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1. the act of beating, whipping, or thrashing;
2. a decisive defeat;
3. unprovoked physical assaults
Fixed Curved Ramp with 45-Degree Exit
This ramp is lightweight, relatively easy to build, and inexpensive. It does take up some space in the garage and you'll have to make a couple long, curved cuts, but it's a very fun, smooth jump to have on hand. The plans below are for the ramp pictured above. All you'll need is a 4'x4' sheet of 3/8" CDX (cheap) plywood, a 4'x4' sheet of 3/4" CDX plywood, two 8-foot 2x4s, and some screws.
Step 1 - Cutting Lumber: This is where most of the work takes place. You'll use the 4'x4' piece 3/8" plywood as is, so set that one aside for now. If you bought a 4'x8' sheet, rip it down into two 4'x4' pieces. Put one in storage for your next ramp project and keep the other one handy. Now cut up your 2x4s into 46-1/2" lengths. Why? The ramp is 48" wide, but we're using 3/4" plywood for the sides under the ramp surface, so the distance between the sides is (48" - 3/4" - 3/4") 46-1/2". Now your driving surface and supports are cut up, but the sides remain. Here's the plan (all dimensions are in inches, if you want to convert decimals to 1/16ths of an inch, just multiply the decimal by 16. For example if the measurement is 36.3", take the portion to the right of the decimal x 16: .3" x 16 = 4.8", round that up to 5 and you have 5/16", so the total is 36-5/16"):
Lay your 48"x48" piece of 3/4" plywood on a couple sawhorses and get out a pencil and tape measure. From one corner measure along the edge 36-5/16" and mark that spot. That's the length of the bottom edge of your side panel, the edge from which you measured is going to be the back of the side panel.
To lay out the curve of the ramp surface, we'll need to do some more measuring and marking. Don't worry, it's easy! From that same spot along the back of the side panel where you started your last measurement, mark off a spot every six inches, marking at 6", 12", 18", 24", 30", and 36". Move the tape measure up along the side panel about two feet and repeat this procedure. Using a straight edge, draw a line connecting the two marks at the 6" spot and continue drawing that line down to the bottom of the side panel. Repeat for the marks at 12", 18", etc. At this point, your 4'x4' panel should look something like this:
Now, using this next image as a reference, measure up from the bottom edge of your future side panel by the amount shown and mark the spot on the appropriate line. You're marking the height of the side panels at several spots to help lay out the curve.
You could just connect the dots if you wish and make your cut, but a smoother method is to put a relatively stiff object like an aluminum 4-foot straight edge on its edge and clamp it in place on one end, and force it to bend along the points you just marked. You can do this using clamps on both sides of the straight edge to keep it in place. This is probably the trickiest part of the procedure, so if you skip it, I don't necessarily blame you. Either way, trace as smooth a line as possible making sure to connect through the points marked to define the curved edge of your side panel. Now break out the jigsaw or saber saw and carefully cut along the line you just scribed, making the curve as smooth as possible.
Now that you've got one side cut out, just flip it over, match the bottom and back edges to the remaining piece of 3/4" plywood, and trace the curved cut you just made onto the other piece and cut that one out as well. Here's the 4'x4' panel with the two sides traced onto it. Note that a sizeable chunk of plywood will not be used, so if you cut carefully it's definitely worth saving for some future project. Also shown is one side panel by itself.
Step 2 - Assembly: To assemble this thing, it's nice to have a friend's help to get started. Here's what it'll look like:
Do the same thing for the #3, #4, and #5 2x4s. Once that's done, the assembly should be quite rigid and stable and ramp-shaped. The only thing remaining is the driving surface. Rotate the 48"x48" piece of 3/8" plywood so that the exposed grain runs left-right as you face the ramp's driving surface (so you'll be driving across the grain, not along it). Set the top edge of the plywood even with the top tips of the side panels and make it square to the ramp so the sides of the driving surface are parallel to (and hopefully even with) the side panels. Drill pilot holes in the plywood with a 1/8" drill about 1" from the top end of the plywood, and 3/8" from the side edge, being sure to drill into the side panel as well. The pilot holes will ensure that the plywood doesn't split as you install your attaching screws. Drive a 1-1/4" screw through each pre-drilled hole and into the plywood side panel.
Now it's a matter of pushing the plywood down against the tops of the curved side panels and attaching it with a pile of fasteners. I recommend drilling 1/8" holes every six inches or so along both sides of the driving surface, 3/8" in from the edge, and driven into the side panels as well to prevent splitting. Drill straight and perpendicular to the ramp's surface so the screws will be straight and flush. Work your way down the ramp, turning a screw into each pilot hole. If you sense too much resistance to the wood bending, don't sink the screws to flush right away, you can just get them started and move to the next one. Every time you add one, the ramp's surface will be drawn closer and closer and when you get to the bottom and get them all tight, you should have a nice, smooth, curved ramp!
I promote overkill when it comes to building things, so I also like to put screws through the driving surface and into the cross braces as well. There are three cross braces contacting the driving surface, so I'd put two or three screws through the ramp and into each brace. Necessary? Probably not, but this ramp will be abused by 12-pound trucks doing over 30mph, not to mention getting hauled around and dropped and flipped over and walked on by children and everything else. Build it solidly.
That's it! Your new ramp is complete; go beat on it! I'm usually too anxious to use the ramp to take time to paint it, but some people have more patience than I and painting could preserve the ramp's life if you let it get wet. Plywood and wet conditions don't get along well!
Enjoy!
Copyright © 2008 RCBASHER