Hydraulic Propulsion

[brian eiland]

...a portion from my website....http://www.runningtideyachts.com/power/
"While working on a new bow thruster design, a Hungarian gentleman has developed and built several entirely new and unique gearless, twin-rotor, angular-piston, hydraulic motors. This patented mechanism employs two rotors which are interconnected by angular pistons that are all contained and bearing mounted in a common housing. The linear displacement of the pistons in one of the rotors is directly converted into the rotational motion of the other rotor, interactively. The geometrical and mechanical relationship between the two interconnected rotors provides optimum conditions for direct conversion of linear displacement of the pistons into rotational displacement of the rotors. Barring frictional losses, the conversion is 100% efficient. None of the commercially available axial piston motors have such direct and efficient means for converting linear displacement into rotational motion."

I was contacted over 6 months ago by a British firm wishing to know more about this design. I believe thay made contact with the patent holder. Don't know the outcome yet.

[John Perry]

Brian

Looking at the pictures on your website the new hydraulic motor referred to would appear to be a 'bent axis' design, I think with pairs of pistons connnected by rigid 90 degree links spaning between the two rotors. As I mentioned above, I was involved at one time in a R+D project on hydraulic motors and this was one of umpteen configurations we considered in the early stages of the project. We found that almost all of the many configurations that we considered had been patented, if not as hydraulic machines then as rotary steam engine possibilites by victorian engineers. I cannot remember whether or not the design with rigid 90 degree links was one for which we found an existing patent but I have definitely seen drawings of the same mechanism used not as a hydraulic machine but as a means of transferring rotational power through an angle from one shaft to another, the linked pistons will do that even without any hydraulic fluid present.

My initial thought regarding the design you refer to, assuming I have interpreted it correctly from the small picture, is that it is potentially a pretty good design but it still suffers from the same power losses which apply to all designs of hydraulic motors, the main ones being viscous friction loss, leakage losses and compressibility losses. I would be surprised if it turns out to be so much more efficient than existing hydraulic machines that it changes the direction of development of ship/boat transmissions. Comparing it with a conventional axial piston machine, which is the 'gold standard' for high efficiency hydraulic machines, it has the advantage that it avoids the frictional losses of the 'slippers' which drive the pistons of a conventional machine in and out of their bores. However this advantage is not as huge as one might imagine, slippers run with surprisingly little friction since they glide on a cushion of high pressure fluid fed from the cylinders, rather like small hovercraft. Against this advantage, the pistons in this design are going to be more heavily loaded sideways against the cylinder bores than in a conventional design.

The design which our R+D project eventually adopted for further development was a rotary vane design with unusual axially moving vanes. This was not my decision and I think it was a mistake, a conventional axial piston pump would have done the job better. In fairness to my bosses there was an externally imposed requirement to keep the diameter of the machine as small as possible and the axial vane design was good that way.

John

[brian eiland]

Hello John,
That is real interesting that you should be so knowledgable about this subject. I will definitely get back to you on this subject. I just happen to be real busy with 4 unrelated projects at the moment

[the yacht shop]

you guys bring up many good points but i can tell you from past experience that a good hydraulic drive setup can be (no, make that is ) just as efficent as a hydraulic transmission such as a paragon or borg warner. I had a westerbeke 4/107 with a paragon in a 40' sail and then changed to the vickers hydraulic pump and motor. fuel consumtion was the same with both units but the vickers was smooooooth and quiet. and it blows the socks off a conventional trans in close quarter docking.

[FAST FRED]

The advantages are many , besides effortless shifting at any engine speed the ability to power a gen set , bow thruster (with out 30 second restrictions ), hoists anchor windlas and even stabelizers is grand.

The problem is efficency as most pumps are at best 92% efficent as are the motors (in the correct operating range) .

The problem is these 2 efficencys multiply , and compare poorly with the 2 or 3% loss in a std mechanical tranny.

One saving is the engine speed under way can be matched to the power required, if the pump has large enough low RPM output.

If fuel consumption is less of a hassel than burning out electric motors in windlasses and thrusters , GO for it!!


FAST FRED

[Dynaset]

Only one petro/diesel engine and hydraulic pumps are enough.
Hydraulic system gives the variable speed control, very fast exchange of the propeller rotation direction without breaking anything, bow thrusters, stabilizers, generator, high pressure bow thruster/washing system and etc.

Your ideas are just the limit.

[Easy Rider]

I'm surprised no one has mentioned Vetus. They offer 100% ready to go hyd systems around 20 to 30 hp.
I wonder if one used a 2-1 to 3-1 gear w a hyd pump on the end of the gear and located the pump and motor very close to each other one would have very low velocity fluid w large dia and fairly short hoses. In my hyd steering system the friction seems to come from cylinders and pumps. If the majority of the friction came from fluid in the hoses rather than pumps and motors this idea would seem to have merit.

Easy

[joseph fasola]

Originally Posted by Jmarkley

I'm convinced that it's possible to use hydraulic fluid to turn a prop instead of using a direct mechanical connection. The advantages are less maintenance, less vibration, placement of the engine anywhere on the boat.

Does anyone know of a firm which markets this type of drive system?

YES I DO YOU NEED TO SEE PLAN AND VESSEL .I'm in the patent process need a parnter let's talk 205-504-9416

[joseph fasola]

Originally Posted by Jmarkley

I'm convinced that it's possible to use hydraulic fluid to turn a prop instead of using a direct mechanical connection. The advantages are less maintenance, less vibration, placement of the engine anywhere on the boat.

Does anyone know of a firm which markets this type of drive system?

yes , need someone not afraid to go out there in the water where nobody else has gone call me at 205-594-9416 emIL ME AT onicefishing@att.net are visit my web site at www.reeldealpolecaddys.com click about us you would not believe what I've done 53' vessel 54m.p.h 3800 mile range on 400 gals of diesel propane is off the chart and your right no maintenance sealed unit, no vibration, and take up 80% less room in engine space and it's green propulsion no emissions in water

[brian eiland]

Originally Posted by joseph fasola

.... or visit my web site at www.reeldealpolecaddys.com click about us you would not believe what I've done 53' vessel 54m.p.h 3800 mile range on 400 gals of diesel propane is off the chart and your right no maintenance sealed unit, no vibration, and take up 80% less room in engine space and it's green propulsion no emissions in water

Your website reference could not be accessed??
Brian

[gonzo]

The website sells fishing rod holders. Joseph: can you provide any evidence of you claims? No vibration, for example, is a good sales pitch but an engineering impossibility. No emissions in water is another claim that is not possible.

[FAST FRED]

"you would not believe what I've done 53' vessel 54m.p.h 3800 mile range on 400 gals of diesel propane is off the chart and your right no maintenance sealed unit, no vibration, and take up 80% less room in engine space and it's green propulsion no emissions in water"

Yes it is unbelievable , so how about posting an article on your method of operating?

Details , photos and logs?

[tugboat]

http://www.youtube.com/watch?v=-cWoy...pjjaS4ZRwHAkGQ

they work great ---watch all this guys vids...im doing this on my tug--engine to pumps to two drive units...might be a little extra fuel but it has advantages i really lik e such as on a tug-instant reverse and the motors i want are continuous duty,...two props beats one for maneuverability and i can use two cheaper common props...

i like your idea ...let me know how it works...

[tugboat]

Originally Posted by Easy Rider

I'm surprised no one has mentioned Vetus. They offer 100% ready to go hyd systems around 20 to 30 hp.
I wonder if one used a 2-1 to 3-1 gear w a hyd pump on the end of the gear and located the pump and motor very close to each other one would have very low velocity fluid w large dia and fairly short hoses. In my hyd steering system the friction seems to come from cylinders and pumps. If the majority of the friction came from fluid in the hoses rather than pumps and motors this idea would seem to have merit.

Easy

i agree with you easy rider--i corresponded with someonme off here- who used the same setup i plan--i think he even coolled the motors by running them under water..in this vid the hydraulic motors are just standard cooled with oil reservoirs...

http://www.youtube.com/watch?v=-cWoy...pjjaS4ZRwHAkGQ

[brian eiland]

Originally Posted by John Perry

Brian

Looking at the pictures on your website the new hydraulic motor referred to would appear to be a 'bent axis' design, I think with pairs of pistons connnected by rigid 90 degree links spaning between the two rotors. As I mentioned above, I was involved at one time in a R+D project on hydraulic motors and this was one of umpteen configurations we considered in the early stages of the project. We found that almost all of the many configurations that we considered had been patented, if not as hydraulic machines then as rotary steam engine possibilites by victorian engineers. I cannot remember whether or not the design with rigid 90 degree links was one for which we found an existing patent but I have definitely seen drawings of the same mechanism used not as a hydraulic machine but as a means of transferring rotational power through an angle from one shaft to another, the linked pistons will do that even without any hydraulic fluid present.

My initial thought regarding the design you refer to, assuming I have interpreted it correctly from the small picture, is that it is potentially a pretty good design but it still suffers from the same power losses which apply to all designs of hydraulic motors, the main ones being viscous friction loss, leakage losses and compressibility losses. I would be surprised if it turns out to be so much more efficient than existing hydraulic machines that it changes the direction of development of ship/boat transmissions. Comparing it with a conventional axial piston machine, which is the 'gold standard' for high efficiency hydraulic machines, it has the advantage that it avoids the frictional losses of the 'slippers' which drive the pistons of a conventional machine in and out of their bores. However this advantage is not as huge as one might imagine, slippers run with surprisingly little friction since they glide on a cushion of high pressure fluid fed from the cylinders, rather like small hovercraft. Against this advantage, the pistons in this design are going to be more heavily loaded sideways against the cylinder bores than in a conventional design.

The design which our R+D project eventually adopted for further development was a rotary vane design with unusual axially moving vanes. This was not my decision and I think it was a mistake, a conventional axial piston pump would have done the job better. In fairness to my bosses there was an externally imposed requirement to keep the diameter of the machine as small as possible and the axial vane design was good that way.

John

Hi John, Are you still around on the forum?

If so, what do you think of this??
Hydraulic Motor In Water


http://www.wolfhartindustries.com/