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

On 22/02/2014 16:17, Alan wrote:

...You don't get kiting if you fly normal "high" tow behind the towplane,
if you remain in control.

If you don't remain in control, starting from low tow is not going to
make a lot of difference.

Experience (tens of thousands of aerotows) shows there is an enormous
difference. The inadequate control and time to go from high tow to
kiting is orders of magnitude different from that required to go from
low tow to kiting. In fact, I've never heard of that ever happening.
Even with low time students. Kiting from high tow, however, is
apparently so common as to need a whole new system of electronic
whizzbangery and gallons of bandwidth to stop.

If the tug has just lifted off, being in low tow sounds a bit difficult,
but that would be a particularly hazardous time.

Yes. Liftoff is a time to be wary and we train accordingly.
Nevertheless, all I can say is that low tow has prevented kiting
accidents for many years. But don't take my word for it, keep this
ridiculous discussion going with another screwball idea for pivoting,
autoswivelling, pitch-sensing, stick-following nonsense.

If the issue is serious - as it was in Australia - flying low tow will
solve it. If it isn't - see my previous post.

GC



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

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


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

Alan

The time difference to go from low tow to kiting compared to high tow to
kiting is about 1 second - try it at safe altitude. As observed you can't
take-off in low tow so the highest risk time, just after take off when the
combination is accelerating, is exactly the same. The transition from
normal tow to low tow, early in the climb, puts the glider into the
turbulence of the prop-wash which may well cause the, less than one second,
loss of control which is all that is needed to start the kiting. Finally,
low tow on a glider with a C of G hook, leaves the rope wrapped around the
side of the cockpit, not really a good idea and C of G hooks are where the
danger lies.

The cheapest mechanical solution is, fit a nose hook to any glider that is
going to be aerotowed.

My best estimate of low level kiting fatal/serious accident frequency is of
the order of one in a million. "Tens of thousands of aerotows" is not a
big enough sample to draw conclusions.

At 07:58 22 February 2014, GC wrote:
On 22/02/2014 16:17, Alan wrote:

...You don't get kiting if you fly normal "high" tow behind the
towplane,
if you remain in control.

If you don't remain in control, starting from low tow is not going
to
make a lot of difference.

Experience (tens of thousands of aerotows) shows there is an enormous
difference. The inadequate control and time to go from high tow to
kiting is orders of magnitude different from that required to go from
low tow to kiting. In fact, I've never heard of that ever happening.
Even with low time students. Kiting from high tow, however, is
apparently so common as to need a whole new system of electronic
whizzbangery and gallons of bandwidth to stop.

If the tug has just lifted off, being in low tow sounds a bit
difficult,
but that would be a particularly hazardous time.

Yes. Liftoff is a time to be wary and we train accordingly.
Nevertheless, all I can say is that low tow has prevented kiting
accidents for many years. But don't take my word for it, keep this
ridiculous discussion going with another screwball idea for pivoting,
autoswivelling, pitch-sensing, stick-following nonsense.

If the issue is serious - as it was in Australia - flying low tow will
solve it. If it isn't - see my previous post.

GC



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

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


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

Alan

On Saturday, February 22, 2014 1:58:28 AM UTC-6, GC wrote:
On 22/02/2014 16:17, Alan wrote:



...You don't get kiting if you fly normal "high" tow behind the towplane,

if you remain in control.



If you don't remain in control, starting from low tow is not going to

make a lot of difference.



Experience (tens of thousands of aerotows) shows there is an enormous

difference. The inadequate control and time to go from high tow to

kiting is orders of magnitude different from that required to go from

low tow to kiting. In fact, I've never heard of that ever happening.

Even with low time students. Kiting from high tow, however, is

apparently so common as to need a whole new system of electronic

whizzbangery and gallons of bandwidth to stop.



If the tug has just lifted off, being in low tow sounds a bit difficult,

but that would be a particularly hazardous time.



Yes. Liftoff is a time to be wary and we train accordingly.

Nevertheless, all I can say is that low tow has prevented kiting

accidents for many years. But don't take my word for it, keep this

ridiculous discussion going with another screwball idea for pivoting,

autoswivelling, pitch-sensing, stick-following nonsense.



If the issue is serious - as it was in Australia - flying low tow will

solve it. If it isn't - see my previous post.



GC







As for automatic methods to mitigate the problem, perhaps the solution

is not to modify tow planes, but to modify gliders. If the glider is

in a very high pitch attitude on tow, it might be a good time to automatically

release.



Another modification might be to attach the tow rope to the top of the glider.

This would cause the tow force to pitch the glider down.





Is this more of a problem when folks try to tow a slow glider like a 2-33 at

high speeds?



Alan


GC is making his point for low tows very convincingly - why is he immediately being ripped, Chris? Preparing and steering into low tow at a safe altitude, say 300', means to mentally and then practically pushing the stick forward and then holding in the low tow position. That's the opposite maneuver of what's leading to kiting. Drifting upwards takes you into the prop wash and again, it takes forward stick pressure to move into the safe spot. That feedback mechanism is correctly maintaining the intended safe spot while 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

Huh! Sounds good to me!


"GC" wrote in message
eb.com...
On 22/02/2014 16:17, Alan wrote:

...You don't get kiting if you fly normal "high" tow behind the towplane,
if you remain in control.

If you don't remain in control, starting from low tow is not going to
make a lot of difference.

Experience (tens of thousands of aerotows) shows there is an enormous
difference. The inadequate control and time to go from high tow to kiting
is orders of magnitude different from that required to go from low tow to
kiting. In fact, I've never heard of that ever happening. Even with low
time students. Kiting from high tow, however, is apparently so common as
to need a whole new system of electronic whizzbangery and gallons of
bandwidth to stop.

If the tug has just lifted off, being in low tow sounds a bit
difficult,
but that would be a particularly hazardous time.

Yes. Liftoff is a time to be wary and we train accordingly. Nevertheless,
all I can say is that low tow has prevented kiting accidents for many
years. But don't take my word for it, keep this ridiculous discussion
going with another screwball idea for pivoting, autoswivelling,
pitch-sensing, stick-following nonsense.

If the issue is serious - as it was in Australia - flying low tow will
solve it. If it isn't - see my previous post.

GC



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

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


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

Alan

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 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

GC, the GFA put out a safety poster around 30 years ago that actually had
line drawings, of the photos taken of the test I described, all
superimposed on one another (if you can find a copy and make it accessible,
that would help the discussion). I believe the banning of C of G hooks for
aerotowing and the adoption of low tow at about that time were also, at
least in part, the result of those tests.

I think the banning of C of G hooks is the primary reason for Australia's
good record on these sort of accidents, the use of low tow, whilst it may
have other benefits does not, in my opinion, contribute significantly, if
at all.

When the weather improves in the UK and I can get some spare time, I plan
to conduct some more tests, with another aircraft alongside to video them.
I'll include a kiting departure on a C of G hook from low tow as one of the
tests.

It is possible to get tow plane upsets resulting from significant glider
out of position events when on a nose hook. However they don't happen as
fast and there is often time for one or other pilot to release and they
don't become irrecoverable in the way that a kiting event is.

At 04:17 24 February 2014, GC wrote:
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