Lou Wambsganss
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For reference, I'm about 6'2" to 6'3", depending on what time of day it is. I have an Arai Signet-Q helmet (full face), which is pretty quiet compared to most helmets, but I still had a problem with the volume of wind noise I was getting with the stock windshield.
First, I tried some mods to my helmet. I found that most of my observed noise was coming from my helmet's visor hinge cover plates. I taped around the perimeter with Scotch Tape, but the leading edge where the visor needs to be able to move up and down cannot be taped, and that is the source of most of the noise. I added some 0.060" sound dampening sheet to the interior of my helmet shell around the ear areas. All of my helmet mods put together made only a minor difference. I needed to do something about the air hitting my helmet.
I started looking into taller windshields. There are many options in this field, and many previous threads about them. I'm trying to keep this thread specific to tall riders, since that is my experience.
One of the popular tall screen makers is Cal Sci (California Scientific). Honda NC700X NC700S Windshields Of all the websites I've seen, theirs looks like an old Web 1.0 high schooler's homepage, but it has a wealth of technical information. They are the only manufacturer who provides a detailed procedure to find the correct height of screen for any rider. Motorcycle Fairings and Windshields. I noticed that most of their shields include a NACA style duct in the lower portion. Their explanation is that this helps to fill in the low pressure area behind the shield, which prevents the lower pressure from pulling in the higher pressure air that travels over the top of the shield and creating turbulence (Von Karman vortices). Motorcycle Fairings and Windshields.
I probably would have gotten a Cal Sci, but I found a good deal on the Honda Tall Screen, so I bought it (thanks, hmcp88!). In addition, it also had a Clear MRX X-Creen already attached. X-creen - MRA ? Motorcycle Windshields. Overall, I was happy with the Honda Tall Screen, but there was still some room for improvement. I decided to try to mod the Honda Screen with an opening like the Cal Sci shields have to cut down on upper lip turbulence. Rather than trying to make an aerodynamically correct NACA duct, I just drilled holes. It's quick, easy, and free. I drilled three holes, using the Honda logo as a reference point for my straight line. I started each hole at #21 (5/32") and stepped them up to 3/4" using a step drill. It seemed to cut best at around 3000-3500 rpm and low pressure. I am very happy with the hole quality. No chips or burrs. It looks like the shield was made that way.
These three holes have been the single most effective noise reduction step that I have taken. The air coming in the holes seems insignificant. You can only feel it if you put your hand right up to the instrument panel. It disperses into the low pressure area behind the shield quickly, as intended.
I might even enlarge them a little bit more to increase the effect. Maybe take them up to 1". Even if these holes might not move quite as much air as a NACA duct, I see them as more structurally stable for the shield overall. If you have one large cutout in the middle of the shield, the remaining side material must carry all of the aero load placed on the shield, and must handle the fatigue of the constant vibration while riding. With the three smaller holes, there is still structure between the holes to help carry the load and avoid stress concentration points at the corners of the duct cutout.
I usually leave the X-Creen down in the stowed position (as low as possible and as close to the Honda Shield as possible) for in-town riding, which is most of my riding (commuting to work). However, for interstate riding, this caused some low-frequency buffeting. At high speeds, I have found that if I put the X-Creen all the way up, as close to the shield as can be permitted by the hinges, and angled slightly back (not parallel to the shield) this effectively reduces the angle of attack of the trailing edge (upper edge) of the shield, thus reducing the tendency of the Von Karmon vortices to form. As noted earlier, the duct holes also reduce the vortices. The end result is that I can now cruise at interstate speeds with MUCH reduced wind noise. The air hits my helmet at the forehead level and is smooth. I can still hear the wind, but it is like a faucet now, instead of a firehose like before.
I will also add, just FYI, that I have my Honda Tall Screen bracket installed in the lower of the hole sets on the original fitting. I could even switch to the higher hole sets and get even more wind protection if required. If I'm going to go on a planned long trip, I will probably do that. Otherwise, for my normal riding, this current setup is completely satisfactory to me.
First, I tried some mods to my helmet. I found that most of my observed noise was coming from my helmet's visor hinge cover plates. I taped around the perimeter with Scotch Tape, but the leading edge where the visor needs to be able to move up and down cannot be taped, and that is the source of most of the noise. I added some 0.060" sound dampening sheet to the interior of my helmet shell around the ear areas. All of my helmet mods put together made only a minor difference. I needed to do something about the air hitting my helmet.
I started looking into taller windshields. There are many options in this field, and many previous threads about them. I'm trying to keep this thread specific to tall riders, since that is my experience.
One of the popular tall screen makers is Cal Sci (California Scientific). Honda NC700X NC700S Windshields Of all the websites I've seen, theirs looks like an old Web 1.0 high schooler's homepage, but it has a wealth of technical information. They are the only manufacturer who provides a detailed procedure to find the correct height of screen for any rider. Motorcycle Fairings and Windshields. I noticed that most of their shields include a NACA style duct in the lower portion. Their explanation is that this helps to fill in the low pressure area behind the shield, which prevents the lower pressure from pulling in the higher pressure air that travels over the top of the shield and creating turbulence (Von Karman vortices). Motorcycle Fairings and Windshields.
I probably would have gotten a Cal Sci, but I found a good deal on the Honda Tall Screen, so I bought it (thanks, hmcp88!). In addition, it also had a Clear MRX X-Creen already attached. X-creen - MRA ? Motorcycle Windshields. Overall, I was happy with the Honda Tall Screen, but there was still some room for improvement. I decided to try to mod the Honda Screen with an opening like the Cal Sci shields have to cut down on upper lip turbulence. Rather than trying to make an aerodynamically correct NACA duct, I just drilled holes. It's quick, easy, and free. I drilled three holes, using the Honda logo as a reference point for my straight line. I started each hole at #21 (5/32") and stepped them up to 3/4" using a step drill. It seemed to cut best at around 3000-3500 rpm and low pressure. I am very happy with the hole quality. No chips or burrs. It looks like the shield was made that way.
These three holes have been the single most effective noise reduction step that I have taken. The air coming in the holes seems insignificant. You can only feel it if you put your hand right up to the instrument panel. It disperses into the low pressure area behind the shield quickly, as intended.
I might even enlarge them a little bit more to increase the effect. Maybe take them up to 1". Even if these holes might not move quite as much air as a NACA duct, I see them as more structurally stable for the shield overall. If you have one large cutout in the middle of the shield, the remaining side material must carry all of the aero load placed on the shield, and must handle the fatigue of the constant vibration while riding. With the three smaller holes, there is still structure between the holes to help carry the load and avoid stress concentration points at the corners of the duct cutout.
I usually leave the X-Creen down in the stowed position (as low as possible and as close to the Honda Shield as possible) for in-town riding, which is most of my riding (commuting to work). However, for interstate riding, this caused some low-frequency buffeting. At high speeds, I have found that if I put the X-Creen all the way up, as close to the shield as can be permitted by the hinges, and angled slightly back (not parallel to the shield) this effectively reduces the angle of attack of the trailing edge (upper edge) of the shield, thus reducing the tendency of the Von Karmon vortices to form. As noted earlier, the duct holes also reduce the vortices. The end result is that I can now cruise at interstate speeds with MUCH reduced wind noise. The air hits my helmet at the forehead level and is smooth. I can still hear the wind, but it is like a faucet now, instead of a firehose like before.
I will also add, just FYI, that I have my Honda Tall Screen bracket installed in the lower of the hole sets on the original fitting. I could even switch to the higher hole sets and get even more wind protection if required. If I'm going to go on a planned long trip, I will probably do that. Otherwise, for my normal riding, this current setup is completely satisfactory to me.
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