Cullman Derby Ramp – Part 2 – The Slope

As described in Part 1 of this series, we were really starting from scratch on the derby ramp design. The first and most important design decision for the project was to set the profile of the slope.

Slope Length – The original sketch we received indicated an 8′ long ramp, which is a convenient plywood size. We quickly realized that with derby cars being somewhere between 4′ and 6′ long, 8′ would be too short. So we set a ramp length not to exceed two sheets of plywood = 16′ long.

Slope Height – What is the right height to balance speed and safety? Something in the 3′ to 4′ range felt right.

Slope Shape – The ramp could be a simple, straight slope. However, custom curved glulam is something Unalam is known for, and a straight ramp would have an abrupt transition to the roadway. 

Initial Straight Profile

Possible Curved Profile

The Curved Profile would give a nice transition to the road, but it ends up reducing the effective starting height of the car while also putting it on quite a steep incline.

We settled on an intermediate profile which is straight with a short transition curve at the end.

 

Final Profile