The Search for Fuel Economy

Pages from a Designers' Notebook

Sep 25, 2008

Chap. 18: Where should the nose weight be? How much?
Well, we are not quite finished with the weight. After riding this thing for a while, I realized that there might be a difference between having the weight low - or the weight high. I decided to build a structure at the nose that would allow me to add or subtract weights - and move them up or down.
5 pound divers' weights
10 pounds installed
When I removed the original bar bell weight and lead balls, I weighed them. Instead of 25 pounds, they added up to only 20 pounds. Never the less, they felt too heavy. This was not because they collapsed the front end. The front suspension handled the weight just fine....

They just "Felt" heavy.

I found 5 pound lead weights at a local dive shop and put 10 pounds at the top and10 at the bottom.

Riding with 20 pounds of lead
U-turns were hard to do with 20 pounds. One nice thing: I did not have to put my feet down at stop signs. The streamliner wanted to balance upright, by itself.

I began to realize that the weights tended to do what I thought they would do. I began to distrust the way I was doing things. It was time for a double blind test.

Double blind test
We rode down to Big Sur and found a very windy pass where the air whipped back and forth. It was a very scarey place to ride but a perfect place to test.

Son, Zak randomly arranged the weights while I averted my eyes. After each pass, I wrote down my impressesions... how it felt in the wind and other observations. I also noted where I thought the weights might be bolted on. It was soon clear that four weights were too much so we reduced the tests to three weights, or 15 pounds.

I was surprized at how hard it was to do a double blind test. Right away, I could tell when the weights were high because it was harder to get off the side stand and harder to turn onto the road.

Weights at the bottom made the bike feel much lighter. U-turns had a normal feeling and still seemed to defeat the winds fine.

Other than that, any combination of three weights seemed to do defeat side winds the same. The logical conclusion, then was to put all three at the bottom, which was convenient.

Weight at bottom just "feels better."

I should have known that weight at the front was good for stability.

We feel the stability everytime we load a big bag of dog food at the front of our shopping cart. A cart loaded like this is very hard to turn and wants to go straight.

Three, 5 pound lead diver's weights fit neatly in behind the nose cap. I suspect that 10 pounds will do the job. I will ride with this for a while and after I get used to three weights, I will remove the bottom one and see how it feels.
Now it is time to return to finishing up the streamlining...
Page posted Sep 25, 2008
Chap. 3: Road Testing the Long Tail Mar 28, 08
Chap. 1: Streamlining Saves Fuel Feb 20, 08
Chap.2: CAD Streamlined Body Mar 8, 08
Chap. 4: Planking with Foam Apl. 5, 09
Chap. 5: More Wind Testing Apl. 7, 08
Chap. 6: The Final Shape Apl. 17, 08
Chap. 7: Decisions about Details May 10, 08
Page 8: Making the Center Bulkhead June 1, 08
Chap. 9: Rear Bulkhead and Truck bed June 8, 08
Chap. 10: Finish Rear and go for ride June 17, 08

If you have not yet watched my DVD, How they Got 470 mpg it is time to get it for the basic foundation for what we are doing here

Chap. 11: Finish the Tail June 29, 08
Chap. 12: Heading for Ohio, July 13-23, 08
Introduction to Fuel Economy
Chap. 13: Riding in the Midwest July 24, 08
Chap. 14: Vintage Days Ohio, July 25-7, 08
Chap. 15: Summary to date Aug 12, 08
Chap. 16: Adding Weight to the Front Sep. 1, 08
Chap. 17: Truth and Motorcycle Design Sep 4, 08
Chap. 18: Where should the weight be? Sep 25, 08
Chapter 19: Finishing the Streamlining Oct 14, 08
Chapter 20: Streamlining the Handlebars Nov 4, 08
Chapter 21: Unexpected Problems Nov 11, 08
Chapter 23: Getting my feet in and out Dec 19, 08
Chapter 22: Streamlining is working Nov 25, 08
Chapter 24: Streamlining is beginning to work! Jan 1, 09
Chapter 25: Tuft Testing Mar 2, 2009
Chapter 26: Starting Over April 9, 09
Chapter 27: More Ideas for Starting over April 20, 09
Chapter 28: Show time! Aug 1, 2009
Chapter 29: Getting the big parts right Dec 10, 2009
Chapter 30: First evaluation from an outsider Dec 20, 2009
Chapter 31: Visit with Allert Jacobs Dec 24, 2009
Chapter 32: Prius Headlights Jan 18, 2010
Chapter 33: New Gears Feb 17, 2010
Chapter 34: New Mileage Records April 25, 2010
Chapter 35: The Quail Gathering of Motorcycles May 9, 2010
Chapter 36: End of the line with the Helix June 19, 2010
Chapter 37: Vetter Challenge Oct. 9, 2010
Chapter 38: John Keogh helps out Dec 8, 2010
Chapter 39: Working with Keogh Dec 17, 2010
Chapter 40 and up (Work continuing in 2011)
Designing the Last Vetter Fairing

Chapters 1 thru 39 (2007-2010)

Chapters: 40 thru 51 (2011)

Chapters: 52 thru 61 (2012)

Chapters 62 thru 68 (2013)

Chapters 69-up (2014)