Re: I have problem. I correct the aileron the wrong way at takeoff

[Todd]

I concur with the other postings for windy day practice. It is a
great reflex builder.

You may also consider some training flight with an instructor doing
"un-assisted" takeoffs (no wing runner). It seems that this skill is
no longer part of the typical training syllabus, but is a good way to
get used to the control inputs required to steer the glider (feet/
rudder) and simultaneously pick up the wing dragging on the ground
with out over controlling. When you can complete this task in a
smooth coordinated manner, you should have no problems dealing with a
wing drop.

Hang in there! Wings drop The causes of a wing drop are many and most
are out of your control. Your focus should be on early recognition of
the problem and a timely and appropriate corrective action.
Todd

[bildan]

On Jan 19, 11:34*am, Todd > wrote:
> I concur with the other postings for windy day practice. *It is a
> great reflex builder.
>
> You may also consider some training flight with an instructor doing
> "un-assisted" takeoffs *(no wing runner). *It seems that this skill is
> no longer part of the typical training syllabus, but is a good way to
> get used to the control inputs required to steer the glider (feet/
> rudder) and simultaneously pick up the wing dragging on the ground
> with out over controlling. *When you can complete this task in a
> smooth coordinated manner, you should have no problems dealing with a
> wing drop.
>
> Hang in there! *Wings drop The causes of a wing drop are many and most
> are out of your control. *Your focus should be on early recognition of
> the problem and a timely and appropriate corrective action.
> Todd

I'm a big fan of Condor but wing balancing isn't one of its strong
suites due to the limited peripheral vision afforded by a computer
monitor. Many "wing leveling" problems can be traced to students not
using their peripheral vision - tunnel vision tends to develop under
the stress of a takeoff roll.

In fact, PC flight simulators demonstrate just how hard it is to
control a glider without peripheral vision. You really need a 3-
monitor set up to use A PC flight simulator in a training environment.

Wing down 'no-wing runner' takeoffs are mostly a relic from 2-33's
with tip wheels and should be used sparingly. I'm not saying it's not
a skill to know but I question teaching it to a primary student
considering the glider types any new student can be expected to fly
these days. Wing down takeoffs should NEVER be used with a CG hook or
on a winch.

The "simulated" ground roll practice using a glider facing into the
wind allows logging hours of practice doing something you pass through
in seconds on a real flight. I'm thinking a lot of broken fiberglass
could be avoided if all of us would spend an hour doing this each
spring.

Bill Daniels

[Doug Hoffman]

bildan wrote:

> I'm a big fan of Condor but wing balancing isn't one of its strong
> suites due to the limited peripheral vision afforded by a computer
> monitor. Many "wing leveling" problems can be traced to students not
> using their peripheral vision - tunnel vision tends to develop under
> the stress of a takeoff roll.

Fair enough. Though the horizon in Condor is a darn good indicator (I
just checked with mine) and you *will* know it if your wings aren't
level and likely be punished (possible ground loop, not staying behind
the towplane, etc). Seems to me that after a few hours on a sim one
will *not* have a problem with right vs left aileron. I'm not
suggesting that the horizon should always be used to check wings level
during ground roll-out. I am saying that a sim like Condor *will*
solidly teach you left-stick from right-stick.


> In fact, PC flight simulators demonstrate just how hard it is to
> control a glider without peripheral vision. You really need a 3-
> monitor set up to use A PC flight simulator in a training environment.

I have to disagree. While 3 monitors would be nice a TrackIR device
works marvelously. Even the coolie hat switch isn't that bad, but for
serious work like coring thermals the TrackIR is the way to go.


> Wing down 'no-wing runner' takeoffs are mostly a relic from 2-33's
> with tip wheels and should be used sparingly. I'm not saying it's not
> a skill to know but I question teaching it to a primary student
> considering the glider types any new student can be expected to fly
> these days. Wing down takeoffs should NEVER be used with a CG hook or
> on a winch.

Who suggested 'no-wing runner'? Not I. Condor runs your wing for you.


> The "simulated" ground roll practice using a glider facing into the
> wind allows logging hours of practice doing something you pass through
> in seconds on a real flight. I'm thinking a lot of broken fiberglass
> could be avoided if all of us would spend an hour doing this each
> spring.

Agreed. If you have all that readily available it seems like a fine way
to go.

I am just suggesting a simulator as a possible alternative if using that
is more convenient.

Living in Michigan it is common to not fly anything (real) from October
through April. I once had to take my flight review as my very first
flights after a long winter layover. I was complemented on how well I
kept the turns crisp and coordinated. I attributed that to "staying
current" using Condor.

I would also strongly recommend that a sim be used with rudder pedals. I
think it is a bad idea to get in the habit of using the stick without
your feet pressing the pedals properly.

Will the "simulated" ground roll practice using a glider facing into the
wind teach proper use of the rudder? Condor will.

Regards,

-Doug

[bildan]

On Jan 19, 2:56*pm, Doug Hoffman > wrote:
> bildan wrote:
> > I'm a big fan of Condor but wing balancing isn't one of its strong
> > suites due to the limited peripheral vision afforded by a computer
> > monitor. *Many "wing leveling" problems can be traced to students not
> > using their peripheral vision - tunnel vision tends to develop under
> > the stress of a takeoff roll.
>
> Fair enough. *Though the horizon in Condor is a darn good indicator (I
> just checked with mine) and you *will* know it if your wings aren't
> level and likely be punished (possible ground loop, not staying behind
> the towplane, etc). *Seems to me that after a few hours on a sim one
> will *not* have a problem with right vs left aileron. *I'm not
> suggesting that the horizon should always be used to check wings level
> during ground roll-out. I am saying that a sim like Condor *will*
> solidly teach you left-stick from right-stick.
>
> > In fact, PC flight simulators demonstrate just how hard it is to
> > control a glider without peripheral vision. *You really need a 3-
> > monitor set up to use A PC flight simulator in a training environment.
>
> I have to disagree. While 3 monitors would be nice a TrackIR device
> works marvelously. *Even the coolie hat switch isn't that bad, but for
> serious work like coring thermals the TrackIR is the way to go.
>
> > Wing down 'no-wing runner' takeoffs are mostly a relic from 2-33's
> > with tip wheels and should be used sparingly. *I'm not saying it's not
> > a skill to know but I question teaching it to a primary student
> > considering the glider types any new student can be expected to fly
> > these days. *Wing down takeoffs should NEVER be used with a CG hook or
> > on a winch.
>
> Who suggested 'no-wing runner'? *Not I. *Condor runs your wing for you.
>
> > The "simulated" ground roll practice using a glider facing into the
> > wind allows logging hours of practice doing something you pass through
> > in seconds on a real flight. *I'm thinking a lot of broken fiberglass
> > could be avoided if all of us would spend an hour doing this each
> > spring.
>
> Agreed. If you have all that readily available it seems like a fine way
> to go.
>
> I am just suggesting a simulator as a possible alternative if using that
> is more convenient.
>
> Living in Michigan it is common to not fly anything (real) from October
> through April. I once had to take my flight review as my very first
> flights after a long winter layover. *I was complemented on how well I
> kept the turns crisp and coordinated. *I attributed that to "staying
> current" using Condor.
>
> I would also strongly recommend that a sim be used with rudder pedals. I
> think it is a bad idea to get in the habit of using the stick without
> your feet pressing the pedals properly.
>
> Will the "simulated" ground roll practice using a glider facing into the
> wind teach proper use of the rudder? *Condor will.
>
> Regards,
>
> -Doug

I'm not really arguing here - I like Condor and would like to see it
more widely used. Although, without a really good setup with rudder
pedals, it's somewhat limited. I tend to use it as an "animated
whiteboard" to illustrate a maneuver.

However, if you create a complete cockpit setup, Condor is a VERY
effective training tool.

BTW, Condor is also VERY good at creating flight training
illustrations with its jpeg screen capture feature. Any photo editor
can add text and graphics to the image. I wrote a highly illustrated
winch training syllabus with this technique.

Don't discount the peripheral vision thing. Track IR effectively
simulates swiveling your head which isn't the same thing as peripheral
vision. A pilot need to get visual information from the sides while
looking straight ahead.

Three monitors is a much better experience than Track IR - though more
expensive. I've seen some curved ultra-wide monitors that would
provide nearly 180 degree field of vision - ultra expensive but very
cool.

[Andy[_1_]]

On Jan 19, 12:56*pm, bildan > wrote:
>*Wing down takeoffs should NEVER be used with a CG hook

Why not? Works just fine for unassisted aero retrieve with my stick
on wing tip wheel. Would I prefer to have a wing runner - sure, but
NEVER is far too strong a prohibition.

Andy

[Doug Hoffman]

bildan wrote:


> I'm not really arguing here - I like Condor and would like to see it
> more widely used.

Sorry, I didn't mean to argue.

> Although, without a really good setup with rudder
> pedals, it's somewhat limited.

Yes. I would say that flying a sim without rudder pedals will teach
dangerous habits.

> I tend to use it as an "animated
> whiteboard" to illustrate a maneuver.
>
> However, if you create a complete cockpit setup, Condor is a VERY
> effective training tool.
>
> BTW, Condor is also VERY good at creating flight training
> illustrations with its jpeg screen capture feature. Any photo editor
> can add text and graphics to the image. I wrote a highly illustrated
> winch training syllabus with this technique.

I believe there is also a way to create mini videos in various formats.


> Don't discount the peripheral vision thing. Track IR effectively
> simulates swiveling your head which isn't the same thing as peripheral
> vision. A pilot need to get visual information from the sides while
> looking straight ahead.

I don't disagree. But how does one look straight up with 3 screens and
no TrackIR? TrackIR allows one to easily, naturally "look up". Helps
when trying to see where you are relative to a cu or if in a gaggle what
is above you.


> Three monitors is a much better experience than Track IR - though more
> expensive. I've seen some curved ultra-wide monitors that would
> provide nearly 180 degree field of vision - ultra expensive but very
> cool.

Yeah. I've seen some very elaborate setups for sims.

My wife still looks at me funny while in my study wearing a baseball cap
and the infrared reflectors. :-)

Regards,

-Doug

[TonyV[_2_]]

Andy wrote:
> On Jan 19, 12:56 pm, bildan > wrote:
>> Wing down takeoffs should NEVER be used with a CG hook
>
> Why not? Works just fine for unassisted aero retrieve with my stick
> on wing tip wheel. Would I prefer to have a wing runner - sure, but
> NEVER is far too strong a prohibition.

Agreed. I like the stick idea but I manage to need a GC hook unassisted
take off once or twice a year during an aero retrieve (LS-6). The trick
is to anticipate the wingtip drag and angle the glider slightly away
from the down tip. Grass needs more angle than pavement.

Tony V.

[bildan]

On Jan 19, 6:41*pm, TonyV > wrote:
> Andy wrote:
> > On Jan 19, 12:56 pm, bildan > wrote:
> >> *Wing down takeoffs should NEVER be used with a CG hook
>
> > Why not? *Works just fine for unassisted aero retrieve with my stick
> > on wing tip wheel. *Would I prefer to have a wing runner - sure, but
> > NEVER is far too strong a prohibition.
>
> Agreed. I like the stick idea but I manage to need a GC hook unassisted
> take off once or twice a year during an aero retrieve (LS-6). The trick
> is to anticipate the wingtip drag and angle the glider slightly away
> from the down tip. Grass needs more angle than pavement.
>
> Tony V.

You guys can't believe how nasty a ground loop can be when a wing tip
catches and the glider is being pulled with he CG hook. A nose hook
will help keep you straight if a tip digs in. A CG hook will just
accelerate the ground loop. If it happens with enough speed (or power
in the case of a winch launch), you'll likely end up inverted - and
dead.

There's no way I'd attempt a takeoff without a wing runner using my CG
hook - wing stick or no. I stand by never - with emphasis!

Bill Daniels

[[email protected]]

On Jan 19, 11:56*am, bildan > wrote:

> The "simulated" ground roll practice using a glider facing into the
> wind allows logging hours of practice doing something you pass through
> in seconds on a real flight. *I'm thinking a lot of broken fiberglass
> could be avoided if all of us would spend an hour doing this each
> spring.

I do this regularly when I am on the runway when waiting for a tow -
it's great practice to see how low you can get the wing and pick it up
again.

This may be more for the advanced course, but you should keep in mind
that full aileron away from a dropping wing may not always be the
right answer, depending on the angle of attack for the wing with the
tailwheel on the ground as well as airspeed, wind speed and direction
and the overall configuration of the glider. I have on occasion been
able to pick up a falling wing by relaxing the opposite aileron. The
reason is that a drooped aileron increases the angle of attack of the
wing, potentailly making the difference between being stalled and
unstalled. Avoiding tip stalls is why many flapped gliders have the
ailerons go negative with full flaps and why negative flaps is
normally advised for the start of the takeoff roll.

I don't like the idea of doing a wing dragging takeoff with a cg hook
if I can avoid it, but will consider giving it a shot on something
like a remote aero retreive if I've got reasonable wind down the
runway and other factors aren't adverse. If you don't get the wing up
by '3-Mississippi' you need to pull the release. The only times I've
gone in the weeds were when I had wing runners who didn't know what
they were doing in a crosswind. By the time I realized the wing was
going down and pulled the plug I was going too fast to avoid an off-
runway adventure. I'm not sure that a bad wing runner is a better
situation than a wing-down takeoff - at least in the latter case you
aren't taken by surprise.

[Doug Hoffman]

wrote:

> This may be more for the advanced course, but you should keep in mind
> that full aileron away from a dropping wing may not always be the
> right answer, depending on the angle of attack for the wing with the
> tailwheel on the ground as well as airspeed, wind speed and direction
> and the overall configuration of the glider. I have on occasion been
> able to pick up a falling wing by relaxing the opposite aileron. The
> reason is that a drooped aileron increases the angle of attack of the
> wing, potentailly making the difference between being stalled and
> unstalled. Avoiding tip stalls is why many flapped gliders have the
> ailerons go negative with full flaps and why negative flaps is
> normally advised for the start of the takeoff roll.

I used to fly an RS-15 with fixed ailerons (did not raise or droop with
the flaps). I learned to do exactly what you describe. The RS has very
strong landing gear with a large amount of oleo shock travel. The
downside of this is the high angle of attack sitting on the ground.
Just a *small* amount of opposite aileron would actually lift the wing
as desired. This only worked for the first 100 feet or so of initial
rollout. When I told others what I was doing they thought I was a bit daft.

Regards,

-Doug

[Andy[_1_]]

On Jan 19, 6:58*pm, bildan > wrote:
>
> You guys can't believe how nasty a ground loop can be when a wing tip
> catches and the glider is being pulled with he CG hook. *A nose hook
> will help keep you straight if a tip digs in. *A CG hook will just
> accelerate the ground loop. *If it happens with enough speed (or power
> in the case of a winch launch), you'll likely end up inverted - and
> dead.

I'd guess from your reply that your glider has both CG and nose
hooks. Many pilots have flown hundreds of aerotows without incident
despite the fact that their gliders only had CG hooks.

I had a few wing drop incidents with aerotow using a CG hook but those
were all when using a wing runner. Most I immediately released, one or
two I recovered and completed the takeoff. As a general rule I'll
release as soon as the wing drops.

At the start of an aerotow takeoff the probability of a high energy
ground loop is very low since the ground speed is low and the
acceleration is fairly low. The risk of a high energy ground loop is
later in the takeoff roll and is there whether a wing runner is used
or not. It is a very different situation for a winch launch.

The yaw restoring moment of the tow rope is directly related to the
distance from the main wheel, or from the CG once airborne. A typical
CG hook is forward of both the main gear and the CG, so the moment of
the tow rope is in the same sense as for a nose or belly hook and,
although smaller, is still stabilizing rather than destabilizing.
Given that, can you please explain why you believe a CG hook will
accelerate a ground loop.


Andy

[bildan]

On Jan 20, 9:04*am, Andy > wrote:
> On Jan 19, 6:58*pm, bildan > wrote:
>
>
>
> > You guys can't believe how nasty a ground loop can be when a wing tip
> > catches and the glider is being pulled with he CG hook. *A nose hook
> > will help keep you straight if a tip digs in. *A CG hook will just
> > accelerate the ground loop. *If it happens with enough speed (or power
> > in the case of a winch launch), you'll likely end up inverted - and
> > dead.
>
> I'd guess from your reply that your glider has both CG and nose
> hooks. *Many pilots have flown hundreds of aerotows without incident
> despite the fact that their gliders only had CG hooks.
>
> I had a few wing drop incidents with aerotow using a CG hook but those
> were all when using a wing runner. Most I immediately released, one or
> two I recovered and completed the takeoff. *As a general rule I'll
> release as soon as the wing drops.
>
> At the start of an aerotow takeoff the probability of a high energy
> ground loop is very low since the ground speed is low and the
> acceleration is fairly low. * The risk of a high energy ground loop is
> later in the takeoff roll and is there whether a wing runner is used
> or not. *It is a very different situation for a winch launch.
>
> The yaw restoring moment of the tow rope is directly related to the
> distance from the main wheel, or from the CG once airborne. *A typical
> CG hook is forward of both the main gear and the CG, so the moment of
> the tow rope is in the same sense as for a nose or belly hook and,
> although smaller, *is still stabilizing rather than destabilizing.
> Given that, can you please explain why you believe a CG hook will
> accelerate a ground loop.
>
> Andy

Andy you assume too much. I don't have a nose hook.

I wrote, "If it happens with enough speed (or power in the case of a
winch launch)". I think that makes the distinction between aero tow
and winch launch.

So, how would a CG hook accelerate a ground loop? If a wing tip
catches the ground loop pivot point is now the wing tip. The pull at
the CG hook will rapidly accelerate the other wing so it lightens up
the weight on the main wheel. Basically, it's a Frisbee launch.

Yes, it could happen with either nose or CG hooks but the CG hook will
produce a more violent ground loop. If it's violent enough, the
glider will roll inverted.

The wing tip doesn't have to actually catch and stop. If it is
retarded enough by ground friction, the pivot point shifts toward that
tip enough to amplify the ground loop.

[[email protected]]

On Jan 20, 8:42*am, bildan > wrote:
> On Jan 20, 9:04*am, Andy > wrote:
>
>
>
> > On Jan 19, 6:58*pm, bildan > wrote:
>
> > > You guys can't believe how nasty a ground loop can be when a wing tip
> > > catches and the glider is being pulled with he CG hook. *A nose hook
> > > will help keep you straight if a tip digs in. *A CG hook will just
> > > accelerate the ground loop. *If it happens with enough speed (or power
> > > in the case of a winch launch), you'll likely end up inverted - and
> > > dead.
>
> > I'd guess from your reply that your glider has both CG and nose
> > hooks. *Many pilots have flown hundreds of aerotows without incident
> > despite the fact that their gliders only had CG hooks.
>
> > I had a few wing drop incidents with aerotow using a CG hook but those
> > were all when using a wing runner. Most I immediately released, one or
> > two I recovered and completed the takeoff. *As a general rule I'll
> > release as soon as the wing drops.
>
> > At the start of an aerotow takeoff the probability of a high energy
> > ground loop is very low since the ground speed is low and the
> > acceleration is fairly low. * The risk of a high energy ground loop is
> > later in the takeoff roll and is there whether a wing runner is used
> > or not. *It is a very different situation for a winch launch.
>
> > The yaw restoring moment of the tow rope is directly related to the
> > distance from the main wheel, or from the CG once airborne. *A typical
> > CG hook is forward of both the main gear and the CG, so the moment of
> > the tow rope is in the same sense as for a nose or belly hook and,
> > although smaller, *is still stabilizing rather than destabilizing.
> > Given that, can you please explain why you believe a CG hook will
> > accelerate a ground loop.
>
> > Andy
>
> Andy you assume too much. *I don't have a nose hook.
>
> I wrote, "If it happens with enough speed (or power in the case of a
> winch launch)". *I think that makes the distinction between aero tow
> and winch launch.
>
> So, how would a CG hook accelerate a ground loop? *If a wing tip
> catches the ground loop pivot point is now the wing tip. *The pull at
> the CG hook will rapidly accelerate the other wing so it lightens up
> the weight on the main wheel. *Basically, it's a Frisbee launch.
>
> Yes, it could happen with either nose or CG hooks but the CG hook will
> produce a more violent ground loop. *If it's violent enough, the
> glider will roll inverted.
>
> The wing tip doesn't have to actually catch and stop. *If it is
> retarded enough by ground friction, the pivot point shifts toward that
> tip enough to amplify the ground loop.

Interesting point - I would think it would depend on the relative
stabilizing moment along the hook-to cg pivot (inertial) and the hook-
to wheel pivot versus the destabilizing moment from the wing tip to
wheel pivot and the wing tip to hook pivot. Unless your wing tip hits
a ton of friction (not so likely with the tip wheel Andy describes) or
a relatively immovable object I doubt the glider would totally pivot
around the tip. If the tip did really dig in a 25 foot moment arm is
going to matter a lot more than the inches of difference between a
belly hook and a cg hook for the first 15 degrees or so of rotation
that are going to decide your fate. I agree that there is a bigger
restoring moment arm the further forward the hook is, but it would be
a pretty narrow set of circumstances where the tow rope force helps
more than it hurts with the tip totally dug in.

THis line of thinking does raise a question in my mind on whether
tapping the wheel brake would help pull the nose straight in a wing
down situation - it slows your acceleration so it's a bit of a
tradeoff. I'm normally on the divebrakes until I have positive aileron
control - partly for improved aileron effectiveness (not sure this has
ever been proven but it doesn't seem to hurt) and partly to have them
unlocked in case I need to pull the plug and get stopped. From
experience I will say if the wing goes down (tip skids, not wheels)
and you are on a typical asphalt runway you will have only a 2-count
to get it back up before your are sure to end up in the weeds - be
ready and don't try to save it - once you get 15-degrees off runway
heading you just won't get it straightened out in time.

Excellent point on wing running technique - I always tell wing runners
to let the wing go up or down in response to the force they feel - a
foot or two so I can notice and correct, but not all the way to the
ground. They don't always get it. If you don't trust your wing runner
consider your options. One day last year I had a choice between three
wing runners - one in flip-flops, one with a bad hip and one who'd
never run a wing before. Who would you choose?

9B

[Andy[_1_]]

I see nothing in your reply that convinces me that making a wing low
aerotow retrieve from a paved runway using a wing tip wheel and a CG
hook is an unacceptable risk.

Andy

[Mike the Strike]

Although slightly off-topic, the gyro effect of the wheel on bicycles
and motorbikes is not nearly as important as most people think. Check
out tests run with a contra-rotating wheel attached to the front wheel
of a bicycle:

http://www2.eng.cam.ac.uk/~hemh/gyrobike.htm

Mike

[Nyal Williams[_2_]]

Bad hip; has better judgment than flip-flop artist. He is expecting a fall
and is prepared to let go.

At 17:46 20 January 2009, wrote:
>On Jan 20, 8:42=A0am, bildan wrote:
>> On Jan 20, 9:04=A0am, Andy wrote:
>>
>>
>>
>> > On Jan 19, 6:58=A0pm, bildan wrote:
>>
>> > > You guys can't believe how nasty a ground loop can be when a wing
>tip
>> > > catches and the glider is being pulled with he CG hook. =A0A nose
>hoo=
>k
>> > > will help keep you straight if a tip digs in. =A0A CG hook will
just
>> > > accelerate the ground loop. =A0If it happens with enough speed (or
>po=
>wer
>> > > in the case of a winch launch), you'll likely end up inverted -
and
>> > > dead.
>>
>> > I'd guess from your reply that your glider has both CG and nose
>> > hooks. =A0Many pilots have flown hundreds of aerotows without
incident
>> > despite the fact that their gliders only had CG hooks.
>>
>> > I had a few wing drop incidents with aerotow using a CG hook but
those
>> > were all when using a wing runner. Most I immediately released, one
or
>> > two I recovered and completed the takeoff. =A0As a general rule
I'll
>> > release as soon as the wing drops.
>>
>> > At the start of an aerotow takeoff the probability of a high energy
>> > ground loop is very low since the ground speed is low and the
>> > acceleration is fairly low. =A0 The risk of a high energy ground
loop
>i=
>s
>> > later in the takeoff roll and is there whether a wing runner is used
>> > or not. =A0It is a very different situation for a winch launch.
>>
>> > The yaw restoring moment of the tow rope is directly related to the
>> > distance from the main wheel, or from the CG once airborne. =A0A
>typica=
>l
>> > CG hook is forward of both the main gear and the CG, so the moment
of
>> > the tow rope is in the same sense as for a nose or belly hook and,
>> > although smaller, =A0is still stabilizing rather than destabilizing.
>> > Given that, can you please explain why you believe a CG hook will
>> > accelerate a ground loop.
>>
>> > Andy
>>
>> Andy you assume too much. =A0I don't have a nose hook.
>>
>> I wrote, "If it happens with enough speed (or power in the case of a
>> winch launch)". =A0I think that makes the distinction between aero
tow
>> and winch launch.
>>
>> So, how would a CG hook accelerate a ground loop? =A0If a wing tip
>> catches the ground loop pivot point is now the wing tip. =A0The pull
at
>> the CG hook will rapidly accelerate the other wing so it lightens up
>> the weight on the main wheel. =A0Basically, it's a Frisbee launch.
>>
>> Yes, it could happen with either nose or CG hooks but the CG hook will
>> produce a more violent ground loop. =A0If it's violent enough, the
>> glider will roll inverted.
>>
>> The wing tip doesn't have to actually catch and stop. =A0If it is
>> retarded enough by ground friction, the pivot point shifts toward that
>> tip enough to amplify the ground loop.
>
>Interesting point - I would think it would depend on the relative
>stabilizing moment along the hook-to cg pivot (inertial) and the hook-
>to wheel pivot versus the destabilizing moment from the wing tip to
>wheel pivot and the wing tip to hook pivot. Unless your wing tip hits
>a ton of friction (not so likely with the tip wheel Andy describes) or
>a relatively immovable object I doubt the glider would totally pivot
>around the tip. If the tip did really dig in a 25 foot moment arm is
>going to matter a lot more than the inches of difference between a
>belly hook and a cg hook for the first 15 degrees or so of rotation
>that are going to decide your fate. I agree that there is a bigger
>restoring moment arm the further forward the hook is, but it would be
>a pretty narrow set of circumstances where the tow rope force helps
>more than it hurts with the tip totally dug in.
>
>THis line of thinking does raise a question in my mind on whether
>tapping the wheel brake would help pull the nose straight in a wing
>down situation - it slows your acceleration so it's a bit of a
>tradeoff. I'm normally on the divebrakes until I have positive aileron
>control - partly for improved aileron effectiveness (not sure this has
>ever been proven but it doesn't seem to hurt) and partly to have them
>unlocked in case I need to pull the plug and get stopped. From
>experience I will say if the wing goes down (tip skids, not wheels)
>and you are on a typical asphalt runway you will have only a 2-count
>to get it back up before your are sure to end up in the weeds - be
>ready and don't try to save it - once you get 15-degrees off runway
>heading you just won't get it straightened out in time.
>
>Excellent point on wing running technique - I always tell wing runners
>to let the wing go up or down in response to the force they feel - a
>foot or two so I can notice and correct, but not all the way to the
>ground. They don't always get it. If you don't trust your wing runner
>consider your options. One day last year I had a choice between three
>wing runners - one in flip-flops, one with a bad hip and one who'd
>never run a wing before. Who would you choose?
>
>9B
>

[bildan]

On Jan 20, 10:46*am, wrote:
> On Jan 20, 8:42*am, bildan > wrote:

> Excellent point on wing running technique - I always tell wing runners
> to let the wing go up or down in response to the force they feel - a
> foot or two so I can notice and correct, but not all the way to the
> ground. They don't always get it. If you don't trust your wing runner
> consider your options. *One day last year I had a choice between three
> wing runners - one in flip-flops, one with a bad hip and one who'd
> never run a wing before. Who would you choose?
>
> 9B

I'd take any of them but give special instructions.

1. Balance the glider carefully so it takes 5 or 6 seconds for the
wing to drop when released.
2. Don't run, just stand there and let the tip go as the glider starts
to move.

I will carefully center the ailerons so the wing runner can precisely
balance the glider and not move them again until the glider starts to
move and then only if a wing starts down. I'm often airborne before
any serious aileron inputs are needed.

This technique works extremely well and is easy to teach - please give
it a try. The current system doesn't properly divide the task between
pilot and runner and they often fight each other.

Bill Daniels

[[email protected]]

On Jan 20, 2:07*pm, bildan > wrote:
> On Jan 20, 10:46*am, wrote:
>
> > On Jan 20, 8:42*am, bildan > wrote:
> > Excellent point on wing running technique - I always tell wing runners
> > to let the wing go up or down in response to the force they feel - a
> > foot or two so I can notice and correct, but not all the way to the
> > ground. They don't always get it. If you don't trust your wing runner
> > consider your options. *One day last year I had a choice between three
> > wing runners - one in flip-flops, one with a bad hip and one who'd
> > never run a wing before. Who would you choose?
>
> > 9B
>
> I'd take any of them but give special instructions.
>
> 1. *Balance the glider carefully so it takes 5 or 6 seconds for the
> wing to drop when released.
> 2. Don't run, just stand there and let the tip go as the glider starts
> to move.
>
> I will carefully center the ailerons so the wing runner can precisely
> balance the glider and not move them again until the glider starts to
> move and then only if a wing starts down. *I'm often airborne before
> any serious aileron inputs are needed.
>
> This technique works extremely well and is easy to teach - please give
> it a try. *The current system doesn't properly divide the task between
> pilot and runner and they often fight each other.
>
> Bill Daniels

I should have added some more context to my multiple-choice question:

- 10 kt crosswind with gusting
- 6,000 field elevation
- 90+ degrees F

That's not a circumstance where I recommend just letting go of the
tip. I do always direct wing runners to hold the tip by the trailing
edge so it's hard to push or pull the nose around.

Another decent piece of advice to to have the towplane run the engine
up before releasing the brakes - even if you get a little catapult
from the stretch in the tow rope you'll still get to Vmc more quickly.

9B

[bildan]

On Jan 20, 4:48*pm, wrote:
> On Jan 20, 2:07*pm, bildan > wrote:
>
>
>
> > On Jan 20, 10:46*am, wrote:
>
> > > On Jan 20, 8:42*am, bildan > wrote:
> > > Excellent point on wing running technique - I always tell wing runners
> > > to let the wing go up or down in response to the force they feel - a
> > > foot or two so I can notice and correct, but not all the way to the
> > > ground. They don't always get it. If you don't trust your wing runner
> > > consider your options. *One day last year I had a choice between three
> > > wing runners - one in flip-flops, one with a bad hip and one who'd
> > > never run a wing before. Who would you choose?
>
> > > 9B
>
> > I'd take any of them but give special instructions.
>
> > 1. *Balance the glider carefully so it takes 5 or 6 seconds for the
> > wing to drop when released.
> > 2. Don't run, just stand there and let the tip go as the glider starts
> > to move.
>
> > I will carefully center the ailerons so the wing runner can precisely
> > balance the glider and not move them again until the glider starts to
> > move and then only if a wing starts down. *I'm often airborne before
> > any serious aileron inputs are needed.
>
> > This technique works extremely well and is easy to teach - please give
> > it a try. *The current system doesn't properly divide the task between
> > pilot and runner and they often fight each other.
>
> > Bill Daniels
>
> I should have added some more context to my multiple-choice question:
>
> - 10 kt crosswind with gusting
> - 6,000 field elevation
> - 90+ degrees F
>
> That's not a circumstance where I recommend just letting go of the
> tip. *I do always direct wing runners to hold the tip by the trailing
> edge so it's hard to push or pull the nose around.
>
> Another decent piece of advice to to have the towplane run the engine
> up before releasing the brakes - even if you get a little catapult
> from the stretch in the tow rope you'll still get to Vmc more quickly.
>
> 9B

That would take a little more skill from the wing runner but the basic
balancing technique still works better than the traditional way.
10,000' + density altitudes are routine for me as are gusty
crosswinds.

The only change I would make is to ask the wing runner to run a bit.
The glider can be balanced against a crosswind even if it's gusty -
just not as precisely which is why he needs to run a little.

It's frustrating for me as a wing runner to be trying to balance a
glider and the pilot won't let me do it. If they will just put the
ailerons in neutral long enough for me to find the balance point, the
takeoff will go a lot better.

Bill Daniels