Landracing Forum
Tech Information => Aerodynamics => Topic started by: neandethal on April 05, 2022, 01:05:55 PM
-
Due to go to the panel shop soon to have the aluminium bodywork made for my motorcycle streamliner and an area still unresolved is the use of a tail fin.
From the 4 bikes I've seen on the salt they all have them of varying sizes. Now I think I know that they help with the equation of CoG vs CoP but wonder whether they add to stability or detract. Is the still air benefit worth it over the potential downside is the wind gusts up?
Words of wisdom and experience appreciated, previous posts seem more car related, cheers Ian.
-
If you use Facebook you might try finding Rocky Robinson and asking him. He posts pretty much daily, and he has some m/c 'liner experience. I'm pretty sure he can discuss the relative merits of fins, even though he's not the designer. Still, having run a 394 mile in the Ack Attack and piloted a few of the other fast 'liners and currently holds the FIM record - yeah, he might be a worthy resource for you. :-D
-
A vertical stabilizer is desirable on any streamliner but is only affective if it's in clean air. Liners are so often designed with a diverging curved shape behind the driver & this creates a cross feed low pressure turbulent wake. Expecting a positive result from a tail fin in this situation is going to be disappointing.
Location in relationship to the rear axle is also important for what you are trying to achieve & this will be more critical on a bike liner. On the axle line it will steer the back of the vehicle but the further behind the axle it is the more leverage it will have to steer the front end & that could get interesting if the back stepped out under power.
Sid.
-
Have messaged Rocky. Interesting points Sid, need to break out the ruler.
-
There is a reason why some liners tow a tiny drogue on a pass,