Frontal Area vs Frontal Curve Smoothness

[Frank Lee]

Originally Posted by winkosmosis

A bike with a faired front end is going to be better than one without. Just because you're preoccupied with the idea of rear end aerodynamics being the most important doesn't mean that the front doesn't matter. Like I said, think of it as a kamm back

A faired bike is NOT necessarily more aero! I have a Cycle World article with wind tunnel test data from several styles of bikes. What do you have?

AND it's NOT comparable to a Kamm back. Think about what makes a Kamm back a Kamm back and get back to us.

[Otto]

Front and back are both important.

I won't venture to say what the relative proportions are, but a brief perusal of Hoerner's Fluid Dynamic Drag compilation of aero studies makes me think the front is more critical.

Then, there's always the bugbear of what to do with the rider's feet at a stoplight, etc..

[winkosmosis]

Originally Posted by Frank Lee

A faired bike is NOT necessarily more aero! I have a Cycle World article with wind tunnel test data from several styles of bikes. What do you have?

AND it's NOT comparable to a Kamm back. Think about what makes a Kamm back a Kamm back and get back to us.

I have pictures of those old salt flat bikes with front fairings. Of course a bike can be low-drag enough in the front that adding a fairing and increasing frontal area increases drag. But what does that have to do with what you said about the big problems being at the rear?

What makes a kamm back a kamm back is the rearward decrease in cross section that is truncated... Just like some front end fairings.
My point is that a kamm backed vehicle doesn't have a boat tail like your "teardrops" but a void space in the back, and an aerodynamic front because front end aero matters.


Should this bike do away with the front fairing? Notice the tapered flanks BTW

[Frank Lee]

Now THAT's a fairing!

Is this the kind of fairing ANYONE puts on anything on the street? Was OP gonna do something like this? I wonder if x-wind issues kept it from acceptance?

99.9% of fairings don't taper in before cutting off, thus not qualifying for "Kamm" status.

Just think if that Honda had a nice tail section too.

The Britten racer had kind of a "non-fairing" design. Cycle World in '92 had an article describing the aero theory of it. Supposedly it was the best around. Didn't necessarily go for ultimate smoothness, but frontal area reduction.

KIWI WONDERBIKE

[tinkerdave]

try this link

Tony Foale Designs, article on motorcycle aerodynamics.

[NeilBlanchard]

Hi Frank,

Originally Posted by Frank Lee

The Britten racer had kind of a "non-fairing" design. Cycle World in '92 had an article describing the aero theory of it. Supposedly it was the best around. Didn't necessarily go for ultimate smoothness, but frontal area reduction.

KIWI WONDERBIKE

The Britten has so many innovations -- a key element of the aerodynamics is the way the cooling system is set up! Can you spot the water cooling radiator?

Here are two more photos with visual clues:




Hint: the intake is in the nose, and the exhaust is in the "stinger"!

[theycallmeebryan]

Originally Posted by Frank Lee

Now THAT's a fairing!

Is this the kind of fairing ANYONE puts on anything on the street? Was OP gonna do something like this? I wonder if x-wind issues kept it from acceptance?

Whats wrong with putting a fairing like that on a daily driven street bike?

The design im going for is going to look something like this. Im sure many of you have seen his design before. Its a Ninja 250 converted to electric.


However, im not sure how much more drag will be created by having a fairing designed for up-right seating. How much less drag would this fairing design have, if you guys had to make an educated guess?


I would say that 75% of my riding on my Ninja 250 is in a crouched/layed down position, and i dont really have a problem with it.