Replacing the MKIV yaw string - tips

[bumper[_4_]]

Depending on how you store your glider, your MKIV yaw string should provide many hours of carefree soaring, free from that embarrassing "kluged tape on the canopy syndrome". How long? Anywhere from a few years to many more than I wish (planned obsolescence and repeat business being part of my retirement business model :c). When it's finally time to put a pretty new one up front, it's easy . . .

These instructions are for use if you're happy with the current position of the MK## yaw string. If not, please refer to the new installation instructions available at http://www.cumulus-soaring.com/bumper.htm or http://www.williamssoaring.com/catalog/sailplane-parts.html or from me via email (below).

Please remember MKIVs and QVs make great Christmas presents. Your friends will be reminded of how truly nice you are to them every time they fly!


At or above room temperature:

The MKIV clear base is "V" shaped with pointed end facing forward. Apply masking or wing tape to form a "V" parallel to and close to each straight side of the MKIV base. The taped "V" will serve as a guide to aid in positioning the new MKIV.

With your fingernail or the tip of a knife blade* being careful not to touch the canopy plastic, lift the leading edge of the old MKIV base and pull back to remove. The plastic base with adhesive layer will usually come off cleanly, leaving no residue behind. If the adhesive layer or any residue remains on the canopy, rub with your thumb roll it off cleanly.

*If using a knife blade, catch the tip of the old base slightly above the canopy surface so as to avoid any risk of scratching the canopy.

Clean area within the taped "V" with denatured or rubbing alcohol applied sparingly to a soft clean cloth. Hold the new MKIV by the yarn or by the base edges and use a knife tip to lift the red backing film starting at a rear corner of the base - be careful not to touch exposed adhesive with fingers.. Peel away red backing and then re-apply pointed tip of backing to form a "handle". The pointed tip of the red backing overlapping the rear of the exposed base adhesive about 1/8" or a little more.

Holding base with red backing "handle", and using the taped "V" as a guide, place the tip of the new MKIV base centered within the apex of the "V" maintaining even gap from base to tape on each side - - do not allow MKIV adhesive to touch tape. You get only one chance to get it on straight, once adhesive touches canopy, removal and reapplication won't look nice.

With tip in place, and holding rear of base up at 30 degrees or so with red liner handle, use finger nail or retracted ball pen tip (something smooth)to gently work adhesive down toward rear to avoid bubbles. Red liner can be pulled aft to remove before rear of base is smoothed down. Apply even downward pressure to base for a few seconds. Adhesive gains full strength in 24 hours but is ready for flight immediately.

Do not store your new uninstalled MKIV yaw strings or Quiet Vent kit in direct sunlight or high temperatures (e.g. on the dash of a vehicle) as this will degrade the red plastic adhesive liner making it difficult or impossible to remove (return for free replacement if you've already screwed up).

all the best,

bumper

bumperm at frontier (insert dot here) com
zz
Minden, NV

[Mike Mike Ground]

The MKIV is clearly the pinnacle of yaw string technology. Meticulously crafted, it looks great on my glider. However, it suffers from the same problem I have noticed on all yaw strings I have flown. In flight, it constantly swings off the centerline 10, 20, sometimes even 30 degrees, particularly while thermalling. What’s up with that?

MM



On Friday, November 30, 2012 12:36:29 PM UTC-8, bumper wrote:
> Depending on how you store your glider, your MKIV yaw string should provide many hours of carefree soaring, free from that embarrassing "kluged tape on the canopy syndrome". How long? Anywhere from a few years to many more than I wish (planned obsolescence and repeat business being part of my retirement business model :c). When it's finally time to put a pretty new one up front, it's easy . . .
>
>
>
> These instructions are for use if you're happy with the current position of the MK## yaw string. If not, please refer to the new installation instructions available at http://www.cumulus-soaring.com/bumper.htm or http://www..williamssoaring.com/catalog/sailplane-parts.html or from me via email (below).
>
>
>
> Please remember MKIVs and QVs make great Christmas presents. Your friends will be reminded of how truly nice you are to them every time they fly!
>
>
>
>
>
> At or above room temperature:
>
>
>
> The MKIV clear base is "V" shaped with pointed end facing forward. Apply masking or wing tape to form a "V" parallel to and close to each straight side of the MKIV base. The taped "V" will serve as a guide to aid in positioning the new MKIV.
>
>
>
> With your fingernail or the tip of a knife blade* being careful not to touch the canopy plastic, lift the leading edge of the old MKIV base and pull back to remove. The plastic base with adhesive layer will usually come off cleanly, leaving no residue behind. If the adhesive layer or any residue remains on the canopy, rub with your thumb roll it off cleanly.
>
>
>
> *If using a knife blade, catch the tip of the old base slightly above the canopy surface so as to avoid any risk of scratching the canopy.
>
>
>
> Clean area within the taped "V" with denatured or rubbing alcohol applied sparingly to a soft clean cloth. Hold the new MKIV by the yarn or by the base edges and use a knife tip to lift the red backing film starting at a rear corner of the base - be careful not to touch exposed adhesive with fingers. Peel away red backing and then re-apply pointed tip of backing to form a "handle". The pointed tip of the red backing overlapping the rear of the exposed base adhesive about 1/8" or a little more.
>
>
>
> Holding base with red backing "handle", and using the taped "V" as a guide, place the tip of the new MKIV base centered within the apex of the "V" maintaining even gap from base to tape on each side - - do not allow MKIV adhesive to touch tape. You get only one chance to get it on straight, once adhesive touches canopy, removal and reapplication won't look nice.
>
>
>
> With tip in place, and holding rear of base up at 30 degrees or so with red liner handle, use finger nail or retracted ball pen tip (something smooth)to gently work adhesive down toward rear to avoid bubbles. Red liner can be pulled aft to remove before rear of base is smoothed down. Apply even downward pressure to base for a few seconds. Adhesive gains full strength in 24 hours but is ready for flight immediately.
>
>
>
> Do not store your new uninstalled MKIV yaw strings or Quiet Vent kit in direct sunlight or high temperatures (e.g. on the dash of a vehicle) as this will degrade the red plastic adhesive liner making it difficult or impossible to remove (return for free replacement if you've already screwed up).
>
>
>
> all the best,
>
>
>
> bumper
>
>
>
> bumperm at frontier (insert dot here) com
>
> zz
>
> Minden, NV

[[email protected]]

The first time I saw one advertised, I thought it was an April Fool's joke. But I was intrigued. Months later I ordered one. Could this be real? Have I been duped? I received it in the mail and have yet to install it but looking at the package I'm still not sure. Then, I read posts like the one that started this thread and I'm still feeling like someone is going to jump out and say, "gotcha!"

[Martin Gregorie[_5_]]

On Sat, 01 Dec 2012 14:29:59 -0800, Mike Mike Ground wrote:

> The MKIV is clearly the pinnacle of yaw string technology.
> Meticulously crafted, it looks great on my glider. However, it
> suffers from the same problem I have noticed on all yaw strings I have
> flown. In flight, it constantly swings off the centerline 10, 20,
> sometimes even 30 degrees, particularly while thermalling. What’s up
> with that?
>
How careful were you to place it on the center-line?

The tighter the curvature of your canopy near the centre line the more
critical yaw string placement is. For instance I think that, on a
Libelle, you need to place it within 5mm (1/4") or better of the exact
centre line, but probably canopies that aren't so sharply curved near the
centre line would make the string placement less critical. I stretched a
thread from the exact top of the fin down to the nose and took a lot of
care that both ends were correctly placed and that it wasn't deflected by
the top of the canopy before marking that line and fitting the yaw
string.

By contrast, I suspect that aligning the axis of symmetry of the
transparent sticky bit with the glider's centre line is more important
for aesthetics than for the yaw string's operation. In any case, by using
pencil marks on masking tape placed before and behind the sticky bit and
taking care, you should be able to align it well enough that errors can't
be seen once the masking tap and thread are removed.

You say the string is often deflected to one side: of course, it should
be tail out in a properly flown thermal turn and dead straight when you
cruise straight between thermals.

If it doesn't do that, it might be that:

1) its mounted off to one side. Check with a thin line as I did to see
if its not accurately on the centre line.

2) you've picked up the habit of flying sideways.

Either could make it hang consistently to one side. Either way you need
to work out what's causing it and correct the problem.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[bumper[_4_]]

On Saturday, December 1, 2012 2:29:59 PM UTC-8, Mike Mike Ground wrote:
> The MKIV is clearly the pinnacle of yaw string technology. Meticulously crafted, it looks great on my glider. However, it suffers from the same problem I have noticed on all yaw strings I have flown. In flight, it constantly swings off the centerline 10, 20, sometimes even 30 degrees, particularly while thermalling. What’s up with that?
>
>
>
> MM

Mike-Mike,

Each MKIV "high tech" yaw string leaves our shop eager to learn, but obviously young and impressionable - - they do have a tendancy towards having a short attention span and will often display a wild tendancy to go whichever way the wind blows.

After installation, especially during early training it's important to treat your young MKIV gently, they are sensitive. Never sweat at it, unless it's obviously heading entirely the wrong way. It's okay to firmly tell it to "straighten up and fly right".

We are working on providing better pre-shipment training on our end. Until then, if you have a really bad one, you can tape the end down straight before flight to show it what you expect of it. Don't do this often though as you risk breaking it's spirit. Not good.

all the best,

bumper

[bumper[_4_]]

On Saturday, December 1, 2012 4:05:25 PM UTC-8, wrote:
> The first time I saw one advertised, I thought it was an April Fool's joke. But I was intrigued. Months later I ordered one. Could this be real? Have I been duped? I received it in the mail and have yet to install it but looking at the package I'm still not sure. Then, I read posts like the one that started this thread and I'm still feeling like someone is going to jump out and say, "gotcha!"

Gotcha!

A bit of history . . . ever since I saw gliders for the first time in "Popular Mechanics" in the late 50's, I believed they were the prettiest, most sensuous thing man had created to fly.

While getting my glider add-on, I flew in gliders that had tape over tape and old adhesive residue doing an ugly job of holding on a bit of string or yarn. Didn't seem right that something so innately beautiful should be graced by a kluged-on yaw string. Shortly after buying my first glider in '98, a S10-VT, the "MKI" was born and sold only to other Stemme owners.

It was named "MKI" in honor of the Supermarine Spitfire suffix, my English heritage, and my father's 30 years in the RAF. The MKIV yaw string has been refined and improved over the past 13 years, many more times than its MKIV designation would suggest. Only a big change, or a bunch of little ones, warrants a new Mark numper! I believe the current MKIV is about as good as it's possible for me to make, requiring almost 30 steps and numerous special tools and fixtures to craft each by hand.

No joke or gotcha, honest. There are thousands of MK## yaw strings gracing beautiful gliders all over the world. Might sound silly, but I'm kind'a proud of that!

If you buy a MKIV and are disappointed, within a year of purchase return it to me and I'll refund your money plus a dollar for your trouble. I hope no one ever takes me up on that offer.

bumper

[son_of_flubber]

On Saturday, December 1, 2012 8:54:16 PM UTC-5, bumper wrote:

> We are working on providing better pre-shipment training on our end. Until then, if you have a really bad one, you can tape the end down straight before flight to show it what you expect of it. Don't do this often though as you risk breaking it's spirit. Not good.

For those who appreciate the finer things in life, I recommend a yaw string made of golden fleece. Attach it with a dot of clear silly-con adhesive.

[Jonathon May[_2_]]

At 04:57 02 December 2012, son_of_flubber wrote:
>On Saturday, December 1, 2012 8:54:16 PM UTC-5, bumper wrote:
>
>> We are working on providing better pre-shipment training on our end.
>Unti=
>l then, if you have a really bad one, you can tape the end down straight
>be=
>fore flight to show it what you expect of it. Don't do this often though
>as=
> you risk breaking it's spirit. Not good.
>
>For those who appreciate the finer things in life, I recommend a yaw
>string=
> made of golden fleece. Attach it with a dot of clear silly-con
adhesive.
>

Have you thought of a fibre optic string for low light situations ,like
cloud
bases

[Mike Mike Ground]

On Saturday, December 1, 2012 5:54:16 PM UTC-8, bumper wrote:
> On Saturday, December 1, 2012 2:29:59 PM UTC-8, Mike Mike Ground wrote:
>
> > The MKIV is clearly the pinnacle of yaw string technology. Meticulously crafted, it looks great on my glider. However, it suffers from the same problem I have noticed on all yaw strings I have flown. In flight, it constantly swings off the centerline 10, 20, sometimes even 30 degrees, particularly while thermalling. What’s up with that?
>
> >
>
> >
>
> >
>
> > MM
>
>
>
> Mike-Mike,
>
>
>
> Each MKIV "high tech" yaw string leaves our shop eager to learn, but obviously young and impressionable - - they do have a tendancy towards having a short attention span and will often display a wild tendancy to go whichever way the wind blows.
>
>
>
> After installation, especially during early training it's important to treat your young MKIV gently, they are sensitive. Never sweat at it, unless it's obviously heading entirely the wrong way. It's okay to firmly tell it to "straighten up and fly right".
>
>
>
> We are working on providing better pre-shipment training on our end. Until then, if you have a really bad one, you can tape the end down straight before flight to show it what you expect of it. Don't do this often though as you risk breaking it's spirit. Not good.
>
>
>
> all the best,
>
>
>
> bumper

Tape that bothersome loose end down. Why didn’t I think of that! Thanks, Bumper. In addition to great products, your customer support is unequalled. I also appreciate learning it’s okay to tell the MKIV to “straighten up and fly right”. Silly me. I thought that’s what it was telling me. Anyway, with that cleared up, now I can concentrate on why my flights are always so much slower that everybody else’s.

Michael

[Mike Mike Ground]

On Saturday, December 1, 2012 5:54:16 PM UTC-8, bumper wrote:
> On Saturday, December 1, 2012 2:29:59 PM UTC-8, Mike Mike Ground wrote:
>
> > The MKIV is clearly the pinnacle of yaw string technology. Meticulously crafted, it looks great on my glider. However, it suffers from the same problem I have noticed on all yaw strings I have flown. In flight, it constantly swings off the centerline 10, 20, sometimes even 30 degrees, particularly while thermalling. What’s up with that?
>
> >
>
> >
>
> >
>
> > MM
>
>
>
> Mike-Mike,
>
>
>
> Each MKIV "high tech" yaw string leaves our shop eager to learn, but obviously young and impressionable - - they do have a tendancy towards having a short attention span and will often display a wild tendancy to go whichever way the wind blows.
>
>
>
> After installation, especially during early training it's important to treat your young MKIV gently, they are sensitive. Never sweat at it, unless it's obviously heading entirely the wrong way. It's okay to firmly tell it to "straighten up and fly right".
>
>
>
> We are working on providing better pre-shipment training on our end. Until then, if you have a really bad one, you can tape the end down straight before flight to show it what you expect of it. Don't do this often though as you risk breaking it's spirit. Not good.
>
>
>
> all the best,
>
>
>
> bumper

Tape that bothersome loose end down. Why didn’t I think of that! Thanks, Bumper. In addition to great products, your customer support is unequalled. I also appreciate learning it’s okay to tell the MKIV to “straighten up and fly right”. Silly me. I thought that’s what it was telling me. Anyway, with that cleared up, now I can concentrate on why my flights are always so much slower that everybody else’s.

Michael


On Saturday, December 1, 2012 5:54:16 PM UTC-8, bumper wrote:
> On Saturday, December 1, 2012 2:29:59 PM UTC-8, Mike Mike Ground wrote:
>
> > The MKIV is clearly the pinnacle of yaw string technology. Meticulously crafted, it looks great on my glider. However, it suffers from the same problem I have noticed on all yaw strings I have flown. In flight, it constantly swings off the centerline 10, 20, sometimes even 30 degrees, particularly while thermalling. What’s up with that?
>
> >
>
> >
>
> >
>
> > MM
>
>
>
> Mike-Mike,
>
>
>
> Each MKIV "high tech" yaw string leaves our shop eager to learn, but obviously young and impressionable - - they do have a tendancy towards having a short attention span and will often display a wild tendancy to go whichever way the wind blows.
>
>
>
> After installation, especially during early training it's important to treat your young MKIV gently, they are sensitive. Never sweat at it, unless it's obviously heading entirely the wrong way. It's okay to firmly tell it to "straighten up and fly right".
>
>
>
> We are working on providing better pre-shipment training on our end. Until then, if you have a really bad one, you can tape the end down straight before flight to show it what you expect of it. Don't do this often though as you risk breaking it's spirit. Not good.
>
>
>
> all the best,
>
>
>
> bumper

[Mike Mike Ground]

On Saturday, December 1, 2012 5:54:16 PM UTC-8, bumper wrote:
> On Saturday, December 1, 2012 2:29:59 PM UTC-8, Mike Mike Ground wrote:
>
> > The MKIV is clearly the pinnacle of yaw string technology. Meticulously crafted, it looks great on my glider. However, it suffers from the same problem I have noticed on all yaw strings I have flown. In flight, it constantly swings off the centerline 10, 20, sometimes even 30 degrees, particularly while thermalling. What’s up with that?
>
> >
>
> >
>
> >
>
> > MM
>
>
>
> Mike-Mike,
>
>
>
> Each MKIV "high tech" yaw string leaves our shop eager to learn, but obviously young and impressionable - - they do have a tendancy towards having a short attention span and will often display a wild tendancy to go whichever way the wind blows.
>
>
>
> After installation, especially during early training it's important to treat your young MKIV gently, they are sensitive. Never sweat at it, unless it's obviously heading entirely the wrong way. It's okay to firmly tell it to "straighten up and fly right".
>
>
>
> We are working on providing better pre-shipment training on our end. Until then, if you have a really bad one, you can tape the end down straight before flight to show it what you expect of it. Don't do this often though as you risk breaking it's spirit. Not good.
>
>
>
> all the best,
>
>
>
> bumper

Tape that bothersome loose end down. Why didn’t I think of that! Thanks, Bumper. In addition to great products, your customer support is unequalled. I also appreciate learning it’s okay to tell the MKIV to “straighten up and fly right”. Silly me. I thought that’s what it was telling me. Anyway, with that cleared up, now I can concentrate on why my flights are always so much slower that everybody else’s.

Michael

[[email protected]]

On Sunday, December 2, 2012 2:27:28 PM UTC-5, Mike Mike Ground wrote:
> On Saturday, December 1, 2012 5:54:16 PM UTC-8, bumper wrote:
>
> > On Saturday, December 1, 2012 2:29:59 PM UTC-8, Mike Mike Ground wrote:
>
> >
>
> > > The MKIV is clearly the pinnacle of yaw string technology. Meticulously crafted, it looks great on my glider. However, it suffers from the same problem I have noticed on all yaw strings I have flown. In flight, it constantly swings off the centerline 10, 20, sometimes even 30 degrees, particularly while thermalling. What’s up with that?
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > MM
>
> >
>
> >
>
> >
>
> > Mike-Mike,
>
> >
>
> >
>
> >
>
> > Each MKIV "high tech" yaw string leaves our shop eager to learn, but obviously young and impressionable - - they do have a tendancy towards having a short attention span and will often display a wild tendancy to go whichever way the wind blows.
>
> >
>
> >
>
> >
>
> > After installation, especially during early training it's important to treat your young MKIV gently, they are sensitive. Never sweat at it, unless it's obviously heading entirely the wrong way. It's okay to firmly tell it to "straighten up and fly right".
>
> >
>
> >
>
> >
>
> > We are working on providing better pre-shipment training on our end. Until then, if you have a really bad one, you can tape the end down straight before flight to show it what you expect of it. Don't do this often though as you risk breaking it's spirit. Not good.
>
> >
>
> >
>
> >
>
> > all the best,
>
> >
>
> >
>
> >
>
> > bumper
>
>
>
> Tape that bothersome loose end down. Why didn’t I think of that! Thanks, Bumper. In addition to great products, your customer support is unequalled. I also appreciate learning it’s okay to tell the MKIV to “straighten up and fly right”. Silly me. I thought that’s what it was telling me. Anyway, with that cleared up, now I can concentrate on why my flights are always so much slower that everybody else’s.
>
>
>
> Michael

Seriously now, any tips on how to fly without a yaw string should our beloved MKIV high tech devise fail?

[[email protected]]

On Sunday, December 2, 2012 5:36:16 PM UTC-5, wrote:
> On Sunday, December 2, 2012 2:27:28 PM UTC-5, Mike Mike Ground wrote:
>
> > On Saturday, December 1, 2012 5:54:16 PM UTC-8, bumper wrote:
>
> >
>
> > > On Saturday, December 1, 2012 2:29:59 PM UTC-8, Mike Mike Ground wrote:
>
> >
>
> > >
>
> >
>
> > > > The MKIV is clearly the pinnacle of yaw string technology. Meticulously crafted, it looks great on my glider. However, it suffers from the same problem I have noticed on all yaw strings I have flown. In flight, it constantly swings off the centerline 10, 20, sometimes even 30 degrees, particularly while thermalling. What’s up with that?
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > >
>
> >
>
> > >
>
> >
>
> > > > MM
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Mike-Mike,
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > Each MKIV "high tech" yaw string leaves our shop eager to learn, but obviously young and impressionable - - they do have a tendancy towards having a short attention span and will often display a wild tendancy to go whichever way the wind blows.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > After installation, especially during early training it's important to treat your young MKIV gently, they are sensitive. Never sweat at it, unless it's obviously heading entirely the wrong way. It's okay to firmly tell it to "straighten up and fly right".
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > We are working on providing better pre-shipment training on our end. Until then, if you have a really bad one, you can tape the end down straight before flight to show it what you expect of it. Don't do this often though as you risk breaking it's spirit. Not good.
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > all the best,
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > >
>
> >
>
> > > bumper
>
> >
>
> >
>
> >
>
> > Tape that bothersome loose end down. Why didn’t I think of that! Thanks, Bumper. In addition to great products, your customer support is unequalled. I also appreciate learning it’s okay to tell the MKIV to “straighten up and fly right”. Silly me. I thought that’s what it was telling me. Anyway, with that cleared up, now I can concentrate on why my flights are always so much slower that everybody else’s.
>
> >
>
> >
>
> >
>
> > Michael
>
>
>
> Seriously now, any tips on how to fly without a yaw string should our beloved MKIV high tech devise fail?

Correction...device, lets not make this confusing...

[BobW]

On 12/2/2012 3:36 PM, wrote:
<Snip...>
>> Tape that bothersome loose end down. Why didn’t I think of that!
>> Thanks, Bumper. In addition to great products, your customer support is
>> unequalled. I also appreciate learning it’s okay to tell the MKIV to
>> “straighten up and fly right”. Silly me. I thought that’s what it
>> was telling me. Anyway, with that cleared up, now I can concentrate on
>> why my flights are always so much slower that everybody else’s.
>>
>>
>>
>> Michael
>
> Seriously now, any tips on how to fly without a yaw string should our
> beloved MKIV high tech device fail?
>

Hmmm... Assuming this is a serious question, in the days before even the MKI
was available, I experienced total yaw string failure. More than once,
actually, on ships ranging from 1-26 (captured by canopy rail) to 15-meter
glass (adhesive failure...and the tape was hardly even 10 years old!).

Being a cheap (rhymes with "dastard"), I continued soaring, coordinating by
feel and sound. Easy if you have a noisy ship. (Sorry if this costs you future
sales, Bumper!)

Bob - I plead "winter", Yr'onner! - W.

[C-FFKQ (42)]

On Sunday, December 2, 2012 8:26:04 PM UTC-5, BobW wrote:
>> Being a cheap (rhymes with "dastard"), I continued soaring...

Custard?
BobW is a Custard?
Which flavour?

-John
(and I plead encroaching senility, brought about by too much R.A.S., the glider being in storage and impending white stuff on the ground)

[Gary Ittner[_3_]]

"C-FFKQ (42)" > wrote in message
...
> On Sunday, December 2, 2012 8:26:04 PM UTC-5, BobW wrote:
>>> Being a cheap (rhymes with "dastard"), I continued soaring...
>
> Custard?
> BobW is a Custard?
> Which flavour?

No, that rhymes with "bustard":

The bustard's an exquisite fowl
With almost no reason to howl.
It escapes what would be
Illigitimacy
By the grace of a fortunate vowel.

-P7 unit

[bumper[_4_]]

On Sunday, December 2, 2012 5:26:04 PM UTC-8, BobW wrote:
>
> Hmmm... Assuming this is a serious question, in the days before even the MKI
>
> was available, I experienced total yaw string failure. More than once,
>
> actually, on ships ranging from 1-26 (captured by canopy rail) to 15-meter
>
> glass (adhesive failure...and the tape was hardly even 10 years old!).
>
>
>
> Being a cheap (rhymes with "dastard"), I continued soaring, coordinating by
>
> feel and sound. Easy if you have a noisy ship. (Sorry if this costs you future
>
> sales, Bumper!)
>
>
>
> Bob - I plead "winter", Yr'onner! - W.


After a critical failure, such as a premature yaw string departure, the safe choice would, of course, be to bail out. There will always be the "hero" types that will ride her down I suppose, but consider the risks involved. You might be in a deadly tail spin and not even know it.

Clearly prevention is the best policy. To help reduce the chance of yaw string departure, each MKIV base yarn is injected with a clear polymer adhesive as a final assembly step. This to help prevent the unpleasant "early pull out" failure.

bumper

[[email protected]]

Your right, if I can't fly this thing straight I'm gettin' the hell out....-/

[JohnDeRosa]

In the past my yaw strings were made of everything from boars hair to alfalfa stalks and held onto the can-o-pee with rivets and bailing wire. Now having flown with the Bumper MKminus3 on up to the MKIV I have since never landed out, have earned a quadruple diamond with gold oak leaf clusters and have used my glider for a Flight-For-Life mission (which, let me tell you, was a little crowded with the stretcher on board). Zounds! What an advance for mankind! Is there a Nobel prize for glider particle astrophysics?

[glidergeek]

What are the possibilities of a tour of the factory? I'd be intreeged to see the manufacturing process.

[Grider Pirate[_2_]]

On Dec 1, 5:24*pm, Martin Gregorie >
wrote:
> On Sat, 01 Dec 2012 14:29:59 -0800, Mike Mike Ground wrote:
> > The MKIV is clearly the pinnacle of yaw string technology.
> > Meticulously crafted, it looks great on my glider. * *However, it
> > suffers from the same problem I have noticed on all yaw strings I have
> > flown. * *In flight, it constantly swings off the centerline 10, 20,
> > sometimes even 30 degrees, particularly while thermalling. * What’s up
> > with that?
>
> How careful were you to place it on the center-line?
>
> The tighter the curvature of your canopy near the centre line the more
> critical yaw string placement is. For instance I think that, on a
> Libelle, you need to place it within 5mm (1/4") or better of the exact
> centre line, but probably canopies that aren't so sharply curved near the
> centre line would make the string placement less critical. I stretched a
> thread from the exact top of the fin down to the nose and took a lot of
> care that both ends were correctly placed and that it wasn't deflected by
> the top of the canopy before marking that line and fitting the yaw
> string.
>
> By contrast, I suspect that aligning the axis of symmetry of the
> transparent sticky bit with the glider's centre line is more important
> for aesthetics than for the yaw string's operation. In any case, by using
> pencil marks on masking tape placed before and behind the sticky bit and
> taking care, you should be able to align it well enough that errors can't
> be seen once the masking tap and thread are removed.
>
> You say the string is often deflected to one side: of course, it should
> be tail out in a properly flown thermal turn and dead straight when you
> cruise straight between thermals.
>
> If it doesn't do that, it might be that:
>
> 1) its mounted off to one side. Check with a thin line as I did to see
> * *if its not accurately on the centre line.
>
> 2) you've picked up the habit of flying sideways.
>
> Either could make it hang consistently to one side. Either way you need
> to work out what's causing it and correct the problem.
>
> --
> martin@ * | Martin Gregorie
> gregorie. | Essex, UK
> org * * * |

I carefully leveled Uniform Fox, then used a laser level to 'draw' a
line perfectly centered line on the fuselage from the nose to the TE
probe on the tail. I'm quite certain I netted a 10% performance gain
with the MkIV.

[AGL]

On Friday, 30 November 2012 15:36:29 UTC-5, bumper wrote:

> These instructions are for use if you're happy with the current position of the MK## yaw string. If not, please refer to the new installation instructions available at http://www.cumulus-soaring.com/bumper.htm or http://www..williamssoaring.com/catalog/sailplane-parts.html or from me via email.

How can I calibrate it to warn about air pockets? There're everywhere!

[bumper[_4_]]

On Thursday, December 6, 2012 8:46:53 AM UTC-8, AGL wrote:

>
> How can I calibrate it to warn about air pockets? There're everywhere!

Dear AGL,

The MKIV comes factory calibrated for air pockets and no further adjustment should be necessary.* The MKIV will indicate the presence of a significant air pocket (at least the ones we have around here) by pointing straight up.

Assuming your head has not punched a hole in the canopy, air pocket recovery will be reliably indicated by the MKIV yarn coiling neatly around the base in a counter-clockwise direction - - watch for it as this moment will be fleeting.

*Unfortunately there is a little bit of hysteresis error that we have not been able to correct for.

bumper

[Dave Nadler]

On Thursday, December 6, 2012 10:33:40 AM UTC-5, Grider Pirate wrote:
> I carefully leveled Uniform Fox, then used a laser level to 'draw' a
> line perfectly centered line on the fuselage from the nose to the TE
> probe on the tail. I'm quite certain I netted a 10% performance gain
> with the MkIV.

But, its hard to tell, on account of semi-blindess after staring
into the laser...

[[email protected]]

On Thursday, December 6, 2012 1:14:42 PM UTC-8, Dave Nadler wrote:
> On Thursday, December 6, 2012 10:33:40 AM UTC-5, Grider Pirate wrote:
>
> > I carefully leveled Uniform Fox, then used a laser level to 'draw' a
>
> > line perfectly centered line on the fuselage from the nose to the TE
>
> > probe on the tail. I'm quite certain I netted a 10% performance gain
>
> > with the MkIV.
>
>
>
> But, its hard to tell, on account of semi-blindess after staring
>
> into the laser...

What?! You don't have your own set of laser protective goggles?

[bumper[_4_]]

Several of our customers have written asking, "What's up with all this blue flame stuff? I thought I was experiencing the rapture.".

At no extra charge, all MKIV "high tech" yaw strings are designed to cleverly "self-illuminate" using luminous plasma (St. Elmo's Fire) for better visibility during exceedingly adverse soaring conditions while flying in and near thunderstorms - - when you need it most.

MKIV's are in use on all continents save Anartica. To remedy this troubling lapse in our world coverage, the first three Antartican glider owners who contact me will get a free MKIV. (Optional propylene glycol treatment available, just pay shipping and handling).

bumper
zz
Minden, NV

[Tony V]

I can't believe that the topic of MKIV winter maintenance has gotten no
coverage.

We all know that you have to run an aircraft engine once in a while if
the aircraft is not flown to get rid of acids forming in the crank case
- or whatever. Surely something must be done to the MKIV during the long
winter months in order to keep it performing in top condition.

Every couple of weeks, I pull the fuselage out of the trailer and blow
air from a hair drier (at the *cool* setting) over the MKIV, but wonder
if this is sufficient to maintain optimal performance. Your expert
advice on this subject is requested.

Tony "6N"
P.S. I do *not* simulate tail slides with the hair drier

[JP Stewart]

I'm glad this discussion came back up, I love the MKIV (though club mates enjoy making fun of BUYING a yaw string, ha) Anyway.... I love it so much I have to ask: Is there any advantage to installing one inside the canopy as well? (I though I heard of a near 10% performance gain from such) Also, would my internal turbulators cause any interference?

JP

[Lars Peder Hansen]

Hi gang,

I brought one of the Mk. IV's back from SoaringNV this spring, and has used
it on my DG600 in Europe since then, with substantial performance gains, I
might add.
It has gathered crowds everywhere I went, both in my native Denmark and in
the French Alps. The interest seems to be there, so the question is: Bumper,
does any of your R&D divisions have plans for a metric version? I'm sure it
would be an instant hit.

Happy New Year to all,
Lars Peder


"Tony V" > wrote in message
...
>
> I can't believe that the topic of MKIV winter maintenance has gotten no
> coverage.
>
> We all know that you have to run an aircraft engine once in a while if the
> aircraft is not flown to get rid of acids forming in the crank case - or
> whatever. Surely something must be done to the MKIV during the long winter
> months in order to keep it performing in top condition.
>
> Every couple of weeks, I pull the fuselage out of the trailer and blow air
> from a hair drier (at the *cool* setting) over the MKIV, but wonder if
> this is sufficient to maintain optimal performance. Your expert advice on
> this subject is requested.
>
> Tony "6N"
> P.S. I do *not* simulate tail slides with the hair drier

[bumper[_4_]]

On Monday, December 31, 2012 6:58:37 AM UTC-8, Tony V wrote:
> I can't believe that the topic of MKIV winter maintenance has gotten no
>
> coverage.
>
>
> Every couple of weeks, I pull the fuselage out of the trailer and blow
>
> air from a hair drier (at the *cool* setting) over the MKIV, but wonder
>
> if this is sufficient to maintain optimal performance. Your expert
>
> advice on this subject is requested.
>
>
> Tony "6N"

Tony, great idea, but suggest the hair dryer on warm setting to better emulate tropic climes. MKIV's are resilient but susceptable to the winter blues if not flown often enough.

Jp, with sugarplums dancing, we headed for the lab to see if an "inside-the-cockpit" MKIV would be advantageous (and increase sales!). Unfortunately, MKIV's are sensitive little guys and easily confused. With two in close proximity, but in widely diverse environments, both got more confused than the pilot. I'm sure the turbultors would only make matters worse - - definitely not recommended.

Lars, thanks for the kind words, but your "metric model" idea stinks. It's hard enough grabbing the right wrench with two draws full of SAE and Metric stuff. If I came out with a Metric MKIV, next thing you know there'd be clamoring for a Whitworth version and who knows what else.

Having said that, I'll attempt to be reasonable and still keep things simple. I'm ceasing production of the English SAE version of the MKIV. Starting New Year's day, I will only make the metric version - - this should dramatically raise the bar for soaring performance in Europe and 3rd world countries. The SAE version will doubtless become a collector's item and much sought in the USA - - get'um while you still can.

bumper
zz

[howdy]

On Monday, December 31, 2012 10:15:38 AM UTC-5, Jp Stewart wrote:
> I'm glad this discussion came back up, I love the MKIV (though club mates enjoy making fun of BUYING a yaw string, ha) Anyway.... I love it so much I have to ask: Is there any advantage to installing one inside the canopy as well? (I though I heard of a near 10% performance gain from such) Also, would my internal turbulators cause any interference?
>
>
>
> JP

Now we're on to something! The inside the canopy model would be an "inertial" yaw detector. Just connect some wires to your flight computer and it would show every movement you make. If it hangs straight down, you've just landed out. And the internal turbulators would be obsolete. This is real progress.

Mark

[Jim Britton]

I haven't been following this "thread" (pun intended) too closely so
forgive me if this has already been covered, but I am wondering if you have
thought of supplying left-handed MKIV's sometime soon. Us lefties have
enough barriers to overcome as it is - maybe if we had one less thing to
worry about...


At 18:41 31 December 2012, bumper wrote:
>On Monday, December 31, 2012 6:58:37 AM UTC-8, Tony V wrote:
>> I can't believe that the topic of MKIV winter maintenance has gotten
no=
>=20
>>=20
>> coverage.
>>=20
>>=20
>> Every couple of weeks, I pull the fuselage out of the trailer and
blow=20
>>=20
>> air from a hair drier (at the *cool* setting) over the MKIV, but
wonder=
>=20
>>=20
>> if this is sufficient to maintain optimal performance. Your expert=20
>>=20
>> advice on this subject is requested.
>>=20
>>=20
>> Tony "6N"
>
>Tony, great idea, but suggest the hair dryer on warm setting to better
>emul=
>ate tropic climes. MKIV's are resilient but susceptable to the winter
>blues=
> if not flown often enough.
>
>Jp, with sugarplums dancing, we headed for the lab to see if an
>"inside-the=
>-cockpit" MKIV would be advantageous (and increase sales!).
Unfortunately,
>=
>MKIV's are sensitive little guys and easily confused. With two in close
>pro=
>ximity, but in widely diverse environments, both got more confused than
>the=
> pilot. I'm sure the turbultors would only make matters worse - -
>definitel=
>y not recommended.=20
>
>Lars, thanks for the kind words, but your "metric model" idea stinks.
It's
>=
>hard enough grabbing the right wrench with two draws full of SAE and
>Metric=
> stuff. If I came out with a Metric MKIV, next thing you know there'd be
>cl=
>amoring for a Whitworth version and who knows what else.=20
>
>Having said that, I'll attempt to be reasonable and still keep things
>simpl=
>e. I'm ceasing production of the English SAE version of the MKIV.
Starting
>=
>New Year's day, I will only make the metric version - - this should
>dramati=
>cally raise the bar for soaring performance in Europe and 3rd world
>countri=
>es. The SAE version will doubtless become a collector's item and much
>sough=
>t in the USA - - get'um while you still can.
>
>bumper
>zz
>
>

[[email protected]]

And, how about a reduced cost back seat repeater model for the two seater trainers out there...

On Monday, December 31, 2012 8:17:28 PM UTC-6, Jim Britton wrote:
> I haven't been following this "thread" (pun intended) too closely so
>
> forgive me if this has already been covered, but I am wondering if you have
>
> thought of supplying left-handed MKIV's sometime soon. Us lefties have
>
> enough barriers to overcome as it is - maybe if we had one less thing to
>
> worry about...
>
>
>
>
>
> At 18:41 31 December 2012, bumper wrote:
>
> >On Monday, December 31, 2012 6:58:37 AM UTC-8, Tony V wrote:
>
> >> I can't believe that the topic of MKIV winter maintenance has gotten
>
> no=
>
> >=20
>
> >>=20
>
> >> coverage.
>
> >>=20
>
> >>=20
>
> >> Every couple of weeks, I pull the fuselage out of the trailer and
>
> blow=20
>
> >>=20
>
> >> air from a hair drier (at the *cool* setting) over the MKIV, but
>
> wonder=
>
> >=20
>
> >>=20
>
> >> if this is sufficient to maintain optimal performance. Your expert=20
>
> >>=20
>
> >> advice on this subject is requested.
>
> >>=20
>
> >>=20
>
> >> Tony "6N"
>
> >
>
> >Tony, great idea, but suggest the hair dryer on warm setting to better
>
> >emul=
>
> >ate tropic climes. MKIV's are resilient but susceptable to the winter
>
> >blues=
>
> > if not flown often enough.
>
> >
>
> >Jp, with sugarplums dancing, we headed for the lab to see if an
>
> >"inside-the=
>
> >-cockpit" MKIV would be advantageous (and increase sales!).
>
> Unfortunately,
>
> >=
>
> >MKIV's are sensitive little guys and easily confused. With two in close
>
> >pro=
>
> >ximity, but in widely diverse environments, both got more confused than
>
> >the=
>
> > pilot. I'm sure the turbultors would only make matters worse - -
>
> >definitel=
>
> >y not recommended.=20
>
> >
>
> >Lars, thanks for the kind words, but your "metric model" idea stinks.
>
> It's
>
> >=
>
> >hard enough grabbing the right wrench with two draws full of SAE and
>
> >Metric=
>
> > stuff. If I came out with a Metric MKIV, next thing you know there'd be
>
> >cl=
>
> >amoring for a Whitworth version and who knows what else.=20
>
> >
>
> >Having said that, I'll attempt to be reasonable and still keep things
>
> >simpl=
>
> >e. I'm ceasing production of the English SAE version of the MKIV.
>
> Starting
>
> >=
>
> >New Year's day, I will only make the metric version - - this should
>
> >dramati=
>
> >cally raise the bar for soaring performance in Europe and 3rd world
>
> >countri=
>
> >es. The SAE version will doubtless become a collector's item and much
>
> >sough=
>
> >t in the USA - - get'um while you still can.
>
> >
>
> >bumper
>
> >zz
>
> >
>
> >

[bumper[_4_]]

On Monday, December 31, 2012 6:17:28 PM UTC-8, Jim Britton wrote:
> I haven't been following this "thread" (pun intended) too closely so
>
> forgive me if this has already been covered, but I am wondering if you have
>
> thought of supplying left-handed MKIV's sometime soon. Us lefties have
>
> enough barriers to overcome as it is - maybe if we had one less thing to
>
> worry about...

Jim,

No offense, quit whining . . . have you considered Lefty Aversion Therapy?

We used to have a "don't ask don't tell" policy here at Bumper Soaring (or BS for short). Under intense political pressure, we had to end that. We still do our best to force all MKIV's from the same mold, ambidextrous and "straight". Unfortunately, we've noted a few with left leaning tendancies, some mostly go to the right, and nearly all, if given half an opportunity, will quite happily go both ways.

Yes, it's a source of embarrasement for us and for some MKIV owners. You may even notice in YouTube videos that many of these same owners will carefully edit out any shots where their MKIV is, um, wildly playing the field so to speak.

bumper

[bumper[_4_]]

On Monday, December 31, 2012 7:43:37 PM UTC-8, wrote:
> And, how about a reduced cost back seat repeater model for the two seater trainers out there...


resi,

We considered that, but concluded it would be much safer to have full redundancy with two individual MKIV's. They will almost always "sync up" just like magic, then continuously update each other so they stay in step . . . it's really quite amazing. Plus with two you get a free thermal centering/emergency tornadic condition indicator. If the front MKIV is pointing off to one side, and the rear MKIV is to the opposite side, you are either in a tornado or have accurately centered one of our strong Minden thermals.

Beta testing is almost finished on our Student Harassment Instructor Training verion of the MKIV. It comes with a handy remote giving the instructor complete control of the MKIV SH&T (e.g. the harassed student can be standing on the left rudder pedal and the MKIV will still be hanging way off to the right). Great fun for bored instructors.

bumper

[Tony V]

On 12/31/2012 11:11 PM, bumper wrote:
> On Monday, December 31, 2012 6:17:28 PM UTC-8, Jim Britton wrote:
>> I haven't been following this "thread" (pun intended) too closely so
>>
>> forgive me if this has already been covered, but I am wondering if you have
>>
>> thought of supplying left-handed MKIV's sometime soon. Us lefties have
>>
>> enough barriers to overcome as it is - maybe if we had one less thing to
>>
>> worry about...
>
> Jim,
>
> No offense, quit whining . . . have you considered Lefty Aversion Therapy?


How typical. It's always OUR problem. We've learned to live in a right
handed world. Is it really to much to ask for you to consider our
plight? You're probably against lefties marrying each other too.

Tony

[bumper[_4_]]

On Monday, December 31, 2012 8:49:20 PM UTC-8, Tony V wrote:
>
> How typical. It's always OUR problem. We've learned to live in a right
>
> handed world. Is it really to much to ask for you to consider our
>
> plight? You're probably against lefties marrying each other too.
>
>
>
> Tony

I had no idea what you are going though. A quick search found http://www.cracked.com/article_19808_5-reasons-being-left-handed-screws-you-life.html

Do you fling cats at passers by? Should lefties be allowed to marry at all?

bumper

[xcnick]

Hi bumper, I am the Schweizer driver at the airport. With great interest I read the many sophisticated suggestions, but I fear they miss the most basic improvement needed. Your instrument gets right up in the pilots face with constant criticism. I get enough of that at home.

This is not all tongue in cheek. You may have noticed I have no instruments for just this reason. However as you are the most innovative builder perhaps you could come up with something with positive reinforcement. I am thinking pneumatic. ;-)

[bumper[_4_]]

On Monday, December 31, 2012 11:24:28 PM UTC-8, xcnick wrote:

> This is not all tongue in cheek. You may have noticed I have no instruments for just this reason. However as you are the most innovative builder perhaps you could come up with something with positive reinforcement. I am thinking pneumatic. ;-)

xcnick,

I'm sure it can be done pneumatically, and fairly simply too. Something like two ports, one on each side of a forward facing vane, the port openings lateral to the ship's axis to avoid ram air. With no yaw, delta-p on ports is equal. With any yaw, delta-p increases.

Display could be analog, digital, or audio.

However, this yaw indicator would violate the KISS rule. More complexity for little or no gain in functionality over a yaw string.

It's also done with a slip or skid bank indicator ball, used in powe planes where prop wash precludes the use of a yaw string. http://www.aircraftspruce.com/pages/in/slipindicators/bank_indicat.php
Though I think a yaw string is more sensitive than most ball indicators I've flown with - - plus you don't have to look at the panel to read the yaw string.

bumper