The mystery called chassis

[bernard]

A couple of weeks ago there was a topic here about the correct meaning of "chassis". I looked for it, but couldn't find it.
Anyway, in that topic somebody, I believe it was Monstrobolaxa, proved with his books that chassis equals monocoque, because some old fart used that in his book (just kidding)
Well, anyway, i stumbled upon this article, in which Ross Brawn talks about their updates to Hungary.

The Bridgestone tyres should be improved for the Hungarian Grand Prix," said Ferrari's technical director Ross Brawn. "The chassis is more or less frozen for the rest of the season though.

I take it by chassis he means the whole body of the car, including all aerodynamic devices.
So.
It is not just the monocoque.
P.S I'm sorry I coulnd't find the topic in question.

[sharkie17]

aerodynamic devices by definition cannot be a chassis.

this is what Renault F1 website calls the "chassis"



Chassis - Moulded carbon fibre and aluminum honeycomb
composite monocoque, manufactured by Renault F1 team and designed for maximum strength and stiffness with minimum weight. Engine installed as a fully stressed member.

[tempest]

When McLaren were having all their engine blow ups, it was suggested by people in this forun that their chassis wasnt stiff enough. How is this possible?

As a civil engineer, we design things for deflection (i.e. stiffness) and we keep making it bigger until it is stiff enough. I understand that there are weight issues, but if the car is already 100kgs under weight wouldnt it make sense to put in a lot more stiffening to make sure you get to the end of the race? Or were there other factors, like the engine being more powerful or having different resonant frequencies than expected?

Also, doesnt a stiffer chassis give more adjustible suspension?

[Monstrobolaxa]

Well just bought the book:

"Formula 1 Racing For Dummies" it's written by 2 Autosport magazine journalists and they also write as the Chassis being te monocoque....

But like I said in the previous topic I do not agree 100% on what is written.

[bernard]

My point exactly was that different people use different meanings for chassis in different contexts.
Renault F1 site says it is the monocoque, some books also say it is the monocoque, some people say it is monocoque+some other things, some people(like Ross Brawn) say it is the body of the car. So there really is no one answer like; "this person uses that term, he is correct, because he has been a mechanic for 60 years."

[sharkie17]

Ferrari website says it is the monocoque.

[sharkie17]

oops, double post

[CFDruss]

a chassis does not mean its a monocoque, a monocoque is simply a design of a chassis, in which everything is integral. This type is used in F1

By definition, the chassis is the structual member to which the main components, such as the engine, transmission, and body are attached, I.E, the skeleton of the vehicle.

Although a seperate frame can be used, also known as a space frame and used in some racing clases such as lower end formula, karting, and on everyday vehicle such as trucks, the majority of modern cars combine the frame with the body; this integral construction produces a stonger and lighter vehicle.

With reference to a comercial side (mass manufacturing), In the earlier work on frames it was said that the body shell resisted torsional movement of a simple frame, but defects in the construction soon showed up because the shall was not designed to withstand these stresses. Abouit 1934, the development of the all-steel body made possible the elimination of a seperate frame, the body shell being capable of withstanding the various frame stresses when suitably designed. This frameless or integral arrangement gives a stiff, light construction.

F1 cars use this integral construction (monocouqe) design, cause it offer a very good strength to weight ratio

[sharkie17]

By definition, the chassis is the structual member to which the main components, such as the engine, transmission, and body are attached, I.E, the skeleton of the vehicle.

umm.. wouldnt that make the monocoque of an F1 car a chassis?

[Guest]

look,we all have brains.you said a chassis is the part of the car to wich all major components are bolted to.Right.
Omit the engine and gearbox of the car and you have the forward half of a formula 1 car and nothing to bolt a suspension or a rear wing or crashstructure to.So by definition the engine and gearbox are part of the chassis ,their design influences the stiffness of the car totally.And if someone decides to make no difference between the monocoque and the chassis ,he might do so but he is NOT right.If someone chose to build an engine in one piece with the drivers compartment would this mean the car had no chassis because the engine cannot be a chassis...so this extreme tells us all.

[CFDruss]

So by definition the engine and gearbox are part of the chassis ,their design influences the stiffness of the car totally.

By definition, the engine and transmission are completely seperate to the chassis, yes there design influences the stiffness of the veichle structure, but so does the aerodyanmic package, the wheels, every structual part of the vechile has some influence of the car....but we dont call them all the chassis. Chassis design is its own field, and is designed as such. Stress/design analysis is carried out using the known forces of all the components attached but modeled as its seperate.

look,we all have brains.you said a chassis is the part of the car to wich all major components are bolted to.Right.

Not once have I said anyone has no brain, I was simply stateing a quote from V.A.W Hillier, if you feel you have the expert knowledge to argue with the definitions that a well known automotive technical consultant, with 40 years automotive experience then feel free.

If someone chose to build an engine in one piece with the drivers compartment would this mean the car had no chassis because the engine cannot be a chassis...so this extreme tells us all.

The car would still have a chassis, as it would still incorporate integral structual members, crumple zones, etc, these all being part of chassis engineering, which is a completely different specialized area of engineering.

[CFDruss]

sharkie17 wrote:

umm.. wouldnt that make the monocoque of an F1 car a chassis?

Yes a monocoque is a form of chassis[/b]

[marcush.]

i´m challenging those 40 Years of experience,yes.
If the engine designer and Gearbox designer has no clue about the loads his new baby has to transmit in its function as a main loadbearingmember the thing will never ever perform.The stiffness issues are main considerationsas you don´t want to have peaks of stiffness or lows in weakness along the wheelbase of the car.
When Teams used Magnesium Gearbox castings very often the Car became undriveable during a weekend or even in a race when temps got too high and the magnesium lost its strength.Torsional rigidity suffered dramatically and made a dog out of the beauty ,with no chnce to find a setup.
If you take of a aero device or apiece of the sidepot or a nosecone,you still have a car ,but if you dismount the engine or gearbox this is a bit of a different storyin the case of a f1 car,is this so hard to understand?
If I´d ask you where the suspension is mounted to you´d always say it´s mounted to the chassis.
The point is In F1 the engine and Gearbox double as chassis members.This is the reason why the Teams want the manufacturers to integrate their engine design to their theircar design.only if you design it as a functional unit you get the results.
but lets get over this now,i´m a bit tired to discuss this any frther.as we are just discussing the meaning of a word..or would you say gearbox s/engine /installation stiffness are not major design criteria foggr chassis performance?????So basically we should have the same view on the subject itself but hey I say the monocoque is the forward part of the chassis and you say it is the chassis.My view is the integrated one wich all big heads proclaim for years now,whereas yours is the one written in the books separating a car into chassis ,engine gearbox.
Just one more for thought:In the early days of motoring the chassis and body of the car where two different entities.Today the cars (most of them) do not even have something like a frame underneath,if at all they sport subframes for the suspension ..You cannot tell the Body from the chassis anymore it is both and it is correct to say it´s a chassis as well as it is the body shell of the car.so it´s the Same story with,different players

[sharkie17]

you can tell a difference where the chassis of a modern day car is and where the body is. its just that some part of the chassis is a part of the body. (exposed c a,b and c pillars for example.) 99 percent of all modern cars use unibody chassis construction. its been done that way forever now.

[MRE]

I'm also keep wondering what is exactly chassis for F1 car. For me,let start with the nosecone.The part that connected to the end front monoque.Then the suspension is bolted to the monocoque.But,what about the floor of F1 cars? Are they mounted to the monocoque? Sidepods is a part to cover the part of the car and engine.So where about the rear suspension was bolted?May be I'm wrong,but what kind of improvement could we do to the chassis?What's the chassis exactly is?