MKIV "high tech" yaw string (tech note)

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

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

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

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

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

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

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?

Global climate change, winter is here already.

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

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.