Aluminium Monocoque Chassis
Aluminium Monocoque Chassis
Author
Discussion

Joe T

Original Poster:

487 posts

247 months

Wednesday 24th August 2005
quotequote all
I was interested in opinions regarding making a kit Car with a Aluminium Monocoque over a traditional Box or Tube space frame. Some manufacturers are offer this type of construction now. Any experiences?

[URL]Monocoque Website|http://www.race-car-replicas.com/Chassis.html[/URL]

groomi

9,330 posts

266 months

Wednesday 24th August 2005
quotequote all
In theory it could be a much simpler way to make a good peformance car. The problems lie in compaability as you can't just move a few bars around to make space for a different shape engine etc. Also, repairs will be more specialist and therefore expensive, so higher insurance too.

Good for performance, bad for costs IMHO

Joe T

Original Poster:

487 posts

247 months

Wednesday 24th August 2005
quotequote all
I see what your saying, but take the design above as an example I would have thought it could accomodate most V engines without too much grief, interesting point on the insurance, how would they know regarding premiums etc? most of these cars are low volume does anyone know how insurance figures are arrived at?

On the repair I agree, repairing ally is more skilled, but wouldnt the damage be more localised?

When replacing a chassis would it not be cheaper as no chassis panelling is involved? less labour?

Thanks



millard

77 posts

263 months

Wednesday 24th August 2005
quotequote all
They are begining to appear as a cheap option: Robin Hood are now offering an all alloy light weight chassis that you just poprivet together. it comes in about £1000 cheaper to buy than the B2 (or 2B).

I would have thought that you would have more engine options than a traditional chassis due to its layout and repairs should be very cheap as you just replace the damaged panels.



Incorrigible

13,668 posts

284 months

Wednesday 24th August 2005
quotequote all
Pop rivits shake loose though

Cracking idea, all the same. Are Robin Hood doing that in a seven type car ?

Joe T

Original Poster:

487 posts

247 months

Wednesday 24th August 2005
quotequote all
Maybe that why the modern type on Monocoques went for TIG welding. Race cars used to be riveted?

Do you think it costs more to make a chassis this way?

ERP

25 posts

306 months

Wednesday 24th August 2005
quotequote all
Theoretically a monocoque can be stiffer for the same weight.

Cost of materials wise I doubt there is much if anything in it. Manufactuing wise I have no idea.

I think the barrier to these chassis in the kitcar industry has been design. They are much harder to design and to verify that design, it's relatively easy to find FEM software that will analyse a spaceframe, there are consiferably fewer packages that will analyse a monocoque design.

If you were in a serious accident, you're probably going to have to replace a significant porttion of the chassis, but that's likely true of a space frame aswell.

Joe T

Original Poster:

487 posts

247 months

Thursday 25th August 2005
quotequote all
I suppose what I am trying to assess opinion on is, if on your chosen kit car you were given the choice between spaceframe or ally monocoque, and the price was the same, what would people go for?

I suppose the lack of them on the market means its not something that most people have considered.

I wonder if any other kit car manufacturers have plans to build this sort of thing?



millard

77 posts

263 months

Thursday 25th August 2005
quotequote all
Incorrigible said:
Pop rivits shake loose though

Cracking idea, all the same. Are Robin Hood doing that in a seven type car ?


Indeed www.robinhoodengineering.co.uk/Bolteon.htm

anonymous-user

77 months

Thursday 25th August 2005
quotequote all
Joe T said:
I suppose what I am trying to assess opinion on is, if on your chosen kit car you were given the choice between spaceframe or ally monocoque, and the price was the same, what would people go for?
One of the reasons I bought the Libra was the composite monocoque tub. It's been tested at 14,000Nm/degree torsional stiffness which isn't bad in any book (better than the Elise apparently).

groomi

9,330 posts

266 months

Thursday 25th August 2005
quotequote all
Incorrigible said:
Pop rivits shake loose though


Indeed. Ideally both echanical and chemical fasteners would be used; ie. glue to hold the thing together and rivets to prevent the glue from moving/peeling.

revo1101

2 posts

246 months

Saturday 17th September 2005
quotequote all
Interesting thread this one, bonded alloy structures offer lots of advantages, but the technology in treating and curing the extrusions makes it difficult to do cost effectively in low volumes. In modern bonded alloy structures rivets are not used for strength, just to hold the extrusions in place in the jigs as the chassis go through the curing process allowing the adhesives to bond the extrusions together.

I am about to launch (target January) a Subaru Impreza Turbo based kit car initially using a GRP monocoque construction, with the Mark 2 version due in two years time using a bonded alloy structure.

This will be a radical departure from the component car norm of seven or replica styles as it has totally contemporary styling, and of course that iconic Impreza drivetrain.

Two versions will be available initially, fully trimmed option, or a stripped out road racer.
The fully trimmed development mule comes in at just under 900kgs, with the donor vehicle being a 260hp imported WRX. Performance as you would expect is, how should I put this, strong!!
Target weight for the stripped out version will be 825kgs, and a demondtrator using the 280hp STI as a donor is planned for the new year.

Total build price for a reasonable specification home built vehicle will be in the £12-15k mark.

Interested parties can e-mail me, and as launch date approaches I will keep all informed of what is happening. Indeed, I will be looking to invite a panel of independant people to test the vehicle prior to final launch so you may find yourselves driving this car before any of the mainstream pres get their hands on it!!

fuoriserie

4,560 posts

292 months

Saturday 17th September 2005
quotequote all
revo1101

Very interesting news. is the car going to be a front engine 4wd or rear(mid-engine) car?

Shape, 2 seat roadster or coupe?

Target market?, very curious and I wish you the best of luck with the project, the kit industry needs more modern cars

Italo

revo1101

2 posts

246 months

Saturday 17th September 2005
quotequote all
Front engine, four wheel drive, most of drivetrain being straight bolt over job to enable simple home build.
2 seater soft top with optional hard top.
Definately designed to be everyday realistic for people who need one car for all purposes.
Of course stripped out version for those just needing big rushes! Impreza type R is a donor option for the really brave, with DCCD and hand brake release box as standard!!
Lets hope that the industry and buying public support some one trying to do something different and new.

speedy_thrills

7,850 posts

266 months

Sunday 18th September 2005
quotequote all
What about a semi-monocoque chassis? This way you could design chassis that is truly buildable for the amateur enthusiast in his garage. Why limit yourself to just alluminium though when you could use other materials that can be formed easily like fiberglass, plastics and other exotics.

Ferg

15,242 posts

280 months

Sunday 18th September 2005
quotequote all
speedy_thrills said:
Why limit yourself to just alluminium though when you could use other materials that can be formed easily like fiberglass.......
Sounds like a good idea to me!!!

neilrallying

200 posts

246 months

Sunday 18th September 2005
quotequote all
With the project in question the chassis will be alloy, but the bodywork will still all be GRP layup. The build would be very easy for the DIY market as all components will simply bolt up to the alloy structure, which will be deliverd complete.

This is some way off however, with the initial kits being a GRP monocoque to which engine/drivetrain sub assemblies will attach, making for a very straigtforward build with superb torsional rigidity.

Joe T

Original Poster:

487 posts

247 months

Sunday 18th September 2005
quotequote all
It seems a few of the welded Ally monocoque cars will be on the road in early 2006,
Lighter and Stiffer than a spaceframe, one guy is putting 650 BHP through it

Time to start saving!

fuoriserie

4,560 posts

292 months

Monday 19th September 2005
quotequote all
revo1101

It reminds me a lot of the Delfino Feroce
www.delfino.co.uk/index.htm

the early and first car, not the later now being shown on the website.

I remeber that the first prototype was based on a Minari, with modyfied bodywork and running gear. Both founders of the Minari were involved at the beginning of the project, and it was an upmarket development of the Alfa based Kit.

Should have had more luck, unfortunately it didn't have enough support and financial backing.

Will be following your project, I believe you have a winner as a concept;

scotmac

1 posts

245 months

Monday 10th October 2005
quotequote all
Besides the obvious reason of increased rigidity of monocoque design, OTHER reasons robin hood produced the monocoque'd chassis'd lightweight are :

- international export: the design can be boxed and shipped MUCH MORE easily than a fully welded tubular chassis. in fact, see the prominent advertizing for export agent on the robin hood web page, *and* their advertizing shipping to almost anywhere!!

- production costs: the costs to produce basically cookie cutter chassis/body panels is obviously much less than the cost of precision welding a tubular space-frame. This fact is obviously reflected in the price of the robin hood lightweight.

All round, i think it is a great concept...especially considering the EXTREME lack of a even semi complete locost 7 KIT in the US market. I just hope that i can get it past the rules in the NASA Seven Series Challenge!!!