Front Floor Suspension Devices

[vorticism]

3.15.6 Front Floor Flexibility
Bodywork flexibility will be tested by applying a load vertically upwards using a 50mm diameter pad with a gimbled interface to the loadcell. The position of the centre of the pad will be given by the FIA and will be on the underside of the plank within a quadrilateral area, with vertices at points [XF=460, 50], [XF=610, 65], [XF=610, -65], [XF=460, -50]. The deflection will be measured along the loading axis.
At all times during the test, the load at a given deflection must exceed the load given by a straight-line graph defined by connecting the following coordinates in order: (0 mm, 0 N) (1 mm, 0 N) (5 mm, 4000N) (25mm, 6000N). This must be the case whether the deflection is increasing, decreasing, or held constant. The test will have no more than a maximum load of 8000N or a maximum deflection of 15mm (whichever is reached first) unless specifically requested by the FIA to investigate behaviour above these limits.
The load deflection relationship must be strictly monotonic with both increasing and decreasing deflection.

If I read this correctly, 15mm of allowable travel by a force less than 8 kN. No limit on total travel necessarily as long as it complies with the force curve specified. Compression and rebound properties must by symmetric although no acceleration figures are specified.

[Stu]

A spring almost definitely legal (as per the descriptions in the regs), but a damper is expressly forbidden.

I would say that these devices are there purely to reduce driver injury during a hard vertical impact.

Of course, they will be designed to exploit any performance potential that this allows…

[henry]

I wonder how they are going to hold the chassis in place? Without fuel and driver it only weighs about 600kg. And the COG is quite a long way from the load application point.

Maybe it would be better if these were actual 4 wheeled vehicles designed only to ground in extremis and not half the length of any high speed straight. Then simple devices to detect contact would suffice.

[Tzk]

I would say that these devices are there purely to reduce driver injury during a hard vertical impact.

Either this or they want to avoid a reduction in load on the tyres if the car touches the ground with the plank. That'd allow them to effectively reduce ride height, as the plank may touch the tarmac on bumpy straights without the car going off track.

Then simple devices to detect contact would suffice.

Iirc there were rules in the past which limited the wear on the plank, and thus indirectly limiting ground contact.