Physics demonstrations in BeamNG

Downforce due to drag is in the Z direction drag is in the Y direction.

 

It's very impressive what the BeamNG team has done so far. I really look forward to updates for the aerodynamic simulation. I have to admit I'm always a little disappointed when a car spins out at over 200 MPH and stays planted to the ground. I also feel like the current way the air simulation is done results in some weird effects, like the "see-saw" motion that cars with big wings have when the are airborne.

 

Very cool stuff. this is why we need science. no science=no physics engine.

 

This actually can happen. My modified hillclimb sunburst at 150+ mph took a similar flight on @bob.blunderton 's Tennessee Highway map. Terrain was mostly flat but I crested a small hill and went flying up in a similar manner as the video you showed.

 

If you want to see some downforce in action, go see the takeoff that happened to Tripleaye in the FR16 thread on the run at trynelgren. It takes off near the end and is using the downforce stuff that will be released when the FR16 gets updated.

 

really? thats interesting - for me the cars seem to just drop down even at high speeds.

 

This is more the pop-science to everyone's detailed calculation analyses, but I think it still fits in nicely here.

"Testing the extreme downforce of the FR16 at high speeds by driving upside down. Basically the F1 driving upside down myth done using the in-game gravity controls. I waited until specific speeds to change gravity, as it will fall from Earth gravity before about 120 MPH, but at 180 MPH the downforce has increased exponentially and it can handle Jupiter gravity, or 2.5 times Earth. At somewhere over 200 MPH, it can handle twice Jupiter Gravity or a bit over 5 times Earth. At 230 MPH, and with gradual application of gravity to prevent jolting wheels off the ceiling, it's able to tolerate an incredible amount of gravity, enough to crush the tanker trailer under its own weight. The front wheels lose traction first, causing the front to tip and the aerodynamic angle to change, immediately reducing downforce and causing the FR16 to fall."

 

Reminded me of Rollcage Stage actually. Pretty awesome stuff

 

I did some more testing of downforce in extreme scenarios, this time using a 90° vertical surface (in this case a ramp I had a friend make for me). I tested the Hill Climb cars and race cars down the ramp to see if they would stick to the ramp effectively, what speeds they would achieve, and whether or not they could slow enough at the end to exit the ramp at the bottom. I also tested the FR16 driving straight up the ramp to see at what speed it would stall for traction and fall, and at what altitude full acceleration would be too weak to stay on the ramp due to decreased downforce.



I'm going to be mostly lazy on the calculations, but will at least cite a formula for the F1 car vertical driving experiment from this post.

Spoiler: Physics

"The required power to overcome gravity and drag is
P = m·g·v + ρ/2·c_d·A·v³
With P = 550 kW, m = 710 kg, g = 9.81 m/s², ρ = 1.2 kg/m³ and c_d·A = 1.3 m², the car can reach a velocity of v = 58 m/s = 209 km/h.
In order to drive up a wall, the tractive force (downforce · friction coefficient) needs to be greater than the weight + drag of the vehicle:
µ·ρ/2·c_l·A·v² > m·g + ρ/2·c_d·A·v² = 9589 N
For slick tyres on asphalt, µ is at least 1.6, the lift coefficient c_l of an F1 car is at least 3 times the drag coefficient c_d, i.e. c_l·A = 3.9 m².
Thus, µ·ρ/2·c_l·A·v² = 12595 N > 9589 N
The car can drive up a wall, assuming that the wall is made of a grippy material comparable to asphalt and that there is a suitable ramp to pick up speed before the vertical wall.
...
With the same data (µ, c_l·A and so forth), you can just go backwards through the lower half of my previous post. In order to maintain that minimum speed, the tractive force needs to equal the weight + drag of the vehicle:
µ·ρ/2·c_l·A·v² = m·g + ρ/2·c_d·A·v²
=> v = sqrt( (m·g) / (ρ/2·(µ·c_l·A-c_d·A)) ) = 48.5 m/s = 174.5 km/h
In reality, it would be lower. A hot, new F1 tyre is more grippy than µ = 1.6, and a high downforce setup would probably give a greater c_l·A.
Edit: Forgot about the drag with regards to the required tractive force."

The in-game weight of the FR16 is 874 kg and the power is 735 kW, if someone more skilled in that area wants to plug those in and solve for the FR16 explicitly. If you know how to adjust that formula for reduced air pressure, the heights were roughly 2,000 feet (probably insignificant) and 25,000 feet at the point of stalling, with around 101 mph and 135 mph airspeeds respectively.