Bicycle Aerodynamics for those interested.

[A2WindTunnel]

If anyone is interested in Bicycle Aerodynamics, here is a recent article about A2 + Specialized and a collaboration we did with wind tunnel data and how it correlates with on-track data.  Pretty interesting aero article weather your into bikes or not.  But it can illustrate the time and power savings by optimizing the rider into a more aero position while allowing them to produce efficiant power, and while they measure power in watts, it is the same as how much HP they are saving by reducing the drag (1HP = 746 Watts).  70-90% of the power these riders a putting out is just to overcome the air resistance, and any reduction in drag adds up to big time savings over a x-distance race. By optimizing the position of this rider, his reduced drag and added speed would cut off 24min-58sec over an Iron Man distance race which are won by seconds (180.2km or 112miles). 

This post is just intended to help people understand a little more about how wind tunnel testing could be beneficial and how reducing the aerodynamic drag is like adding HP.  I know that bicycles have nothing to do with what you guys are doing (so please don’t blast me), but AERODYNAMICS have everything to do with what you guys are doing and the records you are trying to set.  I am working on more stuff that would directly relate to LS racing and hope to have a video up of a wind tunnel test (A2 in house study) to show changes, and data with instruction to demonstrate what a typical wind tunnel test is and how we view at the data to see what is helping and what is hurting the vehicle. 

http://www.bikeradar.com/news/article/how-aero-is-aero-19273

[fredvance]

Do they have one of those helmets with snell rating/

[Seldom Seen Slim]

Fred-

Well, the Snell folks would probably take issue with the pointy thing in the back, don't you agree?  Maybe if we submit the helmet to the rules and the safety committees -- and then also promise to wear a back protector and even maybe fashion the aero pointy part out of a breakaway material -- then perhaps. . .

I've ofter seen those bike helmets and wished there was a motorcycle racing version.  Not yet, I'm afraid.

[fredvance]

Yeah, they are funny looking but if it was good for  a mph or 2 I would wear it.

[panic]

And make the back protector into a tail...

[A2WindTunnel]

Believe it or not, all helmets are very specific to each bicycle rider and is the same on motorcycle riders as well.  This is because of body size and shape and positioning on the bike.  The bike and rider are a system working together and the air interacts with both.  One helmet might work well for one rider but not another.  Just look at all the different back shapes.  One guy might have a flat horizontal back while another has a curved hump on his back. 

For Motorcycles, a helmet and or a back protector in the right position and configuration for bike and rider would have great benefits in drag reduction if you could minimize the gap from the helmet and the back and also help transition the air down your back to try and keep the separation from the helmet to a minimum.  You would also need the windsheild to transition on to the helmet well.

Here are 3 different back types you can see for yourself the difference and how it could apply to motorcycles and positions.

[Stan Back]

How do butt cracks figure into this?

[landsendlynda]

Creates whistling in the wind.

[fredvance]

I still like Rollie Free's full layout and speedo.

[Glen]

Stan, those are vertical smiles or rear cleavage

[1212FBGS]

the windscreen has to stop at the front of the helmet and can not wrap around the sides

[Glen]

I wonder if Butt Crack Putty is allowed for additional streamlining and stops the whistling??

[landsendlynda]

Seems to me, if the speedo's are tight enough, canyons would be welded together with no chance of wind velocity.

Lynda

[McRat]

Fred-

Well, the Snell folks would probably take issue with the pointy thing in the back, don't you agree?  Maybe if we submit the helmet to the rules and the safety committees -- and then also promise to wear a back protector and even maybe fashion the aero pointy part out of a breakaway material -- then perhaps. . .

I've ofter seen those bike helmets and wished there was a motorcycle racing version.  Not yet, I'm afraid.

Maybe you could pack a parachute into it?   


Kidding...

[A2WindTunnel]

I know that there is a rule on where the windshield ends, but you want the shape to match your helmet the best you can or have a smooth transition.  I other words, you don't want there to be 4" of windshield sticking out from each side of your helmet and you don't want a helmet sticking 4" above your windshield.  Plus, you do have to have your head in a position to see where you are going.

PS:  The butt crack whistle is not as bad as you might think. 

Good smooth transition from windshield to helmet



Head could be lower


This guy alone could benifit from a better position.  Small HP means Aero is VERY important for his top speed.


windshield appears too short for that rider