Table Top jump

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#1
I am building my first table top jump. I had a few questions. The take off is going to be small, 4 feet at the lip and id like to make the whole ramp 6-8 feet wide all made from dirt.
1st? is there any guide line to follow for the angle of the take off and landing
2nd? how long should the top of the table top be for a successful landing on the landing ramp.
3rd? any other tips suggested would be appreciated.

Thanks guy.
 
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#2
They are guidlines to building jump faces correctly. A pro scale jump face is on a 2:1 ratio ( meaning for every foot high the jump is the ramp goes out 2 foot. For instance, a 4 foot jump would have a a ramp extending out 8 foot from the center to the toe of the ramp. You don't measure from the peak down. The best way to get this right is start of by driving two stakes, making sure you have enough to leave 4 foot sticking up on the ouside of the jump where the center is going to be. Now measure from the base of the stakes out 8 foot. Amature scales can vary but are usualy 3:1 and you use the same methode as above to do this also. Tables are figured the same for the on rapm but different for the off. For the off of a table you take the width of the top and add the same to it. A 40 foot long table would ramp off from the off end lip out 80 foot and not measure from the lip, measured from the base in line with the lip.
 
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#3
GoT_GreeN said:
They are guidlines to building jump faces correctly. A pro scale jump face is on a 2:1 ratio ( meaning for every foot high the jump is the ramp goes out 2 foot. For instance, a 4 foot jump would have a a ramp extending out 8 foot from the center to the toe of the ramp. You don't measure from the peak down.
?

GoT_GreeN said:
The best way to get this right is start of by driving two stakes, making sure you have enough to leave 4 foot sticking up on the ouside of the jump where the center is going to be. Now measure from the base of the stakes out 8 foot.
What?

GoT_GreeN said:
Amature scales can vary but are usualy 3:1 and you use the same methode as above to do this also. Tables are figured the same for the on rapm but different for the off. For the off of a table you take the width of the top and add the same to it. A 40 foot long table would ramp off from the off end lip out 80 foot and not measure from the lip, measured from the base in line with the lip.
Huh? You mean length, don't you?

Not meaning to be a jerk here... but.. "height, width, length...hypotenuse... parallel...perpendicular to, rise, run...slope ...


A teeny bit of precision of language would help immensely. As written this is- to put it gently- a mess. Not disputing the accuracy of the ratios...

http://www.dirtwurx.com/track_tips4.php
 
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#4
I get what he's saying. I'm going to draw up some plans and post them if i can

what about the landing ramp. i heard it should be 16 feet long since the height is 4 feet.
 
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#6
1994cr125 said:
I get what he's saying. I'm going to draw up some plans and post them if i can

what about the landing ramp. i heard it should be 16 feet long since the height is 4 feet.
According to GoT_GreeN, It depends on the length of the table top.

I believe he said to double the length of the table top.
 
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#8
It's just math 1994 cr125. You can do this.... Or... perhaps you could make it shorter and borrow from the (ack!) quad forum. 3 1/2 feet tall 3:1 rise on the launch end.

http://forums.atvconnection.com/messageview.cfm/catid/16/threadid/467944.cfm

Look at the last post. (Approach is 10', top is 9, off ramp is 18'- again all measured in a straight line on the ground.....A total of 37' linear run.)

I'd hidely recommend you read the Durt Wurx article.

Here's some numbers for a 4' table top based on GoT_GreeN's formula for amateur's:

12' approach, 10' top, 20' exit (42' straight line on the ground)..... If you want to measure along the ramps themselves add a bit over a half foot on the approach, and just under half a foot on the exit .

(Simple Geometry).

Perhaps one of our engineering students has a formula for the perfect curve of the bowl?;)

Well, that ought to be clear as mud. :whoa:
 
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#9
Thanks i think ill be able to do this. luckily my dad has got a friend with a bobcat he'll let me borrow. so ill be sure to take pics of the ramp as i begin. i expect to start sometime in august but plans could be thrown off easily.

but i still have one small question. what should the curve of the take off be.
 
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#10
1994cr125 said:
but i still have one small question. what should the curve of the take off be.
The million dollar question....


Jeopardy theme....Now to turn it over to someone who actually knows something about riding. lol :rotfl: :rotfl:

You don't want to get your fanny kicked by having it give you too much loft (nose or tail). I'm sure someone here has a formula for the arc....
 
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#12
1994cr125 said:
Thanks i think ill be able to do this. luckily my dad has got a friend with a bobcat he'll let me borrow. so ill be sure to take pics of the ramp as i begin. i expect to start sometime in august but plans could be thrown off easily.

but i still have one small question. what should the curve of the take off be.
Well.. thats up to you.. how i made a jump was make it the eit and length and everything then i added dirt to teh front, i started with a long gentle takeoff ramp to see what it would do.. then modified it from there...

Steper = Hight
flater = your gonna go far straight..

Also for the curve... You dont want it real curvy, just a good smooth transition from the bottom to top.. Or whatever feels comfortable.. Remember if you dont like it you can always add or take off some dirt...

Im not really sure if that helped.. but thats my $0.02