A Rough Day Towing

[Dan Marotta]

Seems I'm towing more than soaring these days...

A couple of days ago, while rolling out on final at about 300' AGL, a strong
gust under the high wing upset the Pawnee. Fortunately (for me), I carry a
lot of energy around the final turn, and was able to recover and land
normally. I had to take a short break to allow my heart to slow down.

Later that day, an experienced pilot was flying his first flight in an
HP-14. At 2,400' AGL we were indicating 1,100 fpm climb and said, "This is
a nice thermal" on the radio. Seconds later the tow plane was jerked to the
left and I looked over my right shoulder to see the glider at my 4 o'clock
with a large loop of slack in the rope. I yelled, "Get off, get off, get
off!!!" and, to my surprise, the response was the glider banking sharply
into me and diving past my tail. Before I could grab the tow release, there
was another sharp jerk and the rope broke. The glider pilot then enjoyed
about 4 hours in the -14.

Next morning, when I arrived to tow (again...), I was told to go have a look
at the HP-14. There was a deep gash in the leading edge of the left wing
(top and bottom), right at the root, where the rope had sawed through the
skin before being cut by he sharp edge of the aluminum. There was also
damage along the leading edge and to the side of the fuselage.

I've got to become less tolerant of gliders getting out of position...

I'll be towing again this morning but, hopefully, will get my LAK out this
afternoon.

[John Carlyle]

Given the damage to the HP-14, I sure hope someone has taken a good look at the tail of the Pawnee...

-John

On Friday, June 1, 2012 10:28:55 AM UTC-4, Dan Marotta wrote:
> Seems I'm towing more than soaring these days...
>
> A couple of days ago, while rolling out on final at about 300' AGL, a strong
> gust under the high wing upset the Pawnee. Fortunately (for me), I carry a
> lot of energy around the final turn, and was able to recover and land
> normally. I had to take a short break to allow my heart to slow down.
>
> Later that day, an experienced pilot was flying his first flight in an
> HP-14. At 2,400' AGL we were indicating 1,100 fpm climb and said, "This is
> a nice thermal" on the radio. Seconds later the tow plane was jerked to the
> left and I looked over my right shoulder to see the glider at my 4 o'clock
> with a large loop of slack in the rope. I yelled, "Get off, get off, get
> off!!!" and, to my surprise, the response was the glider banking sharply
> into me and diving past my tail. Before I could grab the tow release, there
> was another sharp jerk and the rope broke. The glider pilot then enjoyed
> about 4 hours in the -14.
>
> Next morning, when I arrived to tow (again...), I was told to go have a look
> at the HP-14. There was a deep gash in the leading edge of the left wing
> (top and bottom), right at the root, where the rope had sawed through the
> skin before being cut by he sharp edge of the aluminum. There was also
> damage along the leading edge and to the side of the fuselage.
>
> I've got to become less tolerant of gliders getting out of position...
>
> I'll be towing again this morning but, hopefully, will get my LAK out this
> afternoon.

[BobW]

On 6/1/2012 8:28 AM, Dan Marotta wrote:

<Snip...>
>
> Later that day, an experienced pilot was flying his first flight in an HP-14.
> At 2,400' AGL we were indicating 1,100 fpm climb and said, "This is a nice
> thermal" on the radio. Seconds later the tow plane was jerked to the left and
> I looked over my right shoulder to see the glider at my 4 o'clock with a large
> loop of slack in the rope. I yelled, "Get off, get off, get off!!!" and, to my
> surprise, the response was the glider banking sharply into me and diving past
> my tail. Before I could grab the tow release, there was another sharp jerk and
> the rope broke. The glider pilot then enjoyed about 4 hours in the -14.

<Snip...>

Mercy!

Tell me again what that in-glider release is for?

My only self-induced rope break came on a BFR, demonstrating
instructor-induced slack rope recoveries. (Due to lack of practice at slack
rope after obtaining my license, I undoubtedly only got worse at it.) So I
understand the desire to recover an out of position towing situation...just
not at risk of life and limb.

On another BFR the instructor bemused both of us as we watched the rope drift
aft over the top of the G-103's wing until I could barely see the aft end of
the loop from the front cockpit. It was one of the times I almost overrode an
instructor's "My ship." In hindsight, we both agreed I probably should have.
What WERE we thinking?!?

Bob W.

[Dan Marotta]

Yes, we checked the Pawnee and it's OK.

The glider's owner (not the pilot involved) told me that this release won't
let go unless it's under tension. I'm not familiar with the design and
wonder if that's a design defect or a defect in this particular piece of
hardware.

(Did 12 tows this morning and 2.3 hours in the LAK this afternoon!)


"BobW" > wrote in message
...
> On 6/1/2012 8:28 AM, Dan Marotta wrote:
>
> <Snip...>
>>
>> Later that day, an experienced pilot was flying his first flight in an
>> HP-14.
>> At 2,400' AGL we were indicating 1,100 fpm climb and said, "This is a
>> nice
>> thermal" on the radio. Seconds later the tow plane was jerked to the left
>> and
>> I looked over my right shoulder to see the glider at my 4 o'clock with a
>> large
>> loop of slack in the rope. I yelled, "Get off, get off, get off!!!" and,
>> to my
>> surprise, the response was the glider banking sharply into me and diving
>> past
>> my tail. Before I could grab the tow release, there was another sharp
>> jerk and
>> the rope broke. The glider pilot then enjoyed about 4 hours in the -14.
>
> <Snip...>
>
> Mercy!
>
> Tell me again what that in-glider release is for?
>
> My only self-induced rope break came on a BFR, demonstrating
> instructor-induced slack rope recoveries. (Due to lack of practice at
> slack rope after obtaining my license, I undoubtedly only got worse at
> it.) So I understand the desire to recover an out of position towing
> situation...just not at risk of life and limb.
>
> On another BFR the instructor bemused both of us as we watched the rope
> drift aft over the top of the G-103's wing until I could barely see the
> aft end of the loop from the front cockpit. It was one of the times I
> almost overrode an instructor's "My ship." In hindsight, we both agreed I
> probably should have. What WERE we thinking?!?
>
> Bob W.

[T[_2_]]

On Jun 1, 5:40*pm, "Dan Marotta" > wrote:
> Yes, we checked the Pawnee and it's OK.
>
> The glider's owner (not the pilot involved) told me that this release won't
> let go unless it's under tension. *I'm not familiar with the design and
> wonder if that's a design defect or a defect in this particular piece of
> hardware.
>
> (Did 12 tows this morning and 2.3 hours in the LAK this afternoon!)
>
> "BobW" > wrote in message
>
> ...
>
>
>
>
>
>
>
> > On 6/1/2012 8:28 AM, Dan Marotta wrote:
>
> > <Snip...>
>
> >> Later that day, an experienced pilot was flying his first flight in an
> >> HP-14.
> >> At 2,400' AGL we were indicating 1,100 fpm climb and said, "This is a
> >> nice
> >> thermal" on the radio. Seconds later the tow plane was jerked to the left
> >> and
> >> I looked over my right shoulder to see the glider at my 4 o'clock with a
> >> large
> >> loop of slack in the rope. I yelled, "Get off, get off, get off!!!" and,
> >> to my
> >> surprise, the response was the glider banking sharply into me and diving
> >> past
> >> my tail. Before I could grab the tow release, there was another sharp
> >> jerk and
> >> the rope broke. The glider pilot then enjoyed about 4 hours in the -14..
>
> > <Snip...>
>
> > Mercy!
>
> > Tell me again what that in-glider release is for?
>
> > My only self-induced rope break came on a BFR, demonstrating
> > instructor-induced slack rope recoveries. (Due to lack of practice at
> > slack rope after obtaining my license, I undoubtedly only got worse at
> > it.) So I understand the desire to recover an out of position towing
> > situation...just not at risk of life and limb.
>
> > On another BFR the instructor bemused both of us as we watched the rope
> > drift aft over the top of the G-103's wing until I could barely see the
> > aft end of the loop from the front cockpit. It was one of the times I
> > almost overrode an instructor's "My ship." *In hindsight, we both agreed I
> > probably should have. What WERE we thinking?!?
>
> > Bob W.

It sounds like a failure of the release. Any release should "drop the
rope/ring" when pulled. Especially at ground speed = zero on the
launch line. I can see it now, tow line already hooked up, glider
pilot finds something wrong and cannot release and the radio gets
garbled by a walked on transmission, just as the tow plane goes full
throttle.

How did that one pass the condition inspection.

I'm sure the release rope break with the rope over the wing slew that
glider sideways. The pilot could not see the damage to the leading
edge of the wing and flew 4 hours?? WTFO.

T

[Brad[_2_]]

> I'm sure the release rope break with the rope over the wing slew that
> glider sideways. The pilot could not see the damage to the leading
> edge of the wing and flew 4 hours?? WTFO.

Helloooooooooooooooooo, captain CRUNCH, where are you????

Brad

[GARY BOGGS]

What size rope were you using? Was there an weak link?

Boggs

[150flivver]

On Tuesday, June 5, 2012 7:25:16 AM UTC-5, GARY BOGGS wrote:
> What size rope were you using? Was there an weak link?
>
> Boggs

What type of release mechanism?

[Wayne Paul]

The glider's release mechanism is the standard Dick Schreder design.
http://www.soaridaho.com/Schreder/Construction/Towhook/Tow_Hook.htm

Here is a photo of the mechanism as it appears in HP-14T blue-prints.
http://www.soaridaho.com/Schreder/HP-14/Drawings/HP-14T_Tow_Hitch.jpg

This hook has been very reliable for the past 50+ years. The concept has
been copied and install on other sailplane designs including the 1-35A

Wayne
http://www.soaridaho.com/Schreder



"150flivver" wrote in message
...

On Tuesday, June 5, 2012 7:25:16 AM UTC-5, GARY BOGGS wrote:
> What size rope were you using? Was there an weak link?
>
> Boggs

What type of release mechanism?

[BobW]

On 6/5/2012 9:27 AM, Wayne Paul wrote:
> The glider's release mechanism is the standard Dick Schreder design.
> http://www.soaridaho.com/Schreder/Construction/Towhook/Tow_Hook.htm
>
> Here is a photo of the mechanism as it appears in HP-14T blue-prints.
> http://www.soaridaho.com/Schreder/HP-14/Drawings/HP-14T_Tow_Hitch.jpg
>
> This hook has been very reliable for the past 50+ years. The concept has been
> copied and install on other sailplane designs including the 1-35A

And also - at least conceptually/functionally - George Applebay's Zuni design
(though some may now/have-had Tost releases); I can't speak for
dimensionally/geometrically. Difficult (for me) to imagine a simpler release
mechanism.

I never had release a release problem in 106 HP-14 and 655 Zuni aerotows. Had
1-each back release in both ships, from BIG bows in the rope...as should have
happened.

Bob W.

>
> Wayne
> http://www.soaridaho.com/Schreder
>
>
>
> "150flivver" wrote in message
> ...
>
<Snip...>
>
> What type of release mechanism?
>
>

[Dan Marotta]

I think the rope is 3/8 polypropylene. The rope strength is within FAA
requirements for the gliders we tow. We use a weak link with a tost ring,
but not with the Schweizer. There's a Schweizer release on the tug.


"GARY BOGGS" > wrote in message
...
> What size rope were you using? Was there an weak link?
>
> Boggs
>

[Brian[_1_]]

I have been a bit concerned with the ropes some places use.

http://www.engineeringtoolbox.com/polypropylene-rope-strength-d_1516.html
shows the following minimum breaking strength

1/4 1125 lbf 80%= 900 lb minimum glider weight
5/16 1710 lbf 80%= 1368 lb minimum glider weight
3/8 2430 lbf 80%= 1944 lb minimum glider weight

I prefer towing behind 1/4" rope I have seen a few rope breaks with
1/4" all seemed warranted with a rope in good condition.
It seem to me that unless you are towing a fully loaded ASG29 or a two
place that 1/4 rope is probably what should be used unless of course a
weak link is used. And even then 1/4" rope should be adequate at the
200% rating or less.
Am I missing something?

Brian

[Dan Marotta]

Wear on the runway, UV degradation.


"Brian" > wrote in message
...
>I have been a bit concerned with the ropes some places use.
>
> http://www.engineeringtoolbox.com/polypropylene-rope-strength-d_1516.html
> shows the following minimum breaking strength
>
> 1/4 1125 lbf 80%= 900 lb minimum glider weight
> 5/16 1710 lbf 80%= 1368 lb minimum glider weight
> 3/8 2430 lbf 80%= 1944 lb minimum glider weight
>
> I prefer towing behind 1/4" rope I have seen a few rope breaks with
> 1/4" all seemed warranted with a rope in good condition.
> It seem to me that unless you are towing a fully loaded ASG29 or a two
> place that 1/4 rope is probably what should be used unless of course a
> weak link is used. And even then 1/4" rope should be adequate at the
> 200% rating or less.
> Am I missing something?
>
> Brian
>