Yo, Gearheads!

[cx]

Any of y'all auto mechanic types familiar with composite driveshafts being used in the early nineties, or thereabouts?

In question is a 1992 (I think) chevy van-type vehicle. One of them they usta trick up for long trips with alla fold-down seats and refrigerators and such.

Friend bought one and says the driveshaft appears to be some sorta fiberglass stuff with aluminum ends on it.

I ain't never heard tell of no such. Anybody know about that and the theories behind such use?

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[MHI]

I never seen one, but here is a link to a company that makes them
http://www.strongwell.com/selected_markets/comp_driveshaft/

I could ask my brother, who rebuilds transmissions, but he hasn't seen one like I have in my new truck which is all aluminum. Its about 8 inches in diameter.:)

[cx]

Kewl, thanks, Matt. That sounds like his description and that site even give the rationale behind the design. :)

But I gotta admit I ain't never heard tell of this manufacturing method called "pultrusion." I can visualize it, I do believe, but ain't never heard the word. :shake:

What kind truck gots that grat big ol' aluminum shaft?

[MHI]

2007 "all new" GMC Sierra 2500HD. I'll post a picture of it next time I feel like crawling under it. It is impressive looking, because its on a long bed extended cab.:)

[sandbagger]

"pultrusion (http://composite.about.com/library/weekly/aa101397.htm)" is just like it sounds - the material is pulled through the dies instead of pushing (extrusion). Had to do it that way cuz you can't push a wad of fibers any more than you can push on a rope. :rolleyes:

[John Bridge]

Who says you can't push on a rope? You can push on a rope all day long if you want. ;)

[Davy]

Maybe that's why they called it the "all new" GMC.:)

[cx]

Thanks for the link, Art, I'll add all this to my learning something new every day list. :)

[sandbagger]

now John, soaking the rope in VersaBond is cheating. :nya:

[Beaux]

being a poor soul below the forecastle stowing line with a boatswain screaming faster you s#@#@#@$%.m@#$$@. I say yes a man can push a line...or rope as most people call it. Real fast too.

[John Bridge]

What's a swabbie-I-mean-sailor doing up in the back woods of the Big Thicket? :D

And moreover, do you know anything about CX's drive shaft? :D

[cajtar]

I can't proclaim to know ANYTHING about CX's (ahem) driveshaft, but here's what I do know about fibre driveshafts used in trucks.

-they are light, which means higher natural frequency, which means lower vibration levels transmitted to the chassis, which means bearings etc can be downsized. Also permits higher engine speeds (but not such a big factor for trucks)
-the are torsionally very stiff. You can layup the fibres in the exact right orientation to create a stiff assembly with minimal mass.

With steel or aluminum driveshafts to make then stiffer, you need to increase the tube diameter. When you get to >500lb.ft of torque, the driveshaft gets really big and it becomes more difficult to package. Fibreglass or carbon fibre help here significantly.

Trick is attaching the aluminum yokes reliably. Also must keep them cool, the resin can't take the heat.

Cheers,
Cajtar

[Beaux]

living the good life;)

as far as drive shafts go I believe it's under the truck. right?

[Dave Taylor]

I push rope all day!

[cx]

Sounds like a useful application for composite material, for sure. Just surprised I'd never even heard of it. Thanks, guys. :)