The Search for Fuel Economy

Pages from a Designers' Notebook Readers comments P2

Chap. 6: The Final Shape

April 17, 2008: Final sanding

I have stared at it enough and it is time to remove the last 1/4". All those grooves and sections are the result of the liguid nails squishing out in areas that I did not expect. The oozed glue makes "hard spots" that must be cut out before I can do final sanding. It just looks bad. It won't affect the pattern.

Read the shadows

You can read the shape better in the shadow line. Irregularities show up best there. I keep moving the part around so the shadow is where I am doing the final sanding.

Something fishey here

This is the shape! Or, at least, the left side of the shape. It is time to grid it with 3 1/2" parallel lines to match the 3 1/2" blocks of foam that I will cut and assemble into the right side.

Look closely

Between my legs is an X-Y laser projector. It projects a perfectly vertical and perfectly horizontal red beam. Set-up is very important. Notice the foamboard grids on the ground and above. these insure that I am directly in front of the section I am tracing. The pieces of foamboard behind me are an attempt to shade the afternoon sun to more easily read the laser beam.

Tracing the laser beam

Now it is just a matter of drawing a line over the red laser beam. I move the laser beam projector 3 1/2" to the left and draw another line. Thirty-five setups later, I am done.

Left side all gridded

Next, at each of the 35 "Stations" I will make an exact cardboard template of that section. Then I will cut of the 35 shapes from 3 1/2" foam and stack them up in reverse order to generate the other side.

In the meantime, I must figure out how to move this thing around. It is big and heavy and there are no handles.

Today, I was interviewed about this project. click here to hear that broadcast:
30 Minute Radio Interview on Fuel Economy

Where I explain the things I have learned on AM 1240 KNRY, Cannery Row, Monterey California, April 19, 2008

Are you getting the idea?

Through the magic of PhotoShop, I have put the gridded out shape over my Helix to see how it looks compared to the existing foamboard body. See how the widest part... the red line is in the same place? I am resigned to the fact that my head will stick up, in an un-streamlined-like manner. I do this because I do not know any way to fit inside, and peer out thru a bubble that will mist up in the rain. There are no windshield wipers - that I know of - that work on soft plastic.

Besides, if I could get all the way inside, I would have to make the area around my helmet really big so it does not bang around. Until then, I have decided upon an "Open cockpit."

Open cockpit is romantic, actually. Here I am in my 65 hp "FlyBaby in 1975. Riding around on my Helix with the long tail feels very much like flying this plane.
This page updated April 19, 2008