BMW K bikes (Bricks)


You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


jkh

avatar
active member
active member
On Berndt, my '92 K75RT i have a lot of buffeting around the top of my helmet at speeds above 80 km/h. At higher speeds the buffeting can be so severe that it blurres my sight.
So i tried to make a small airfoil to lift oncomming air just 5 cm higher. I used a piece of 4mm acrylic for the prototype airfoil.

I heatet it for 15 minutes in the oven at 170 centigrades - took it out and pressed it down on my premade form til it cooled off. My choosen form was a small invertet wing profile.


My theory is that the inverted wing profile will make the air betqween the airfoil and the windscreen go faster than the air in front of the airfoil. The result is the the air stream between the aitfoil and the windscreen pushes the oncomming air higher up and over my helmet.

For the trial run i cut four small pieces of 4mm acryl as 2 x 8mm standoffs and taped it al to my windscreen. The top of the foil flush with the top of the windscreen.

I went for a ride to test. At speeds lower than 80 km/h there is no difference to detect. But then there was previous no buffetting at this speed so that’s ok. At speeds higher than 80 km/h the buffeting has gone away. I tried speeds up to 140 km/h and there was no buffeting.

Next I will remove the remaining protective foil from the acryl and make a permanent mount.


Highly recomended.




Last edited by jkh on Fri May 06, 2016 2:02 pm; edited 2 times in total


__________________________________________________
'93 K75RT - Previous bikes: '53 AJS matchless, a lot of 70'ties honda sohc/4's and some MZ's
    

k-rider

avatar
Life time member
Life time member
Nice work 

K-rider


nino


Life time member
Life time member
You are right. Airfoil kills buffeting and wind noise. I think you have to mount it no less than 4 centimeters from screen. I have MRA adjustable and for me it is definite solution of wind issue. Here is a link http://www.k100-forum.com/t3793-wind-solution

    

jkh

avatar
active member
active member
@nino wrote:You are right. Airfoil kills buffeting and wind noise. I think you have to mount it no less than 4 centimeters from screen. I have MRA adjustable and for me it is definite solution of wind issue. Here is a link http://www.k100-forum.com/t3793-wind-solution
Hi Nino.
Thanks for the link.
My foil was mountet - actual taped to the windscreen - so there was a 8mm gap (2 x 4 mm acryl in each side) between the airfoil and the windscreen. It seemed to work quite well as the buffeting went avay.


__________________________________________________
'93 K75RT - Previous bikes: '53 AJS matchless, a lot of 70'ties honda sohc/4's and some MZ's
    

Kyle10

avatar
Life time member
Life time member


__________________________________________________
1985 K100rt 0052183
1983 Honda VF750 007713 
    

nino


Life time member
Life time member

    

Sponsored content


    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum