....down the rabbit hole we go.........again

[Audi1]

No, not glued............ :lol:

Upside down because the top is full of markings, making it difficult to see anything but the surface lines. Although running inverted could be an interesting approach to this whole topic. :roll:

I'll post a right-side-up pic later tonight.

Allan

[Audi1]

[Audi1]

Some time on the set-up block today; starting to take shape.



SCC front axle block cut-ins and finishing up the guide holder are next up...................

Allan

[Audi1]

A little further in now.



It's not at what I would call the pretty stage.............yet .........

SCC front axle blocks have been cut into the chassis to get the front axle lower. The guide holder is glued in place and the spacer underneath the guide has been fabricated and glued in place. Front and rear motor pod elevation platforms have been added at the front and the rear of the motor pod mount.

The longitudinal stiffeners are piano wire; glued to the chassis to increase rigidity in the rear-mid of the chassis. Semicircular piano wire stiffeners have also been added around the holes in front of the pod mount, to help resist the plastic cracking at the neck between the front end and the back end.

The holes in front of the motor pod mount have been communicated with the side sausage shaped cut-outs, showing the overall layout of the front end/rear end and the location of the torsion bars. One more cut on each outer side will provide the final front end/rear end chassis separation.

The torsion bars are 1.0mm carbon fiber; housed in styrene tubes, front and rear. The bars will be positioned over the sausage-shaped cut-outs once the chassis is completed.

A lot more to do yet, including testing of this chassis vs. last year's chassis.

Allan

[chappy]

Looks good Allan.
I love it when I see the ingenuity on the board here.
Bob

[chappyman66]

Allan........all I can say is WOW.
That's a ton of work. You have waaaay more patience than I have ever espoused, much less exhibited. I will be interested in how this runs.

[TuscoTodd]

WOW Allan! That is definitely turning into an impressive project! Very cool!

[dreinecke]

Seriously cool work Allan!

[Audi1]

Here it is with the torsion bars mounted. They're carbon fiber epoxied into plastic tubes front and rear. These tubes were then bonded to the chassis with Amboid Pro Weld (styrene-to-styrene glue), followed by encasing in epoxy. Soon it will be time to do some comparative testing.





You have to look hard to see the carbon fiber torsion bars against the black background. The cuts on the outside edges of the chassis separate the front from the rear at the throat (between the two semi-circular piano wire reinforcements. Flex in the front is about 2-fold less than the stock Racer M1 chassis and about 2-fold more than last year's chassis. So, we'll see how it performs now.

I'm glad that the ugly stages are behind me; I think I've now reached the bottom of this particular rabbit hole.......................at this point, I kinda wish I'd taken the blue pill.................!

Allan

[Smokeio]

Nice build Allan. Best of luck with it.

[Audi1]

Thanks Mike. Good luck to you too.

Today was testing day; among other things............best day of the Summer on October 12th!

The testing was 3 ways; two chassis, two motors and two gearings. That's a good sized matrix to test, one parameter at a time. So, I compressed it into two chassis and two motors (with gearing specific for each motor). Here's the starting point; two naked chassis:



The top chassis is last year's Group 5 build, the bottom chassis is this year's build. Last year's chassis was about 4 times stiffer, torsionally, front-to-rear, than the stock Racer chassis. This year's is about 2 times stiffer and, roughly, 2 times less stiff than last year's chassis.

Here are the data and comments:

1. 2014 chassis / motor A / gearing X

Fastest lap - 5.965 sec
Average lap - 6.36 sec

[notes: squirts on acceleration (wheels spin) / needs a lot of brake / stays in the slot]

2. 2014 chassis / motor B / gearing Y

Fastest lap - 5.919
Average lap - 6.13

[notes: easier to control / less squirting / just as fast a motor A/gearing X]

3. 2015 chassis / motor A / gearing X

Fastest lap - 5.732
Average lap - 5.99

[notes: still squirts on acceleration / more drivable in this chassis / doesn't want to de-slot]

4. 2015 chassis / motor B / gearing Y

Fastest lap - 5.820
Average lap - 5.97

[notes: easier chassis for all corners / more subtle / smoother / plenty of power / consistent lap times]

So, I'm taking away that this year's chassis is at least as fast as last year's and seems easier to drive. That was far from a given going down this rabbit hole, again. But, for now, it makes the effort worth it. I wasn't looking forward to shelving the new chassis, but I was prepared to do it if last year's chassis was faster.

Although motor A / gearing X turned a faster lap in the 2015 chassis, it is more of a handful to drive. Motor B / gearing Y is only marginally slower in fastest lap and is the same for average laps and, more importantly, it's more predictable and easier to drive fast.

So, looks like it's going to be the 2015 chassis, motor B / gearing Y.

Time to head for the finish line and wrap up this build. How it will compare to the others in this proxy only races will tell.

Harry, I found my motor........it wasn't orange.............

Allan

[TuscoTodd]

Cool to hear that the new design worked out well Allan!
(like seeing the "notes" as well)
:handgestures-thumbup: