Rifle w/ 18" screen buffeting! HELP!
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Cruiser
Joined: Dec 2014
Posts: 108
Likes: 4
From: Vancouver, BC
Thanks for the diagram. "Tries to rip your head off" does sound about right. They look like wings or something though. Not a fan.
This may seem like a stupid question but before I try the fork baffle...I never had any issues when I didn't have a fairing at all so wouldn't the problem have to be the screen angle / height rather than something below? Wouldn't I have had the same problem without the fairing if it was coming from below? Or is it just the way the air flows with and without a fairing / windshield?
This may seem like a stupid question but before I try the fork baffle...I never had any issues when I didn't have a fairing at all so wouldn't the problem have to be the screen angle / height rather than something below? Wouldn't I have had the same problem without the fairing if it was coming from below? Or is it just the way the air flows with and without a fairing / windshield?
Advanced
Joined: Jul 2014
Posts: 67
Likes: 1
From: Finland
I am by no means an aerodynamics expert and I was also really sceptical by this theory of air coming from the underneath myself, but after some thinking it started to make sense.
The fairing will mess up the airflow, which would otherwise hit you cleanly in the body. Without the fairing the turbulence is still behind you but you will not notice it. The fairing brings the turbulence in front of your body.
The fairing also creates a vacuum immediately behind the fairing, which sucks the air upwards underneath the fairing and brings it up to your helmet area. If you look at the pic it makes sense.
Now looking at your setup the fairing seems to be quite high. If you look at your tank behind the fairing it seems to form a spoiler, which would even intensify the airflow upwards effect. Your sigpic is small, so I cannot be sure. However after I shifted my fairing down and added the tanklift you can see that the tank is now pretty much tucked behind the fairing.
Now I still have the vacuum behind the fairing, which sucks air upwards, and as said earlier, to get completely rid of the upward airflow around the helmet, the lowers would be good. However, I am already quite happy with my setup as it is now.
Hope this helps.
The fairing will mess up the airflow, which would otherwise hit you cleanly in the body. Without the fairing the turbulence is still behind you but you will not notice it. The fairing brings the turbulence in front of your body.
The fairing also creates a vacuum immediately behind the fairing, which sucks the air upwards underneath the fairing and brings it up to your helmet area. If you look at the pic it makes sense.
Now looking at your setup the fairing seems to be quite high. If you look at your tank behind the fairing it seems to form a spoiler, which would even intensify the airflow upwards effect. Your sigpic is small, so I cannot be sure. However after I shifted my fairing down and added the tanklift you can see that the tank is now pretty much tucked behind the fairing.
Now I still have the vacuum behind the fairing, which sucks air upwards, and as said earlier, to get completely rid of the upward airflow around the helmet, the lowers would be good. However, I am already quite happy with my setup as it is now.
Hope this helps.
Cruiser
Joined: Apr 2015
Posts: 186
Likes: 14
From: Lost Wages, NV
I am no aerodynamics expert either but I do work on aircraft and have a pretty good handle on aerodynamics as a whole. in my feeble mind, the buffeting issue does in fact come from below the fairing. As you ride, the fairing creates a low pressure area directly behind the fairing and directly in front of you. That low pressure cannot be avoided, it is actually what you are trying to achive by riding with a fairing. The problem then becomes that the low pressure air is trying to equalize itself with the surrounding air. The air cannot come from the sides or above, it is pushed to far away by the shape of the fairing and it has to come from somewhere so it comes from below the fairing. The problem is compounded by your seating position. With your legs either down or out in front of you, you in essence create a ramp leading to your head for that air to travel. The only real solution is to either lessen the effect or deflect the lower air and move where the low pressure bubble is. Raising the tank as suggested lessens the effect because it takes up some of that bubble. Lowering the fairing forces the air down a little more causing the bubble to move. Ideally, we want the bubble of low pressure to be behind us and the only sure fire way to make that happen is to force the lower air just as far as we force the upper air which is where fork deflectors come into play. If you don't like the looks of fork deflectors, try moving your fairing down and you may find a point where the buffeting is allowable to you.
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Cruiser
Joined: Dec 2014
Posts: 108
Likes: 4
From: Vancouver, BC
Thanks for explaining that. If I understand correctly, cutting down the screen won't make a heck of a lot of difference if the wind is coming from below? In that case, my time would be better spent trying to get the fairing to sit lower and/or working on the baffle?
Thanks again!
Thanks again!
Road Master
Joined: Oct 2014
Posts: 864
Likes: 56
From: U.s.
In one of the longer rifle threads people describe exactly what you're describing. The solution for them was to mount a baffle/wind deflector made for touring models under the headlight. I think one person even used an old license plate he cut up to fit. I'll post some links tomorrow when I get home from work with the info if you like.
Thread Starter
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Cruiser
Joined: Dec 2014
Posts: 108
Likes: 4
From: Vancouver, BC
In one of the longer rifle threads people describe exactly what you're describing. The solution for them was to mount a baffle/wind deflector made for touring models under the headlight. I think one person even used an old license plate he cut up to fit. I'll post some links tomorrow when I get home from work with the info if you like.
Cheers!
Road Master
Joined: Oct 2014
Posts: 864
Likes: 56
From: U.s.
Check around the 3rd page of the thread titled "To the Rifle Fairing guys" I think.
Cruiser
Joined: Apr 2015
Posts: 186
Likes: 14
From: Lost Wages, NV
Thanks for explaining that. If I understand correctly, cutting down the screen won't make a heck of a lot of difference if the wind is coming from below? In that case, my time would be better spent trying to get the fairing to sit lower and/or working on the baffle?
Thanks again!
Thanks again!
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In hindsight, I did change bars from 17" apes to 12" T bars and go from forward to mid controls as well. I'm sure seating/leg position has a good deal to do with it as well.
Last edited by jpace024; Jun 6, 2015 at 10:28 AM.
Outstanding HDF Member
Joined: May 2014
Posts: 3,410
Likes: 143
From: Palm Desert,CA
On the deflector below the headlight idea, another person used a cut up pie plate and painted it to match his lower tree. It was pretty neat.
Here's a link to some pics of it:
https://www.hdforums.com/forum/dyna-...dshield-2.html
Here's a link to some pics of it:
https://www.hdforums.com/forum/dyna-...dshield-2.html
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