Grade Math help

woodlandfarms · Dec 6, 2006

Just real quick. One area that I am interested in mowing has a rise of 40ft every 100. It is not the steepest part of the property, but one that I need to clean up soon .. Is this a 25% grade? I looked around TBN and I know someone had posted the math, just can't seem to find it.

Carl

NJBill · Dec 7, 2006

Hope this will help you understand Carl.

Not my best blueprint drawing, but it should give you the basics.

All the best. Bill

roxynoodle · Dec 7, 2006

Slope equals rise over run. A rise of 40 feet over a run of 100 feet would be a 40% grade. I don't think I'd want to mow that!

Gatorboy · Dec 7, 2006

woodlandfarms said:
Just real quick. One area that I am interested in mowing has a rise of 40ft every 100. It is not the steepest part of the property, but one that I need to clean up soon .. Is this a 25% grade?

That angle is 21.8 degrees

Inverse Tangent of 0.4 (Opposite / Adjacent) = 21.8

Egon · Dec 7, 2006

Is the run measured horizontally or on the slope?

woodlandfarms · Dec 7, 2006

Egon said:
Is the run measured horizontally or on the slope?

It is Horizontal, not on slope. I am using a high quality Topo the county has. It is pretty accurate.

Really, what I want to do is find out what a 40 or 45 degree slope feels like. And what a 30 degree slope is like... May not need the 1845 after all....

Carl

MossRoad · Dec 7, 2006

woodlandfarms said:
Just real quick. One area that I am interested in mowing has a rise of 40ft every 100. It is not the steepest part of the property, but one that I need to clean up soon .. Is this a 25% grade? I looked around TBN and I know someone had posted the math, just can't seem to find it.

Carl

I go up and down stuff like that with my PT425.
40' up in 100' forward is the same as:
up 4' in 10'
up 2' in 5'
up 1' in 2.5'
up 6" in 15"

I have to transfer the weight of my brush mower to the front tires when I go up the hill by taking it out of float and lifting it about a half an inch. Then I have plenty of traction.

Here's a quick reference for you:
A 100% grade is 1' up for 1' forward = 45 degree slope.
A 50% grade is 6" up for 1' forward = 22.5 degree slope.
A 25% grade is 3" up for 1' forward = 11.25 degree slope.
A 12.5% grade is 1.5" up for 1' forward = 5.625 degree slope.

So you can see that your 6" up in 15" forward slope is less than a 22.5 degree slope. You should have no problems with a PT on that slope.

Hope this helps.

woodlandfarms · Dec 8, 2006

I found another spot that needs attention. It is around 27 in slope (110 ft vertical rise for every 400 feet horizontal). Think the 1430 with a brush hog or grapple bucket can handle this slope?

NJBill · Dec 8, 2006

That's 15.4 degrees

Almost any model of P T is supposed to be able to handle that one.

woodlandfarms · Dec 8, 2006

woodlandfarms said:
I found another spot that needs attention. It is around 27 in slope (110 ft vertical rise for every 400 feet horizontal). Think the 1430 with a brush hog or grapple bucket can handle this slope?

Ooops 110 over 300....

MossRoad · Dec 9, 2006

woodlandfarms said:
Ooops 110 over 300....

Get a scientific calculator, because if you want to know the degree of the angle, you need to do trigonmetry.

RISE/RUN = %GRADE of slope.
ARCTAN(RISE/RUN) = DEGREE of slope

For your example:

110' RISE/300' RUN = 0.37 or 37% GRADE of slope.
ARCTAN(110' RISE/300' RUN) = 20.14 DEGREE of slope.

If you have a Windows based computer, there should be a scientific calculator built in. Go to START/AllPrograms/Accessories and launch the calculator. When the Calculator program opens up, pull down the view menu and choose SCIENTIFIC. Then enter your rise in feet divided by your run in feet and hit =. In your case, you will see 0.36666666..... multiply that by 100 to get your percent grade or select the INV check box and then push the TAN (for tangent) button to get your DEGREE of slope.

Hope that helps.

Egon · Dec 9, 2006

Moss; I think six figure tables and interpolation would work much better!

Builds character!

MossRoad · Dec 9, 2006

Egon said:
Moss; I think six figure tables and interpolation would work much better!

Builds character!

I had enough character building in high school!

MrJimi · Dec 9, 2006

Is there someone here that can help me with some numbers?
I have a skidsteer that lifts 1,750 pounds at the pins, how much will it lift 5 feet out, 10 feet out and up to 20 feet out. The reason I ask is because I don't know and I built a long boom pole in my gallery that extends out about 20 feet, I don't think it will be much but I'm curious. And my lift arms will raise 9.5 feet.

Thanks
Jim

bbabineau · Dec 11, 2006

woodlandfarms said:
Just real quick. One area that I am interested in mowing has a rise of 40ft every 100. It is not the steepest part of the property, but one that I need to clean up soon .. Is this a 25% grade? I looked around TBN and I know someone had posted the math, just can't seem to find it.

Carl

Woodlands,

Attached is a conversion chart that I posted sometime ago. Hope this helps.

Bob

MossRoad · Dec 12, 2006

MrJimi said:
Is there someone here that can help me with some numbers?
I have a skidsteer that lifts 1,750 pounds at the pins, how much will it lift 5 feet out, 10 feet out and up to 20 feet out. The reason I ask is because I don't know and I built a long boom pole in my gallery that extends out about 20 feet, I don't think it will be much but I'm curious. And my lift arms will raise 9.5 feet.

Thanks
Jim

Jim,
It all depends on how far back from the pins the lift cylinders are, how far behind that point the lift arms attach to the unit, how far in front or in back of the front wheels the center of gravity is, the weight of the machine with and without attachements and operator, etc... probably too many variables to guestimate.

I would put the boom out horizontally in front of the unit, add a measured amount of weight, get in the unit and see if it lifts it about 6 inches off the ground. Repeat as necessary to see what it takes to tip it. Be careful, etc... the usual safety disclaimer stuff. You know the drill.

When you find what tips it at the end, then move halfway down the boom and add the weight again. It may take more than half, it may take less... who knows? The only way to find out without ALL of the variables and an engineering degree is with experimentation.

woodlandfarms · Dec 12, 2006

bbabineau said:
Woodlands,

Attached is a conversion chart that I posted sometime ago. Hope this helps.

Bob

Thanks for the chart! I think my property is less severe than I thought.

J_J · Dec 14, 2006

MrJimi said:
Is there someone here that can help me with some numbers?
I have a skidsteer that lifts 1,750 pounds at the pins, how much will it lift 5 feet out, 10 feet out and up to 20 feet out. The reason I ask is because I don't know and I built a long boom pole in my gallery that extends out about 20 feet, I don't think it will be much but I'm curious. And my lift arms will raise 9.5 feet.

Thanks
Jim

Hi Jim, This is what I came up with. If at three feet from the center line of the wheels, out to the lifting point of 1750 lbs, I came up with these figures.

If you can lift 1750 at three ft from the fulcrum, which is the center line of the wheels, then the following data will apply. I think. You can probably lift more, but the machine may tip forward. Do some test for yourself and check out the data. I am guessing at the three ft, could be more or less. If you can tell me exactly the distance from the center line of the wheels, to the advertised lifting point, I might can figure more precisely.

3 ft = 1750 lbs
6 ft = 875 lbs
9 ft = 583 lbs
12 ft = 437.5 lbs
15 ft = 350 lbs
18 ft = 291 lbs
21 ft = 250 lbs

If anyone any has better figures, please post.

MrJimi · Dec 18, 2006

J_J, thats better than I expected, Thanks for the info
I played some this past weekend and with the whole pole extended all the way, I could not raise the rear of skidsteer or bend pole in anyway, It seemed good and strong I weigh 170 pounds

Jim