Engine mountings

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10-09-2017, 11:05 AM
EFT

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Engine mountings

Hi everyone,

My name is Etienne Couttenier, member of the Estaca Formula Team from Paris in France,

We have a question regarding the engine mounts we've conceived; our engine, a three-cylinder block off of a triumph street triple and therefore quite
imposing is fully included into the primary structure defined by the regulation (in between the main hoop and main hoop bracing) but one engine
mounting hangs out at the back of the main hoop bracing. We are therefore wondering if the mounting needs to be triangulated and if so, are we allowed to
triangulate it back to the main hoop bracing?Attachment 1260 Attachment 1261

It is a point (specifically T3.13.9) we are struggling to clarify among ourselves and some help would be greatly appreciated

Thanks in advance
10-12-2017, 05:27 AM
Jonny Rochester

In my opinion, this does not breach the rules. There are very few rules about the placement of the engine itself or it's mounts. Only the intake manifold and throtle has to be inside a line drawn between the top of the roll hoop and the tyres.

I am reading FSAE American rules:
IC1.4.1
"All parts of the engine air and fuel control systems (including the throttle or carburetor, and the
complete air intake system, including the air cleaner and any air boxes) must lie within the surface
defined by the top of the roll bar and the outside edge of the four tires."

However, with an aim of triangulating chassis members and getting a good load path, your mounts could be improved a lot. It depends what other mounts you have, but it seams you are creating a cantilever which is just asking for cracks.
10-16-2017, 10:51 AM
JoaoC-IFS

Doesn't seem a rule breach to me, specially with the engine mounted beneath the mounts. And they don't seem to be above the line between the main hoop and the edge of the tire (side view surface envelope).

Quote:

Originally Posted by Jonny Rochester

However, with an aim of triangulating chassis members and getting a good load path, your mounts could be improved a lot. It depends what other mounts you have, but it seams you are creating a cantilever which is just asking for cracks.

I do agree with this. It would help if you could show a CAD of the engine assembled, showing all the mounting points. All the mounts are subjected to stress not just from the weight of the engine but also engine vibration being trasmitted to the structure.
So you will want to ensure a good design of the mounts and proper damping.