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You see , when you look at both of them together , you realize that th

ction has meaning with respect to the tilt axis which is subtle , hidden , not obvious to anybody who looks at the manual , not obvious unless he thinks about how this vehicle can overturn .

Mr . BARNARD . The shaded areas , does that have any meaning at all ?

Mr . MENKES . The shaded areas merely refer to the tread on the tire .

Mr . BARNARD . OK . Mr . MENKES . OK ? Mr . BARNARD . Fine . Mr . MENKES . Now , let ' s move on to the next .

That concerns one of the four modes of instability that are inher ent in this vehicle . We are about to talk about an instability mode related to turning .

The vehicle in question is being turned through a total angle of 90 degrees . And the way in which that happens is that the operator rotates the front wheel , in this case , counterclockwise , looking down , and before the turn and after the turn are the views shown . A very simple thing that you might keep in mind and that is to scale for the minimum radius turn permitted on an ATC 110 .

Now , I would like you to be aware of what makes a vehicle roll over that tilt axis when the operator is in the process of turning the vehicle .

In the view at the bottom , which is again a view from the rear of the cycle , there are four forces shown . The two forces that are hori zontal are labeled with an F and the ones that are vertical are la beled with a W . Those same forces are referenced in the top view as well . W means simply the weights of the vehicle and operation . Those forces are always present , and they are always

and they are always pointing down .

The forces F - 1 and F - 2 are centrifugal forces which come into play because the vehicle is turning . The amount of the centrifugal force is a function of how fast the vehicle is going and how sharply the front wheel is turned , that angle up at the top which is labeled with the Greek letter theta . If you look at the bottom and realize that the forces labeled F are tending to rotate the vehicle clock wise , and the forces labeled W are tending to rotate the vehicle counterclockwise , and then at the top you would realize there is the same thing . There is a tilt axis there .

When the combined moments cause the clockwise moment to exceed the counterclockwise moments , this vehicle will tip over the tilt axis which is shown .

Now , numerically speaking , I do have a slide which will give you some feel for the problem . I may say that these calculations and everything I ' m saying here are about the ATC 110 , because that is the one I looked at in detail , but to the best of my knowledge and belief , in a general sense , they are representative of the other three - wheelers .

This is a table which compares angles of turn and speeds , for ward speeds . The angle is listed vertically in the left - handmost column , 5 degrees , 10 degrees , 15 , 20 , and 25 — you can ' t go higher than that because you can ' t turn the vehicle more sharply - against a speed pattern , 5 , 10 , 15 , and 20 miles per hour . There is a heavy