Wing Drop, Aerotow vs Winch, Grass vs Pavement.

"What else did I miss?"---the other side of the equation in risk analysis.
What is the worst that can happen if I don't release? vs What is the worst that can happen if I do?
There may be a 1-2 second "startle factor" in some cases. So, the decision must be pre-loaded.
There is very little cost (usually) to a release.


On Saturday, March 20, 2021 at 8:41:52 AM UTC-4, Eric Greenwell wrote:
Brian wrote on 3/19/2021 8:41 PM:
... Do you feel lucky???

So back to my risk assessment...IMO..

- tip wheels/skids - Skids and shorter = increased Risk
- surface drag = More Drag = Increased risk
- water ballast = Heaver wings = Increased Risk
- tug acceleration = I don't know. Once the wing drops, things will happen slower with a low power tug, a high power tug seems like it has more prop wash to cause the wing to drop in the 1st place and the energy in t he system is building faster, so I think I am leaning toward a High Power tug = maybe an increased risk
- hook location (no, a nose hook will not save your ass, despite proponents) CG hook = Increased risk.
- wind direction and strength = cross winds = increased risk, less headwind = increased risk.
- glider type = a consideration for sure but takes some experience to know if higher or lower risk.
- spoiler and flap setting = again likely glider dependent but I know a lot of people start with spoilers extended to prevent wing drop. would think less flap would be better. takes some experience to know.
- dumb luck - The whole point of taking a hard look at the details., How many increased risked factor might apply.

here's a couple more
Rope Length = I would think a shorter rope would = increased risk, more propwash to cause drop
Brake Capacity = poor braking capacity = increased Risk
obstructions to the side of launch area = present = increased Risk
My experience with aerotows is:

-Starting in negative flaps until about 20 knots IAS is better than using positive flaps
-Starting with spoilers extended is definitely better(especially noticed with my ASW20C)
-Using a nose hook instead of a CG hook is better with a wing runner, definitely better when
launching without a wing runner; also, much less likely to run over the rope at the very start.
(I had retrofitted my ASW20C with a nose hook, so I could try it both ways)
-Winglets are better than no winglets.\ (I noticed that because my ASH26E came without
winglets, but I retrofitted them several years later).
-A steerable tail wheel is a terrific aid: without one, you are basically ballistic until you
have 15+ knots. I suspect many of the start-of-tow accidents would be avoided if the gliders
had one. It can also be a real asset in crosswind landings, but that depends a bit on the
tailwheel design and your technique.

So, what to do:

-Every glider can use spoilers at the start, so it's worth investigating that to learn if that
will help in your glider.
-If you have flaps, find out if negative flaps help
-If you don't have a nose hook (or "forward hook" on some Schleicher gliders), see if there is
a retrofit for it.
-If you were thinking about adding winglets to your glider, you now have another reason to do it.
-Good luck finding a steerable tailwheel retrofit, but you can still nag your glider
manufacturer about it.


--
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

On 3/20/21 7:52 AM, Hartley Falbaum wrote:
"What else did I miss?"---the other side of the equation in risk
analysis. What is the worst that can happen if I don't release? vs
What is the worst that can happen if I do? There may be a 1-2 second
"startle factor" in some cases. So, the decision must be
pre-loaded. There is very little cost (usually) to a release.

Kudos to BFC for attempting to take this particular
incident/accident/discussion beyond "mere panacea declamations" to which
the RAS medium seems (to me, dry chuckle) prone.

On the off chance there're some lurkers "somewhat earlier along" the
soaring learning curve - as opposed to long-time RAS regulars (which
includes me, and who seem to in recent years be hogging the forum ) -
this thread-to-date contains potentially-personally-useful,
seriously-good, food for thought.

Hartley's "reduction-ad-absurdem" post above is but one example. In my
view, "panacea fixes" (should they in fact be viewed within one's mind
as such) are too-often a blind alley when it comes to such things as
future learning and "properly preparing one's mind" to commit soaring in
as personally-healthy a manner as possible.

A common example of "panacea thinking" - at least in my part of the
Rocky Mountain Front Range west - is close-minded variations of: "I'll
be OK height-wise so long as I have X-thousand feet msl at location Y
back in the hills". Well, yeah, most of the time, maybe...but how to
reconcile that thinking with the thinking inherent within H. Falbaum's
hypothetical line of thought? One size "generally" can't *possibly* fit
every situation, and it's up to Joe Glider Pilot to decide how best to
approach this conundrum.

Given the inherent imperfections in humanity - imperfect
judgment/skills, lack of omniscience, etc. - while perfection isn't an
option, Joe Glider Pilot can still do a whole lot, and go a long way, to
avoid known (to those with greater experience & skills)
situations/physical-harm/death that *should* be avoidable, given their
existing skills/knowledge.
- - - - - -

Switching here from "Sermon from the Mount" mode to (so I hope)
illustrative examples from experience, O'beer thirty, tale-telling mode...

Early in my post-1-26, 15-meter glass, "somewhat-nose-hooked", aerotow
state, while attempting to take off from a grass strip in the mountains
north of Sun Valley, ID, several things made me pre-launch nervous:
slight crosswind, new-to-me tug/pilot of unknown provenances, knee-high
grass to either side of runway. I and my wing-runner/partner discussed
the situation and pre-planned things best we could (both "local
strangers" and prolly 200 hours total time each) and off I went. Pulled
the plug after an upwind wing drop followed by progressive swerving
into-wind along w. failure of the wing to lift. No harm, no foul was the
result outside the cockpit; inside the cockpit...not so much. Serious
dismay, as I felt that "somehow" I could've done better under existing
circumstances.

And so it proved on the 2nd launch attempt following further discussion
w. my partner *and* the tow-pilot, and some refining of my mental launch
go/no-go plan as well as techniques and "overall awarenesses".

Zooming ahead mightily through time, in that and two other ships (HP-14
w. "50% nose/CG hook, 15-meter span, no negative flaps, V-tail, tail
skid; and 15-meter Zuni *with* negative flaps, "somewhat nose-hooked",
heavily-weighted tailwheel) I aborted 1-each aerotow, both times
followed by successful launches behind the same tug/pilot. Both were
5,300'msl, summertime, concerning-but-far-less-so than the C-70
experience...because of successfully pre-planned/decided "mental
scenario-ing". In both ships, I also made more-than-one (several? many?)
no-wing-runner takeoffs entirely w/o incident.

Bragging? Not intended as such. Rather trying to illustrate how
"preparing one's mind 'properly'" can be, likely *will* be, a good thing
for Joe Glider Pilot, if avoiding adrenaline, negative-excitement, and -
potentially - accidents, is deemed personally desirable.

Other than what I've read on RAS, I know zip about the situation and the
pilot in this particular unfortunate - seemingly, avoidable - accident.
I wish him a speedy and full recovery and continued good soaring, if he
so chooses. And part of this *particular* Joe Glider Pilot would
genuinely appreciate hearing from the horse's mouth at some point in the
future, by way of refining my mental picture.

YMMV,
Bob W.

On Saturday, March 20, 2021 at 8:40:53 AM UTC-7, Bob W. wrote:
On 3/20/21 7:52 AM, Hartley Falbaum wrote:
"What else did I miss?"---the other side of the equation in risk
analysis. What is the worst that can happen if I don't release? vs
What is the worst that can happen if I do? There may be a 1-2 second
"startle factor" in some cases. So, the decision must be
pre-loaded. There is very little cost (usually) to a release.
Kudos to BFC for attempting to take this particular
incident/accident/discussion beyond "mere panacea declamations" to which
the RAS medium seems (to me, dry chuckle) prone.

On the off chance there're some lurkers "somewhat earlier along" the
soaring learning curve - as opposed to long-time RAS regulars (which
includes me, and who seem to in recent years be hogging the forum ) -
this thread-to-date contains potentially-personally-useful,
seriously-good, food for thought.

Hartley's "reduction-ad-absurdem" post above is but one example. In my
view, "panacea fixes" (should they in fact be viewed within one's mind
as such) are too-often a blind alley when it comes to such things as
future learning and "properly preparing one's mind" to commit soaring in
as personally-healthy a manner as possible.

A common example of "panacea thinking" - at least in my part of the
Rocky Mountain Front Range west - is close-minded variations of: "I'll
be OK height-wise so long as I have X-thousand feet msl at location Y
back in the hills". Well, yeah, most of the time, maybe...but how to
reconcile that thinking with the thinking inherent within H. Falbaum's
hypothetical line of thought? One size "generally" can't *possibly* fit
every situation, and it's up to Joe Glider Pilot to decide how best to
approach this conundrum.

Given the inherent imperfections in humanity - imperfect
judgment/skills, lack of omniscience, etc. - while perfection isn't an
option, Joe Glider Pilot can still do a whole lot, and go a long way, to
avoid known (to those with greater experience & skills)
situations/physical-harm/death that *should* be avoidable, given their
existing skills/knowledge.
- - - - - -

Switching here from "Sermon from the Mount" mode to (so I hope)
illustrative examples from experience, O'beer thirty, tale-telling mode....

Early in my post-1-26, 15-meter glass, "somewhat-nose-hooked", aerotow
state, while attempting to take off from a grass strip in the mountains
north of Sun Valley, ID, several things made me pre-launch nervous:
slight crosswind, new-to-me tug/pilot of unknown provenances, knee-high
grass to either side of runway. I and my wing-runner/partner discussed
the situation and pre-planned things best we could (both "local
strangers" and prolly 200 hours total time each) and off I went. Pulled
the plug after an upwind wing drop followed by progressive swerving
into-wind along w. failure of the wing to lift. No harm, no foul was the
result outside the cockpit; inside the cockpit...not so much. Serious
dismay, as I felt that "somehow" I could've done better under existing
circumstances.

And so it proved on the 2nd launch attempt following further discussion
w. my partner *and* the tow-pilot, and some refining of my mental launch
go/no-go plan as well as techniques and "overall awarenesses".

Zooming ahead mightily through time, in that and two other ships (HP-14
w. "50% nose/CG hook, 15-meter span, no negative flaps, V-tail, tail
skid; and 15-meter Zuni *with* negative flaps, "somewhat nose-hooked",
heavily-weighted tailwheel) I aborted 1-each aerotow, both times
followed by successful launches behind the same tug/pilot. Both were
5,300'msl, summertime, concerning-but-far-less-so than the C-70
experience...because of successfully pre-planned/decided "mental
scenario-ing". In both ships, I also made more-than-one (several? many?)
no-wing-runner takeoffs entirely w/o incident.

Bragging? Not intended as such. Rather trying to illustrate how
"preparing one's mind 'properly'" can be, likely *will* be, a good thing
for Joe Glider Pilot, if avoiding adrenaline, negative-excitement, and -
potentially - accidents, is deemed personally desirable.

Other than what I've read on RAS, I know zip about the situation and the
pilot in this particular unfortunate - seemingly, avoidable - accident.
I wish him a speedy and full recovery and continued good soaring, if he
so chooses. And part of this *particular* Joe Glider Pilot would
genuinely appreciate hearing from the horse's mouth at some point in the
future, by way of refining my mental picture.

YMMV,
Bob W.

Another factor not mentioned is what do you have on the wing tip: a skid or a wheel. If it is a wheel and you are towing on a hard surfaced runway a wing drop will be a non-event. If fact, when I self launch (with a wing tip wheel) I want the wing down even if offered a wing runner. A wing that starts down can't drop.
If, however, you are launching off of turf there will be more resistance than a hard surface. I don't ever fly off of turf so I can't say if it would make a difference. Probably depends upon how long the grass is.
A nose hook does provide some self-correcting force, but how much? the nose hook is, at most, one meter ahead of the main; an 18m glider gives forces on the wing tip a 9:1 lever arm to the nose hook. While that is better than nothing, what are the restorative forces? Say the towplane is exerting 200lb on the glider and the nose is 10 degrees off centerline; the restorative force is 35lb. This would only offset about a 5lb force on the wing tip - not very much.

Tom

On Saturday, March 20, 2021 at 8:56:44 PM UTC-6, 2G wrote:
On Saturday, March 20, 2021 at 8:40:53 AM UTC-7, Bob W. wrote:
On 3/20/21 7:52 AM, Hartley Falbaum wrote:
"What else did I miss?"---the other side of the equation in risk
analysis. What is the worst that can happen if I don't release? vs
What is the worst that can happen if I do? There may be a 1-2 second
"startle factor" in some cases. So, the decision must be
pre-loaded. There is very little cost (usually) to a release.
Kudos to BFC for attempting to take this particular
incident/accident/discussion beyond "mere panacea declamations" to which
the RAS medium seems (to me, dry chuckle) prone.

On the off chance there're some lurkers "somewhat earlier along" the
soaring learning curve - as opposed to long-time RAS regulars (which
includes me, and who seem to in recent years be hogging the forum ) -
this thread-to-date contains potentially-personally-useful,
seriously-good, food for thought.

Hartley's "reduction-ad-absurdem" post above is but one example. In my
view, "panacea fixes" (should they in fact be viewed within one's mind
as such) are too-often a blind alley when it comes to such things as
future learning and "properly preparing one's mind" to commit soaring in
as personally-healthy a manner as possible.

A common example of "panacea thinking" - at least in my part of the
Rocky Mountain Front Range west - is close-minded variations of: "I'll
be OK height-wise so long as I have X-thousand feet msl at location Y
back in the hills". Well, yeah, most of the time, maybe...but how to
reconcile that thinking with the thinking inherent within H. Falbaum's
hypothetical line of thought? One size "generally" can't *possibly* fit
every situation, and it's up to Joe Glider Pilot to decide how best to
approach this conundrum.

Given the inherent imperfections in humanity - imperfect
judgment/skills, lack of omniscience, etc. - while perfection isn't an
option, Joe Glider Pilot can still do a whole lot, and go a long way, to
avoid known (to those with greater experience & skills)
situations/physical-harm/death that *should* be avoidable, given their
existing skills/knowledge.
- - - - - -

Switching here from "Sermon from the Mount" mode to (so I hope)
illustrative examples from experience, O'beer thirty, tale-telling mode....

Early in my post-1-26, 15-meter glass, "somewhat-nose-hooked", aerotow
state, while attempting to take off from a grass strip in the mountains
north of Sun Valley, ID, several things made me pre-launch nervous:
slight crosswind, new-to-me tug/pilot of unknown provenances, knee-high
grass to either side of runway. I and my wing-runner/partner discussed
the situation and pre-planned things best we could (both "local
strangers" and prolly 200 hours total time each) and off I went. Pulled
the plug after an upwind wing drop followed by progressive swerving
into-wind along w. failure of the wing to lift. No harm, no foul was the
result outside the cockpit; inside the cockpit...not so much. Serious
dismay, as I felt that "somehow" I could've done better under existing
circumstances.

And so it proved on the 2nd launch attempt following further discussion
w. my partner *and* the tow-pilot, and some refining of my mental launch
go/no-go plan as well as techniques and "overall awarenesses".

Zooming ahead mightily through time, in that and two other ships (HP-14
w. "50% nose/CG hook, 15-meter span, no negative flaps, V-tail, tail
skid; and 15-meter Zuni *with* negative flaps, "somewhat nose-hooked",
heavily-weighted tailwheel) I aborted 1-each aerotow, both times
followed by successful launches behind the same tug/pilot. Both were
5,300'msl, summertime, concerning-but-far-less-so than the C-70
experience...because of successfully pre-planned/decided "mental
scenario-ing". In both ships, I also made more-than-one (several? many?)
no-wing-runner takeoffs entirely w/o incident.

Bragging? Not intended as such. Rather trying to illustrate how
"preparing one's mind 'properly'" can be, likely *will* be, a good thing
for Joe Glider Pilot, if avoiding adrenaline, negative-excitement, and -
potentially - accidents, is deemed personally desirable.

Other than what I've read on RAS, I know zip about the situation and the
pilot in this particular unfortunate - seemingly, avoidable - accident.
I wish him a speedy and full recovery and continued good soaring, if he
so chooses. And part of this *particular* Joe Glider Pilot would
genuinely appreciate hearing from the horse's mouth at some point in the
future, by way of refining my mental picture.

YMMV,
Bob W.
Another factor not mentioned is what do you have on the wing tip: a skid or a wheel. If it is a wheel and you are towing on a hard surfaced runway a wing drop will be a non-event. If fact, when I self launch (with a wing tip wheel) I want the wing down even if offered a wing runner. A wing that starts down can't drop.
If, however, you are launching off of turf there will be more resistance than a hard surface. I don't ever fly off of turf so I can't say if it would make a difference. Probably depends upon how long the grass is.
A nose hook does provide some self-correcting force, but how much? the nose hook is, at most, one meter ahead of the main; an 18m glider gives forces on the wing tip a 9:1 lever arm to the nose hook. While that is better than nothing, what are the restorative forces? Say the towplane is exerting 200lb on the glider and the nose is 10 degrees off centerline; the restorative force is 35lb. This would only offset about a 5lb force on the wing tip - not very much.

Tom
Lush turf is pretty grabby and if a pilot tries to roll the glider with ailerons, the down wing aileron only grabs more turf and makes the situation worse. Only opposite rudder should be used until the wing starts to rise.

Frank Whiteley wrote on 3/21/2021 10:51 AM:
On Saturday, March 20, 2021 at 8:56:44 PM UTC-6, 2G wrote:
....
Bragging? Not intended as such. Rather trying to illustrate how
"preparing one's mind 'properly'" can be, likely *will* be, a good thing
for Joe Glider Pilot, if avoiding adrenaline, negative-excitement, and -
potentially - accidents, is deemed personally desirable.

Other than what I've read on RAS, I know zip about the situation and the
pilot in this particular unfortunate - seemingly, avoidable - accident.
I wish him a speedy and full recovery and continued good soaring, if he
so chooses. And part of this *particular* Joe Glider Pilot would
genuinely appreciate hearing from the horse's mouth at some point in the
future, by way of refining my mental picture.

YMMV,
Bob W.
Another factor not mentioned is what do you have on the wing tip: a skid or a wheel. If it is a wheel and you are towing on a hard surfaced runway a wing drop will be a non-event. If fact, when I self launch (with a wing tip wheel) I want the wing down even if offered a wing runner. A wing that starts down can't drop.
If, however, you are launching off of turf there will be more resistance than a hard surface. I don't ever fly off of turf so I can't say if it would make a difference. Probably depends upon how long the grass is.
A nose hook does provide some self-correcting force, but how much? the nose hook is, at most, one meter ahead of the main; an 18m glider gives forces on the wing tip a 9:1 lever arm to the nose hook. While that is better than nothing, what are the restorative forces? Say the towplane is exerting 200lb on the glider and the nose is 10 degrees off centerline; the restorative force is 35lb. This would only offset about a 5lb force on the wing tip - not very much.

Tom
Lush turf is pretty grabby and if a pilot tries to roll the glider with ailerons, the down wing aileron only grabs more turf and makes the situation worse. Only opposite rudder should be used until the wing starts to rise.

Flapped ships can start in a negative setting, and avoid the turf grabbing by the ailerons.

--
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