Clear Yaw string tape?

On 12 Apr 2006 13:18:52 -0700, "Jack" wrote:

I saw one stuck on with a drop of clear RTV (silicone rubber). When I
asked about it, the owner said it stuck up into the airflow a bit
better and was a little more responsive. He also commented that he
didn't fix his gaze on it nearly so often as the little triangle of
white tape that he used in the past. I think I'll try that soon, unless
someone tells me that the RTV will damage my plexiglass.

My partners and I used to keep our yaw string suspended about 3/4"
above the surface on a piece of wire bent to shape and taped into
place. It gave a little better precision by keeping the string out of
the canopy's boundary layer, which was prone to a bit of hysteresis.
However, we eventually decided it wasn't enough of an improvement to
offset the pain in the butt of removing it every time we put the
canopy cover on, so we gave it up.

Just be sure you use *metric* yaw string on a German ship.

rj

Though I haven't really advertised it, a number of years back I invented the
MKII "high tech" yaw string. The high tech part being somewhat
tongue-in-cheek, though generally unreliable and refutable sources indicate
the MKII will add at least 2 points to your L/D - - and even if not, it
still looks a whole lot better than tape! I've sold 70 - 100 MKII's, mostly
to other Stemme owners and a few on the ramp at Minden . . . so perhaps
someone will post their opinion.

The MKII consists of a clear turbulator base w/ clear adhesive. Yarn is
natural wool, as that's reputed to be kinder to the Plexi than synthetic
yarn that scratches. The yarn exits through a small hole in the plastic
base. Included is an index dot for the inside of the canopy, instructions
and a money back guarantee if you're not happy.

Several MKII's were placed on a test strip of Plexiglas and continuously
exposed for over two years in the California sun. After the exposure test,
the base and adhesive could still be easily removed with no damage or
residue. To order, send $9 USD and a self-addressed, stamped envelope to:

John Morgan
194 Taylor Creek Rd.
Minden, NV 89460

I also should have a "quiet vent" kit (QV) available soon. Added to the
standard swing out vent in the canopy sliding window, testing shows a noise
reduction of 10 db - - it quiets the vent to a pleasant, low level. I'm
still working to resolve some issues with a few QV failures while wave
flying, if the QV is mechanically stressed while exposed to sub-zero
temperatures. If you don't "pluck" at the QV while it's super cold, it works
fine as is. When ready for "market", it will be $5 US.

all the best,

bumper



"Bruno" wrote in message
ups.com...
I have seen a few gliders that had yaw strings attached with something
other than the white tape most of us use. It was either a clear tape
or clear sticker. If any of you use something other than the white
tape to attach your yaw string please share what you use. Thanks!

I've always felt (but have no evidence) that positioning a yaw string on
the canopy is not optimal, and that you really want it in clean,
undisturbed, air (yeah, like the 2-33). There could be 2 problems with
the canopy mount. One, it is flush with a compound curve surface and who
knows that the air is doing there. Two, it is in the boundary layer
between the canopy surface and the airflow and who knows that the air is
doing there.

I wonder if any one has experimented with a "normally" mounted yaw
string and one placed on a post several cm higher.

Tony V.

Yep, done that. The string on the canopy surface is about twice as
sensitive to yaw angles as the one on a one inch tall post. In other words,
the string on the canopy surface 'over-indicates' by about 2:1. I think
that's a good thing.

As another poster noted, getting the string placed exactly on the centerline
is the key. I've found that tailors cloth measuring tape is useful for
making those measurements since it won't scratch the canopy.

Despite the aversion expressed to drilling a hole for the yaw string, that
approach has some advantages.
1. It is a very 'clean' attachment with no tape blocking the pilots forward
view.
2. If the measurements are made precisely before the hole is drilled, the
positioning will always be exact.
3. The string is easily removed/replaced for cleaning and polishing the
canopy.
4. There is NO chance of the string blowing off in flight.

Note: If you decide to drill, you MUST use a sharp new drill made
specifically for drilling plastic.

Bill Daniels

"Tony Verhulst" wrote in message
...

I've always felt (but have no evidence) that positioning a yaw string on
the canopy is not optimal, and that you really want it in clean,
undisturbed, air (yeah, like the 2-33). There could be 2 problems with the
canopy mount. One, it is flush with a compound curve surface and who knows
that the air is doing there. Two, it is in the boundary layer between the
canopy surface and the airflow and who knows that the air is doing there.

I wonder if any one has experimented with a "normally" mounted yaw string
and one placed on a post several cm higher.

Tony V.

Does anyone know who still supplies these canopy holes?

"Nyal Williams" wrote in message
...
I have seen a glider that had a very small, round hole
for the yaw string drilled in the canopy. The owner
tied knots inside and out, tighly against the hole.

That was probably 35 years ago and I don't remember
what or who. I would not recommend it.




At 18:00 12 April 2006, wrote:

Bruno wrote:
I have seen a few gliders that had yaw strings attached
with something
other than the white tape most of us use. It was
either a clear tape
or clear sticker. If any of you use something other
than the white
tape to attach your yaw string please share what you
use. Thanks!

Scotch clear packing tape. Cut it into a little triangle
(for style
points), stick the yarn on (I prefer green - with a
knot at both ends),
and carefully place dead center on canopy, as far back
as you can
stand.

Doesn't shrink or leave much residue like white tape.
And you can
kinda see through it...

I also it to cover the big horizontal tail attachment
opening on my LS6
- one piece fits perfectly.

Kirk
66

Tony Verhulst wrote:

I've always felt (but have no evidence) that positioning a yaw string on
the canopy is not optimal, and that you really want it in clean,
undisturbed, air (yeah, like the 2-33). There could be 2 problems with
the canopy mount. One, it is flush with a compound curve surface and who
knows that the air is doing there. Two, it is in the boundary layer
between the canopy surface and the airflow and who knows that the air is
doing there.

I wonder if any one has experimented with a "normally" mounted yaw
string and one placed on a post several cm higher.

Tony V.
Our club gliders all had or still have the yaw string mounted some centimetres
off the fuselage.
The Blanik L13 has its on a TE probe about 5cm long, the two BergFalkes have
wire standoffs on the nose. In all cases the string in the free stream tends to
flap like a flag, which can be a little irritating. They also easily drape
around the support and inattentive pilots then end up flying with no yaw
indication. We recently moved the string to the canopy on one of the Bergies,
and the result is an improvement.

In my experience the canopy mounted string is a stabler, and in most situations
better, tool. The small area occluded by the attachment is not significant as
long as you do move your head when scanning. Otherwise it can obscure other
aircraft.
--
Bruce Greeff
Std Cirrus #57
I'm no-T at the address above.

In article , Tony Verhulst
writes

I've always felt (but have no evidence) that positioning a yaw string on
the canopy is not optimal, and that you really want it in clean,
undisturbed, air (yeah, like the 2-33). There could be 2 problems with
the canopy mount. One, it is flush with a compound curve surface and who
knows that the air is doing there. Two, it is in the boundary layer
between the canopy surface and the airflow and who knows that the air is
doing there.

I wonder if any one has experimented with a "normally" mounted yaw
string and one placed on a post several cm higher.

Tony V.

There used to be a burble round the canopy on my sailplane,
which meant there was only a narrow speed range where the yaw string was
anything like stable.

I wanted to update the TE system from a diaphragm type to a
Braunsweig tube. It occurred to me that if I put the tube immediately
ahead of the canopy I could kill two birds with one stone. Worked a
treat!

I thought maybe I could use the tube as a radio antenna, too, (3
birds?) but never got around to trying it.
--
Mike Lindsay

Are you looking for the EASA approved ones or the traditional ones ?


"Phil Jeffery" wrote in message
...
Does anyone know who still supplies these canopy holes?

"Nyal Williams" wrote in
message ...
I have seen a glider that had a very small, round hole
for the yaw string drilled in the canopy. The owner
tied knots inside and out, tighly against the hole.

That was probably 35 years ago and I don't remember
what or who. I would not recommend it.

On Thu, 13 Apr 2006 08:25:44 -0600, "Bill Daniels"
bildan@comcast-dot-net wrote:

Yep, done that. The string on the canopy surface is about twice as
sensitive to yaw angles as the one on a one inch tall post. In other words,
the string on the canopy surface 'over-indicates' by about 2:1. I think
that's a good thing.

I'm not so sure...there seems to be a definite hysteresis effect in
the boundary layer. I've experimented with two strings, one on a 3/4"
post and one at its base, and they did NOT respond in sync. I found I
could deflect one left, the other right, and hold it that way for a
second or two.

Note: If you decide to drill, you MUST use a sharp new drill made
specifically for drilling plastic.

Better, I think, to poke it with a hot piece of wire to avoid
stress-raising tool marks. Push from the outside in and pull the wire
on through from the inside...that way you don't get a raised lip on
the outside. It works well for stopping cracks, too.

rj

Try a Donut Shop that sells donut holes; they will
have a membership in the Society for Hole Sellers and
will probably allow you to use their directory.


At 20:24 13 April 2006, John Wilton wrote:
Are you looking for the EASA approved ones or the traditional
ones ?


'Phil Jeffery' wrote in message
...
Does anyone know who still supplies these canopy holes?

'Nyal Williams' wrote in
message ...
I have seen a glider that had a very small, round hole
for the yaw string drilled in the canopy. The owner
tied knots inside and out, tighly against the hole.

That was probably 35 years ago and I don't remember
what or who. I would not recommend it.