Drive shaft diameter

[Jeff Brock]

Hey folks, 

Building a new Buick XO / LSR car.
wrestling with come minor clearance issues for the driveshaft.
This would be solved, if I could safely run a 2 3/4" diameter shaft. Is there a chart or school of thought for tube diameter - rpm - hp ?
Should I consider moly tube ?

I'll be running 6000 rpm @ 300 hp. 

Thanks, Jeff Brock

[RichFox]

I would expect that length would come into that also.

[hotrod]

There are some resources out there which might help.
This post has a link that talks about drive shaft critical speed, which is related to the length, and stiffness/diameter of the shaft.

What is important is the maximum shaft rpm and its stiffness relative to its length which is determined by its material of construction, wall thickness and diameter of the tube, they all work together to define the critical speed of the shaft where it is subject to major instability and whipping or whirling and failure.

http://www.landracing.com/forum/index.php/topic,6207.0.html

http://www.markwilliams.com/driveshafttech.aspx

I recall another link from a major manufacture that talked about driveshaft design but can't find it right now, but I found these on google.

http://www.wallaceracing.com/driveshaftspeed.htm

http://www.engineersedge.com/vehicle_driveline_design.htm

Larry

[Jeff Brock]

I forgot to add : 25.5 " centerline to centerline of U-joints.

Thanks HR, I'll look into those posts. I did do a crude search, first .

[Richard 2]

Call PST 1-888-575-7888. Tell them what you have and want and they can tell you if it can be done.
They make Steel, Aluminum, Chromoly and Carbon fiber Driveshafts.
And their turn-around is short. 
Richard 2

http://www.pstds.com/custom_driveshafts.htm

[Jack Gifford]

... 25.5 " centerline to centerline of U-joints...

I doubt you could make that short little shaft whip if you wanted to, even if you went down to around an inch diameter!

[Jeff Brock]

Thanks guys, 
I built a drive shaft tonight using a 3" diameter late 80's Lincoln shaft. It'll work perfect. According to the links / charts on the 2 sites you suggested, it is plenty strong.
 Just took a little "rose bud" metal moving on a crossmember and it's clear.

Thanks again.

[Stan Back]

Come on, Jeff -- show some car pictures.

[Jeff Brock]

I tried the "desktop upload" at "insert image", but no... what do I have to do? join a web photo site or what?

[Elmo Rodge]

Jeff, click on "Additional Options" under the reply box. Then click on "Browse". That should take you to your photos on your computer. Select a photo from there. The only other thing is the photo can't be too large. I always reduce mine to about 850X640 whatchamacallits. I'm no computer whiz. If I can do it..........    Wayno

[Stan Back]

Jeff --

With your permission, I think I can post the two you gave me last year.

Stan

[Jeff Brock]

You bet Stan... although I have no idea what I sent you?

Thank you.

I had to take about 6 months off her progress and do some other art and cars stuff, but I'm back on it, full tilt! 

Thanks Wayno !  But I still couldn't upload... I have to figure out how to make them smaller . Maybe tomorrow night.  I'm pooped!

Jeff

[Stan Back]

Let's see if this works . . .

[Stan Back]

and . . .

[Stan Back]

finally . . .