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 Post subject: A little adivce wanted
PostPosted: July 31, 2017, 5:28 pm 
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Joined: July 31, 2017, 5:01 pm
Posts: 2
Hey guys, I know this isn't really a locost style car but its not really a gokart either anyway this will be my first time creating a chassis from scratch. Below are pictures of the chassis I modeled in Creo (unfortunately the educational version doesn't have the access to the frame builder feature :BH: so the model isn't the neatest most accurate on I've made plus the suspension components are not 100% accurate as well). I know it's probably hard to judge without it in front of you but any glaring issues anyone sees will be appreciated. I plan on using 1.25" 16 ga square tubing for most of the chassis with 1" 16 ga square tubing for support structures. It came out to 134' (100' of 1.25" and 34' of 1") and 150 pounds.

For reference: overall length=115", overall width=27", wheel diameter=22", wheel base= 103", back of seat to pedals=52", height (from bottom frame to top roll bar)=36"
I will be using a Honda VTR1000 motor, miata front and rear suspension and rear diff.

Any advice or comments are appreciated!

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PostPosted: July 31, 2017, 6:38 pm 
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Joined: April 26, 2008, 6:06 pm
Posts: 2872
Location: Under the weather. (Seattle)
Rectangles are your enemy. Triangles are your friend.

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PostPosted: September 13, 2017, 1:34 pm 
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Joined: August 21, 2017, 7:37 am
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It sas a little bit of a look like mine which im trying to fix right now. The area where the seat is appears to be the weakest link. So if you were in an accident the frame would almost hinge there, squishing your head.


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PostPosted: September 13, 2017, 3:29 pm 
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Joined: July 17, 2006, 3:09 pm
Posts: 264
Location: Holly, MI
That's a long wheelbase. Mine is even longer, but I'm using a V8. The result is that the car won't rotate well. It will be stable, and it will recover from slides better, but turn in will be slow. I would suggest trying to get it under 100 inches.

Ken


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PostPosted: September 13, 2017, 11:19 pm 
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Joined: June 8, 2010, 8:02 pm
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Location: White Rock, BC, Canada
I'd suggest giving this book a read:
https://www.amazon.com/Chassis-Engineer ... ngineering

It's easy to read, and the amount of info there is well worth the $20.

As noted, triangles are good and you don't have enough of them. Imagine the end of each tube is pushing and pulling HARD on whatever it is connected to. So if it is in the middle of another tube, that tube is just going to flex. The load should be trying to compress/stretch another tube, not bend it in the middle.

Cheers.

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PostPosted: September 14, 2017, 4:03 pm 
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Joined: July 4, 2006, 5:40 pm
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Location: Novato, CA
Alternately you could consider the whole structure and not just the frame. On sections you plan to sheet rigidly, cross-bracing may just add weight.


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