Mike builds a streamliner

Mike Nelson builds a streamliner

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Mike Nelson racing his version 1 low racer at the Northbrook velodrome in July 2000. Mike says "Fully 3/4 of the bikes that beat me were lower and more laid back. I I lowered it several times netting increases in speed all the while thinking about building a new streamliner"

So, on to the version 2 low racer!

A sharp builder will recognize that the belcrank suspension geometry is set up such that the spring rate actually gets weaker with increased travel and soon goes over center giving no return spring at all.

....Oops

This suspension works very well with a good gradual increase in spring rate and dampening. After this picture was taken I added more upper locating holes to allow an adjustable seat height.
Version 3 low racer:

Over the Winter of 2000/2001, Mike was very busy. This picture shows the CAD drawing of the version 3 fully suspended aluminum low racer that will the chassis for the new streamliner.

Here are a pair of custom machined 150mm very low Q cranks, which needed a custom puller made for them as well. Also shown is the super low-Q 96mm Phil BB and your basic 72tooth chain ring, drawn and cut to the ANSI spec from the machinist handbook. I opted for the 130mm bolt pattern in case I want to play musical chain rings, or musical cranks for that matter.
Early progress report after the first of several trips
to the welder. Shown is the basic frame, rear swing arm assembly, front boom, Action-Tec front shock assembly, and rear shock. 
Making the custom fit low racer seat:

This is the mold plug made by pouring 50 pounds of plaster of Paris into a cavity formed by me sitting in wet sand. After much sanding and filing to make it reasonably smooth, a layer of fiberglass was added to make it a useable male mold that would accept mold release wax. 

Here is the fiberglass mold sitting on the bike to determine if it fits properly. 
This shows the method of making the core from 800 tiny pieces of balsawood. Next time I'll use Nomex honeycomb for the core. It's much more money, but
should be much faster to build with and a little lighter.
Here's the core ready to use including the aluminum inserts for mounting the seat without crushing the core. 
The first carbon fiber layer is on, but was unidirectional fabric I had laying around.
To keep the seat from splitting down the middle I backed the uni-carbon with a layer of bi-directional Kevlar. Next was the pre-finished core. The yellow polypropylene vacuum wick is visible as well.
On top of the core was another layer of Kevlar and the final layer of Carbon fiber. In addition to the Kevlar fixing the uni-carbon mistake, it also acts as a barrier between the carbon and aluminum, common practice dictates their separation.
Streamliner Design:

In the Spring of 2001, Mike started work on the streamliner fairing. Here is a preliminary design for the streamliner body. This version would have had the riders entire body inside the main fairing.

Here's the final design, with a separate canopy for the head to keep the main body smaller, and a rounded tail section. 
The next step was to create a CAD drawing of the different layers of 2" thick foam needed to create the 30 inch high fairing mold. The foam was cut in the shapes created on the CAD program, then sanded smooth to remove the edges.
Putting it all together:

Summer, 2001. Here is a close-up of the Low Q BB and custom short cranks. This will allow the nose of the streamliner to be very narrow.

 

This front end detail picture shows the Action-Tec front suspension and Monoblade fork, idler placement and front fairing mount, which is barely visible through the chain ring. The power side idler was added over the front wheel after discovering that the extremely low Q BB placed the chain so close to the front tire that it make steering difficult.
Rear end suspension detail with fairing mount visible at the back of the seat

This pictures shows the seat and the remote steering from the front.
This pictures shows the remote steering.  If remote steering were not used, tiller style steering would be required. This is a key feature toward enabling the rider to remain in a small aerodynamic package, without have the handlebars hitting the inside of the fairing. 

Finished bike Rev B with idler over the front wheel
Mike Nelson on his new low racer. 

Mike competed the basic streamliner fairing and brought it to the Northbrook races on July 14th, 2001. 

   

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