Hi fellas, was mooching about on the net (am off work with tonsilitis...) and saw the quantum xtreme which looked interesting.



Anyone have one of these, or know how they perform as compared to a regular space frame 7? I'm of two minds, as usual. Good idea, but looks like a lot of steel there. Not sure steel be the best bet for it.
I know westfield did their carbon monocoque thing that was reputedly pretty spectacular but a silly price, but does anyone know if anyone's done an aluminium monocoque 7?
I'm wondering if a similar construction method to what lotus used on the elise, ie main chunky aly box spars as a basis for a pseudo-monocoque might be a good way to make a lighter/stiffer 7-a-like.
What thoughts, fellas?

Don't know much about the Quantum, but I believe it's quite pricey.

Monocoque chassis definiely have their advantages if designed and built correctly. However it would appear to be easy to get it wrong.......Robin Hood Lightweight.

I suspect the cost and complexity of designing a good monocoque chassis and the techniques required to build it properly are what stops most kit manufacturer's from going that route. It would also make it very specific as to what donor components were used as the chassis can't easily be modified like a space frame to take alternative components.

That's my thoughts

Suposed to handle very well and are very good quality but i think they look odd!

Robin Hood Lightweight? (runs for cover!! )

Yeah they do look a bit funky, though I've got a feeling if you're willing to do a bit of your own fabrication (daft thing to say on a locost forum...!) then you could have it looking "normal". DIY nose, dash, scuttle and rear end and it can look however you like. Main thing I'd want to change is the dash - not keen on new funky dashes. Has to be a good old black dials, chrome rings affair for me, and more dials than you can shake a stick at, sort of thing you'd have been looking out over in the battle of britain. Might even put cross hairs on the windscreen (SVA compliant?).

THought that'd be the way with the ally monocoque - I think in theory it'd be great but the development would be outside of garage territory. THat said, I thought it worth asking because I've seen some stuff come out of garages that's ruined the grading curve a few times now. Anyone remember that chap in the 80s who made his own spitfire (the plane?).
All this is pure speculation of course, I'm building a locost chassis in stainless, I'm just really really bored tonight! Damn lurgey.

G'd damn it that cat makes reading anything super hard!!!!

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Originally posted by tegwin
G'd damn it that cat makes reading anything super hard!!!!

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Noted, will change it!

It's a shame in some ways because it was kinda cool! I have two 6 month old cats (brothers) who are always up to all sorts of tricks but when reading the posts I could barely keep my eyes pointing at the text.

Cheers,
Craig.

Better? Little more laid back.
You guys not into hard house then?

there's a whole bunch of them here, made me laugh.

link -->CATS

Brilliant!

Try looking at this site. The car is also given a fair few pages in the book, Lotus Seven and the Independents.

http://www.prbaustralia.com.au/

Look at the PRB Composite section

Robin Hood lightweight is not being sold , At the moment. The Robin Hood owners club have a few very keen and skillfull builders that have been addresing the shortcomings of the original design and whilst the SVA is still looming i would say no more in fear of jinxing their chances.
The original concept by Richard Stewart was well conceved but not well exicuted.
The early Monocoque Robin Hoods S7 to Exmo and series 2, 3, 3a had some interesting inovations such as inboard shocks and engine mounts on sleds which ment almost any engine and gearbox combination could be simply fitted.
That said they were always going to be heavier than the book chassis.

I hope they get it sorted. Nobody'll risk launching anything similar otherwise. Have any got through SVA recently?

As for the Quantum chassis it is of high quality, strong and with good NVH characteristics. The Extreme though is butt ugly, big and heavy for a Seven derivative.

I really don't think that monocoques should be left by the home garage builder. I've have been witness to the design and helped construct a couple of chassis by my father. These were ally monocoques which were bonded and riveted and in 20 years of racing chassis failure was never known. Until something else was hit of course, but then monocoques tend to be very good at absorbing impacts.
Admittedly it was only ever used on the circuit so it's suitability to the road is untested. Below are some pictures of the chassis in construction. It has got a tubular mild steel bulkhead at the back and front for suspension and rear subframe mounting. The car was very light. With a CVH engine with transaxle box it weighed about 360kg.





(A few more in my archive under IJAL)


So go on someone, give it a go!!



[Edited on 12/1/07 by andylancaster3000]

Looks very nice Andy! Maybe a garage mono can be made for the 7 too, and it should be a fair bit simpler than your old man's little beauty, like the elise above. My main worry would be that pesky fatigue problem. I'd hate the idea of thinking it was strong enough when actually the final stress cycle could be the next corner... Not sure about rivetts either, seems a bit temporary for me unless you really know what you're doing (Yeah I know 747s are mainly glued and rivetted!). Needs someone with experience. That ain't me just yet, maybe a retirement project?

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Originally posted by jlparsons
I hope they get it sorted. Nobody'll risk launching anything similar otherwise. Have any got through SVA recently?

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