Project "Snow Drift"

[DennisThornton 4,769]

2 minutes ago, Oldskool said:

I know. Kinda disappointing. Was hoping for more speed.

Was that video top speed?

[Handy Don 10,703]

1 minute ago, Oldskool said:

I know. Kinda disappointing. Was hoping for more speed.

From what you've shared, it is beyond the powertrain's capabilities to transmit enough power from engine to screws. Sometime over the next days you'll get an inspiration on how to overcome that!

[Oldskool 6,585]

8 minutes ago, DennisThornton said:

Was that video top speed?

Yes it was. A snail's pace

[Oldskool 6,585]

8 minutes ago, Handy Don said:

From what you've shared, it is beyond the powertrain's capabilities to transmit enough power from engine to screws. Sometime over the next days you'll get an inspiration on how to overcome that!

I'm sure something will come up. At least its moving.

[DennisThornton 4,769]

3 minutes ago, Oldskool said:

Yes it was. A snail's pace

Oh...  I know you wrote that you weren't happy with the top end but I assumed you didn't film that.

 

So, that is a bit slow for top end...

 

OK!  Big breath!  Regroup...

[Ted Gardner 36]

That's really great! Moving in the right direction. 

[Oldskool 6,585]

5 minutes ago, Ted Gardner said:

That's really great! Moving in the right direction. 

Yes sir. Now I know it actually will move i have a good base point to work from.

[Tractorhead 8,623]

Pretty cool. 

Good you didn‘t stop the work on it,  great Success.

Congrats 

 

About your statement „ it’s slow“ did you try to throttle up?

I think there is more speed possible if you pull the trigger.

 

but however fantastic Build - congrats. 🍾 

 

Edit:

see too late your last statement, begin to write and was interrupted. 

So i see the answers after i sent my comment - sorry.

Edit end

 

maybe a little waxing will reduces the sticky to the snow like on ski‘s

Edited February 18, 2021 by Tractorhead

[Oldskool 6,585]

18 minutes ago, Tractorhead said:

Pretty cool. 

Good you didn‘t stop the work on it,  great Success.

Congrats 

 

About your statement „ it’s slow“ did you try to throttle up?

I think there is more speed possible if you pull the trigger.

 

but however fantastic Build - congrats. 🍾 

 

Edit:

see too late your last statement, begin to write and was interrupted. 

So i see the answers after i sent my comment - sorry.

Edit end

 

maybe a little waxing will reduces the sticky to the snow like on ski‘s

Thanks. I was in to deep to stop. I wish I had more coal to poke to 'er but "That's all she's got captian." It needs more power at the drive units. Something will come along. Wax may help but I'm afraid I may only get a fraction of extra speed

 

[Tractorhead 8,623]

Maybe the other day an bigger engine fells aside to you, that will be picked up.

 

However, it was fun to see it in Action.

great compliment to all your Work.

At least it was a Success.

 

[rjg854 10,768]

It's great to see it in motion.  " It's Alive"  All that work is paying off. Your creation can now improve because you know you're on the right track.

[Oldskool 6,585]

7 minutes ago, rjg854 said:

It's great to see it in motion.  " It's Alive"  All that work is paying off. Your creation can now improve because you know you're on the right track.

There didnt seem to be any over stressing anywhere so yes a good base to start for improvements

[Stormin 9,976]

Well done Sir!

[Ted Gardner 36]

The zero turn mower unit you used to transfer power from motor to screws had a top speed of approx. 5 mph top speed im thinking Is the motor your using up against the governor when full power or just high speed. The reason I ask is that I wondered if with more h.p. if you would get more speed or just go in to relief  on the drive unit. Or get more speed up till it goes in to relief.

 

[wallfish 15,981]

Wooo Hooo  Glad to see it move'n    

 

[Handy Don 10,703]

1 hour ago, Ted Gardner said:

The zero turn mower unit you used to transfer power from motor to screws had a top speed of approx. 5 mph top speed im thinking Is the motor your using up against the governor when full power or just high speed. The reason I ask is that I wondered if with more h.p. if you would get more speed or just go in to relief  on the drive unit. Or get more speed up till it goes in to relief.

 

The zero turn didn't need to transfer a whole heck of a lot of power to the wheels--there isn't a ton of effort needed to move a mower. Most of the engine's power went to the cutting blade(s).

The drift is different. For the movement it's already getting, the motor isn't working hard.

So I'm pretty sure HP isn't the issue here (there are 18 available, if I recall correctly).  It's getting that HP to (via belts that don't slip) and through (past relief valves that don't open) the hydro to the chain sprocket. The sprocket ratio can take care of the speed once the power is there.

Hydros from a heavier duty zero turn? Separate hydro pump(s) and motors (again, weight and complexity with plumbing and valves)?

 

Edited February 18, 2021 by Handy Don

[Maxwell-8 4,271]

you made yourself a badass unit!   congrats!! 

[DennisThornton 4,769]

11 minutes ago, Handy Don said:

The zero turn didn't need to transfer a whole heck of a lot of power to the wheels--there isn't a ton of effort needed to move a mower. Most of the engine's power went to the cutting blade(s).

The drift is different. For the movement it's already getting, the motor isn't working hard.

So I'm pretty sure HP isn't the issue here (there are 18 available, if I recall correctly).  It's getting that HP to (via belts that don't slip) and through (past relief valves that don't open) the hydro to the chain sprocket. The sprocket ratio can take care of the speed once the power is there.

Hydros from a heavier duty zero turn? Separate hydro pump(s) and motors (again, weight and complexity with plumbing and valves)?

 

I agree about there being plenty of horsepower.  Just got to change some ratios without slipping.  

It will happen.

[Oldskool 6,585]

1 hour ago, Ted Gardner said:

The zero turn mower unit you used to transfer power from motor to screws had a top speed of approx. 5 mph top speed im thinking Is the motor your using up against the governor when full power or just high speed. The reason I ask is that I wondered if with more h.p. if you would get more speed or just go in to relief  on the drive unit. Or get more speed up till it goes in to relief.

 

Ya the engine is at top rpm. I wonder if I change pulley size a bit on the jack shaft of I would gain ?

[Oldskool 6,585]

13 minutes ago, Handy Don said:

The zero turn didn't need to transfer a whole heck of a lot of power to the wheels--there isn't a ton of effort needed to move a mower. Most of the engine's power went to the cutting blade(s).

The drift is different. For the movement it's already getting, the motor isn't working hard.

So I'm pretty sure HP isn't the issue here (there are 18 available, if I recall correctly).  It's getting that HP to (via belts that don't slip) and through (past relief valves that don't open) the hydro to the chain sprocket. The sprocket ratio can take care of the speed once the power is there.

Hydros from a heavier duty zero turn? Separate hydro pump(s) and motors (again, weight and complexity with plumbing and valves)?

 

I may be able to go up a size or 2 on the sprocket. I have 10t on the sprocket sizes to play with. Bigger units, maybe. Hydraulics probably. Although the lawn mower racing guys might be able to tell me how to stop the bypass.

[8ntruck 6,445]

Progress.  It moves!

 

Spinning the pumps faster should speed things up - that would be your jack shaft pulley change.  The danger here would probably heat build up in the hyd. oil.  There will be a point where the motion control valves will nothave enough flow capacity to utilize the increased flow from the pumps, resulting in oil heating and bypass through the relief valves.  The flow rating of the control valves will probably be the limiting factor of the system for top speed.

 

Raising the system pressure with stronger springs in the relief valves will increase the torque available to turn larger drive sprockets.  Again, higher operating pressure will heat the oil and increase the stress on both the pumps and motors. 

 

What do you know about the specs of the donor zero turn?  Tire size and top speed would indicate what the design operating speed is for these drive units.  Knowing that and the screw pitch, we can make an estimate of the speed capability of Snow Drift.

[Handy Don 10,703]

8 minutes ago, Oldskool said:

how to stop the bypass

Tempting. What is the next thing to fail once you do that?

Upping the speed of the pumps, and the pressure, with a larger engine pulley only gets you to popping the reliefs quicker I suspect.

The relief valve's job is to send oil back to the pump if there is too much pressure on the hydro motor. You changed the load by going to a lower speed on the final drive so the design pressure is enough to move the machine. Up the load, up the pressure, pop the valve.

 

[Oldskool 6,585]

17 minutes ago, 8ntruck said:

Progress.  It moves!

 

Spinning the pumps faster should speed things up - that would be your jack shaft pulley change.  The danger here would probably heat build up in the hyd. oil.  There will be a point where the motion control valves will nothave enough flow capacity to utilize the increased flow from the pumps, resulting in oil heating and bypass through the relief valves.  The flow rating of the control valves will probably be the limiting factor of the system for top speed.

 

Raising the system pressure with stronger springs in the relief valves will increase the torque available to turn larger drive sprockets.  Again, higher operating pressure will heat the oil and increase the stress on both the pumps and motors. 

 

What do you know about the specs of the donor zero turn?  Tire size and top speed would indicate what the design operating speed is for these drive units.  Knowing that and the screw pitch, we can make an estimate of the speed capability of Snow Drift.

I dont know all the specs. Original tire diameter was 16in. Screw diameter is 17.25in. The blades on the screw make 1 full twist per length of 50in. It was .mentioned that top speed was 5mph.

[Handy Don 10,703]

2 hours ago, 8ntruck said:

Progress.  It moves!

 

Spinning the pumps faster should speed things up - that would be your jack shaft pulley change.  The danger here would probably heat build up in the hyd. oil.  There will be a point where the motion control valves will nothave enough flow capacity to utilize the increased flow from the pumps, resulting in oil heating and bypass through the relief valves.  The flow rating of the control valves will probably be the limiting factor of the system for top speed.

 

Raising the system pressure with stronger springs in the relief valves will increase the torque available to turn larger drive sprockets.  Again, higher operating pressure will heat the oil and increase the stress on both the pumps and motors. 

 

What do you know about the specs of the donor zero turn?  Tire size and top speed would indicate what the design operating speed is for these drive units.  Knowing that and the screw pitch, we can make an estimate of the speed capability of Snow Drift.

I'm going to doubt that the control valves are the next "choke point".

 

My bet is that the hydro motors were spec'd to use every bit of power the pump could deliver and that the pumps were spec'd to deliver only enough power to move a mower at 5 mph (and up moderate grades). That may have been the equivalent of only 2 or 3 horsepower per motor! Why? That machine was not built to push snow or pull a plow--it only had to get its own weight plus an operator around a yard on wheels. Expecting that pump and motor to transmit 18 horsepower isn't, in 20-20 hindsight, a reasonable ask!

 

Moving only on slippery snow, and at slow speed. That sounds like 4-6 horsepower of output.

 

I'll stay with my bet that the relief valve is set to just below what the motor can handle with longevity and reliability and with the expectation that it would open only in circumstances to protect the motor or the pump. Overdriving the pumps and/or tying down the relief valves might transmit more power to the motor but then it isn't clear the motor can convert that extra power into motion (though at this point, there may be nothing to lose by trying ).

 

Drift needs more power to get through from the engine to the screws. Speed will be chain ratio fixes once there is enough power.

 

[DennisThornton 4,769]

This might help for the next larger model:

But, I can't even figure out how the machine works...