LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently June 23, 2018, 5:56 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 9 posts ] 
Author Message
PostPosted: December 5, 2013, 2:31 pm 
Offline

Joined: December 5, 2013, 2:22 pm
Posts: 1
I am trying to find a source for affordable rectangular fiberglass tubing, to build a lightweight car frame out of. I got some samples years ago while trying to compete in the Auto X-Prize, and the material is very light and strong. The big manufacturers will not discuss less than 1,000 feet at a time. Any suggestions? Thanks!


Top
 Profile  
Reply with quote  
PostPosted: December 5, 2013, 3:28 pm 
Offline

Joined: October 29, 2013, 5:15 pm
Posts: 176
Is there any reason why you couldn't use round tubing? It seems like it would be much easier to source.


Top
 Profile  
Reply with quote  
PostPosted: December 5, 2013, 4:32 pm 
Offline
Mid-Engined Maniac

Joined: April 23, 2006, 8:26 pm
Posts: 5864
Location: SoCal
Google finds several, here's one
http://www.eplastics.com/Fiberglass-FRP ... are-Tubing

_________________
Midlana book: Build this mid-engine Locost!, http://www.midlana.com/
Kimini book: Designing mid-engine cars using FWD drivetrains, http://www.kimini.com/book_info/


Top
 Profile  
Reply with quote  
PostPosted: December 6, 2013, 7:47 am 
Offline
User avatar

Joined: November 12, 2008, 6:29 am
Posts: 3536
Unless you intend to use carbon fibre then aluminium tube is lighter for the same strength.

Otherwise any good fibreglass shop can just wrap polystyrene square lengths to order, it's not rocket science.

I think there's some relative info for you in this thread .. viewtopic.php?f=39&t=15283


Top
 Profile  
Reply with quote  
PostPosted: December 7, 2013, 7:57 pm 
Offline

Joined: March 26, 2012, 1:53 am
Posts: 207
Location: Mountain View, CA
cheapracer wrote:
Unless you intend to use carbon fibre then aluminium tube is lighter for the same strength.


Yes, and while 2/3 the weight of aluminum, fiberglass is only 1/3 as stiff and that's if you use pricey S glass.

And steel has the same mass/stiffness ratio as aluminum, so why not use that?

And the metals absorb a lot more energy in a crash.

_________________
------------------------------------
Noah


Top
 Profile  
Reply with quote  
PostPosted: December 8, 2013, 4:55 am 
Offline
User avatar

Joined: November 12, 2008, 6:29 am
Posts: 3536
NoahKatz wrote:

And steel has the same mass/stiffness ratio as aluminum, so why not use that?


It's relative to buckling strength as well but at the safe thicknesses of a Locost chassis, yes, steel is the winner when all the sums are done and that's why even the most expensive Caterhams etc. chassis are still done in steel.


Top
 Profile  
Reply with quote  
PostPosted: December 8, 2013, 1:03 pm 
Offline
The voice of reason
User avatar

Joined: January 10, 2008, 4:47 pm
Posts: 7546
Location: Massachusetts
Quote:
And the metals absorb a lot more energy in a crash.


It isn't the absorbing that is different it is the dissipation! :D Think an Olympic pole vaulter. The tube absorbs the energy but then it returns it during spring back. Worst case a Locost chassis of fiberglass would hit a wall and then launch you backwards at the same speed…

I'd like to see an option for doing the car from Aluminum. Corrosion resistance would be a nice to thing to have in at least some parts of the country. The sums clearly say aluminum wins hands down over steel from a mechanical perspective. It's a hard problem though when considering labor. You see aluminum in planes because weight is much more important for planes than cars. In a Locost the frame and body are also a smaller percentage of the total weight so it becomes evan less important.

Steel is a good material for us because it is very well understood with 50 years of Seven type construction and is forgiving of average builder skills. It also lets you think you are 50% done after building your frame when in fact you haven't even learned how to figure out "done" yet. :rofl:

_________________
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.


Top
 Profile  
Reply with quote  
PostPosted: December 10, 2013, 12:30 pm 
Offline
Mid-Engined Maniac

Joined: April 23, 2006, 8:26 pm
Posts: 5864
Location: SoCal
Here you go, provided on the usual platter: http://www.mgs4u.com/fiberglass-tube-rod.htm

_________________
Midlana book: Build this mid-engine Locost!, http://www.midlana.com/
Kimini book: Designing mid-engine cars using FWD drivetrains, http://www.kimini.com/book_info/


Top
 Profile  
Reply with quote  
PostPosted: December 13, 2013, 1:44 am 
Offline

Joined: March 26, 2012, 1:53 am
Posts: 207
Location: Mountain View, CA
horizenjob wrote:
It isn't the absorbing that is different it is the dissipation! :D Think an Olympic pole vaulter. The tube absorbs the energy but then it returns it during spring back. Worst case a Locost chassis of fiberglass would hit a wall and then launch you backwards at the same speed…


That's true, because of its low modulus and relatively high strength fiberglass is a relatively good energy absorber/spring material (i.e. Corvette suspension leaf spring).

But you don't get much of that benefit unless you build a low stiffness frame.

_________________
------------------------------------
Noah


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 9 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
POWERED_BY