Honda Insight Tail Extension Project

[3-Wheeler]

Originally Posted by silverinsight2

....Will the interior of the tailcone be available for light storage?....

I suppose, but the small hatch leading to the large internal space, will make it 'interesting' to get bulky items in there!!

It would have been nice to store let's say a bicycle back there, but I did not want to create an even larger opening to get the bike in that area. It's just the way the project is working out due to the required mounting system to the car body.

Jim.

[navivovas]

Hello everybody!
Wow,great job..

[discovery]

Yes this is a nice job with a lot of work and love, keep it up
P.S. can't wait to see more of it.

navivovas- ot kude si be brat?

[Jyden]

Nice work - can't wait to hear the results and the mpg gain

[SoobieOut]

Fantastic job so far!
The earlier comment about hammering out aluminum panels into any shape reminded me of the early days of Porsche auto building. Where Dr. Porsche only had one man who was good enough to hammer out his panels. Problem was his only body craftsman was too drunk to work most days, which greatly limited his car production.

[3-Wheeler]

This post is an attempt to clear up what shape the Aerohead Streamlining Template is.

This picture shows just one circle superimposed over the Template.



The next picture shows that there is, to best of my knowledge, only one circle and a tangent line that make up the shape of the Template.



This last picture shows that the template appears to be straight in this section, and that this straight area begins around the 65% mark on the Template length.

The main reason that I think the Template is straight in this area, is that it has to be, and for several reasons:

1) Aerohead has stated on several occasions that the 'tail' of the Template can not exceed an angle of 22° to avoid flow separation.

2) Well, at the 65% length of the Template, the angle is already at this point. Therefore the remainder has to maintain this angle to adhere to the 22° rule. This dictates replication by forming a straight line to the tail end at the 100% point.



The curvature of the Template up to the 65% point, at least as close as the pictorial can be rendered on my CAD program, shows that a single curvature provides a very close replication of the Template curve.

If this is really the case, and everyone thinks this is reasonable, then a math model of these shapes can be developed for future use by others on the forum.

Jim.

[RobertSmalls]

How much better does a circle fit, versus the parabolic fit you discussed here?

[navivovas]

Originally Posted by discovery

Yes this is a nice job with a lot of work and love, keep it up
P.S. can't wait to see more of it.

navivovas- ot kude si be brat?

Botevgrad,Bulgaria.

[3-Wheeler]

Originally Posted by RobertSmalls

How much better does a circle fit, versus the parabolic fit you discussed here?

Hi Robert,

Fortunately, that old file and spreadsheet data were saved by yours truly, such that further numbers could be calculated and shown here:

The previous post had this chart of information that was gleaned from an earlier analysis of the Template. The points shown in the table were 'picked' from the Template via a graphics editing program, thrown into the spreadsheet and analyzed numerically to allow a curve-fit to be developed.

A further column of data shown in yellow is the change in angular curvature for each picked point from the Template.

The change in curvature is not consistent in it's change from point to point, indicating that these picked points are not close to ideal. Therefore another approach to interpreting the Template is in order.



This picture is a collage of three smaller pictures, and shows how closely the a single radius matches the Template in the area from 0% to 60% cordal length.

The match is pretty good, and at least my eye can not determine if multiple radii would provide a better fit in this area.

The section from 65% to 100% cordal length seems pretty clearly identified as angled at the maximum allowable of 22°, so this portion is not under consideration, unless others have different theories on the intent of the Template shape.

To sum up, this is my best guess based on the given shape of the rendered Template.



Jim

[aerohead]

Jim,the template's aft portion is basically modeled on the aft portion of a L/D= 2.5 streamline body of revolution as displayed in one of Hucho's tables.It should be mentioned in the abstract for the 'Template' thread.
I would have done a photo-enlargement of a small image and attempted to 'clean it up' with a French curve,and in so doing,create some of the 'bumps' in the image.
If you can find a large,clean image of this dimension of 'teardrop',it's what you're looking for.