Monocoup Chassis

Could someone explain with a little detail what a monocoup chassis is? I thought I understood but while trying to explain it to someone today I found myself stumbling. Google didn't really help that much either.

 

easiest way to explain is this

On non Monocoque cars the body is not a stressed member, with the engine & running gear bolted to a seperate chassis frame with the body bolted on top

in a Monocoque car the Chassis is an integral part of the body

Or as wikipedia put it.....

Monocoque (French for "single shell") or unibody is a construction technique that uses the external skin of an object to support some or most of the load on the structure. This is as opposed to using an internal framework (or truss) that is then covered with a non-load-bearing skin. Monocoque construction was first widely used in aircraft, starting in the 1930s, and is the predominant automobile construction technology today.

 

Do you mean a monocoque chassis? Most cars up until the 60s used a steel tube frame called a ladder frame. The tubing could be square, round, or elliptical in cross section. The body could be lifted off the frame. The Ford GT used a monococque frame which is basically a type of unibody construction. Not just a belly pan like a Volkswagen. But a structure of metal like a stack of boxes and chambers that give the entire structure its strength. Sort of like the interior structure of an aircraft. The big Greyhound buses from the late 50s and 60s did not have a frame. They were made in the same manner out of boxy constructed chambers.
The bad thing about a monocoque is that once the car is in a bad wreck, the entire structure is damaged and you have to just start peeling back the bad until you get to undamaged panels. But since everything is connected, a lot of damage is usually done. On a regular ladder frame, the body can be badly damaged but the frame can still be in good shape.

Monocoque cars are a nightmare to the restorer because all those boxy chambers collect water and will rust steel and corrode aluminum. I believe that a Lamborghini Miura has a similar construction that is a nasty mess to restore. I can't remember if the Ford GT monocoque was made of aluminum or stainless steel. Probably aluminum.

Napolis has a Ford GT and a Lola. He would know more.

 

OK, I'm getting it. Are Boxers and 308's monocoques?

 

Drew, no the first true Monocoque Ferrari was the 348, until then they had a seperate chassis with the body panels welded to it

 

Mk 1-3 had mild steel monocoques with the mkIV having an composite metal tub


The big benefit of the monocoque is it allows the forces generated in a crash to be distibuted through the car and to specialy designed sections that for deformable sections design to crumple in a crash, it may be a nightmare to repair or restore but I know which one I'd rather be in if I had a big crash!

 

Got it thanks. Never thought about this before in over 20 years of ownership.

Regards,

Drew

 

Colin Chapman was one of the first to introduce a monocoque in F1 in the 60s. As well as the lightness, it was considerably stronger and flexed less than a tubular frame so that far more precise wheel movement (camber, toe etc) could be achieved.

BTW, it was generally a bad idea in F3 and Lotus lost market share to Brabham who used a conventionally framed car, for the reasons highlighted (difficulty and cost to repair).
Philip

 

Lancia introduced the first production monocoque in the 1920's with the lambda, with mass produced monocoques appearing from the late 1930's (the Morris Minor of 1948 being a very good example and one of the first to pass the million made milestoneand leading to the one and only Austin Mini Minor)

 

Hi Andrew, So are our Mondials refered to as spaceframe?

 

No, a Maserati birdcage is a good example of a spaceframe

our Mongo's are just plain old seperate chassis cars built in the same way as most Ferrari's since 1947

 

Ah, but they are tubular aren't they with a sectional body on top?

 

Andrew, I don't want to quibble, but I did say in F(ormula) 1, and "one of" the first, rather than the first, but nonetheless thanks for the data.

On a somewhat related topic, my father used to have a Morris Minor (1000), or "Morrie banger" as my brother and I referred to them. High headlight version. I recall my brother filling up the petrol tank with water, so that when my Dad went to drive back to work the predictable happened. Father wasn't amused. Brother was. I hid thinking I'd surely be blamed.

Recently I saw Tiff Needell (of Fifth Gear fame) driving one around their course (Angelsey I assume). As I recall, his treatise was that the Minor taught fine car control (4 wheel drifts etc) at modest speeds and so was an excellent learning tool. Unfortunately, I don't think the lesson was heeded (or perhaps, applied) to the 1300 (FWD) which replaced the Minor. Both my brother and I had some mishaps in the family 1300 and I succeeded in totaling it, much to the general displeasure of the adults in the family.

Philip