What would a GRM Daytona Prototype/LeMans race car look like....?

alfadriver said:

In reply to sleepyhead :

My limited knowledge of structural engineering would make me think that sheet aluminum honeycomb would be very similar to carbon honeycomb.  Which would say that the loads would have to be designed around.  

IIRC, Carroll Smith book used sheet design for it's race car book.  The ONLY reason to go down this path is if it's faster and cheaper to make in bulk.  Otherwise, cutting and welding does a good job.  

The on really interesting development I've seen are some FSAE teams using folding sheet design for the base chassis- where the big issue is how to cut the folds so that they fold correctly- there was an interesting article in Racecar Engineering about it.  Seemed like something that could be translated to mass production if perfected.  Making bulk sheets that can be later cut and folded would be a whole lot faster than laying out and curing every single chassis (it seems to me).  

Aluminum has two advantages over carbon... it is much less brittle than carbon, and it has a higher shear modulus.  I don't have the numbers handy, so I could be wrong... but I believe that Aluminum has higher shear and compression strength than carbon.  Carbon is primarily a 'miracle worker' in tension only.  And point-loads generally transfer loads into a panel in multiple load types at the same time... iirc.  caveats:  structures was not a... {ahem} strength of mine in school, and it's been a while since I had these things/numbers at my fingertips.  so, I could definitely be wrong.

re: 'folding sheet design for chassis'
I went bombing around trying to find that article, with no luck.  if you come across it again, I'd be interested in reading it.  I agree that a sheet-based chassis could be a haven for 'production'... especially since it could leverage cnc cutting.  but, as Exocet and Palatov have 'proven' to a degree... cutting tubes and welding into a fixture is still a valid approach.

We Have a Member here that has built A Chassis,And a Gourgous Car, Uses Production  Suspinsion, C4

    Ya'll Read Up On the Cheetah Being Built, It's a Super Car And he has Designed it for several engine tranny options. I Doubt It Could be (Forgive me)   Dummied down for this but maybe ?

  Having Grown up Next to Lockheed and A&P school I am Familiar with Honycomb Materials ...Monocoque Construstion... And Box Folding 101.

          Lets stay with Easy Repairable Ol' Fashion DOM.

      READ THE CHEETAH BUILD.

In reply to sleepyhead :

I'll have to go to our library to look it up- but I could not see reference to it on the Racecar Engineering site.

So it's the Sept 2018 edition of Racecar enginneering.  I scanned it, but not the title page, as it had no text.

How does one post a .pdf file? I'll post it up when I get home.

The article is very relevant to this thinking thread- as it's a debate in the FSAE world about a space frame vs. the monocoque.  And the big separator in the technology tends to be the resources available to the teams.  And this idea of folding sheets of honeycomb brings the monocoque to more teams.

If it works, it also brings the idea to more of a backyard builder, too- where you mostly need a CNC mill to cut the sheets prior to folding.

In reply to alfadriver :

I don't think the board does that... and I don't think posting a scanned copy of another publication's IP is really in our best interest... no matter how relevant it might be.  I'll see about finding it online with that info, and or ordering a hard copy back issue.

alfadriver said:

So it's the Sept 2018 edition of Racecar enginneering.  I scanned it, but not the title page, as it had no text.

How does one post a .pdf file? I'll post it up when I get home.

 

My "quick-cheat" way of posting something like that to the forum.  Open the file in question. Open Snipping Tool from Windows (I would assume a Mac has something similar). Snip the desired area - Copy - Paste - Post.  Done.

(snipped from the back-issue preview from the website)

sleepyhead said:

In reply to alfadriver :

I don't think the board does that... and I don't think posting a scanned copy of another publication's IP is really in our best interest... no matter how relevant it might be.  I'll see about finding it online with that info, and or ordering a hard copy back issue.

Good point, but a quick google search for the term "cut and fold aluminum honeycomb" results in some interesting items- some which are public research papers.

http://ojs.unsw.adfa.edu.au/index.php/juer/article/viewFile/1023/651

http://www.universalmetaltek.com/pdf/Honeycomb-Panel-Fabrication.pdf

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.821.4355&rep=rep1&type=pdf

But the article does debate the pros and cosn of the various methods which is interesting.

This is edging into a discussion of how to morph FSAE autocross design into an Endurance Prototype.  I like it!  It echoes of Bruce McLaren's "whoosh-bonk" design philosophy.  We assume street car suspension (e.g. Miata, C4) with a FSAE inspired frame.  If we project transverse mid-engine our options are almost myriad.  If we assume Longitudinal engine then the really big question comes down to affordable transaxle, assuming we're using a Challenge-style budget limit.

In reply to stroker :

It should.  Again, FSAE does have a budget goal that is pretty inexpensive as part of the challenge.  And many teams compete with similar constraints that many challenge cars are built.  So it makes sense to see how FSAE does it, and if that can translate into a 2 seat sports racer or not.

We all know that getting a great transverse powertrain that fits into the challenge budget is totally possible, making a nice mid engined package.  Longitudinal is more tough, as the number of transaxle choices are far more limited- but given the Corvair middie in 2003/4 and the few 914's with big engines- we know it's at least possible- just harder.

I don't really see the powertrain as the main constraint if this is feasible or not.  It's the chassis.  And even then, I'm pretty sure that a Midlandia chassis is possible- since it's just like making a Locost, which has competed a few times.  

But it's interesting to figure out how far one can find the state of the art.

Monocoque Construction has been around a Minute I think the 1962 Lotus 25 was first then F1 ,  Indy cars , Even 'Little' John Buttera Built a Top Fuel Dragster  late 60's. we could do a tub pretty easy, at Least a basic design With add on Susp. mount points. that could weld/ Rivet to the tub

Unless Honycomb cost has dropped Drasticly How can we consider it.

And again repairability.

I Have a cobra chassis here Engine setback Is Such that the Drive shaft is only about 13" long On a 90" wheelbase Car,So A Roadster Car could be easy enough,  I would class that with a Mid engine car built from Factory parts.No Fear. 

There is a small Road race Track At Gainsville I hear!!   A 3-4 Hour event could be enough, Open to all Challengers.

https://www.ebay.com/i/192520006956?chn=ps

May need a few of them bonded together, but they are not hugely expensive.

Not sure how much a basic tub would cost in materials.

GTXVette said:

There is a small Road race Track At Gainsville I hear!!   A 3-4 Hour event could be enough, Open to all Challengers.

Is that Gainesville FL or GA?  Man, I think a one day event with a practice/qualifying session in the morning and a race in the afternoon would rock...

GTXVette has got it.

Repairability makes the aluminum honeycomb chassis an absolute no-go for a grassroots effort unless it would be incredibly cheap to make. 

Also, a honeycomb chassis is always harder to get approved by the insurance for safety. 

And a tubular chassis, while simple, is very labor intensive to fabricate. 

I'm thinking something along the lines of a mid-engined Corvette chassis might be ideal for something that is meant to have two seats and covered wheels.

In reply to fanfoy :

That gets you back to the transaxle problem.

Stroker,FLA. At The Dragstrip In that Field Back of the Parkinglot,  I haven't seen it but heard it was there.

Here's a cheap Shot,    A c4 is only 2" wider and 3 " longer than a Fiero.

   Fiero's have been modded to a Point that ANY GM engine will fit From SBC/ls to 4's and 6's and Northstar Caddy,

   Trans from 3 speed auto to 4t65 hd ( no benifit using a 4t80) OR a 4 speed a 5 speed and the new 6 Speed,  We would just be using transverse engine.

I am already building one that way, But using a Big Block I still want something stronger for a trans,

My Thoughts so far A Shortie Powerglide without a Torque Converter, A 425 set behind the rear wheels connected to engine w/ a grive shaft,  And one looking best so far is a 425 with engine backwards in front of rear axle connected with a Driveshaft to the rear gear, BECAUSE A 425 turns Backwards and Installed Backwarda it's rotation is Correct, Just offset a coule inches

In reply to alfadriver :

I've downloaded those, and will work through them slowly.

Also bought a digital back-issue of the Sept 2018 Racecar Engineering... which...  Wow, that was a hassle.

Nevertheless, I'll attempt to persevere over zinio's garbage display mode to read it.

In reply to sleepyhead :

Too bad more libraries don't have RcE.  Especially for this group.

This morning In the Reading Room I took a Moment to look at the Speedway Motors Race Catalog, We Could put together a body like the Red Car for less than a Grand . I have Two C 4 cars I paid 1000 for one I drove home and one with no e/t for 800 Manual car,   I would stay with my body but could be rebodied easy,

         Think Vette Cart With SlickBody.or not.

GTXVette said:

This morning In the Reading Room I took a Moment to look at the Speedway Motors Race Catalog, We Could put together a body like the Red Car for less than a Grand . I have Two C 4 cars I paid 1000 for one I drove home and one with no e/t for 800 Manual car,   I would stay with my body but could be rebodied easy,

         Think Vette Cart With SlickBody.or not.

You saw said body (or appropriate body) in the Speedway Motors catalog or you're estimating the build cost of said body?

Yea,  doors fenders rear qtrs. about 70 each a variaty of noses for 250ish and tails a bit less but all this is new too. Everyone at GRM should be gitting this catalog anyway Order a new one and note to them you ALSO want a race catalog.

GTXVette said:

Yea,  doors fenders rear qtrs. about 70 each a variaty of noses for 250ish and tails a bit less but all this is new too. Everyone at GRM should be gitting this catalog anyway Order a new one and note to them you ALSO want a race catalog.

I can't find them on the Speedway website.  I'll see about a catalog, then!  Thanks for the tip.

I'll be honest, haven't read thru the whole thread yet... Seems like steel tube chassis, leave drivetrain choices open.  Feels to me like we should look at spec racer Ford for some wisdom.  The cars are built like little tanks, take Ford Escort drivetrain, and are pretty easy to fix the fiberglass.

We'd probably want to stretch the wheelbase a little, hide a 20 gal fuel cell in it somewhere protected and maybe widen to allow for more modern drivetrains.

The SRF prices are inflated due to the spec nature of the class and there being only one supplier. 

In reply to Brotus7 :

Something like that with two seats is what I'm pitching.  Good photos!  Got any details of the suspension?

O K then As I See This, And I have Both Side by side, A Larger two seat chassis that can be modded beyond normal by the Common GRM man / child /Person and could look like the Brotus Offering , Is The Fiero, Pick about any FWD that sits in a Cradle and Screw it in.   in Back

 The other offering has to be a C4 chassis with what ever you want for power up front and ALL the Room for Eng trans and rear you can ask for, and the stock c4 dana 36 rear can handle plenty, But front engine, and I have studieded at length where and how to get an engine in Back.

I just can't find a Transverse setup ( trans)  that I feel will handle the BB I don't want a 4t80 they are too heavy, Andfor a longitudual I just start to run out of room for a Driver without reshaping the Cowl,  But Sawzall,

That's how I got this Far.