The Search for Fuel Economy

Pages from a Designers' Notebook Readers comments P3

Chap. 9: Rear Bulkhead and truck bed

A brief narration regarding where we are going

With tail for cross country
Without tail for the city
As I build and ride this thing, solutions to problems emerge. For example, where will I put the license plate, tail light and turn signals? They cannot go on the point because it is a point and there is nothing there to put them on! The solution appeared when I realized that I could not completely streamline the area around my head. The air will be "Dirty" (unstreamlined there). I will mount these components in the headrest. Better to have just one area of "Dirty-ness" than many small ones. Actually, the lights will be more visible up there, thus we will be safer.

In addition, we don't need the tail in the city. So, I will make the tail go on for cross country cruising and go off easily for inner city riding. This means that, with the tail off, my Helix will be the same length as stock.

Quick! Name me any 2-wheeler than can carry 3 bags of groceries.

I see this thing as a "two wheeled truck." If it cannot carry at least 3 bags of groceries, what good is it? The next step, then, is to make a "truck bed" and be sure it is streamlined.

My friend, Carl is building a 2 door 1948 Lincoln. He also has a sheet metal shear and bender and kindly agreed to make my "truck bed"
Fits me perfectly
Too low for Zak
We have a problem
With the bed and bulkhead finally in place, a serious problem shows up. I made the streamlined body to fit me. (Top, left) My son, Zak, sits 4" higher, from his seat to his shoulders. Top right. Zak won't be able to ride this thing because he won't fit into it. Many of my friends won't either. If I raise the top line 4", frontal area goes up too and I won't be as streamlined as I want. The solution?

Reluctantly, I raise up the rear line 4" by adding an extension to the loop. I will make the seat with a 4" removable cushion for the big guys. This is better for me because a higher seat is more comfortable. Compromises, compromises. This is what design is all about.

"You want this? You gotta give up that"

Vetter Design Truth

Next: making the rear bulkhead:

If you look closely, you can see the 4" extensions in the loop in the background.

Making the rear bulkhead is just like making the middle one. Using CAD and a hot melt gun, I generate the shape and transfer it to a piece of plywood.

Template for the rear bulkhead
Around the plywood I make a cardboard ring and then one made of aluminum, just like before. Oh yes... I added 3" to the rear bulkhead, too. These two rings will serve as mounts for the center portion of streamlining.
Making the rear bulkhead
At this point, all this body assembly can be removed with three nuts for maintenance to the scooter. I am a lazy motorcyclist and have no patience for a machine that is hard to work on.

"A good design is not more trouble than it is worth"

Another Vetter Design Truth

A nightmare of holes and screws
The 4" extensions are clearly visible in this shot. Also, you can see all the extra holes I have drilled and not used. When we make a prototype, we have no printed plans to work from. Everything is made by trial and error. I make a lot of errors. If this ever turns into a kit, you will know exactly where the holes go before you drill them.
Before I can wrap the bulkhead hoops with streamlining, I must tuck in the things that are in the way of the streamlined surface
The Helix engine is its own swing arm and rocks up and down. I must account for this. In addition, the air intake snorkle is in the way. I must make a new airbox cover to relocate the snorkle. All these things take time. (by the way, the engine hardly runs with the snorkle off)

It will not being able to perfectly streamlined at the very bottom because the swing arm has to bounce up and down and the wheels stick out.

The air intake snorkle must be moved
Where we are as of June 8, 2008
There is still another week of boring detail work... mostly focused around the bouncing engine. I want the streamlining to be as close and tight as possible. Soon, I will wrap this and the rear section will be pretty much complete!

And you thought I was going to have to make molds and fiberglass parts.

Next step: Wrap it in a streamlined shape
This page updated June 8, 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)