My car has wheels and a body part at the middle point of them, slightly raised above.
If I give the body block mass more than the wheels
if the car goes off a ramp, it will start turning forward (“front heavy freefall”)
If I make the Body block lighter, (like 1 instead of 7.85) the effect is reduced.
What are the physical principles guiding this rotational momentum, and how can I best counteract them?
This is a fully constraint vehicle.
In the real world, this has to do with air resistance and mass. The more mass an object has, the less it will be affected by air resistance.
As far as I know, Roblox doesn’t have air resistance physics, so I’m guessing the factors contributing here are gravity and the mass of the object falling.
To counteract the heavy front-falling act you are referring to, just keep decreasing the density (which contributes to the mass) until the front no longer immediately falls. In fact, I recommend just making the BodyPart completely massless by enabling the “Massless” property so its mass has no effect on the overall body of the vehicle.
You can also use Align Orientation to keep the car stabilized, you will need to create a part for reference and use that as the attachment, you can see how its done here:
This definitely involves angular momentum.
If I full gas the wheels (so their upper front quadrant is turning down, driver sighting as reference axis),
the car will turn back as it flies through the air.
If I instead let off the gas at the end of the ramp, or in midair, the deceleration of the wheels (wheels accelerating so the front quadrant is not quite turning up but slowing down its rate of turning down), the car continues to barrel forwards instead,
as a satellite system, the wheels exert an equal and opposite force on the body.
This makes the car able to be steered in midair with the wheels slightly, at this lighter mass. Which becomes negligible at the higher body ‘inert % control’ mass. Im still testing that part.
Further testing seems to show the altitude of the Body block in relation to the wheels does not affect this local-X (left to right axis) rotation. After lowering the force of the suspension proportional to the mass decrement of 1/7.85 it is shown that the suspension isn’t a contributing factor either