XR Build Thread

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Robert Culbertson

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Thomas Kimsey

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Robert Culbertson

Anyone can make pretty color plots with FEA. By changing element type and size you could make a bad design actually pass.

Yes, any tool can be misused if you do not know how to use it, whats your point? Also there is no way a cage design would be allowed on FEA designs alone in the US. I was just pointing out that an engineering tool that could be used to help prove that this design is legitimate would not be helpful in this case. I will ask the scrutineer more blatantly tomorrow "Does this not meet the NASA rules".

No real point to be made, and I'm certainly not trying to ruffly any feathers here. I'm just not sure of your experience with FEA or FEA within Solidworks. (hence my comment about changing element type and size, which are only 2-variables of the many that you could change).

It could be useful in comparing the two designs side by side, but looking at absolute strain values of a complex structure without an FEA study and validation is not very accurate, in my opinion.

Solidworks FEA

Abaqus

Also, not worth it as a design validation as it would get me nowhere with the scrutineer. And it surely would only be good for comparison between designs and not as an accurate model of the whole system. Would be a fun side project if I didn't have a whole lot of other projects and a vast lack of time.

Side note: What is on the Clark XRatty for oil cooling? Stock ecoboost heat exchanger or proper cooler?



Edited 1 time(s). Last edit at 06/14/2016 07:59PM by Thomas Kimsey.

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Thomas Kimsey

Side note: What is on the Clark XRatty for oil cooling? Stock ecoboost heat exchanger or proper cooler?

Stock heat exchanger currently. It really needs an external, either with/without the stock water to oil one.

Its not about whats on the car but removing the hood and bumper to stay cool. :-)

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Grant Hughes

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NoCoast
Its not about whats on the car but removing the hood and bumper to stay cool. :-)

Coolant temps dropped from 125C to 99C max (257F to 210) after the hood was removed. The old engine saw 135C/275F a few times... scary hot. That same motor did 4 more races with high temps, and it never skipped a beat... until Rocky this year, when it holed a piston. The 'boost is a pretty tough little motor.

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NoCoast
I think Mike Hurst's Capri was this design too.

Its connections to the rear towers are done like the Izzy's one (the bars are laid out differently though):



I think its cage was built by The Original Dave Clark.

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Self-righteous douche canoe



Edited 2 time(s). Last edit at 06/20/2016 05:11PM by hoche.

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Not Trolling
Scrutineers are not there to give an opinion on the safety of a design, merely to say that the build meets the rules (which include FIA as an option) and that the build appears to have been done properly. (no-one is about to start x-raying the welds)

If only it were that easy.

The problem is that there are a lot of gray areas in the rules and it's in those cases where scrutineer opinion comes into play. And it's complicated by the fact that different scrutineers have different experiences, training, and temperment. Some try to be helpful, some are martinets.

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Self-righteous douche canoe

John, What do you have in stock for brake parts? Mainly calipers, adapters, and rotors. Think anyone has your setup used?

Started the cage last weekend. Waited almost six months to have a local shop make my bends but after a while they told me they didnt have time. Luckily I was able to borrow a bender from a friend last week.

Very nice. Great progress. Wish I could get moving on the cage. Keep it going!

Was it terrible hard, or was rather simple, any tips for people doing it themself?

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p0inT92
Was it terrible hard, or was rather simple, any tips for people doing it themself?

Its not very hard. I do have help from someone who has done a couple cages before. I am certain there are better people to ask on this forum for tips and tricks as I am an extreme novice at this. But I will give you a brief overview.

Boxes for cage feet - 3mm steel plate cut with a cutoff wheel. Pretty simple but time consuming to make everything fit nicely.

Main hoop - Took a large piece of cardboard and cut it until it fit where I wanted the main hoop. Then I took a bent piece of pipe and traced where the bends would be. Trimmed the cardboard in straight lines between the bends and then replicated the cardboard outline in tubing.

Forward legs - I had some bends from a old cage I cut apart so I just mocked up a forward leg out of 2 bends and some straight parts. I couldn't imagine trying to get the fit right on the forward legs without having some pre existing bends to play with. (Attached picture to show mock up forward leg)

Everything else is pretty much measure, cut the tube an inch too long, and take a small cut with a tubing notcher, check fit, if its too long still take more small cuts till it fits. The tubing notcher I borrowed will only cut to 60 degrees so some members have required some sculpting with an angle grinder and a flap disk. I've only scrapped one piece so far and it was because it was less time consuming to make a new one and it was only 6" long.

Nice work thomas! Nice to see another one making its way towards a rally. Shame ya lost 6 months waiting for an answer from that shop but seems to me like you don't actually need them!

It would have been nice if I got the tubes bent a while ago but I was also busy doing other stuff like being lazy and helping my housemate with getting his 96 logbooked and ready. Probably could have pushed the shop to bend them a long time ago, also I got the tubing from them and they gave me a good deal.

More progress this weekend. However the seat mounts are too high and with padding on the forward leg and a helmet on there are clearance issues. This week is going to probably be dedicated to putting the seat mounts as low as possible.

Things left to do on the cage are
-Taco Gussets
-Tie front strut towers to cage
-Harness bars
-Tie rear strut towers together/to floor over diff mount

Learned a good life lesson - Never build seat mounts and weld them in before

1. Building cage first
2. Putting padding on cage
3. test fitting head clearance with helmet on