Project "Snow Drift"

[Tractorhead 9,064]

2 hours ago, Handy Don said:

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.

 

 

I go just the half way together.

 

Why ? before it wasn‘t move sensefully at all, now the gear ratio was reduced it moves, 

that is in my opinion a indicator the friction at all is still a little too high even after the sprocket change.

The mowerdeck needs the most power. I

 

the pure contact surface of a mowerblade compared to the drums is at least on the tips so 

the mowerblade contacts the grass just on front of the blades, the drums lay with a larger contact surface in length and width on floor.

that must be moved only by torque about that thinkering, i can imagine the gearratio at all is still a little to high and the 18 HP are still completely underrated with the actual gearratio used to rotate the loaded drums.

There are also 2 surfaces and the complete weight. Compared to a mowerdeck i would estimate that‘s about a 500“ deck

also compared to colin‘s version the snail is stronger, what i also see as an torque killer.

 

i would go the opposite way and turn one or 2 teeth more on the sprockets on the Drums to help the engine revning up.

 

Just my thoughts

 

[8ntruck 6,998]

Dang it, the forum ate my reply.  Anyhow, after running the numbers, I agree with Handy Don.  Got to get more horsepower through the  drives. 

 

Assuming the zero turn mower needed 5 up to run 5mph, and the drives during Oldschool's test run were running at the equivelant of 5mph on the zero turn, each screw needed about 500 ftlb to turn. 

 

Calculated Snow Drifts speed based on the zero turn's 16" tires and 5mph top speed, 4:1 chain drive ratio and 50"per turn screw lead to be .65mph during the test - about the same as compound low on an 8 speed.  Sound about right?

[Tractorhead 9,064]

@8ntruck  and @Handy Don you both be right.

the needed torque is massive differently on the both systems.

 

@Oldskool what results a completely rotation on a snail in lenght?

i try to find that values but maybe i missed.

 

I don‘t know what tyres diameter are used before on the zero turn mower original on the gearbox even if there was a following second gears.

 

in my thinkering: 

one revolution on a tyre results based on it‘s rolling circumference in the lenght it can moves.

That can be compared to the way on 1 turn on the drum what results in the way it moves - I‘m right?

That is without take a look at any torque or even rpm‘s

 

The reachable rpm‘s on tyre or the drums finally equally results than in the max. reachable speed on both systems.

the torque on both systems vary massive, because of the differently rolling and moving resistance.

 

I didn‘t find any measurings, so it‘s hard to calculate without that given parameters and just hard estimations can be done.

 

[Oldskool 6,643]

@Handy Don @Tractorhead  @8ntruck

I just read thru your responses. I think I did over look the torque capabilities of the drive units. Not being familiar with the limits of the zero turn

 

If they could have transferred the torque without issue my thoughts were

 

Briggs 3600rpm 

1:1 driving the units

Drive units 15:1

Original tire 16in diam travel distance approx 50in per rotation.

Screw approx 50in in length with 1 twist.

So I should have been able to go 1:1 ratio = same speed as the zero turn.

 

When I went to the 2:1 to start with that was what I thought would be realistic. Knowing my speed would be cut in half. With that ratio the engine never bogged Although it didnt get the chance with the bypassing.

Now with the 4:1 it travels. It didnt bypass not even while maneuvering.

I could try for 3:1 but it may put me at a point where it will travel, but bypass during maneuvering

 With my ground clearance of the large sprocket i think I can only get the 3:1 by changing both sprockets.

As it is at the moment a would guess top speed at 1mph. Alot has to change to hit double digits.

 

Edit:

if I did the math correctly. top speed is 2.84mph. That's without slippage.

 

Edited February 19, 2021 by Oldskool

[ebinmaine 67,420]

Movement is a win in my opinion. 

 

You learned a ton along with several others of us so not one second of what you did was wasted.

It also kept you busy for a while. 

 

Might not exactly be a high-speed ball of fire but I think you done all right. 

[Oldskool 6,643]

Just now, ebinmaine said:

Movement is a win in my opinion. 

 

You learned a ton along with several others of us so not one second of what you did was wasted.

It also kept you busy for a while. 

 

Might not exactly be a high-speed ball of fire but I think you done all right. 

Thank you. It was definitely a fun project. There will be upgrades I'm sure of it. Although with more rpms comes more of a chance for the next weak link to show up.

[DennisThornton 4,769]

38 minutes ago, Oldskool said:

Thank you. It was definitely a fun project. There will be upgrades I'm sure of it. Although with more rpms comes more of a chance for the next weak link to show up.

Absolutely great job!

"weak link"?

That's what prototypes do!  And they all come with them!  

[Handy Don 12,212]

2 hours ago, Oldskool said:

Thank you. It was definitely a fun project. There will be upgrades I'm sure of it. Although with more rpms comes more of a chance for the next weak link to show up.

Frankly, to me this thing is a great success with, as Dennis pointed out, the usual discoveries of a prototype. Period.

Contrast this endeavor with one where a lot of ideas get down on paper but nothing gets built and so no one ever knows if any of the ideas would have worked out or why they didn't work! It's prompted me to think about other ways to put 18hp through independent hydro transmissions and made me do the math on universal joints used in unexpected ways. I doubt I would have thought much about the transmission of power as a limiting factor, that's for sure.

Thank you, sir, for inviting us all to come along for the ride.

[DennisThornton 4,769]

What he said!

 

If this project stops right here, as is, it IS a major success!  And I've enjoyed every step!  I would never have and still won't tackle something this radical.  But someone might, because of this! 

 

This is just remarkable as is!  AND, I know it won't stay as is!

[Oldskool 6,643]

Thank you all for joining in. There was alot of good ideas thrown my way. I'm sure there will be more. I have already started looking into upgrades. It will take some help from you all to pull it off. Evertime I start into gear ratios and torque multiplication I'm stepping into the DEEP end of the pool.

 

Like for example, how do you figure the torque at the end of the drive units. Engine (x) amount of torque thru a 15:1 reduction? Thing like this will help in the upgrades.

[8ntruck 6,998]

Great project.  We all learned a lot along the way.  I've enjoyed the mental exercise along the way while ideas were bouncing around.

 

Thanks for sharing the build.  I'm looking forward to your next adventure. 

[8ntruck 6,998]

9 minutes ago, Oldskool said:

Thank you all for joining in. There was alot of good ideas thrown my way. I'm sure there will be more. I have already started looking into upgrades. It will take some help from you all to pull it off. Evertime I start into gear ratios and torque multiplication I'm stepping into the DEEP end of the pool.

 

Like for example, how do you figure the torque at the end of the drive units. Engine (x) amount of torque thru a 15:1 reduction? Thing like this will help in the upgrades.

When there is a mechanical speed reduction (gears or belts), the torque will be multiplied by the same ratio.

 

Last night when I ran the numbers to estimate the torque required to turn the screw, I figured that each drive was supplying about 125 ftlb at the output shaft.  That was assuming each drive unit was supplying 2.5 hp to drive the zero turn.  The amount of power those hydraulic drives are able to transmit is determined by pressure ratings and flow capacity.  I suspect you can pass more power through the drives by over driving the pumps and beefing up relief valves, but it might not speed the beast up very much.

[Handy Don 12,212]

9 minutes ago, Oldskool said:

Thank you all for joining in. There was alot of good ideas thrown my way. I'm sure there will be more. I have already started looking into upgrades. It will take some help from you all to pull it off. Evertime I start into gear ratios and torque multiplication I'm stepping into the DEEP end of the pool.

 

Like for example, how do you figure the torque at the end of the drive units. Engine (x) amount of torque thru a 15:1 reduction? Thing like this will help in the upgrades.

Torque comes from the pressure of the fluid to the motor similar to a gas engine where it's the pressure of the expanding fuel. More pressure means more torque (with several caveats). 

To do the math, we need details about both the pump and the motor. If a variable pump (a la the Eaton 1100), what are the gallons per minute at different RPM? What are the design limits of GPM, RPM, and PSI? Paired with a fixed-displacement motor (a la Eaton 1100 again!) running within its limits, the math is straightforward.

This setup is, from my research, the most common for equipment like garden tractors. What's needed are the specs for the hydros in question.

I'd be happy to help with research if you have the manufacturer and model numbers

[Handy Don 12,212]

6 minutes ago, 8ntruck said:

When there is a mechanical speed reduction (gears or belts), the torque will be multiplied by the same ratio.

 

Last night when I ran the numbers to estimate the torque required to turn the screw, I figured that each drive was supplying about 125 ftlb at the output shaft.  That was assuming each drive unit was supplying 2.5 hp to drive the zero turn.  The amount of power those hydraulic drives are able to transmit is determined by pressure ratings and flow capacity.  I suspect you can pass more power through the drives by over driving the pumps and beefing up relief valves, but it might not speed the beast up very much.

I agree with this.

The value of extra power comes from permitting better final drive ratios (therefore higher speeds) or by allowing it to operate at current speeds in higher friction surfaces (like snowy gravel!)

The biggest issue is that these hydro units's components are designed for specific RPM, GPI, and PSI. Tinkering might be possible but radical change is probably not on.

Edited February 19, 2021 by Handy Don

[Handy Don 12,212]

Looked up the Eaton 1100 specs for comparison. At 3600 RPM with 20hp input:

• Torque, Output 
  • Continuous - 31 Nm [360 lb-in]
  • Intermittent - 61 Nm [540 lb-in]
  • Peak - 81 Nm [720 lb-in]

Not "more power than a locomotive" or "able to leap tall buildings with a single bound" but several times what @8ntruck calculated as an estimate from the zero turn hydros.

 

While doing this noticed the much lower capacity of the Eaton 700's. Reinforces the common understanding that they are fine for mowing or snowplowing but not as well suited for plowing snow or soil. One third the guts of the 1100.

• Torque, Output
  • Continuous - 14 Nm [120 lb-in]
  • Intermittent - 20 Nm [180 lb-in]
  • Peak - 27 Nm [240 lb-in]

 

[Oldskool 6,643]

I couldnt find anything definitive but I'm thinking it's around 300ftlbs.

It's a 

Hydro Gear 105-3492

[Oldskool 6,643]

It says 300ftlbs but i would figure that as peak and these are probably more the 125 continuous.

[Oldskool 6,643]

So if they are 125ftlbs continuous it took approx 500ftlbs to make it move?

[Handy Don 12,212]

10 minutes ago, Oldskool said:

So if they are 125ftlbs continuous it took approx 500ftlbs to make it move?

More like 250 is my estimate (peaks seem to be double continuous and above that the relief pops)

 

[Tractorhead 9,064]

I absolute agree with the others stated above , 

it‘s a fantastic built. The Way you did it was a brut straight build.

For a Prototype a fantastic positive result, even if it stay as it is.

 

I heared in the Video, that the engine sounds stressed and can not revning up freely to max RPM.

if i interpret the Audio right it runs somewhere about 1800-2000 RPM.

 

Like Handy Don allready mentioned as a sidekick, it is maybe easier now to change the intake belt ratio.

i don‘t know if you be simply able to change the pulley on the Engine to a smaller one.

maybe 1 or 2 sizes down.

 

but that‘s maybe a way to be able changing again the ratio.

My thinking about that step is 

 

Engine in high RPM have much more torque as just in little over half RPM

and this can maybe end up in  a little faster move in result.

But it is also just a proof of concept 

[Oldskool 6,643]

29 minutes ago, Handy Don said:

More like 250 is my estimate (peaks seem to be double continuous and above that the relief pops)

 

Right so if my drives are 300 peak 150 continuous then 600 to make the machine work? Per side.

[Oldskool 6,643]

3 minutes ago, Tractorhead said:

I absolute agree with the others stated above , 

it‘s a fantastic built. The Way you did it was a brut straight build.

For a Prototype a fantastic positive result, even if it stay as it is.

 

I heared in the Video, that the engine sounds stressed and can not revning up freely to max RPM.

if i interpret the Audio right it runs somewhere about 1800-2000 RPM.

 

Like Handy Don allready mentioned as a sidekick, it is maybe easier now to change the intake belt ratio.

i don‘t know if you be simply able to change the pulley on the Engine to a smaller one.

maybe 1 or 2 sizes down.

 

but that‘s maybe a way to be able changing again the ratio.

My thinking about that step is 

 

Engine in high RPM have much more torque as just in little over half RPM

and this can maybe end up in  a little faster move in result.

But it is also just a proof of concept 

I think what you was hearing or not hearing was a combo of the home built muffler and my hand muffling the mic on my phone. Its definitely turning up.

[Handy Don 12,212]

40 minutes ago, Oldskool said:

I couldnt find anything definitive but I'm thinking it's around 300ftlbs.

It's a 

Hydro Gear 105-3492

On HG's website, there is no info on that model.

However, their current ZT-2200 model seems to resemble what you have (yeah, looks can be deceiving!) However, its capacity seems to be more than what you are experiencing and seems like overkill for your donor ZT.

Input Speeds Max Hi-Idle (no load) Min (loaded)	3000 rpm 1800 rpm
Output Torque	Up to 215 lb-ft [291 Nm]
Speed	Up to 7 mph [11 kph]
Gross Vehicle Weight	Up to 900 lbs [408 kg]

 

 

This one seems closer, the ZT-1800. Note the 100 lb-ft to torque.

Input Speed Maximum Hi-Idle (No Load) Minimum (Loaded)	3000 rpm 1800 rpm
Output Torque	up to 100 lb-ft [up to 136 Nm]
Speed	up to 6 mph [up to 10 kph]
Gross Vehicle Weight	up to 667 lbs [up to 302 kg]

 

The speed thing is interesting. Its because the unit expect to have a hub/wheel attached directly I guess. The manual says the "overall reduction" is  22.92:1 so about 160 RPM at 3600 engine.  For a 16" wheel/tire that's pretty close to 6 mph!

 

But it's the torque that is the constraint. No matter how strong the engine, this is what it can deliver.

 

[Handy Don 12,212]

8 minutes ago, Oldskool said:

Right so if my drives are 300 peak 150 continuous then 600 to make the machine work? Per side.

With this power, I'd anticipate either more grunt at low speeds (pulling or climbing) or supporting a higher gear ratio (speedier)

Just looked at Hydro Gear's current offerings and their most powerful ZT drive can do "up to 300 lb-ft." -- not sure if that is peak or intermittent (but it's marketing so probably peak!)

 

 

58 minutes ago, Oldskool said:

So if they are 125ftlbs continuous it took approx 500ftlbs to make it move?

Sorry, misread this. 

Yes, 125 continuous, 250 peak EACH. 500 to make the machine break inertia and "stiction" and move.

 

Know anyone with a blown-engine, rusted out deck, flat tired, high-end ZT that can be a new donor?

[Oldskool 6,643]

3 minutes ago, Handy Don said:

On HG's website, there is no info on that model.

However, their current ZT-2200 model seems to resemble what you have (yeah, looks can be deceiving!) However, its capacity seems to be more than what you are experiencing and seems like overkill for your donor ZT.

Input Speeds Max Hi-Idle (no load) Min (loaded)	3000 rpm 1800 rpm
Output Torque	Up to 215 lb-ft [291 Nm]
Speed	Up to 7 mph [11 kph]
Gross Vehicle Weight	Up to 900 lbs [408 kg]

 

 

This one seems closer, the ZT-1800. Note the 100 lb-ft to torque.

Input Speed Maximum Hi-Idle (No Load) Minimum (Loaded)	3000 rpm 1800 rpm
Output Torque	up to 100 lb-ft [up to 136 Nm]
Speed	up to 6 mph [up to 10 kph]
Gross Vehicle Weight	up to 667 lbs [up to 302 kg]

 

The speed thing is interesting. Its because the unit expect to have a hub/wheel attached directly I guess. The manual says the "overall reduction" is  22.92:1 so about 160 RPM at 3600 engine.  For a 16" wheel/tire that's pretty close to 6 mph!

 

But it's the torque that is the constraint. No matter how strong the engine, this is what it can deliver.

 

Interesting. I think I had read somewhere earlier in the build that these were 15:1 but maybe not. Not having exact numbers it's hard to calculate. Somehow I have to get a baseline rpm and torque output to move further.