What does H-Flip mean ?

On the gear calculator past ZD there is an option H-Flip

What is that?

How do you do that?

Where can I learn more?

A gear set is composed of 2 gears. One is on the output shaft and the other is on the input shaft. H gear is a 2nd or 3rd (i don't remember)
When you "flip" the gears, you switch the two from output to input,, and move it's position to 5th on the gear stack because it's a really tall gear.

upon reading this,,I probably confused you.
-Robert

H-Flip means that you take an "H" gear, and trade places between the two gears in the set putting the one from the output side, and putting it on the input shaft; and replacing the one on the output side with the one that it just replaced on the input side.

More info in Dr Evil's video.


Edit: Robert posted while I was typing. I probably confused you, too.

Gears come in pairs, and input gear and an output gear. If you divide the number of input teeth by the number of output teeth, you come up with a gear ratio for that pair. If they are "flipped" the ratio is reversed and the (original) output gear is then divided by the (original) input gear, giving you an inverse ratio.

1:1 for example, means that the number of input teeth is equal to the number of output teeth. 1/1 = a ratio of 1. Lower gears have a ration of less than 1. The input gear turns more times than output gear When you flip them they have a ration greater than 1. Think of that as "overdrive".

The "H" gear-set is used as 2nd gear on a 904 mainshaft. Unlike the standard 914 mainshaft that has 2nd gear permanently attached (part of the forging) the 904 shaft has a changeable 2nd.

A flipped H is an H gear-set that has the input and output ratio switched by putting the original input gear on the output shaft (pinion shaft) and the original output gear on the Input shaft (main shaft).

One outcome is that the teeth angle is reversed whenever you flip helical gears, so the axial thrust on the two shafts is reversed when you apply torque to that gearset. It's not usually a problem but when you build a box that way you need to pay close attention to all of the tolerances. You don't want your ring-and-pinion backlash to go out of spec. Especially if you're running big horsepower, which most folks who are interested in a flipped-H would be.

There's a bunch of threads on this topic both in here and in the Paddock as well. In this thread are links to other threads resources too.

http://www.914world.com/bbs2/index.php?showtopic=79893

Good luck

Thanks guys!!!!

excellent point in the direction I needed...