Calculating Minimum Clearance for The Great Sand Dunes Track
Hello Diecast racers!
I'm excited for the upcoming Great Sand Dunes Showdown, but a question has come up multiple times about knowing if your entry will have enough clearance.
This example will help you calculate the minimum clearance required so you can verify your measured clearance is enough. If you HATE math, go to the cheat sheet at the bottom after measuring the distance from the front axle to the rear axle.
This has been added to the tournament rules.
Cheers,
Mark H.
Discussion
Three criteria come into play when designing your vehicle... Approach, Breakover and Departure Angles
This calculation is looking at something called the Breakover Angle...
The breakover angle comes into play as the vehicle goes over the top of the hill. The pointier the hill, the greater the breakover angle needed to get over it. The vehicle’s breakover angle is dictated by wheelbase and ground clearance, specifically ground clearance at the center of the vehicle.
A vehicle’s ground clearance is usually measured from the lowest point, which could be the front or rear axles (not typically a concern when cresting a hill). That’s why you sometimes see off-road vehicles raised far off the ground, which provides more ground clearance in the center, and thus allows the vehicle to traverse a steeper-angled crest.
For a given amount of center ground clearance, the closer the axles are together — the distance from the front axle to the rear axle is called the wheelbase — the sharper the peak angle that can be cleared. So, for the optimal breakover angle, you want a short wheelbase and a lot of center ground clearance.
If your vehicle’s breakover angle is less than the peak’s angle, the center of your vehicle will scrub on the peak of the hill, possibly causing the front or rear tires to come off the ground. This is called being high-centered. In effect, your vehicle could act a bit like a playground teeter-totter — fun when you were a kid, but not so fun when you’re off-roading.
An excellent video that explains the variables needed to design an off road vehicle...
Some folks may already know this, hopefully some will find it useful. If you like the math... there is a good calculator here:
- Hey, and now I know the terms! — GravityThrottleRacing
- Good stuff!! Good luck !! — CutRock_R_Marc_D
Ha ! I had done your math, but flunked communication!!
Good luck all!!
Cheers !
Now....THIS....I can understand. Thank you!