Mowing mowing wow that fast? finish, rotary and flail

[shady1701]

I seen several different makes saying they finish mow between 5 and 9 mph. I also seen some info on flail mowers at 7mph. My question is what speed is normal or what range do most people mow in? i use the highest gear in low range or lowest in high gear range about 3mph or so i think?

any comments? Ideas on mowing speeds with finishing,rotary or flail mowers?

 

[chrisjbell]

I can theoretically mow at something fast (maybe 8 MPH?) but there's no way I could actually do it without bouncing my A-- off my tractor. On the hills I'd flip it, on the flat I'd roll it. You don't move real fast when mowing - unless you're Jesse James on Monster Garage /forums/images/graemlins/grin.gif.

 

[RoyJackson]

Reckon it depends on the layout of your property. If you've a fairly large flat area with few obstructions, 5-9 MPH seems reasonable. We're talking something like a football field or other playing field. This would be an improved area where there's few things to worry about.

It's also your comfort level with your equipment. Just yesterday, I saw a guy swing an older Deere CUT (855, I think...didn't look too hard as I was driving) around on a minor slope that I'd of really slowed down on, or approached from another direction. Couple weeks back, saw a guy on a New Holland, loadder bucket way too high, swing his machine around on a minor slope. Boy, I thought he'd roll, but he didn't.

My property is mostly slopes. There's only a few steep (in excess of 15°) areas, but there are some trees, a fence and other obstructions to consider. So, I'm normally running in 2nd or 3rd gear LOW (gear tractor, BTW). This is under 5 MPH...more likely around 3 MPH.

 

[nomad]

Moving speed depends on grass/hay and land surface condition. Tractor power is another factor as well.
THEORETICALLY, tractor speed should be equal to the speed of mower blade. Lets take finish mower. Its spindle rotational speed is around 2750 RPM. Then, its blade tip speed equals to V = RPM x 2 x PI x R (radius of rotational motion) (R can be considered half length of blade length. Lets assume R = 1 ft) - Then, V = 2750 rpm x 2 x 3.14 x 1 ft = 17270 Ft per Min. = approx. 200 miles per hour is the blade tip speed. A perfect (!) mowing should be at that speed. But there is friction on the ground which depends on land surface condition, there is reactional force from the grass which can change from grass to grass and finally the tractor power restrict mowing speed.
OK, my answer isn't a practical answer to your question which its answer must be between 5-10 miles per hour. But why so high blade speed (~200 mph)? is a point that can be thought about.

 

[Hoeman00]

W/ my 35D and 84" MMM I mow in fast side of low range (6mph) and because of large tires and semi-mounted mower it handles the bumps in the yard ok.
W/ the old Kubota L2900 and 6' woods RFM 4 mph was about it, if the tractor wasn't bouncing the mower was.

 

[Henro]

<font color="blue"> approx. 200 miles per hour is the blade tip speed. A perfect (!) mowing should be at that speed. </font>

nomad,

Since you obviously were serious in you analysis and could start down the path of developing a prototype to test the hypothesis, I thought I might point out a possible flaw in your analysis.

The blades are rotating under the tractor, and on one side they are moving in the forward direction, while on the other they are moving towards the rear.

As tractor forward speed increases, this causes cutting speed difference to develop, with blade speed [relative to the grass] slowing on one side and increasing on the other. It appears that perfect mowing should occur at zero speed.

As a matter of fact, I think I proved that theory yesterday, as I sat in a lawn chair at zero speed, sipping a beverage of choice, while my wife was mowing the grass.

No doubt in my mind...perfect mowing...perfect car washing...perfect meal preperation...perfect house cleaning...all happen at zero speed and proven best many times where I come from... /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

 

[fivestring]

Shady, I have a 5 ft. mower and I usually use High, 3-5. My Iseki has 12 forward gears (Low, 1-6 & High, 1-6).

 

[nomad]

Henro, of course, I was serious in my analysis.

</font><font color="blue" class="small">( <font color="blue">
blade speed [relative to the grass] slowing on one side and increasing on the other. It appears that perfect mowing should occur at zero speed.</font>)</font>

Is that blade working like a scissor? Isn't that blade following a rotational motion? If so, then how is it (blade tip speed) slowing on one side and increasing on the other side? Maybe, I didn't understand what you told here. By the way, the blade speed relative to the grass is the same as absolute blade speed as the speed of grass is zero.

</font><font color="blue" class="small">( <font color="blue">
No doubt in my mind...perfect mowing...perfect car washing...perfect meal preperation...perfect house cleaning...all happen at zero speed and proven best many times where I come from... /forums/images/graemlins/grin.gif </font> )</font>

My use of "Perfect" above was different. Of course, I agree with you in that the perfect happens at zero relative speed if its a mechanical motion because the frictional and other losses also depends on that relative speed. By the way, the perfect happens not only at zero speed difference. For example, perfect heat transfer theoretically happens at zero temperature difference. etc. The universe is perfect only at kinetically, dynamically, chemically, thermodynamically static conditions. The larger speed/temperature/etc difference the more imperfectness. From this philosophy, our life/world getting faster and faster is worse and worse from efficiency point of view and we call this faster life is a progress. Anyways, back to topic; mowing speed or back to perfect meal preparation;]

 

[shady1701]

Well i'm interested now to see some people mow that fast i can't even transport my mower going in high gear. Mine's calmed down after i filled front/rear tires with fluid but i was amazed to see 7-9mph even on flat land that seemed fast. Most lawnmowers top out at 5.5-6mph..

Which we don't have flat land here in east Tn realy.



Thanks for info..

 

[DavidJ]

I mow with the pedal to the floor in 2nd range. I only have to slow down when mowing under the trees and close to the fence.