We could talk for a week and not explain driveshaft operation as effectively as this little two-minute demonstration video does. Watch this.
Thanks, internet. Demonstration rigs like this one are most commonly found at vocational colleges and suchlike, or you can buy or construct your own if you must, but lucky us. This video fell right into our laps via the YouTube.
With utter clarity and simplicity, this clever machine demonstrates two things: the effects of 1) universal joint angle and 2) universal joint phasing on driveshaft operation. And as a bonus, both sight and sound are used to drive home the essential points.
As you know if you have ever tried it, propeller shaft velocity—and how it changes—can be incredibly difficult to describe, especially to mechanical rookies. However, this setup makes the issue totally easy to understand. And while it’s not covered here, the video also points to the value of constant-velocity couplings like the Rzeppa joint, as used on modern front wheel-drive autos. (For a great little animation that shows how Rzeppa joints work, be sure to click here.) This is one of those cases where a picture is worth far more than the proverbial thousand words. Check it out.
Light bulb moment!
I knew universal joints weren’t constant velocity when at an angle, but I didn’t realize you could completely cancel it out with another universal joint with correct phasing. Nice, simple video.
Good eye, that’s exactly how it works. In fact, if you double up two joints one behind the other, you have a type of constant velocity joint known as a double Cardan joint.
The double Cardan joint is actually not a constant velocity joint. It simply halves the individual joint angles and velocity change but there is still a velocity change. Therefore cannot be a constant velocity joint.
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YES. IT STILL WORKS TODAY. 1-26-16
Very interesting.
I would like to know how to achieve correct driveshaft phasing
I have always thought that 23 degrees was the limit to the angle . 10 to 15 was considered the best angle????
Wow – great demo!
Very cool idea! Really brings home the velocity changes that happen as universal joint angle changes. Great demo.
Really points out a driveline area where if the factory does not do this exactly right (can you say supplier problem?) there could be serious vibration consequences. Lots of 2014 Sierra Truck owners are interested in this that is for sure.
When you hold your angel finder at anything but 90 degrees to your driveshaft you fail to obtain a true measurement.