Does anyone use a tug tow hook that releases automatically whenglider kites?

On Saturday, February 22, 2014 10:25:23 AM UTC-6, Iain Baker wrote:
For those who consider using a nose hook largely solves the

problem of kiting, I suggest watching

http://www.youtube.com/watch?v=4MkCnVYa3VY


Excellent video.

But interestingly, not a case of kiting - more like the recent US case of upset by flying too high (distracted by open canopy). In the video (made by the pilot himself - bravo!) he remarks that the tow pilot realized something was wrong and released BEFORE the glider did. He then released to get rid of the tow rope trailing from his nose hook and flew his pattern. Pretty cool for a second solo...

I'll bet a new JS-1 that the Rallye towplane had a Tost hook!

In a scenario of the glider flying high due to inattention, with a nose hook, the climb should be slow enough for the tuggie to recognize and release (IF HE CAN - see Schweizer discussion!) because the glider pilot hopefully isn't just yanking back on the stick.

HOWEVER, if this same scenario had happened with a CG hook, it may have turned into a kiting incident, and could easily have been fatal for the tuggie..

Thanks for pointing out this video - I'm definitely showing it at our club's spring safety meeting!

Cheers,

Kirk

At 16:15 22 February 2014, GC wrote:
On 23/02/2014 01:46, Chris Rollings wrote:

I've been aware of the Australian preference for low tow and the
reasons
for it for over 30 years. My own flight testing and experience lead me
to
believe that it does not significantly reduce the probability of a
kiting
accident.

Well, Australia's experience shows that it does.

I would also say that, having flown in the UK, the Oz rules are
sometimes seen there as somewhat wussy - along the lines of "real men
don't fly low tow". Chris's irrational vehemence makes me think he may
be one of that 'sometimes' group.

I seem to recall reading somewhere in this thread that Australia does not
aerotow on C of G hooks, I think that is probably what accounts for the
better safety record.
I do fly low tow, for cross country tows and to teach students how to do it
and to get them used to flying through the prop wash so they are not
alarmed by encountering it accidentally for the first time.

GC

A very nasty "out of position" event but not kiting, the glider was never
enormously nose up. That was a particularly extreme example of the sort of
event I described in the very first of the series of tests we carried out.

At 16:25 22 February 2014, Iain Baker wrote:
For those who consider using a nose hook largely solves the
problem of kiting, I suggest watching
http://www.youtube.com/watch?v=4MkCnVYa3VY
It is a video of a pilot's second solo flight in a K13 with an aerotow
launch using the nose hook. The pilot is distracted when the
airbrakes open, he looks out at the airbrakes, closes/locks them
and when he looks forward again the tug is disappearing below the
nose. The glider pilot releases. This is at 90m agl.
The commentary and text (in French) gives some extra insight and
analysis. CRIS is the acronym for the French pre-flight checks.
I met the tug pilot some months after this incident - he said that it
was very fortunate that the glider pilot released so promptly as the
towplane was starting to be tipped. It was a big lesson learnt for
him personally, not least to keep a hand VERY close to the release.
Enlightening and interesting thread...

Exactly right John, that's what causes the kiting event. That's exactly
what I found with a K8 on a C of G hook.

At 22:14 22 February 2014, John Firth wrote:
Elevator power.
I may have missed the comment , but has anyone experienced
insufficient pitch down authority with full forward stick?
Our club had an incident in very rough conditions.
A PIK20B , belly hook, flown by a very experienced pilot,
was forced to release as a snatch caused an uncontrollable
pitchup. CG position not known, but the pilot was not large.
I did a calculation ( 30 years ago) to see if this was plausible
and indeed, if the CG was is near the aft limit with a PIK 20,
the transient pitchup couple in a snatch can probably overpower
full nose down elevator, thus initiating kiting.
There a re probably many other sailplanes susceptable to
this near the aft CG limit.
John firth

At 14:46 22 February 2014, Chris Rollings wrote:
At 14:28 22 February 2014, wrote:
On Saturday, February 22, 2014 1:58:28 AM UTC-6, GC wrote:
On 22/02/2014 16:17, Alan wrote:
=20
=20
=20
...You don't get kiting if you fly normal "high" tow behind the
towplan=
e,
=20
if you remain in control.
=20

=20
If you don't remain in control, starting from low tow is not
going
t=
o
=20
make a lot of difference.
=20
=20
=20
Experience (tens of thousands of aerotows) shows there is a
enormous=20
=20
difference. The inadequate control and time to go from high tow
to=20
=20
kiting is orders of magnitude different from that required to g
from=20
=20
low tow to kiting. In fact, I've never heard of that eve
happening.=20
=20
Even with low time students. Kiting from high tow, however, is=20
=20
apparently so common as to need a whole new system of electronic=20
=20
whizzbangery and gallons of bandwidth to stop.
=20
=20
=20
If the tug has just lifted off, being in low tow sounds a bit
diffic=
ult,
=20
but that would be a particularly hazardous time.
=20
=20
=20
Yes. Liftoff is a time to be wary and we train accordingly.=20
=20
Nevertheless, all I can say is that low tow has prevented kiting=20
=20
accidents for many years. But don't take my word for it, keep
this=20
=20
ridiculous discussion going with another screwball idea fo
pivoting,=20
=20
autoswivelling, pitch-sensing, stick-following nonsense.
=20
=20
=20
If the issue is serious - as it was in Australia - flying low to
will=20
=20
solve it. If it isn't - see my previous post.
=20
=20
=20
GC
=20
=20
=20

=20

=20
As for automatic methods to mitigate the problem, perhaps the
soluti=
on
=20
is not to modify tow planes, but to modify gliders. If the glider
is
=20
in a very high pitch attitude on tow, it might be a good time to
automa=
tically
=20
release.
=20

=20
Another modification might be to attach the tow rope to the top
of
t=
he glider.
=20
This would cause the tow force to pitch the glider down.
=20

=20

=20
Is this more of a problem when folks try to tow a slow glider
like
a=
2-33 at
=20
high speeds?
=20

=20
Alan
=20

GC is making his point for low tows very convincingly - why is he
immediate=
ly being ripped, Chris? Preparing and steering into low tow at a safe
alti=
tude, say 300',

If you wait 'till 300 feet the majority of the risk of a fatal kitin
incident is already behind you, once past 400 feet there is just abou
enough height for the tow pilot to recover.

means to mentally and then practically pushing the stick
fo=
rward and then holding in the low tow position. That's the opposite
maneuv=
er of what's leading to kiting. Drifting upwards takes you into the
prop
w=
ash and again, it takes forward stick pressure to move into the saf
spot.
=
That feedback mechanism is correctly maintaining the intended safe
spot
wh=
ile in the normal tow position only visual cues are being used.
I think I'll give the low tow a try, if ever that polar vortex over
Chicago=
makes like tree...
Herb


I've been aware of the Australian preference for low tow and the reason
for it for over 30 years. My own flight testing and experience lead me
t
believe that it does not significantly reduce the probability of a kitin
accident.

I hear you on the low tow, GC. It is another of those perceptions of "It isn't what we do, so it must be dangerous." Agree that it will change the dynamics involved, as well. Did Australia go to low tow to prevent kiting, or was it for some other reason and that was a side benefit? I know that high tow increases the trim drag on the towplane, and low tow reduces it, so on low powered towplanes, this can be the difference between climbing and not. With America tending to be a land of excess (horsepower in our towplanes), it is seldom an issue.

So, I am curious. Was the change made to improve climb rates and you just have not seen kiting events in Australia, or was there a significant kiting problem, and low tow was determined to be a solution? No, I am not being snide or snarky, I do not know and would like ot learn.

Eyes and ears open, willing to learn.

Steve Leonard

On Sunday, February 23, 2014 10:00:51 AM UTC-5, Steve Leonard wrote:
I hear you on the low tow, GC. It is another of those perceptions of "It isn't what we do, so it must be dangerous." Agree that it will change the dynamics involved, as well. Did Australia go to low tow to prevent kiting, or was it for some other reason and that was a side benefit? I know that high tow increases the trim drag on the towplane, and low tow reduces it, so on low powered towplanes, this can be the difference between climbing and not. With America tending to be a land of excess (horsepower in our towplanes), it is seldom an issue. So, I am curious. Was the change made to improve climb rates and you just have not seen kiting events in Australia, or was there a significant kiting problem, and low tow was determined to be a solution? No, I am not being snide or snarky, I do not know and would like ot learn. Eyes and ears open, willing to learn. Steve Leonard

I'll speak for one operation in US using low tow.
1- Reduced trim drag- glider is on the thrust line of the tug.
2-Easier to fly and teach due to visual picture being good and getting near the wake gives feel of vertical tail touching the wake allowing minor correction to stay away. In high tow the fuselage and wing get in first acusing a bit more disturbance to the glider attitude.
3- Many students fly the tow without help on their first try. I doubt that happens much in high (normal) tow.
4- Almost never get slack rope because descending position is easily seen. We have to go out of our way to teach slack rope correction.
5- No broken ropes.
6- No affect on attitude of tug due to rope reduces tug pilot workload.
7- Glider is not in the wake on takeoff because ground effect dissipates the wake below about 1 wing span.
8- I have not heard of any dead tug pilots in low tow.

Flame suit on
UH

I'm confused by a couple of statements in this thread...

1) "Low tow prevents kiting"
Doesn't the kiting event often happen in early take-off,
just as glider is leaving the ground, and before low-tow
is established???

2) "Nose hook prevents kiting"
Didn't we have at least one fatal accident in USA
with a nosehook (L-13 IIRCC)??? Others???
Anybody have any facts (Yes, I know, its RAS, but...)???
I'm not saying nose-hooks don't help, however...

But then, I'm easily confused...
Thanks,
Best Regards, Dave

On 2/23/2014 10:23 AM, Dave Nadler wrote:
I'm confused by a couple of statements in this thread...

1) "Low tow prevents kiting"
Doesn't the kiting event often happen in early take-off,
just as glider is leaving the ground, and before low-tow
is established???

2) "Nose hook prevents kiting"
Didn't we have at least one fatal accident in USA
with a nosehook (L-13 IIRCC)??? Others???
Anybody have any facts (Yes, I know, its RAS, but...)???
I'm not saying nose-hooks don't help, however...

But then, I'm easily confused...
Thanks,
Best Regards, Dave


To me, "kiting" is a dynamic event initiated by a pull on the "kite line",
geometrical effects then combining to result in the glider ascending up the
arc of the line despite Joe Pilot's subsequent full-forward stick inputs. How
the glider gets into the position where it can kite might be (say) on a winch
launch (think CG-hook-equipped Ka-6, K-8, Nimbus II [Dick Johnson]), or (say)
on an aerotow where Joe Pilot (for some reason) puts in a quick, ill-advised
aft stick, thus presenting the belly of the CG-hook-equipped glider to the
free stream airflow.

By this definition, "kiting" is distinct from Joe Pilot simply getting out of
position above the towplane for any other reason (say, inattention).

I've the same question as you regarding 1) above...

As for 2) I'm satisfied an incompetent or inattentive Joe Pilot can yank a tug
into a dive regardless of the type of hook the glider has. Which conclusion is
100% independent (IMO) of the "kiting" issue.

Bob W.

On 24/02/2014 02:00, Steve Leonard wrote:
I hear you on the low tow, GC. It is another of those perceptions of
"It isn't what we do, so it must be dangerous." Agree that it will
change the dynamics involved, as well. Did Australia go to low tow
to prevent kiting, or was it for some other reason and that was a
side benefit? I know that high tow increases the trim drag on the
towplane, and low tow reduces it, so on low powered towplanes, this
can be the difference between climbing and not. With America tending
to be a land of excess (horsepower in our towplanes), it is seldom an
issue.

So, I am curious. Was the change made to improve climb rates and you
just have not seen kiting events in Australia, or was there a
significant kiting problem, and low tow was determined to be a
solution? No, I am not being snide or snarky, I do not know and
would like ot learn.

The change was made well before my time in soaring (at least 30 years
ago - in the era where K-6's were just disappearing) but I understand
that kiting specifically and easier control on tow generally were the
reasons for the change. Certainly, it was nothing to do with climb rates.

Like the Western US and South Africa, Australia experiences strong,
sharp-edged thermals which can be challenging to handle on tow. As
Chris's experiments showed, low wing loading gliders are more
susceptible to kiting and it was a real problem at the time. Low tow
isn't a silver bullet (nothing in aviation is) but it certainly stops
these problems becoming accidents in a way that apparently still happens
in the UK and US.

I believe that mandatory nose hooks for aerotow came in at the same time
but I can't confirm that. As Kirk said, nose hook aerotow is probably
the more important change but my instructing experience makes me think
that both play an important part.

I'm sure that what Australia did may well be overkill for the Eastern US
and much of Europe but I entered the discussion simply to point out that
no electronic solution was needed. A perfectly simple operational
change would secure all the safety anyone wanted - if that was the point
of the discussion. Otherwise it looked like a solution in search of a
problem.

I have nothing useful to contribute on low/high-powered tugs. I've
never noticed any difference. I will say that I've never complained of
excess power in any aircraft I've flown!

GC

Eyes and ears open, willing to learn.

Steve Leonard

On 24/02/2014 04:23, Dave Nadler wrote:
I'm confused by a couple of statements in this thread...

1) "Low tow prevents kiting"
Doesn't the kiting event often happen in early take-off,
just as glider is leaving the ground, and before low-tow
is established???

I don't know. We haven't had enough recent kiting accidents in Oz to know.


2) "Nose hook prevents kiting"
Didn't we have at least one fatal accident in USA
with a nosehook (L-13 IIRCC)??? Others???
Anybody have any facts (Yes, I know, its RAS, but...)???
I'm not saying nose-hooks don't help, however...

So what ARE you saying? Swallows, summer? Just stirring the pot?

Dave, I'm well aware of the much yada yada on r.a.s. regarding low/high
tow of which you've been part. I'm not going to be drawn into it. As I
said, a lot of it appears to me to be based on personality in the form
of "real men fly high tow - and they do it on CG hooks!"

I only wanted to say that if kiting is a problem, nose hooks and low tow
will reduce it to insignificance. If those practices are not worth
adopting, kiting's not a real problem.

GC

But then, I'm easily confused...
....just keep taking the tablets like I told you...
Thanks,
Best Regards, Dave