How short can a driveshaft be?

I ended up building a setup using construction paper, rubber bands, and Elmer's glue. I then applied glitter in a precise manner to get the proper balance. I could do a tech post if anyone is interested.

 

Remember the Cheetah? No driveshaft at all. One u-joint, transmission yoke to rear end. Not exactly a lot of articulation, though.

 

My senior dragster has only one u joint. It bolts to the rear end and the slip yoke goes into the trans. I was always led to believethis wouldnt work but have seen a few pics of old rails with this set up so since it is my car and i can change it if need be I tried it. It works perfectly with not even a hint of vibration. I have made driveshafts as short as 9 inches in the past. As long as it is straight it will be fine. With two u-joints they must be phased properly.
Don

 

thanx for the cheap shot.
& what? start all over asking the very same question, gettin the very same answers?
Thought the thread was about short driveshafts, not about a particular Stude.
We are talkin' 50+ yr old cars here, these discussions are age-old.
I'm building a torque tube in a Banty roadster,for street use, & am wondering how bad i need to work at shortest tranny.

 

Some of the Cad/LaSalle transmissions did not use a slip yoke in the tail shaft. They had a solid yoke on the tranny and a slip joint in the drive shaft. If your tailshaft does not use a slip yoke then you must have one in the drive shaft. The drive shaft can be made from an old Cad driveshaft or something from a modern 4 x 4.

 

Thanks fritz! My long Lasalle tailshaft has a solid yoke at the trans, running the driveshaft would make a mighty short driveshaft, This gives me this thought...
Find a 50'olds tailpiece...
Convert the gearbox to torque tube by welding on the back of a
ford trans. or convert the rear to a slip yoke...a major pain in the ...
or convert the rear axle to a slip yoke !

 

Think about suspension travel and the extreme angles at the very top and very bottom of its travel. With a long drive shaft, the angles would not be as extreme as with a short one... If things are too extreme, you might even worry about pulling the slip yoke out too far and jamming it in too far.

 

that said, what is the max angle a drive shaft can be angled at?
and i am thinking cross ways not up and down...

 

Just for reference purposes, the eighties-vintage XJ6/XJ12/XJ-S Jaguars have bulletproof two-piece driveshafts with a slip yoke in the center.

This is an example of their overkill design since these cars have an independent rear. The diff does not move much relative to the transmission, except for the motor/trans and the rear cage wiggling around on their rubber mounts.

This would probably not be a solution for Inkorekt as the overall length is on the long side with all this hardware. But they might be a good solution for someone running an older torque-tube tranny with an open rear.