F1 engine - stressed member

[Robmarriott]

I was reading about the 2014 engines earlier and apparently the reason the teams battled to go to V6s over 4 pots was so it could be used as a stressed member, the 4 pot would have required a space frame.

Why is this?

Is it that an inline engine can't be used as a stressed member at all, or is it just because of suspension design constrains in the regulations (ie wishbone lengths)

Anyone know

[Scuffers]

shape of the engine...

V is wider than I

[Robmarriott]

I thought that may be the case but was hoping that there was a more interesting answer

[PhillipM]

Mainly the shape, but also the vibrations.

[funkyrobot]

Stressed member.

[NRS]

funkyrobot said:

Stressed member.

It's not a laughing matter,

[Megaflow]

Scuffers said:

shape of the engine...

V is wider than I

Yep.

F3 cars use I4's as stressed members, but the cars are much smaller, do not generate as much force as an F1 car, and the head cover and sump are typically twice as wide the the engine itself.

[stoocake]

Good picture! Very intersting to see. Anyone got any similar of an F1 engine showing hte mounting points, either previous or future ones?

[Derek Smith]

stoocake said:

Good picture! Very intersting to see. Anyone got any similar of an F1 engine showing hte mounting points, either previous or future ones?

2-year old Merc F1 engine:



I would have thought that if you are designing a car from scratch you could make it so that it was strong enough to be a structural member.

I remember reading that there were fors and againsts with regards to strapping things to the engine, especially with regards to the forces exerted by the rear wing. Wasn't this one of the reasons given for limiting the rear wing?

Didn't one of Chapman's Lotuses damage the engine casing via the forces exerted by a wing pressing down on the rear suspension wishbones?

[vrooom]

Does the engine flex when its running hot?

[RealSquirrels]

i wouldn't have thought so. the block should be the same temperature, maybe slightly warmer, as the oil or water.

put another way: do baking trays get significantly bendier in a hot oven?

[JimPetrol]

RealSquirrels said:

put another way: do baking trays get significantly bendier in a hot oven?

Yes. And they often buckle, too.

[RealSquirrels]

I've not noticed them get mor e flexible.

The buckling is I'd due to expansion/contraction for heating/cooling, not a function of the temperature but the changes in temperature.


Anyway, this document should settle it for us http://ia600500.us.archive.org/25/items/effectofte...

[PhillipM]

Of course it flexes. How much is the issue

[anonymous-user]

RealSquirrels said:

I've not noticed them get mor e flexible.

The buckling is I'd due to expansion/contraction for heating/cooling, not a function of the temperature but the changes in temperature.


Anyway, this document should settle it for us http://ia600500.us.archive.org/25/items/effectofte...

Gah, not wading through that...will just go look at the curves in Mil Hbk 5.

[anonymous-user]

It often amuses me when bolting a DFV into an F1 car how small the fixing points are, the entire rear end is held on to the tub by four small bolts. The engine and gearbox does grow when you heat it up, which is why the engine mount points are designed to cater for this. All engines grow when heated, which is one of the reasons why cam belts and chains have automatic tensioners, to take up the growth in the distance between the crank centre line and the camshaft centre line.

The first F1 car to use a stressed engine was the 1967 Lotus 49, with the Ford Cosworth DFV designed specifically for the job.

[Monty Zoomer]

johnfelstead said:

All engines grow when heated, which is one of the reasons why cam belts and chains have automatic tensioners, to take up the growth in the distance between the crank centre line and the camshaft centre line.

Does that mean that the compression ratio goes down or do the conrods grow as well?

[anonymous-user]

Engines never actually run at their cold static compression ratios due to growth in the components due to heat expansion and effects of inertia. It's why when really pushing the boundaries you have to pre-heat the engine before you crank it.

Some engines, like an Alloy Blocked Big Block Chevy Can Am engine for example, have a change in valve clearance large enough to mean there is no valve clearance at all when cold, you have to set that when the engine is hot. If not pre-heating it, there is a noticeable change in engine noise when it reaches 80 degrees C. It's quite strange when strapped in and the engine suddenly goes quieter and smoother as all the clearances come into spec.

[Monty Zoomer]

Thanks, I wondered about that. So is the CR just a nominal thing for comparison purposes?

[Scuffers]

Monty Zoomer said:

Thanks, I wondered about that. So is the CR just a nominal thing for comparison purposes?

its just a number...