The Search for Fuel Economy

Pages from a Designers' Notebook Readers comments P2

Chap. 5: More Wind Testing

More sidewind testing, April 7, 2008

Highway 68 from Carmel to Salinas is infamous for its powerful afternoon sidewinds. Today was predicted to be a good one. My buddy, Don, agreed to follow me over to Salinas today to see what might happen with my Helix with the long tail. Now, there is probably no motorcycle made that does not react in sidewinds. Some more, some less. As we gain experience, we learn how to anticipate the effects of passing trucks. etc. Even tho I have been riding this thing for hundreds of miles as my daily transportation - I must admit I was a little worried. Don said he would never ride his KLR there again.

The foamboard is not going to last much longer.

You can see why I don't consider this to be streamlined - yet. Look at all those gaps. Remarkably, mileage, which is always around 64 mpg, is unchanged with or without the tail.

Let me summarize my experiences:

This is the best fairing I have ever ridden behind.

It reacts no worse in crosswinds and better than most bikes I have ridden

It must be the tail - which seems to "Smooth out" side wind gusts. Don, on his new Concourse was very impressed. So was I.

Perhaps the best part of this design is that the air does not blow backwards into my back or neck. There is no flutter of air from the windshield, either.

Isn't it remarkable what one can learn after doing this for 42 years?

My fairing designs beginning in 1966 are basically what you see on motorcycles today. This is the future.

2008: Making the Last Vetter Fairing
1966: Making the first Vetter Fairing
The pattern is becoming big and unwieldy. Keeping the fairing light weight will be a challenge.

It is important to not sand off too much. The only way to know what to do is to stop work and stare at it, waiting for it to tell me what to do.

It "Tells me what to do"
I call this the Last Vetter Fairing because it is represents everything I know about motorcycle design.
At this stage, the streamlined shape is within 1/4" of its final design. You can see how I have sanded it down to the two original bulkheads. I know that it will fit over my Helix and I know that I will fit into it. Now, I know the exact streamlined shape. Round at the front... pointed at the rear, not too big... not to small. I also know that it does well on the road in severe sidewinds - in its slab sided form - on my scooter. will this be better or worse. There is a lot of controversy regarding this.

Readers comments P2

The next step will to make templates or "stations" every 31/2". From those templates, I will cut 31/2" foam sections to assemble in reverse order on another piece of plywood to generate the other side.

This page updated April 18, 2008