SBR Retractable Spoiler... Doesn't seem to do anything....

The electric SBR got me very excited again about the SBR in general. I have a massive soft spot IRL for push-rod suspension and rear engines. Well.... Thats the SBR

Which got me thinking, does that fancy stock retractable spoiler do anything? It should, as it varies the angle on speed, and comes up for braking to help slow the car down faster right? We all know that TopGear episode referring to a flappy rear wing alone has the braking force of a Ford Fiesta. (I can't remember what car. P1?)


Well, take the brakes off the SBR, shift into neutral and hit the brakes, the spoiler will come up, but you don't slow down any quicker. Even more, the load on the rear tires is actually reduced. Bare in mind, this is also at the top speed of the 6-manual... 300+ km/h. At lower speeds, downforce is pretty much negligible. Putting the wing into lift reducer, more so than adding downforce realm

Digging into the SBR files, you find the LUA for controlling the hydro angle, and the Jbeam for the spoiler itself

In the Spoiler tab for the Spoiler Jbeam, you'll see 2 parts, the first is the actual aero, and the second is the hydros which are controlled by the LUA

Spoiler: Jbeam for Aero

"triangles": [
["id1:","id2:","id3:"],
//trunk
{"groundModel":"plastic"},
{"group":"sbr_spoiler"},
{"dragCoef":20}
["sp1ll","sp2ll","sp2l",{"liftCoef":80, "stallAngle":0.25}],
["sp1ll","sp2l","sp1l",{"liftCoef":80, "stallAngle":0.25}],
["sp1l","sp2l","sp2",{"liftCoef":80, "stallAngle":0.25}],
["sp1l","sp2","sp1",{"liftCoef":80, "stallAngle":0.25}],
["sp1r","sp1","sp2",{"liftCoef":80, "stallAngle":0.25}],
["sp1r","sp2","sp2r",{"liftCoef":80, "stallAngle":0.25}],
["sp1rr","sp1r","sp2r",{"liftCoef":80, "stallAngle":0.25}],
["sp1rr","sp2r","sp2rr",{"liftCoef":80, "stallAngle":0.25}],
{"group":""},
],
"hydros": [
["id1:","id2:"],
{"beamDeform":55500,"beamStrength":145000},
{"beamSpring":1183050,"beamDamp":150},
{"breakGroupType":1},
{"breakGroup":["spoiler_hinge_R","spoiler_hinge_L"]},
{"deformGroup":"tailgateglass_break"}
["sp3r","t4r",{"inputSource":"spoiler","inLimit":0,"outLimit":1.55,"inRate":1,"outRate":1,"inputFactor":1}],
["sp3l","t4l",{"inputSource":"spoiler","inLimit":0,"outLimit":1.55,"inRate":1,"outRate":1,"inputFactor":1}],
{"breakGroupType":0},
{"breakGroup":""},
],

My guess is, it has to do with the "Stall Angle". The spoiler comes up, past its stall angle, doesn't create lift anymore. Which to some degree makes sense why the car downforce reduces when the wing comes up (The flow path of the car may effect this if it were IRL, I have 0 education in fluid dynamics).... However, drag should also increase dramatically. But it seems that drag coefficient in BeamNG Drive is calculated like a sphere, so as the wing angle comes up, the drag is exactly the same. There might be calculations linked to the "Stall Angle" on the back end that handle changes in drag as well, but Im not sure


Perhaps some smarter people than me can shed some light?