atb

Looks like we have the cost down to about $100 plus shipping, anyone else want in?

Tom. M

Yep....I'm in for a set..

atb

I'm going to do a cardboard mock up this week to make sure the sizing is right and to make sure that the top surface will accomodate the appropriate range of wing angle. Once that checks out I'll start collecting funds. You'll need to paypal me $100. When all the funds are in I'll make the order. When the order is received I'll figure out what the shipping charges are and make a request for those additional charges and get them out upon receipt.

It may be a better option do this on your own time if you can pair up with someone local to you. One pair of uprights is going to run you about $150, but if you even just double the order to two pair, you get down to about $110, and that's shipped to your doorstep and not having to mess with me acting as a go-between (which I'm happy to do, but it's just extra time and shipping charges for you).

You may find that you also want to do some personal tweaks to the design to meet your needs, as I did. the critical dimension is the compound curve on the base, which is designed to match the curvature of the hatch (YMMV).

Thanks again to Mike Simard for sharing his design work, so much easier than re-inventing the wheel on this, and getting a much better designed product in the end.

atb

Latest update. So i decided to mock up a set of uprights based upon my latest amendments to Mike's design to make sure I was within SCCA rules.

Here are the requirements:


The wing height is pretty good. With the leading edge of the foil almost parallel to the ground, you can see that the roof of the car is higher than the trailing edge of the wing when measured with a straight edge:





I have almost 2” of extra height at my disposal for wing adjustments.



But, it looks like I’ve struck out on the rearward position of the wing:



Rearward of the rear bumper by 1-5/8”.



So it looks like I need to go back to solidworks and make my uprights more “upright” with less sweep.
I’ll post more after my second attempt.

atb

Okay, a quick redesign on solidworks and got it right:


Mocked up in wood so I could get an idea how it would all go together. Wing is shown with a lot of rake, just wanted to see how much adjustment I had before matching the roof height.
Also, mock up uses1" wood, the finished product will be 1/2" aluminum. The centers will be cut out on the final product. There was no need to do the mock ups that way.

worf928

In your mock-up, it looks like the wing is at a 40+ degree angle of attack. Are you planning something else? Or is that where you intend to run it?

atb

That was just to see how much adjustment I had. The trailing edge is the highest part of the wing, which can't be higher than the roof of the car. The position shown in the photo puts the trailing edge at the same height as the roof, which as you've noticed is much more adjustment than I'll need (unless I want to use it as an air brake )

BC

Is this position changing the requirements for the all-important curve to match the hatch?

atb

I was able to keep that curve a constant.

Below you can see the two bucks side by side. If you ccould see the bottoms, you'd see that the curves line up perfectly in this photo.

atb

Latest update.

I went through a couple more redesigns on solidworks, and put in my order. I didn't want to commit to a bulk order because I'm still not convinced that this design will work. As is, the base of the mounts will still need an angle cut made to match the lateral contour of the hatch. Essentially, the inner edges have to be 3mm shorter than the outer edges of the bottom mounting surface. Having that one additional cut done by emachine shop quadrupled the price. As is, this pair as seen below cost $140.
I'm going to see what a local machinest will charge to make the final angle cuts on the bottoms. If its ridculous, I may just go at it by hand. BTW, these are very stout. The material is much heavier than I would have anticipated.

BC

So what I hear you saying is that the lateral curve of the hatch to the SIDE of of the car from the center line is something that we had not anticipated?

atb

That's kind of correct. Mike's original plans were 2D then rendered in 3D when you input the thickness of the material in solidworks. There were some instructions to the machinist in a separate text file that I believe dealt with the finish work that I'm needing done.

atb

Finally got a chance to do a test fit on the contour of the mounting surface. I must say that Mike nailed it.




Rather than deal with the complexity of further machining on these uprights, I'm going to see if I can make a plastic strip to sandwich between the base and the deck lid, that will have the requisite 3mm wedge along its length. I think that will be the easiest way to deal with the outward canting of the uprights if bolted straight onto the hatch.

atb

This pic shows the need for a wedged spacer between the bracket and hatch. If anyone has any ideas, I'm open to suggestions.

mark kibort

you also should consider keeping the uprights solid (no cut out) ... they act as vertical stabilizers at high speed.
I would also suggest making them thinner, to be more aero and lighter. by welding on a base, it will look better too.