[WeeVgone]

Been reading the messages regarding windshield turbulence and installed a Laminar lip. I also added a tank bag. I have K7 650 but imagine this applies to 1000's also.

Test ride after mods was interesting. Windshield turbulence gone but then encountered MORE turbulence coming up under my chin and couldn't figure out where it was coming from. Turns out it is the air hugging the tank fairing, running above my legs, up my front between me and the tank bag which acts as a venturi! Enough to jostle head around!

I think this didn't show up before because without the tank bag and Laminar lip, the air was coming around tank fairing and being pulled foward by vacuum behind windshield instead of hitting me.

I could almost negate all turbulence by raising my legs upward; pushing up on footpegs with balls of my feet. I can also stop it by leaning forward until contacting tank bag which effectively blocks air. So, now I'm going to design some type of "wind wing" mounted to fairing to break up air stream coming around tank.

I'm 5'10" with 30" inseam. I imagine that taller rider's legs may already be blocking this mind-numbing turbulence. Just FYI.

 

[Heavy]

I'm 5'10" with a 30" inseam too. I have been running a cut-down stock shield and the wind is no issue. I recently put on a Givi shield for a long trip and found the same upward airflow over my thighs. At one point, I actually had rain running up the face shield of my helmet, inside and out. Put your left arm horizontally across your chest and it becomes still and silent. I'm interested in what you come up with as a fix.

 

[zed88]

Keep us informed. Post pictures

 

[WeeVgone]

Out of pocket for a couple of weeks

but I will be working on this problem when I return and will post any findings/solutions.

 

[allonsye]

i've noticed the exact same thing as weeVgone.

the solution i think is some sort of vortex generator.

here's an explanation to you non-aeronautical types:
http://www.aerospaceweb.org/question/aerodynamics/q0009.shtml
http://www.aerospaceweb.org/question/aerodynamics/q0255.shtml

granted the v-strom is not an aircraft but i suspect the principals of air-flow apply here. seemingly, the design of the fairing/windshield starts to direct air but fails to direct it smoothly around the bike and rider.

one idea i had was fabricating something like these mini-vortex generators as illustrated on this website:

http://www.microaero.com/ImageGallery/pages/Cessna_A185F_.html

and placing them on the tank fairing.

a working solution would not only quiet things down on the V-strom but probably help fuel economy.

 

[Tom-S]

I have noticed the same upward direction of the windblast. I thought this was rather strange since I have demoed many bikes with various sized fairings and have owned a Nighthawk-S with a full fairing for years and the direction of the wind was always down over my helmet and my chest. So I'm wondering, could these vortex generators help and where would they be placed??

 

[Big B]

Hmmm...I haven't noticed anything unusual, about wind flow. Maybe I am just built weird, or the Givi just really works for me!

 

[kamloopsal]

After installing the Laminar Touring Lip in '05 I've had zero wind problems.
(Except after a bowl of chilli on a long ride )

Al

 

[allonsye]

OK you guys w/no turbulence issues [i find this facinating].

we're not talking issues with the windscreen. it's seems those w/issues have found solutions w/laminar lip, new windscreen, or new mounts or it just dosen't bother them.

we're talking issues w/the fairing here guys - air flow coming up from under the bike!!!

how about a simple 'lil test?

the next time you're riding at least 60mph, hold up your left hand and see if you feel air flow coming up in front you between your knee and the handle bars. pass you hand to your left below your helmet - any harsh air flow there? notice any changes in air flow as you pass your hand directly in front of you, to your left and below chin level?

i can literally rest my L/hand on what feels like a ducted flow of air that comes between my knee and the gas tank at 70mph indicated.

this is where i'm hearing/feeling windnoise/turbulence under my helmet (not around or atop). when i block this flow with my arm, things become much quieter.

my configuration:

hepco crash bars, explorer tank bag, emgo mirrors, OEM knuckle guards, mad-stat w/s mount, laminar touring lip, flush mount turn signals & forks lowered 1/2".

i'm still toying the w/idea of [inconspicuous] vortex generators and hope to do some experiments this week which i'll report on.

 

[allonsye]

I THINK I'M ON TO SOMETHING!

this afternoon i decided to play around with aerodynamics on the strom fairing.

WeeVgone, i think you'll pleased to hear that i'm on to something and that my thinking that the air-flow is getting all messed up after it goes past the fairing is correct.

so, i tried blocking the air coming between the crash bars and the fairing on the left side:

then on the right fairing, i placed a couple of vortex generators i cobbled together with cardboard and alum. tape:

a test ride showed no change on the L/H side. however, i noticed a SIGNIFICANT change on the R/H side. no longer the ducted flow coming up and striking me in the shoulder. feeling about for the air-flows with both hands it was clear that the vortex generators actually work - in this case, helping to direct the air evenly around the bike - the air was (no pun intended) clearly less turbulent on the R/H side where my experimental devices were installed - flowing more smoothly than the L/H side w/out the devices.

i'm going to try to source these devices from aircraft supply hopefully in plastic and in red to match my fairing. i've also thought of making them of aluminum stock or plexiglass. the trick with the clear plexi will be afixing them to the fairing.

I think i'd like to have the vortex generators smaller and more numerous - say 3 or 4 per side. they might look sort of weird but for the difference in improved riding comfort i felt well worth it.

 

[Tom-S]

Yes, that's it. The air blast comes around the back edge of the fairing, then upward, channeled by the fairing, the gas tank, and my thigh. The blast continues up over the torso and for the most part goes over the shoulders and to the rear. Depending on speed, the air at face shield level, may go up, down, or stay relatively still.

 

[allonsye]

Yes, that's it. The air blast comes around the back edge of the fairing, then upward, channeled by the fairing, the gas tank, and my thigh. The blast continues up over the torso and for the most part goes over the shoulders and to the rear. Depending on speed, the air at face shield level, may go up, down, or stay relatively still.

right you are tom!

my 'lil cardboard thingies actually caused the air to sweep past my shoulder.

perhaps the attention being paid to the windscreen to reduce turbulence noise is just a band-aid - DOES IT REALLY ADDRESS THE ISSUE of getting the air to flow completely around the bike and the rider :?:

until proven otherwise, i believe the holy grail lies in correct placement of VG's on the fairings to help control the huge amount of air that moves over them. :wink:

anyone out there have access to a windtunnel! :roll:

 

[Big B]

You are on a motorcycle....you realize that...right? :wink: I can't seem to grasp what you are complaining about, am I missing something?
I simply got some buffeting with the stock screen, it is all but gone with my new Givi screen. I notice no turbulent air swirling around me, unless I am farting! :lol:

Seriously....hope you get your little issue fixed, sounds like you are onto something!

 

[water warrior]

Allonsye, looks like you are on to something. Keep experimenting and you will have eternal gratitude from many riders.

 

[RockyMtnRoadRash]

I'm listening. I don't need a giant bubble of still air, but I sure could do with less turbulence.

 

[Colin]

After riding to work in -2 Celsius temperatures this AM I can tell you the idea of routing that chilly blast off my thighs would be very welcome.:!: I hope we can discover something not quite so, so...Red Green looking.

ps. for those who do not get Canadian TV or the Red Green Show, Red Green is a home handy man character who uses duct tape to great advantage.

 

[RockyMtnRoadRash]

Remember, if the ladies don't find ya handsome, they can at least find ya handy.

 

[greywolf]

I consider myself useful as well as decorative.

 

[kamloopsal]

OK, I tried the 'hand waving thing'.
Sure enough there is a rush of upward air to about knee height - but it stops there. I have still air from the top of my helmet to my testicles .
A recent ride in rain confirms this, wet knees but dry crotch.
This is interesting, but not a problem. If it was, I'd consider wearing a Kevlar kilt .

Al

 

[allonsye]

*ROTFLOL*!!!! i miss the red green show and thought it amazing what he'd do w/the duct tape.

i'll take this as a compliment.