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Old 10-02-2011, 04:17 PM   #1 (permalink)
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(Project) Boat tail-4 Door Sedan VW Mk2 (1990 Jetta GL)

I started building a boat tail on my '90 VW Jetta. The plan is/was to use the Aero templates, both versions, for a true, attached flow boat tail.


Through my measurements, the cars height is 54.5" tall. Giving me a 100% tail length of 194.02" and each 10% on the second template of 19.4" from Max roof camber. So, at 19.4 inches( or 10%), there should be 3.5degree down turn from level. At 38.8"( or 20%) it should be 7.5 degrees, and so on. I had planned on going out to 60% for length/space reasons, and that put me out to 45" from the end of the bumper.
I measured out the elevation drops on the template, and for my height vehicle, the drops are as follows;

10%= .76"
20%= 2.3"
30%= 5.37"
40%= 9.98"
50%= 16.12"
60%= 23.8"
70%= 31.48"
80%= 39.15"
90%= 46.82"
100%=54.5"

The original lights will be moved to the rear and the third brake light will be mounted as I get the rear window put in. There will be a trunk opening and the old trunk lid and window are removed.

This is not intended as a one time project, to be completely finished when simply fully enclosed. It will be an ongoing project that probably won't end until the car is completely destroyed. It also, probably, will show what NOT to do as much as what to do.

Criticisms and ideas are always welcome.

I did want to note here, as there has been some discussion about finding Max roof camber, that I did it on the car, not the computer. Using a level gauge, I traced from the front of the roof toward the back until the gauge read equal to the floor reading between the front and rear tires. I then did the same thing starting at the rear of the roof and moved toward the front. I took the middle of those two marks as the max roof camber or starting point for the rest of my measurements.

Post two will have updated pics and building material used.


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Boat tail project
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Last edited by JethroBodine; 03-13-2012 at 09:22 PM.. Reason: Added template drop values
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Old 10-02-2011, 04:17 PM   #2 (permalink)
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Here is the link to the pics in this thread with a lot more thrown in.

Pictures by JethroBodineEM - Photobucket
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It is always very amusing how our imagination is put to the test when overcoming reality. Redyaris
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Last edited by JethroBodine; 10-27-2011 at 09:52 PM..
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Old 10-02-2011, 04:44 PM   #3 (permalink)
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After getting the measurements, I planned on making a solid base for the extension out of round steel tubing( free) and supports our of thin steel flat bar and and round stock( cheap or free). I was going to use cardboard and fiberglass resin for the skin, but further reading of MetroMPGs thread said that he was having issues with moisture bubbling before he removed his. A friend at work had used cloth fabric, chicken wire( for shaping) and resin for builds, followed by body filler( Bondo, if you will) for final smoothing. Sounded like a plan to me. I grabbed the welder and set to work.


Rear window and trunk removed( sorry for the blurry pics, it was dark in the shop, flash only lit near objects, and when I turned off the flash to lighten the pics, I couldn't hold the camera steady enough, which I couldn't tell viewing them on the camera, found out while downloading them).


Wiring harness already extended and run through( temporarily) the old light opening.



First loop welded to the body of the car.( Sorry, again)



The full frame welded in place. The rod down the center is just a place marker for measuring angles at different percentages of template.
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Old 10-02-2011, 04:47 PM   #4 (permalink)
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awesome work. cant wait to see more pics
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Old 10-02-2011, 04:58 PM   #5 (permalink)
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Here are a couple pics of the lights on the end of the frame. I don't have any pics of the chicken wire/frame assembly, but pics of the fabric on the framework will show what's happening.


and blurry,


More to come.
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Old 10-02-2011, 05:30 PM   #6 (permalink)
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Here's the cloth stretched over the framework.



Gaffer tape is holding it in place. I didn't sand the body where it meets the tail as I'm going to do the final attachment with screws and body sealer to allow for flexing( hopefully).



Here is the first coat of resin. The fabric did sag a bit, but I pulled it tighter after this pic and before the next coat. Took a whole gallon of resin to saturate the fabric. And for those who are wondering, that is a queen sized sheet with little snowmen on it.



I put more fabric around the edges, both as a sealer for now and to give me something to cut/fit as I need. The edges of the sheet, also, started to pull away in places and this seemed to help.



I had to extend beyond the sheet on the end, so now it covers the whole top side, bottom belly pan will be aluminum sheeting, and I haven't decided on the end, yet.
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Old 10-02-2011, 05:43 PM   #7 (permalink)
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I decided to paint the tail so that it would be less conspicuous.



I...um... ran out of hide-in-plain-sight black and had to finish with a can of metallic blue(all I had).




More to come.
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Last edited by JethroBodine; 10-02-2011 at 05:49 PM..
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Old 10-02-2011, 07:09 PM   #8 (permalink)
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How long did it take from start through Post #6 with the fabric stretched and painted? The posts are all dated the same afternoon but I can't believe you did it all in one day - or did you??
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Old 10-02-2011, 08:17 PM   #9 (permalink)
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Quote:
Originally Posted by JethroBodine View Post
I decided to paint the tail so that it would be less conspicuous.
No matter the color, I can't see paint being the answer on this.

You need to replace/cover the bed sheet-cum-snowmen with a
Cloak of Invisibility


That said, I admire your initiative, your let's go get 'em approach.
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Old 10-02-2011, 08:44 PM   #10 (permalink)
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Looks like a pretty good job. I'd like to see a tuft test to determine if the air is attached over those surface undulations. Any plans for testing it?

Also, what does the bottom of it look like?


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