not teach you the corners of your flight envelope.

Eric Greenwell[_4_]

February 19th 17, 04:35 AM

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/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

Mike the Strike

February 19th 17, 05:04 AM

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

krasw

February 19th 17, 10:11 AM

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/motorgliders/publications/download-the-guide-1
> - "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm
>
> http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf

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

Martin Gregorie[_5_]

February 19th 17, 11:31 AM

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 |

[email protected]

February 19th 17, 01:29 PM

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

krasw

February 19th 17, 08:53 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.
>
>
> --
> 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 Marotta

February 19th 17, 09:10 PM

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

jfitch

February 20th 17, 03:25 AM

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/motorgliders/publications/download-the-guide-1
> - "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm
>
> http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-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.

Eric Greenwell[_4_]

February 20th 17, 04:53 AM

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/motorgliders/publications/download-the-guide-1
- "Transponders in Sailplanes - Dec 2014a" also ADS-B, PCAS, Flarm

http://soaringsafety.org/prevention/Guide-to-transponders-in-sailplanes-2014A.pdf