MKIV "high tech" yaw string (tech note)

[bumper[_4_]]

I recently heard from an owner having installed a MKIV yaw string on a FES (front, electric, self-launch/sustainer) equipped glider. He said that the MKIV was not indicating straight back centered in level flight, being slightly off to the side and deflection in turns was "not even, more sensitive in one direction" (my words).

Since all MKIV yaw strings are carefully obedience trained and calibrated before leaving my shop (g), there had to be something affecting the flow over the canopy. I suspected the culprit might be the folded prop, given the ship's rigging apparently checked fine. I suggested installing temporary yaw strings further back on the canopy to determine how far aft the string would need to be located to behave in an acceptable manner - then mark that spot for the warranty* replacement. I think that worked and all is well (I hope).

If installing a MKIV on a FES equipped glider, please determine suitability of chosen location by test flying with temporary yarn/s prior to installing the MKIV.

MKIV's and Quiet Vents are available on-line at Craggy Aero, Cumulus, and Wings & Wheels!

*For warranty replacement - please contact me directly. IF you read the installation instructions and still goof, that's covered too (once!), warranty coverage is at my sole discretion (but I'm easy).

all the best,

bumper

bumperm at frontier dot
com

[Tony[_5_]]

Been flying all week in the Electro with a brand new Mark IV. My yaw string must be more obedient than that other guys...its nice and straight all the time :)

[2KA]

Or maybe an installation error. Perhaps taped at both ends?

[Dan Marotta]

Hey! I just installed a MK-4 on my LAK-17a and it seems to fly
straighter than before. Do you think I made that same double tape mistake?

I also installed Bumper's quiet vent mod and am very pleased with the
smoother, quieter air coming in the vent.

On 8/9/2015 2:31 PM, 2KA wrote:
> Or maybe an installation error. Perhaps taped at both ends?
>

--
Dan Marotta

[Bryan Searle]

Beat this, I heard of a pilot (!) who drilled a hole in the canopy for the
yaw string!

Doh..

At 04:44 10 August 2015, Dan Marotta wrote:
>Hey! I just installed a MK-4 on my LAK-17a and it seems to fly
>straighter than before. Do you think I made that same double tape
mistake?
>
>I also installed Bumper's quiet vent mod and am very pleased with the
>smoother, quieter air coming in the vent.
>
>On 8/9/2015 2:31 PM, 2KA wrote:
>> Or maybe an installation error. Perhaps taped at both ends?
>>
>
>--
>Dan Marotta
>

[PBA]

So wait, were do I download the firmware update for the yaw string?

[Steve Leonard[_2_]]

On Monday, August 10, 2015 at 6:09:11 AM UTC-5, PBA wrote:
> So wait, were do I download the firmware update for the yaw string?

And do the yearly firmware updates make it incompatible with the old firmware on another MKIV, say, over the canopy for the back seater? Or on your flying buddies plane?

[SoaringXCellence]

Global climate change, winter is here already.

[bumper[_4_]]

On Monday, August 10, 2015 at 4:09:11 AM UTC-7, PBA wrote:
> So wait, were do I download the firmware update for the yaw string?

Why that's proprietary, updates and calibration are done in a lead lined clean room at the factory - $15 includes return shipping. But for about the same sum you can have the very latest firmware along with all brand new hardware from most of the better on-line glider accessory suppliers.

Or, you could drill a hole in the canopy . . .

bumper

[Bob Whelan[_3_]]

On 8/10/2015 4:03 PM, bumper wrote:
> On Monday, August 10, 2015 at 4:09:11 AM UTC-7, PBA wrote:
>> So wait, were do I download the firmware update for the yaw string?
>
> Why that's proprietary, updates and calibration are done in a lead lined
> clean room at the factory - $15 includes return shipping. But for about the
> same sum you can have the very latest firmware along with all brand new
> hardware from most of the better on-line glider accessory suppliers.
>
> Or, you could drill a hole in the canopy . . .
>
> bumper
>

Should the drilled hole be round or square? I'd think a square hole would have
less drag if one assumes equal hole widths and perfect sailplane alignment
with the oncoming air. Geez, for $15, is it unreasonable to expect decent
customer service, like some directions for drilling the preferred square hole?
Is it winter yet?

Bob - I'll shut up now - W.

[Craig Funston]

On Monday, August 10, 2015 at 3:03:03 PM UTC-7, bumper wrote:
> On Monday, August 10, 2015 at 4:09:11 AM UTC-7, PBA wrote:
> > So wait, were do I download the firmware update for the yaw string?
>
> Why that's proprietary, updates and calibration are done in a lead lined clean room at the factory - $15 includes return shipping. But for about the same sum you can have the very latest firmware along with all brand new hardware from most of the better on-line glider accessory suppliers.
>
> Or, you could drill a hole in the canopy . . .
>
> bumper

Everyone needs to remember to use special bits when drilling through their plexi. http://www.eplastics.com/plexiglass_lexan_plastic_drill_bits

Have fun!
Craig

[Papa3[_2_]]

Laugh all you want. The square hole allows me to retract the Yaw String during high speed flight, resulting in significant drag reduction. I hear that the Mark V Yaw String includes "Speed Sense"TM Technology out of the box for this very purpose. At least, that's what I heard from a guy who knows a guys who....

P3

[[email protected]]

On Monday, August 10, 2015 at 6:34:49 PM UTC-4, Craig Funston wrote:
> On Monday, August 10, 2015 at 3:03:03 PM UTC-7, bumper wrote:
> > On Monday, August 10, 2015 at 4:09:11 AM UTC-7, PBA wrote:
> > > So wait, were do I download the firmware update for the yaw string?
> >
> > Why that's proprietary, updates and calibration are done in a lead lined clean room at the factory - $15 includes return shipping. But for about the same sum you can have the very latest firmware along with all brand new hardware from most of the better on-line glider accessory suppliers.
> >
> > Or, you could drill a hole in the canopy . . .
> >
> > bumper
>
> Everyone needs to remember to use special bits when drilling through their plexi. http://www.eplastics.com/plexiglass_lexan_plastic_drill_bits
>
> Have fun!
> Craig

Any machinist knows you don't drill a square hole. It has to be broached.
Jeeeeez! What kind if misinformation are you guys trying to spread?
UH

[Papa3[_2_]]

https://www.youtube.com/watch?v=ALiqAXiTQBg

[Luke Szczepaniak]

On 08/10/2015 7:45 PM, Papa3 wrote:
> Laugh all you want. The square hole allows me to retract the Yaw String during high speed flight, resulting in significant drag reduction. I hear that the Mark V Yaw String includes "Speed Sense"TM Technology out of the box for this very purpose. At least, that's what I heard from a guy who knows a guys who....
>
> P3
>
I simply installed mine on the inside of the canopy, this offered the
best drag reduction possible. It also works as a rudimentary turn and
bank indicator - shh, don't tell the C/D or the R/C...

[pstrzel]

Has the problem with the yaw string not being coordinated with inputs been addressed? It doesn't stay coordinated with either rudder or aileron inputs. It only works when both are applied somewhat simultaneously. Not beginner friendly at all!

There should be something like a beginner or intermediate setting on every yaw string.

[David Hirst]

I fitted a turn-o-matic feature to my yaw string. It's water-activated. Just fly fast through rain and hey presto! All your turns for the next 5 minutes become perfectly co-ordinated.

Send no money now, folks!

[Charlie M. (UH & 002 owner/pilot)]

Sounds like mid winter "cabin fever" here..... but in August (in the northern hemisphere)......

Maybe some need to get a life, or a different job......

----- ;-)

[Picking, not slamming....]

[[email protected]]

A job? No time for such trivialities UH! Too busy scouring eBay for gliding paraphernalia. As I've found the turbulator effect of the Mk IV to be a little too effective in raising the string into the free stream airflow, I've decided a constant charge of static electricity on the canopy should get my wobble dampening a.k.a. string friction juuuuuust right. All I need now is a Van der graaf generator and a slightly taller canopy in which to fit it.

CJ

[Dan Marotta]

....Or simply apply epoxy liberally to the string. A few hours setup
time should provide for great indications of coordinated flight.

On 8/11/2015 11:30 PM, wrote:
> A job? No time for such trivialities UH! Too busy scouring eBay for gliding paraphernalia. As I've found the turbulator effect of the Mk IV to be a little too effective in raising the string into the free stream airflow, I've decided a constant charge of static electricity on the canopy should get my wobble dampening a.k.a. string friction juuuuuust right. All I need now is a Van der graaf generator and a slightly taller canopy in which to fit it.
>
> CJ

--
Dan Marotta

[Peter von Tresckow]

2KA > wrote:
> Or maybe an installation error. Perhaps taped at both ends?

Well Tony did install it backwards with the pointy but facing back.
Apparently Tony didn't RTFM ;-)

Peter