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Compare/Contrast: CG hook on aerotow vs. CG hook on winch



 
 
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  #1  
Old June 1st 12, 04:21 PM posted to rec.aviation.soaring
Bill D
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Posts: 746
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

On May 31, 7:05*pm, "noel.wade" wrote:
To add to the chorus:

Any of the more-modern ships I've flown (70's glass/metal and newer)
seem to fly just fine on Aerotow with a CG hook. *There are three
points to consider during the launch, in this order:

1) Wing position and cross-wind corrections. *This has been covered by
others in the thread well-enough; but I'd like to emphasize that
starting with full downwind rudder helps a lot, at least in my
experience. *And, as others have said: The best thing to do is watch
your first 50 feet of ground-roll. *If it is going from bad to worse
yank the release and come to a controlled stop. *In my experience with
auto-racing and flying, the worst situations always seem to happen
when something starts to go wrong and a person tries to "save it" (by
leaving their foot on the gas, or over-correcting, or whatever).
Don't try that - just call it off and try again.

2) On liftoff - as you get rolling try to use forward-stick and stick-
trim to get the tailwheel off the ground as soon as your rudder is
effective. *That'll give you better steering control on the remainder
of takeoff *and* put the wing at a lower angle of attack (so you won't
jump/kite as quickly). *Be prepared to add forward stick as you come
off the ground, and don't be shy about changing your trim multiple
times on the takeoff and aerotow. *I'm not yet a CFIG but I've been
flying with a lot of new-to-XC pilots recently and I've noticed that a
LOT of them don't trim on aerotow, during thermalling, or in many
other phases of flight. *Trim is your friend - the less you're pulling
or pushing on the stick, the better control-inputs you can provide for
roll & pitch excursions and the more relaxed you'll fly (making you
better able to feel and focus on other things).

3) Throughout the launch and aerotow - USE YOUR FEET! *Aerotowing with
a CG hook means that you can pretty-much point the nose in any
direction you want. *I actually view it as a nice "bonus" and prefer
towing with a CG hook for this reason (excepting the crosswind
difficulties during the beginning of the ground-roll). *But I again
have found many newbies recently that don't think to use their feet on
aerotow. *Its far easier to make small corrections with a bit of
rudder and slipping, than with big bank-angles on tow. *Keep your feet
active and don't be shy about using some rudder (within reason) to
keep the glider behind the towplane and pointed in the direction you
want.

Just my $0.02,

--Noel
P.S. *The back-release of the rope is a tricky thing on the ground in
my DG-300; like others I find a bit of wheelbrake while taking up
slack and just at the beginning of the roll is an effective "cure".


I like your analytical approach. You'll make a great instructor.
  #2  
Old June 1st 12, 04:59 PM posted to rec.aviation.soaring
Mike the Strike
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Posts: 952
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

I'm not sure that the advice to keep hold of the release on tow would be advisable in more turbulent environments (like Arizona) where unexpected glider movement could cause an unintended release.

Mike
  #3  
Old June 1st 12, 08:04 PM posted to rec.aviation.soaring
noel.wade
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Posts: 681
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

On Jun 1, 8:59*am, Mike the Strike wrote:
I'm not sure that the advice to keep hold of the release on tow would be advisable in more turbulent environments (like Arizona) where unexpected glider movement could cause an unintended release.

Mike


I've had the same thought, Mike.

When I take friends up for rides, I tell them to put their hand(s) on
their thigh(s). That way if they make any kind of reactionary grab,
they grip their leg and not an important control. I find that for
myself this technique works in turbulent conditions pretty well - keep
a hand on the thigh, preferrably near the release-handle. As part of
my pre-takeoff checklist, I practice reaching from my thigh to the
release a couple of times; so that I'm prepared in an emergency. Then
I put my hand back on my thigh. (Of course, my DG-300 makes this easy
by having the release-handle at the base of the panel, and I don't
have any flaps to deal with - so your mileage may vary).

--Noel

P.S. Bill - Thanks for the compliments! I appreciate the feedback
and comments that you and others have given on my various recent
postings. I'm still relatively new in the sport (just hit the 5 year
mark), and its nice to be able to pitch all these theories and ideas
and see everyone's different opinions and points of view. Its all
good food for thought.

  #4  
Old June 1st 12, 09:55 PM posted to rec.aviation.soaring
Bill D
external usenet poster
 
Posts: 746
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

On Jun 1, 1:04*pm, "noel.wade" wrote:
On Jun 1, 8:59*am, Mike the Strike wrote:

I'm not sure that the advice to keep hold of the release on tow would be advisable in more turbulent environments (like Arizona) where unexpected glider movement could cause an unintended release.


Mike


I've had the same thought, Mike.

When I take friends up for rides, I tell them to put their hand(s) on
their thigh(s). *That way if they make any kind of reactionary grab,
they grip their leg and not an important control. *I find that for
myself this technique works in turbulent conditions pretty well - keep
a hand on the thigh, preferrably near the release-handle. *As part of
my pre-takeoff checklist, I practice reaching from my thigh to the
release a couple of times; so that I'm prepared in an emergency. *Then
I put my hand back on my thigh. *(Of course, my DG-300 makes this easy
by having the release-handle at the base of the panel, and I don't
have any flaps to deal with - so your mileage may vary).

--Noel

P.S. *Bill - Thanks for the compliments! *I appreciate the feedback
and comments that you and others have given on my various recent
postings. *I'm still relatively new in the sport (just hit the 5 year
mark), and its nice to be able to pitch all these theories and ideas
and see everyone's different opinions and points of view. *Its all
good food for thought.


I teach the heel of the left hand guarding the airbrake lever. That's
usually very close to the release knob. This covers two bases - open
spoiler on tow and quick release.
  #5  
Old June 2nd 12, 02:13 AM posted to rec.aviation.soaring
Don Johnstone[_4_]
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Posts: 398
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

At 15:59 01 June 2012, Mike the Strike wrote:
I'm not sure that the advice to keep hold of the release on tow would be
advisable in more turbulent environments (like Arizona) where unexpected
glider movement could cause an unintended release.

Mike


Should have made it clear, it is only necessary to have your hand on the
release during the ground run and take off for both aerotow and winch
launch, once airborne and stable you can just keep your hand near the
release as normal. I use the looped paracord so I have some slack in the
sytem anyway.

  #6  
Old June 2nd 12, 02:09 AM posted to rec.aviation.soaring
Andreas Maurer
external usenet poster
 
Posts: 345
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

On Thu, 31 May 2012 18:05:10 -0700 (PDT), "noel.wade"
wrote:



2) On liftoff - as you get rolling try to use forward-stick and stick-
trim to get the tailwheel off the ground as soon as your rudder is
effective. That'll give you better steering control on the remainder
of takeoff *and* put the wing at a lower angle of attack (so you won't
jump/kite as quickly).


Hi Noel,

I have to admit that I regard this technique as bad airmanship. Really
bad airmanship (for example, an LS-6 will not lift off at all with
that technique).

Let me explain:
I've often seen gliders roll behind the towplane for ages, balancing
on the main wheel, creating lots of rolling drag and bouncing all over
the place with each bump they hit. Usually lots of control deflections
to balance crosswind (a tail wheel in the air doesn't really help to
stabilize against a crosswind...), and often multiple touchdowns after
the first lift off due to PIO.

Sometimes I even see gliders with a pith attitude, effectively
creating negative lift until the pilot decides it's time to lift off.
Scary.


In my opinion it's so much easier to simply lift off with tail and
main wheel at the same time and let the glider float behind the tow
plane - once in the air, any glider is a lot easier to control, and in
my experience on grass strips the acceleration of the tow plane is
significantly better.

I fly from a 2000 ft grass strip where one really can see the
difference in the length of the takeoff run.
It doesn't make a huge difference with a light DG-300, but flying a
fully ballasted open class ship or a Duo Discus the correct technique
(liftoff at minimum speed) is usually the difference between the tow
plane being able to lift off or not (don't ask...).

One additional benefit: If the glider lifts off close to its minimum
speed, control authority of the elevator is less agressive, therefore
it's far less likely to overcontrol the glider and enter a PIO.




Be prepared to add forward stick as you come
off the ground, and don't be shy about changing your trim multiple
times on the takeoff and aerotow.


I'm a little bit puzzled why one should mess with the trim during
aerotow.
By setting the elevator trim to the recommended position for aerotow
before launch (trim forward) you get a slight nose-down stick
pressure on all the (German built) gliders I've flown, which in my
opinion is extremely effective to prevent ballooning: The glider is a
lot more likely to descent behind the tow plane if you don't pay
attention for a moment. Better be too low behind the tow plane than
too high.

In my opinion messing with the trim during aerotow is not a good idea
for an inexperienced pilot - gliders with modern trim systems like the
DG-300 cannot be trimmed nose-down at all (as you have probably
noticed in your 300, it needs a significant stick push which isn't the
best idea if you want to keep your position behind the towplane).

Make one mistake, and you have a neutrally or even nose-up trimmed
glider - one further mistake and you might create brown pants in that
tow plane in front of you that is just disappearing under the nose of
your glider.



3) Throughout the launch and aerotow - USE YOUR FEET!


Indeed. Always. And ignore that yaw string.

But I again
have found many newbies recently that don't think to use their feet on
aerotow.


Clear case of bad training. One needs to learn to actively fly the
glider during an aerotow, otherwise problems are pre-programmed.




Best wishes
Andreas
  #7  
Old June 2nd 12, 05:12 PM posted to rec.aviation.soaring
Dan Marotta
external usenet poster
 
Posts: 4,601
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

All the concern about nose vs. CG release and the correcting force of the
nose release indicates, to me, poorly trained or lazy pilots. If you will
simply fly the aircraft and pay attention to your flight path, you'll find
that it makes no difference what type of release you have (unless you're
doing a ground launch).

Do some of you actually rely on the nose release to keep the nose aligned
rather than flying the aircraft?


"Andreas Maurer" wrote in message
...
On Thu, 31 May 2012 18:05:10 -0700 (PDT), "noel.wade"
wrote:



2) On liftoff - as you get rolling try to use forward-stick and stick-
trim to get the tailwheel off the ground as soon as your rudder is
effective. That'll give you better steering control on the remainder
of takeoff *and* put the wing at a lower angle of attack (so you won't
jump/kite as quickly).


Hi Noel,

I have to admit that I regard this technique as bad airmanship. Really
bad airmanship (for example, an LS-6 will not lift off at all with
that technique).

Let me explain:
I've often seen gliders roll behind the towplane for ages, balancing
on the main wheel, creating lots of rolling drag and bouncing all over
the place with each bump they hit. Usually lots of control deflections
to balance crosswind (a tail wheel in the air doesn't really help to
stabilize against a crosswind...), and often multiple touchdowns after
the first lift off due to PIO.

Sometimes I even see gliders with a pith attitude, effectively
creating negative lift until the pilot decides it's time to lift off.
Scary.


In my opinion it's so much easier to simply lift off with tail and
main wheel at the same time and let the glider float behind the tow
plane - once in the air, any glider is a lot easier to control, and in
my experience on grass strips the acceleration of the tow plane is
significantly better.

I fly from a 2000 ft grass strip where one really can see the
difference in the length of the takeoff run.
It doesn't make a huge difference with a light DG-300, but flying a
fully ballasted open class ship or a Duo Discus the correct technique
(liftoff at minimum speed) is usually the difference between the tow
plane being able to lift off or not (don't ask...).

One additional benefit: If the glider lifts off close to its minimum
speed, control authority of the elevator is less agressive, therefore
it's far less likely to overcontrol the glider and enter a PIO.




Be prepared to add forward stick as you come
off the ground, and don't be shy about changing your trim multiple
times on the takeoff and aerotow.


I'm a little bit puzzled why one should mess with the trim during
aerotow.
By setting the elevator trim to the recommended position for aerotow
before launch (trim forward) you get a slight nose-down stick
pressure on all the (German built) gliders I've flown, which in my
opinion is extremely effective to prevent ballooning: The glider is a
lot more likely to descent behind the tow plane if you don't pay
attention for a moment. Better be too low behind the tow plane than
too high.

In my opinion messing with the trim during aerotow is not a good idea
for an inexperienced pilot - gliders with modern trim systems like the
DG-300 cannot be trimmed nose-down at all (as you have probably
noticed in your 300, it needs a significant stick push which isn't the
best idea if you want to keep your position behind the towplane).

Make one mistake, and you have a neutrally or even nose-up trimmed
glider - one further mistake and you might create brown pants in that
tow plane in front of you that is just disappearing under the nose of
your glider.



3) Throughout the launch and aerotow - USE YOUR FEET!


Indeed. Always. And ignore that yaw string.

But I again
have found many newbies recently that don't think to use their feet on
aerotow.


Clear case of bad training. One needs to learn to actively fly the
glider during an aerotow, otherwise problems are pre-programmed.




Best wishes
Andreas


  #8  
Old June 3rd 12, 04:01 AM posted to rec.aviation.soaring
Chris Nicholas[_2_]
external usenet poster
 
Posts: 197
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

At 16:12 02 June 2012, Dan Marotta wrote:
All the concern about nose vs. CG release and the correcting force of the


nose release indicates, to me, poorly trained or lazy pilots. If you will


simply fly the aircraft and pay attention to your flight path, you'll find


that it makes no difference what type of release you have (unless you're
doing a ground launch).


[snip]

The concern in the UK about towing on CG hook when a nose hook is available
came from tug pilot fatalities. The first, and most of the other, such
accidents happened with CG hooks, and one or more of the other factors,
which led to kiting, tug upset, and tug hitting the deck. As a result, the
BGA issued a poster listing the 6 factors most closely associated with
upsets, and advised having not more that two (IIRC) such factors on any one
launch.

More recently we started to have upsets again, so far fortunately without
fatality. Unable to find the original poster, we issued another which had
the following:
-------------------
Tug Upsets

These happen when the glider suddenly zooms above the tug, putting it into
a steep dive requiring considerable height to recover.

The BGA ran a successful campaign to end these fatalities to tug pilots,
but several years without incident now appear to have ended. This year
there have been two reported upsets and at least one other not reported.
Fortunately none resulted in crashes.

Six factors make upsets more likely:

 Lightweight, low wing-loading

 C of G hooks intended for winch launching

 Short ropes

 Inexperienced pilots

 Near aft C of G.

 Turbulent conditions

If two of these are present the danger becomes significant. More than
two should be considered unacceptable.

-----------------
Chris N


  #9  
Old June 3rd 12, 04:28 AM posted to rec.aviation.soaring
Chris Nicholas[_2_]
external usenet poster
 
Posts: 197
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

At 16:12 02 June 2012, Dan Marotta wrote:
All the concern about nose vs. CG release and the correcting force of the


nose release indicates, to me, poorly trained or lazy pilots. If you will


simply fly the aircraft and pay attention to your flight path, you'll find


that it makes no difference what type of release you have (unless you're
doing a ground launch).


[snip]

The concern in the UK about towing on CG hook when a nose hook is available
came from tug pilot fatalities. The first, and most of the other, such
accidents happened with CG hooks, and one or more of the other factors,
which led to kiting, tug upset, and tug hitting the deck. As a result, the
BGA issued a poster listing the 6 factors most closely associated with
upsets, and advised having not more that two (IIRC) such factors on any one
launch.

More recently we started to have upsets again, so far fortunately without
fatality. Unable to find the original poster, we issued another which had
the following:
-------------------
Tug Upsets

These happen when the glider suddenly zooms above the tug, putting it into
a steep dive requiring considerable height to recover.

The BGA ran a successful campaign to end these fatalities to tug pilots,
but several years without incident now appear to have ended. This year
there have been two reported upsets and at least one other not reported.
Fortunately none resulted in crashes.

Six factors make upsets more likely:

 Lightweight, low wing-loading

 C of G hooks intended for winch launching

 Short ropes

 Inexperienced pilots

 Near aft C of G.

 Turbulent conditions

If two of these are present the danger becomes significant. More than
two should be considered unacceptable.

-----------------
Chris N


  #10  
Old June 3rd 12, 04:30 AM posted to rec.aviation.soaring
Eric Greenwell[_4_]
external usenet poster
 
Posts: 1,939
Default Compare/Contrast: CG hook on aerotow vs. CG hook on winch

On 6/2/2012 9:12 AM, Dan Marotta wrote:
All the concern about nose vs. CG release and the correcting force of
the nose release indicates, to me, poorly trained or lazy pilots. If you
will simply fly the aircraft and pay attention to your flight path,
you'll find that it makes no difference what type of release you have
(unless you're doing a ground launch).

Do some of you actually rely on the nose release to keep the nose
aligned rather than flying the aircraft?


I did in some conditions, such as cross winds and unassisted (no wing
runner) takeoffs. When the glider is moving slowly at the beginning of
the launch, there is no "flying" the glider - you are ballistic for a
length of time that depends on the wind and towplane acceleration.

Once aerodynamic control is available, then the differences between CG
and nose hooks are reduced, but in all the gliders I've flown, it was
still noticeable. How noticeable did depend on the glider type.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
 




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