Newbie question: Advantages of monocoque frame

[Mike Dozier]

The simple answer is that 95% of us would prefer a mono because it is more historically accurate.

The reason most replicas are space frame
instead of mono is due to the higher cost
to make a good mono.

The good news is that well constructed
space frames perform as well (or better)
than a mono, so unless you are hung up
on authenticity, a space frame is great.

MikeD

 

I tried searching for an answer on this, but couldn't find an answer I could understand. Could someone give me the beginner's answer as to why a monocoque frame is more desirable than a tube-built one? Is it just for historical accuracy? For my kit, I'll be primarily interested in safety, reliability, ease of assembly, and performance (in that order) - how does my choice of frame affect these?

 

[David Morton]

Weight is another major factor. It takes approximately four people to lift a GTD chassis but two can handle a monocoque.
Weight does not translate into structural integrity and properly constructed monocoques will invariably be just as strong
as the space frame equivalent, if not more so. Three materials can be used in monocoques
- Steel(zintac type? - anti rust properties)
Aluminium, and Stainless. I dont know if a Carbon Fibre monocoque has been made yet - but it may be just a matter of time, though C/F panels (outer and roof) are becoming more available.
You 'pays your money and takes your choice'
excepting buying anything from GTD in 2002 where you simply pay money and get nothing.
Dave M

 

[James]

My opinion,

The monocoque is ultimately the better option, with regard to rigidity and lightness and originality. However, once dinged, damaged or fractured watch out - the chasis rigidity will be compromised. Think about an empty can of Coke. It will support a person, but one small dent and complete structural failure!

A space frame is much safer in this regard.
A dent in the frame work is not going to be as damaging as it is to a monocoque.

I would always choose a space frame. Cheaper too!

One thing I nearly forgot! The other possible advantage, and I think this might be the best, with the mono you can talk down at the mere peasants who only have a space frame.

Regards,

J.P

 

[Guest]

I reckon the GTD chassis Dave Morton lifted with three others must have been filled with lead because it only took two to lift mine and that was after complete alloy panelling and i,m no weight lifter!!!!
GTA.

 

I'm not sure about the 95% number, since there have been quite a few non-monocoque chassis cars sold.

It is my understanding that if you damage a monocoque chassis that it's either harder or impossible to repair; replacement of parts is the only option. That's not necessarily the case with a space frame.

Your pal,
Meat.

 

[Jim Glickenhaus]

Monocoque tubs can be repaired. I've repaired the one in my Lola T-70. The one in my MK-IV which is honeycomb would be harder but for enough money I'm sure it could be done. the J car tubs cost Ford $250,000 each in 1967!
The trick is to have a chassis jig. I have one for my Lola.

 

[Howard Jones]

I would like to say that althought a ERA, the only mono I knew of at the time, was beyond my buget and I ended up buying a GTD, price was not the only reason I liked the idea of a space frame.
In my younger years I raced motorcycles and I learned that if you take your toy out onto a racetrack enought you will sooner or later hit something. I asked ERA what the prospect of getting a mono fixed if it got hurt and their responce was take all the stuff off and send back the mono, wait a year or two and then when they get done fixing it you can put it back together. To keep it short any good sprint car frame shop can fix a space frame local and in months instead of years.The space frame GTD just seamed like a better street car/ track car for me. I will also say that the GTD can be completed for the cost of the kit from ERA. That is if you could get a GTD today. I'm still not sure about their business status. Ohters could comment on that I'm sure. My only contact was more than three years ago. I bought my GTD here in the states from a local party, now good friend. Performance should be about the same. These cars, both types, can be made to go as fast as 99.99% of us can drive, or want to drive them. Big tires, big brakes, more power. You know what I mean!

[ January 14, 2003: Message edited by: Howard Jones ]

 

I'd say Monocoques have a bigger 'coolness' factor and are lighter and in general more rigid, but they are easier to damage. The space frame is a bit heavier (but not extremely heavier) but are definately stronger structually and can be made as rigitd as a Monocoque if designed right. Space Frames are definately safer and less expensive than a Monocoque.

Then there's the originality factor in the case of the GT40.

I haven't gone down the GT40 path yet myself. I'm currently building a 427 Cobra Replica. But the GT40 is one of the 3 cars I'm considering for my second replica build (Daytona Coupe and Ferrari 250 GTO are the other two.)

TAZ

 

It's my understanding that a monoque gt40 chassis is quite a bit stronger then space frame design. Tests conducted at CAV on there mono against there space frame design witch is really a GTD, showed mono to be 50% stronger. To me it's not a issue as neither chassis is designed to collapse on impact anyway. These cars were built to go very fast and handle great. Both chassis do that,neither one any better.
We probally all agree that monoques are a little lighter an neater to look at. As far as repairing, thats what I pay insurance.

 

[Heath]

Hi, I've also heard that mono's have less leg-room for taller drivers than a space frame chassis.

Is this BS or were they speaking the truth?

 

cavs monoque has infact more leg and headroom then a space frame. But I'm not very familar with many other mfg's.

 

[Hershal Byrd]

Vic,
Is that more head and leg room than in a CAV space frame ?
I have had the pleasure of sitting in the first CAV mono to be delivered to Roy Hunt in Vegas. It is a fine car with plenty of room. But I will say that the RF space frame has more room. Unless they have changed the design recently on the mono.

Hersh

 

[Steve Toner]

Hershal,

Would that be my car? Are the seats in? I haven't gotten a status report from them since before the Barrett-Jackson auction...

It was up on stands and pretty much stripped down when I saw it at Christmas.

[ January 23, 2003: Message edited by: Steve Toner ]

 

[Hershal Byrd]

Steve, it was dark blue. Also I should clarify that I saw this car while attending
the Shelby bar BQ early last year. I believe
it was the first mono shipped to the states.
Bob Lacy was also present.

Hersh

 

[Steve Toner]

OK, that was Lacey's car. I sat in it myself a week or so after the SAAC event. It was in LV for some dyno work I think. Rather handy having Kroyer Engines right next door to your shop

And yes, I believe that was the first CAV mono in the country.

 

Steve
Check the vin # . I beleive 001mono1b was the first CAV monoque . Yours could be it.

 

[Steve Toner]

Mine is 1A09. First ZF car, but not the first monocoque...

[ January 24, 2003: Message edited by: Steve Toner ]