Turbulence

guscar65

Member
Riding for 10 Years
Local time
Today, 12:04
Joined
Jun 15, 2019
Messages
63
Points
17
Age
70
Location
kirkcaldy fife scotland
First Name
angus
My Ride
blue/white T120 2018
Ok, I slightly am going out on a limb on this one. I am making comment on the basis that as a long time aeromodeller I do have some insight. Its a big problem for us , it can be so bad as to rattle our helmets -----in my case one time so much that I suffered a detached retina! (now healed). Our bikes are far from aero dynamically clean, we all know and accept this ------but when whatever setup you have causes noise that you just can't put up with ------what to do?. Now it irritates me that manufacturers just don't take enough care to provide screens (and mirrors even) that do not cause excessive turbulence and hence noise. Its not that they do not have the knowledge ---they often either favour form over function or just don't give the issue enough care. a good example would be the mirrors on bonnevilles T100/120 street twin etc. They ARE in the right place for ease of use, I just need to glance to either to look behind-----but they do show a lot more of your arms/shoulders than they should. Worse they are the worst possible shape for turbulence ------and boy do they ever! . So what do we do----bar ends? hmmm they take a deliberate look away from front view --- not ideal , but they do look good. What about the rectangular ones that Triumph are selling off cheap currently ----well i did buy a set ----unfortunately they were black and NOW they are selling the chrome ones ---bugger! anyway I fitted them , yes they cure the turbulence but they are still show too much 'arm' SO next move get extenders and try again. Now the long haul screen shouldn't really work due to its rounded off shape -----but you know what it does , to a degree , to make it quieter one possible cure is to use an aero as in MRA Xscreens ------don't maybe look so good but have used one before on an America of all things ----and it was really effective. So these are my next moves Let you know how it goes.
 

triumph david

Riding for 61 Years
Staff
Local time
Today, 06:04
Joined
Nov 25, 2013
Messages
5,945
Points
390
Age
73
Location
brookhaven
First Name
david
My Ride
1976 t140 Triumph, 2006 Road King, 1982 Honda CB 900 C, 1973 Yamaha 360 Enduro, 1972 Corbin
I have been bothered with this on just about every bike i have ever had, i an not sure there is a cure.
 

nickjaxe

Member
Riding for 5 Years
Local time
Today, 12:04
Joined
Dec 30, 2020
Messages
25
Points
7
Age
68
Location
England.
First Name
Nick
My Ride
2020 T100 Bonnie.
I bought my 2020 bonnie knowing I was going to get buffeted by the airstream....I am a pilot so like you understand airflows and drag.....

Saying that the Bonnie in std setup inc mirrors is how I want my bike to be....I hanker after 60s bikes.....

So I tailor my riding speed to suit.....60mph is my max comfy speed....55mph is better....I wear an open face helmet and that lets me know when I am going fast enought....wind on my face ect.....with a tail wind I can comfortably go a bit faster.....headwind bit slower.

I bought a naked bike knowing all this and accept it as part of owning a Retro Classic Style of Bike.....the only bike I would ever contemplate owning.

I could never contemplate bar end mirrors.....so out of place....and IMHO....unsafe.
 

guscar65

Member
Riding for 10 Years
Local time
Today, 12:04
Joined
Jun 15, 2019
Messages
63
Points
17
Age
70
Location
kirkcaldy fife scotland
First Name
angus
My Ride
blue/white T120 2018
I have been bothered with this on just about every bike i have ever had, i an not sure there is a cure.
Well in a way you are right, it goes along with bikes in general---BUT you can make a big difference to your setup, don't just give in . So if you read all the reviews (I am so sad) you will see that even bikes designed as long distance tour/adventure can suffer, but not them all so its not just a given. For example the old model Tiger sport has a dreadful reputation----the new one is good. Thats why there is such a healthy market for aftermarket screens!. Manufacturers have nowhere to hide on this ---as there has been plenty research and knowledge is available .
So, somethings that I believe happen.
IF your mount is a naked then it is likely that any turbulence is coming from your helmet alone ---there are good and bad helmets for noise.----choose carefully.
So you want or actually have a screen----what then.
Basically a screen is a flat-plate wing section which is set at a high angle of attack working at different airspeeds., as such it is difficult to have one which works at all speeds and rider heights/distance from screen. BUT hey, thats what adjustments are for , and some clever design can mitigate greatly.
The problem is caused when high pressure air hitting the screen meets low pressure air behind the screen at the edges. You will note some screens have a 'letterbox' opening to alleviate this -----but its not the cure. The real way around is to raise the whole screen some 10mm or so above the fairing to allow free flow under and around . Now if you have a screen on a cruiser etc. the problem is mostly that the shape of the screen is made to look good ----but rounded screens just make it worse as the air spills off in all directions so you get lots of small vortexs ,hence noise. You can see on some modern bikes that the screens are 'fan shaped' or have a 'channel ' up the centre -----both methods are there to guide the air in a controlled duct to keep it smooth at the centre where the rider is----so the fast smooth air just comes off the screen at one place ---that place can then be slightly 'kicked' or have an aerofoil to make the vortexes form behind or above the rider. Of course one really good way of controlling the vortex is by reducing the angle of attack (tipping the screen back, very evident if you see a side on view of an old BMW R100LT) So the air slips quickly past and the vortexs dont form until the air is past the rider. In the opposite case on real adventure bikes you can see that the fairing is almost vertical !! that I guess is to make room for the road book ---but I suppose it works because of lower speeds and the fact that the rider stands a lot of the time---in any case the vortexs will form almost directly behind the screen.
So there is a lot you can do to personalise a bike to best meet YOUR comfort ----I tried three differnet screens on my Versys before settling on an MRA X ----which then worked well . I used an MRA on my CBF 1000 and had to also raise it it make it quiet at most speeds .
I have been bothered with this on just about every bike i have ever had, i an not sure there is a cure.
 

nickjaxe

Member
Riding for 5 Years
Local time
Today, 12:04
Joined
Dec 30, 2020
Messages
25
Points
7
Age
68
Location
England.
First Name
Nick
My Ride
2020 T100 Bonnie.
Well in a way you are right, it goes along with bikes in general---BUT you can make a big difference to your setup, don't just give in . So if you read all the reviews (I am so sad) you will see that even bikes designed as long distance tour/adventure can suffer, but not them all so its not just a given. For example the old model Tiger sport has a dreadful reputation----the new one is good. Thats why there is such a healthy market for aftermarket screens!. Manufacturers have nowhere to hide on this ---as there has been plenty research and knowledge is available .
So, somethings that I believe happen.
IF your mount is a naked then it is likely that any turbulence is coming from your helmet alone ---there are good and bad helmets for noise.----choose carefully.
So you want or actually have a screen----what then.
Basically a screen is a flat-plate wing section which is set at a high angle of attack working at different airspeeds., as such it is difficult to have one which works at all speeds and rider heights/distance from screen. BUT hey, thats what adjustments are for , and some clever design can mitigate greatly.
The problem is caused when high pressure air hitting the screen meets low pressure air behind the screen at the edges. You will note some screens have a 'letterbox' opening to alleviate this -----but its not the cure. The real way around is to raise the whole screen some 10mm or so above the fairing to allow free flow under and around . Now if you have a screen on a cruiser etc. the problem is mostly that the shape of the screen is made to look good ----but rounded screens just make it worse as the air spills off in all directions so you get lots of small vortexs ,hence noise. You can see on some modern bikes that the screens are 'fan shaped' or have a 'channel ' up the centre -----both methods are there to guide the air in a controlled duct to keep it smooth at the centre where the rider is----so the fast smooth air just comes off the screen at one place ---that place can then be slightly 'kicked' or have an aerofoil to make the vortexes form behind or above the rider. Of course one really good way of controlling the vortex is by reducing the angle of attack (tipping the screen back, very evident if you see a side on view of an old BMW R100LT) So the air slips quickly past and the vortexs dont form until the air is past the rider. In the opposite case on real adventure bikes you can see that the fairing is almost vertical !! that I guess is to make room for the road book ---but I suppose it works because of lower speeds and the fact that the rider stands a lot of the time---in any case the vortexs will form almost directly behind the screen.
So there is a lot you can do to personalise a bike to best meet YOUR comfort ----I tried three differnet screens on my Versys before settling on an MRA X ----which then worked well . I used an MRA on my CBF 1000 and had to also raise it it make it quiet at most speeds .
I have been bothered with this on just about every bike i have ever had, i an not sure there is a cure.
The thought of a windscreen on my stunning T100 horrifies me.

Do you ride very fast Gus.
 

guscar65

Member
Riding for 10 Years
Local time
Today, 12:04
Joined
Jun 15, 2019
Messages
63
Points
17
Age
70
Location
kirkcaldy fife scotland
First Name
angus
My Ride
blue/white T120 2018
I bought my 2020 bonnie knowing I was going to get buffeted by the airstream....I am a pilot so like you understand airflows and drag.....

Saying that the Bonnie in std setup inc mirrors is how I want my bike to be....I hanker after 60s bikes.....

So I tailor my riding speed to suit.....60mph is my max comfy speed....55mph is better....I wear an open face helmet and that lets me know when I am going fast enought....wind on my face ect.....with a tail wind I can comfortably go a bit faster.....headwind bit slower.

I bought a naked bike knowing all this and accept it as part of owning a Retro Classic Style of Bike.....the only bike I would ever contemplate owning.

I could never contemplate bar end mirrors.....so out of place....and IMHO....unsafe.
Yes totally agree with you----the T120 screen is really good at 55 ----I have a flip-back and use it open face when in town and just mooching about----however , and it ain't very pretty when out with the boys on a day tideout ---i fit the clamp-on MRA X which really helps at 60 ish.
 

guscar65

Member
Riding for 10 Years
Local time
Today, 12:04
Joined
Jun 15, 2019
Messages
63
Points
17
Age
70
Location
kirkcaldy fife scotland
First Name
angus
My Ride
blue/white T120 2018
The thought of a windscreen on my stunning T100 horrifies me.

Do you ride very fast Gus.
Thing is that my bike needs to meet two situations -----When my wife is fit enough we enjoy the T120 together ----its perfect, and so we never above 50. Which is why I bought it -----a better option than the America I traded .However when out with the boys , although we are not hammering around ----we try to keep 'making progress' so that's keeping on the speed limit ----ish (60) and sweeping the corners as smoothly as possible --its great .but a bit quicker than the bike design was really aimed at . It really handles well if a requiring a bit of effort in the turn. It also has acceleration that you would not expect when required (passing motorhomes lorries etc) . I also lowered the overall gearing by 5% which makes it a tad quicker and easier to ride slowly -----it also returns 66mpg day after day! i should really have two bikes and was considering a street triple as a second bike but will need to see how the money goes!. When I had the America I also had an ageing CBF1000 to do the boys thing. ---that had to go though so currently on one bike.
 

nickjaxe

Member
Riding for 5 Years
Local time
Today, 12:04
Joined
Dec 30, 2020
Messages
25
Points
7
Age
68
Location
England.
First Name
Nick
My Ride
2020 T100 Bonnie.
Thing is that my bike needs to meet two situations -----When my wife is fit enough we enjoy the T120 together ----its perfect, and so we never above 50. Which is why I bought it -----a better option than the America I traded .However when out with the boys , although we are not hammering around ----we try to keep 'making progress' so that's keeping on the speed limit ----ish (60) and sweeping the corners as smoothly as possible --its great .but a bit quicker than the bike design was really aimed at . It really handles well if a requiring a bit of effort in the turn. It also has acceleration that you would not expect when required (passing motorhomes lorries etc) . I also lowered the overall gearing by 5% which makes it a tad quicker and easier to ride slowly -----it also returns 66mpg day after day! i should really have two bikes and was considering a street triple as a second bike but will need to see how the money goes!. When I had the America I also had an ageing CBF1000 to do the boys thing. ---that had to go though so currently on one bike.
I like the wind in my face.....reminds me of my open cockpit aeroplane.

Happy never to go faster than 60....so my open face and its buffeting if I go faster keeps me grounded.

I 99% of the time ride solo....so I dont have the added pressure of keeping up with the boys.
 

guscar65

Member
Riding for 10 Years
Local time
Today, 12:04
Joined
Jun 15, 2019
Messages
63
Points
17
Age
70
Location
kirkcaldy fife scotland
First Name
angus
My Ride
blue/white T120 2018
I like the wind in my face.....reminds me of my open cockpit aeroplane.

Happy never to go faster than 60....so my open face and its buffeting if I go faster keeps me grounded.

I 99% of the time ride solo....so I dont have the added pressure of keeping up with the boys.
I guess we all have slightly differing things we want from our bikes-----wind in the face is fine , I can see the attraction but not for a whole day. Yep , I would like to have flown -----its damn expensive in UK , a few of my buds from the aeroclub have licences for gliders , powered micro-lights but they admit its very, very expensive a few have PPLs and we even have a few RAF pilots too. At least if I make a big mistake with my model ----its just a plastic bin bag! . When I say 'boys' ----we are all over 70. , its more mutual encouragement than competition , we are careful but the company is great and it does encourage you to ride well, forget to cancel a turn signal , and someone will give you the 'crocodile fingers' so reminds you to concentrate.---keep in the moment .
 
Premium

Support TriumphTalk by becoming a Premium Member.

 What You Get

Donate

 

 

Search

Top Bottom