FAQ #279
F.5.9 External Items

Last Updated On 12/02/2019 04:45 PM by

sayovitz

Question
What items outside the rollover protection envelope require additional bracing?
Answer
Components primarily above 350mm and outside the Rollover Protection Envelope may pose a risk to the primary structure in a rollover.
The rule is intended to make sure all external object loads are easily carried before the Primary Structure itself impacts the ground.

A. Aerodynamic devices and their mounts should be mounted at nodes, or will require additional bracing.

B. High, rear mounted radiators are sometimes completely inside the Rollover Protection Envelope.
High, rear mounted radiators that are outside the Rollover Protection Envelope require additional bracing.

C. Suspension mounted to the middle of the MHB will require additional bracing.
Suspension mounted on the MH above the SIS, and not at a fully triangulated node, require additional bracing.
Any rear suspension mount above 350mm in the middle of an Upper MHBS tube require additional bracing.

D. Air filters and IC intake manifolds are considered crushable.

Exception 1:

Mounting points and components separated and rearward from the MHB and MHBS structure are not a cause for concern.

Exception 2:

Components primarily below 350mm are considered in the context of side and rear impacts.

W. Nosecones, side bodywork, side aerodynamics, front wings, and diffusers are considered crushable.

X. Radiators are usually good energy absorbers in a side impact, and are considered crushable.

Y. Suspension assemblies, especially control arms, are considered crushable.

Z. Per F.8.6.1, Low Voltage batteries are not considered crushable, so the following assumptions should be met:
Battery is attached directly to the frame, per T.9.1.1.
Battery is small enough and far enough inboard of the track width to be protected by the suspension assemblies.

In frontal impacts, except for nosecones and tires, none of these examples are exempt from the maximum attenuator force calculation of F.8.6.2.
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Rule Numbers
2020:F.5.9