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Tail

As mentioned in the Vacuum process results section, the reasons for having a removable tail are to reduce the overall shell length when transporting the streamliner in a car and so the streamliner will fit on my porch where it is parked. In addition, to fix a rear tire flat simply remove the tail instead of removing the entire bike from the shell. Another reason is that the split line for the tail happens to be near the maximum length of the sheet of LD60 Zote material (72”).

As shown in Vacuum process results, the series of alignment blocks did not work well enough to control the uniformity of the mating edges of the tail to the main shell. The fit along those edges had too much waviness and was not stable enough. A better system is using a tongue & groove. This drawing shows a sectional view of that construction.

This shows an end view of a typical groove used throughout this streamliner. In this particular example, it is the joint between the tail and turtledeck. Because the tail foam is thinner than the shell foam, I had to use an extra spacer on the tail so that the grooves would be in alignment. The turtledeck tongue has to fit in both the shell and tail grooves. Although this added an extra piece of material, this worked very well as an edge stiffener for the tail. Remember the rule: All foam edges need an edge stiffener. Also, it is handy to have a few different HD80 foam thicknesses that can be used as spacers and or stiffeners. (0.08”, 0.1”, 0.15”, and 0.2” could be a range of materials to have on hand).

One of the important tail supports is off the end of the luggage rack. This shows a T-brace bolted to the luggage rack.


This shows the bottom side construction, consisting of a flat sheet of 0.2” thick material with a central U-shape stiffener and two sidepieces. These sidepieces increase the glue surface area when this assembly is glued to the tail. If you glue the 0.2” HD80 foam to the shell surface, that joint generally will be seen on the outside surface as a concave or even convex line, depending on the load surface. I found this to be true with the U-shape internal braces also. They should have a piece of material glued across the open part of the U (also increases the glue surface area).

This shows the inside view of the tail lying on its side, complete with tongue & groove top edges (left side of photo), two clips to attach the turtledeck to the tail along this tongue & groove joint (two more clips are on the shell side of the turtledeck), the T-brace, four smaller internal U-braces which plug into the shell’s larger internal braces, four clips to attach the tail to the shell’s internal U-braces, and the two clips at the juncture of the shell to tail tongue & groove joint. Sounds like a lot of clips, but they are relatively easy to use and are very light. I will be interested to see how well they hold things together in a crash.

The turtledeck needs to be swung open to allow access to the panniers, so one half of an aluminum hinge is glued to the very end of the turtledeck. The other half is on the tail. A removable brass pin joins the two together.

This shows the upside down tail. The wheel opening is at the top in this photo. I chopped the tail rather than bring it to a knife-edge so that a tail light and (future) reflectors could fitted, and to reduce the overall vehicle length. I doubt if this seriously degrades the CdA on this type vehicle. I did not finish the end of the tail until a good part of the turtledeck was finished, since I didn’t know what the final trim shape would look like.

Because this vehicle will be used mainly on the road for alternate transportation (maybe some racing and giving the upright riders a hard time), I need panniers to carry cargo. This photo shows two panniers clipped to the luggage rack inside the tail. The rack needs to be quite narrow, 2” wide. It is made from 0.25” diameter carbon tubes and weighs about 6 oz. (see LFWD section). In addition, a bib will be installed which will lie across the top of the panniers, attached to the seat back and Velcro’ed to the sides of the tail. I find that 95% of my cargo is thrown in the bib rather than in the panniers on the OFS.

Next section: Turtledeck