How Does a Hydrostatic Transmission Work?

As a 'mechanical layman', this explained how hydrostatic transmission works simply & clearly - well done, and thank you!

Videos like this are what make YouTube worthwhile.

I just love the amount of entusiasm when explians the math of the transmission. And at the end, as a final conclussion, he finishes it with a "pretty cool". Love it.

My friend rebuilt the powertrain for a 15” gauge miniature train locomotive. The train as built in 1947 used a simple clutch between the gas engine and the driveshafts for the trucks. Obviously, it had no reverse! When the clutch suffered a catastrophic failure, we could not find a direct replacement for it or even parts to repair it. The most recent parts list from the manufacturer was dated 1963. So we swapped the ancient, smoky Onan motor for a new Honda 25HP and, instead of the clutch, used an Eaton Series 11 hydrostat. All it took was moving to motor mounts forward a few inches and fabricating a couple of brackets for the transmission. We got excellent power throughout the speed range, plus a reverse. No more pushing the train backwards 400’ to put it away at night! It helped that the company I worked for was an Eaton distributor, so I got him the employee price of cost + 10%.

Appreciate the explanation. How these mechanisms are conceptualized and manufactured is amazing. I have a compact tractor with a hydrostat, which is super convenient and smooth compared to the traditional gear transmission. I could picture early farmers being skeptical of this incredibly complex mechanism initially though. The whole rotation mechanism is similar in concept to a helicopter rotor hub with the awash plate, connecting rods and bearings. I’m going to go easier on my ride on mower and tractor now, keep ‘em in low gear. Stuff is intricate.

This is all new to me, but I got a 2-wheel tractor and wanted to understand how it works. Your explanation of a challenging subject is exceptionally clear. Thanks.

I’ve been using my zero turn lawnmower for 3 years now and I always wondered how the transmission works. I do believe those have 2 small transmissions (one for each wheel) but this explained perfectly and very clearly how the magic happens. I love knowing how things work!

Nicely done. Great to listen to someone explain things efficiently.

What an interesting way to create a continuously variable transmission. Thanks for taking the time to rip one apart and dig into the subject!

I'm so glad I found your channel! Your excitement for all things mechanical is exactly like how mine is, so I can totally relate! You've earned a sub!

Awesome, your disassembly was the most intuitive way to visualize it, well done

Thank you so much for your demonstration! I have wondered about hydrostatic drive principles, but never have delved into it.

Absolute best video explaining anything about these seemingly mysterious mower transmissions

Thanks for this video. I've seen 3d animations of these, but your process of going through it step by step really helped me get a better understanding of these.

I have an early Murry with such a drive and am totally spoiled. I have often wondered how it worked, but I wasn't about to take it apart just to see. I think it's absolutely brilliant. Kudos to Mr. Hydro. LOL Thanks for sharing.

Bravo...well done! What's amazing is the mind of the engineer that created machinery like this.

Thank you for this video, I am a very mechanical person, but I’ve never given a hydrostatic transmissions a second thought, thank you for this! Perfect

This is a really good video explaining how the hydrostatic transmission works. What a really cool, amazing technology!

Your time is Appreciated I’m trying to figure out how to make this transmission more powerful this really helped a lot

If I had had you as a teacher I would have definitely gotten better grades. Thanks for your thorough explanations.