Naca Ducts

Wrinkly

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After purchasing and fitting an MRA screen to my 1150gsa all was well,bit more wind on my upper arms and shoulders but no buffeting.
When Jo was on the back,which is 60% of the time,it was a different story,as the bike lowered at the back it brought the line of the screen in a direct line with my line of vision,the screen was already on it's lowest setting so the only way i could see over the top was to tilt the screen fully toward me,so when it rained it was just like a constant steam onto my visor.
The constant readjustment of the screen was becomeing a right PITA so i decided to give the NACA vents ago on my old screen.
Here's what i found.

......Standard GSA Screen............MRA Vario............Naca Ducts GSA Screen.

40....mild wind noise................mild wind noise............mild wind noise
...no buffeting......................no buffeting..................no buffeting.

50....moderate wind...............mild wind noise..............mild wind noise
noise.mild......................no buffeting.................no buffeting
.buffeting

60...moderate wind...............moderate wind..............moderate wind noise
..noise.moderate................noise. no....................no buffeting
..buffeting.......................buffeting..................................................

70....moderate wind...............moderate wind................moderate wind noise
..noise.moderate...............noise.no........................no buffeting.no wind
...buffeting.......................buffeting.wind.................on shoulders
.................................. ....on shoulders

80....severe wind....................moderate wind...............severe wind noise.
...noise. severe..................noise.no.......................mild buffeting. no
....buffeting........................buffeting.moderate.........wind on shoulders.
........................................wind on shoulders.


90...severe wind.....................severe wind noise.............severe wind noise
.noise.severe.....................no buffeting....................mild buffeting.no
..buffeting.........................strong wind on................wind on shoulders
..........................................shoulders


Rider 5'9" seat 2" lower than standard GSA seat.
Helmet Shoei Multitec.

Both the standard screen and the "naca vent" screen gave much better protection from the rain than the MRA screen around the hands,upperarms and shoulders.

Do the "naca vents" work?

To a certain extent i think they do, they almost certainly reduce buffeting,though not quite as much as the MRA screen which appears to eliminate it,although the standard screen does offer better wet weather protection.

I will try to enlarge the vents slightly to see if this makes any difference,although not to much as i do not want to compromise the stength of the screen.

Watch this space.

Steve
 
Interesting, I was riding in heavy rain yesterday and it was strange to see just how much water was coming up the gap in my MRA and where it was flying to.

Stewart
 
Steve.

you may want to try a different helmet, the multi tec is sooo noisy, by changing to a shcuberth s1 the noise was easily halved, try a few different helmets and see how you get on.
also try it with a top box,youll find the aero-d will change again maybe for the better, maybe worse..atb Paul
 
who's brave then?

who fancies naca ducting up an mra screen then?
im just about to chop the std gs screen and duct it, off to the shed and out with the dremel.!!!
 
I understand the multitec is a noisy helmet.
All the testing was done with OE GSA topbox in place.
I have read reports that buffeting is less severe with a tank bag.
Not much point in ducting an MRA screen as it already follows the principle.

Steve
 
ah but does it.

Look at the position of the naca ducts, and look at the position of the big ole on the mra, the mra ole is in the middle of the screen, and the modded screen they are at the bottom.
im about to post up some pics.
 
naca ducts project

1st pic template stage
2nd picone hole done, getting there
3rd pic 2 holes done
next 3 pics shows the angles in involved
next 44 pics shows reverse of screen.
just got to test it now....screen courtesy of OGNI.
if anyone wants to try it later on pm me.
 

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piccys
 

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