The Search for Fuel Economy

Pages from a Designers' Notebook

Nov 4, 2008

The goal: 100 mpg at 70 mph, into a 20 mph headwind, with four bags of groceries. It looks like we'll be calling this the Freedom Machine.
Chap. 20: Streamlining the windshield area
This is a pretty tricky design problem. I am pleased at how it is working out.

The goal is to totally streamline this machine. Streamlining, as you will recall, is a smooth, continuous shape, round at the front, pointed at the rear.

So far, it still ain't streamlined.

The moving handlebar is one of the hardest areas to deal with.

Specifically, I want full, lock-to-lock turning.

Here we deal with the moving handlebars.
I have welded a flat mounting plate onto the handlebars, perpendicular to the axis of turning. On this surface I will build the rotating part of the streamlining - the streamlining that covers my hands.
My granite stone and surface gauges help me to keep things true. After I checked the handlebar for accuracy, I wire brushed it off and spray painted it so it wouldn't rust.
CAD-Cardboard Aided Design bulkhead helps me determine the shape. I also cut away a window so I could see my gauges.
Cutting two, aluminum sides exactly the same, insures symmetry. I left the little circular tab in the center to keep track of where the center is. I cut it off later.

By the way, I am building this thing with very few power tools: A band saw, sabre saw, drill press, 1/4" drill and, 16" disc sander and a 120 v. wire welder. Most of you can do this.

Mounting plate in place

At this point, I shimmed and trimmed until I had a perfect, 1/4" air gap between the moving and non-moving parts. Full steering travel, right and left is guaranteed.

When the wheel is pointed straight forward, the shapes match up. The air will pass by it easily. When the wheel is turned, the handlebar streamlining rotates over the body and does not match up. This is no problem because if the wheel is turned this sharp, you are probably pushing it around the garage and are not going very fast.

I call the opening shape for the turning wheel the "Smiley Face." The smiley face is less pronounced here because of the Helix's small 12" wheel front wheel. The smiley face can also be reduced by limiting the handlebar turning, a solution I won't ever do again. Limiting the handlebar turning makes it too hard to push around the shop.

The Dodge Caravan headlights sure fit better than the stock Helix light

(Note the inflated tail on the floor. It weighs 3 pounds)

Now I can clip strips of aluminum along the sides to help visualize where the streamline surface needs to go. The idea is to make the streamlining on the moving portion (with the handlebars) match up exactly with the non-moving streamlining of the body. The aluminum stringers will be my guide

On days like this, when the Freedom Machine is in my shop, I cannot ride it. I have to ride my backup red Helix. I am getting spoiled by streamlinig.

Time to make a new bulkhead to go around the handlebars. 1 1/4" x .100" aluminum is easy to bend. A drawing helps symmetry. After I am sure it will slip inside the existing loop, I will cover it in yellow plastic streamlining
This is the moment of truth. Will the handlebar bulkhead slip in between the frame bulkhead?
QuickTime Movie of handlebar motion. Don't have QuickTime? Click here for a free download from Apple.
It is now safe to add the plastic sheet streamlining to this new portion. Plastic, barbed push fasteners hold it all together, just like on the rest of the body.

Yeah... I am not happy with this "Approximate Streamlining." It is so "scaley" looking. But it offers the best compromise for quick construction and road testing. Can you imagine trying to do all this on a computer and not taking your first ride until thousands of Freedom Machines were coming off an assembly line?

Riding comments, November 4, 2008:

It is getting colder in Carmel. California, (but it never gets REALLY COLD like it did in Illinois when I lived there.) But with this streamlining, I no longer need gloves. There is simply no air drawing away my body heat. Very satisfying indeed. This is another one of the rewards of good streamlining.

The only wind I get is in my face. I miss the clear windshield and can't wait to replace it with an even better one than before.

The HID lights are blue-ish and not as illuminating. Part of the problem is that the headlights are not aimed exactly right because the front bulkhead is in the way. On a later version, I will angle the bulkhead back a few inches and the problem will be solved.

I am beginning to notice that, as I add streamlining, it is getting harder to get things (groceries, of course) out of the cargo hold. Maybe I can move the rear bulkhead forward on the next version for easier access to the hatch. I am thinking that it might be easier to lift up the side for access.

I am resigned to the fact that this may not be the "Last Vetter Fairing" after all. It is no longer just a fairing. It has become a vehicle with a name:

The Freedom Machine
Master Index to the Last Vetter Fairing Story

This page posted Nov. 4, 2008