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mid engine chassis?

markf - 29/7/08 at 06:17 PM

evening all,
i know this has been asked many times before,and sorry for being stupid and lazy, but could some one point me in the right direction, where,and if available, can i find plans for a mid engined locost, as i have a 1988 ZX10 that im thinking about using, and what about the pros and cons.

cheers

mark

quinnj3 - 29/7/08 at 06:35 PM

Lancia

take a look at this very nice but not exactly locost would be a nice wee project!

mr henderson - 29/7/08 at 06:38 PM

Well, 36 views and no replies so I suppose I had better have a go.

I don't know of any plans for a mid-engined chassis in the way that there are for front engined versions.

If you really want to use that engine why not go for a front engined car and get the benefit of the plans (such as the Haynes Roadster) that can be bought for the price of the book?

If you really want to do the mid engined thing then you are going to have to draw your own plans, or do what a lot of guys here do and just wing it.

You will need to make a lot of decisions before you satart though, kie what suspension you will use, and how you will get drive to the rear wheels etc etc

John

Edited to add- must type faster!

[Edited on 29/7/08 by mr henderson]

Alan B - 29/7/08 at 06:55 PM

I get asked a lot for plans..but I'd sooner people just browsed what I did and be inspired by the good bits and go from there.

For me to release any kind of drawings they'd have to be proven, tested and updated to a high standard and that will take me time...time that people seem unwilling to pay for.

The other aspect is liability.....people just don't want the risk of being sued so there is little incentive to share their designs....

Until I'm at the point of doing a book, be it Ron/Chris style or Kurt style, then I'll just be sharing photos and ideas.

Alan

Syd Bridge - 29/7/08 at 07:00 PM

I believe most, if not all, of the guys here doing their own middies, have engineering qualifications of some sort, or have help from engineering professionals. To say they are 'winging it', would be a very long way from the truth, and doing them a gross disservice.

There are a couple of projects worth a second look, and a couple of production kits worth a look for inspiration.

Cheers,
Syd.

Neville Jones - 29/7/08 at 07:44 PM

Iv been trying to draw out a mid engine chassis based on the Locost but carnt seem to get the portions to look as good as the locost. the back jsut ends up looking weird.

seems to be what mark is looking for and a lot of others

anyone out ther done it yet?

Cheers,
nev.

les g - 29/7/08 at 07:49 PM

what about the new chassis by mk
cheers les g

kb58 - 29/7/08 at 08:07 PM

quote:
Originally posted by Neville JonesIv been trying to draw out a mid engine chassis based on the Locost but carnt seem to get the portions to look as good as the locost. the back jsut ends up looking weird.

Styling is a completely different - and more difficult - topic than the engineering of it. Emotions usually win over equations!

Alan, I agree completely with you comments, and have thought long and hard about the liability of it all. And as you said, finishing the first car isn't the end of it. There's testing, possible refinements, drawing the plans, then writing the book. It's a long path to create a watertight product.

[Edited on 7/29/08 by kb58]

zilspeed - 29/7/08 at 09:21 PM

If I may chip in some slight advice.

We have a ZX10 and chain drive expert in here in the form of minitici.

He provided me with an extremely simple wiring diagram for the old Kwak.

That's the engine I'm using so would be keen to assist in any way I can.

Cheers

John F

jimmyjoebob - 29/7/08 at 09:36 PM

Liability aside, simply laying out the components you have on a large sheet of card board complete with a seat form is a good starting point. You can quickly sketch up where your suspension needs to sit, allowing for a comfortable cabin size etc.

For simplicity, you could buy the front and rear subframes from an mr2. Laying these out over your floor sketch would show you where to start triangulating to make a rigid 3d design. For a reference take a look at the Sylva Riot frame.

Delinquent - 29/7/08 at 11:03 PM

quote:
Originally posted by Syd BridgeTo say they are 'winging it', would be a very long way from the truth, and doing them a gross disservice.

ermm.... ahhhh... oops

I'll be the one legging it (winging it?) for the door.

mr henderson - 30/7/08 at 07:05 AM

quote:
Originally posted by jimmyjoebob
Liability aside, simply laying out the components you have on a large sheet of card board complete with a seat form is a good starting point. You can quickly sketch up where your suspension needs to sit, allowing for a comfortable cabin size etc.

That is what I meant by 'winging it'. In other words, not designing the whole thing on paper or in CAD first.

Seems simple, straight froward and effective to me.

John

hughpinder - 30/7/08 at 09:05 AM

have a look at the onyx mongoose - someone has done one of them mid engined using a ZX10 engine

http://onyxmongoosezx10.blogspot.com

regards
Hugh

sgraber - 31/7/08 at 09:44 PM

Since I am not a registered trader I am not going to suggest you purchase anything from me... However - If you don't like the look of the current crop of middies just build a your own chassis to fit my bodywork. It's a low cost middy setup.

Just visit my website for lots of information...

Gakes - 4/8/08 at 05:42 PM

love the colour dude

jimmyjoebob - 5/8/08 at 09:40 PM

Sketching out where components are at an early stage still allows for the chassis design to be finalised on cad. It simply aids positioning of main load points before structural framework is set.

Surely this can be considered basic research rather than 'winging it'?

MakeEverything - 8/8/08 at 04:19 AM

Isnt it a bit Ironic, that a Locost Builder accuses others of "Winging it"!!
I think what he means though, is "the trial and execution of ones ideas, through engineering experiment and design"....

We must all admit that at some point, there has and always will be a time where the phrase "...Ah, thatll do" or "thats near enough" will come into play.

Some have tools such as CAD, and others use cardboard layouts or models to picture their design. Ive tried them all, and i think its individual to the builder how they picture, design and adjust to suit the needs of the build.

Cad drawings are really good, but it is difficult to reverse engineer a whole build. It is better to work from drawings, but even then, youll find you need to adjust slightly, which in theory, defeats the object of having a drawing!!!

[Edited on 8/8/08 by MakeEverything]

mr henderson - 8/8/08 at 07:25 AM

OK well this is the second time I've been picked up on my 'winging it' comment. (the first time was just an opportunistic snipe)This is what I said-

"If you really want to do the mid engined thing then you are going to have to draw your own plans, or do what a lot of guys here do and just wing it. "

It seems perfectly clear to me. It poses two alternatives. The first to completely design the car and then build it in the same way as if one was following a published design. The second is to not do that. And the second is the way that it will happen in most cases.

If you show me someone who claims to have done an absolutely, in every detail, complete design before picking up his first piece of chassis material and attaching it to the second piece, then I will show you somebody who is not telling us the whole story.

Obviously one is going to have to do some design work before starting, or else how are you going to know how long the first piece of steel is going to be? One shouldn't need to spell out everything!

Even large manufacturers build mock-ups and prototypes.

John

Fred W B - 8/8/08 at 08:21 AM

Those of us who work in engineering will know that the first "proto" build of a fully engineered/drawn item is in fact to prove the drawings. Mistakes are made in everthing.

I work with a computer all day, so in my spare time in the garage I prefer to go straight to "mock up" . Drawings are then only really necessary if you want to build another, or if you need to get parts made by another party

Cheers

Fred W B

and

rpmagazine - 8/8/08 at 09:49 AM

Indeed a mockup helps a lot:

Fred W B - 8/8/08 at 11:40 AM

Personally, I prefer to rough work in steel, because its so easy to tack together, but each to his own

Cheers

Fred W B

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CraigJ - 9/8/08 at 01:40 PM

quote:
Originally posted by hughpinder
have a look at the onyx mongoose - someone has done one of them mid engined using a ZX10 engine

http://onyxmongoosezx10.blogspot.com

regards
Hugh

That will be me lol.

I have just sold the ZX10 engine about an hour ago lol, its going to be fitted into a Haynes roadster buy its new owner.

Not sure what engine to use now, tempted to go for a K series and supercharge it but not that sure. Got bord of the bike engine idea.

Joe T - 9/8/08 at 08:07 PM

quote:
Originally posted by Fred W B

I work with a computer all day, so in my spare time in the garage I prefer to go straight to "mock up" . Drawings are then only really necessary if you want to build another, or if you need to get parts made by another party

Cheers

Fred W B

I am in exact agreement with Fred, there's no substitute for just starting with a few bits of tubing then mocking up an engine bay round your engine/gearbox unit, the pickup points will start to give you some locations as well as the driveshafts etc.

rpmagazine - 10/8/08 at 02:57 AM

locally steel has gone up over 100% in the past 15 months, so there is no cheap supply. For this reason teh treated pine was used and stuck together with a hot glue gun. Easy, quick and effective.
I do however totally agree that a mockup allows the placement of the chassis members to suit the needs, rather than having a chassis design that in which you have suspension pickup points in the middle of tubes - though this is less critical if you simply want to cruise around in your car and have no ambitions to seriously load up the chassis.

Custardtart - 14/8/08 at 12:59 PM

how about using a tub from a mk1 lotus elise?

Alan B - 15/8/08 at 11:45 AM

quote:
Originally posted by Custardtart
how about using a tub from a mk1 lotus elise?

I'm not saying that's a bad idea, but I think it misses the point for most of us....why not save up even more and buy the whole Elise...and save all the build time too?

If you could get a useable Elise tub at silly money then it may be viable..until then we'll keep building our own.

Just my opinion of course.

And welcome to forum by the way...

kb58 - 15/8/08 at 03:45 PM

I suspect most of us could go into a Lotus dealer and buy - and start making payments on - an Elise. I think, deep down - we do this because it's fun, not because we have no other choice.

It reminds me of a guy who wanted a Ferrari F40 but couldn't afford one... so he had one built for him. While the car's awesome, I can't help but think he could have just bought a real one for what he spent.

[Edited on 8/15/08 by kb58]

Custardtart - 18/8/08 at 06:56 PM

Thanks for the welcome

Eachto their own. I've been looking at this engine http://www.h1v8.com/page/page/1562068.htm would make an awesome partner in an elise chassis.

kb58 - 18/8/08 at 10:04 PM

Dennis of http://www.dpcars.net is considering doing that, and he's already using that very engine.

Ninehigh - 1/10/08 at 07:36 PM

Something I'd really like to know about the whole mid engine set up, where have you all put the fuel tank? Makes sense to me to have it in the front where the engine would have been, only is it (a) safe and (b) legal? Also if it still has to go in the back what weighs the front down for traction?

kb58 - 1/10/08 at 08:38 PM

In my mid-engine Mini I put it at the front, just forward of the shifter. In the current project it's going sideways behind the seats. The latter case places it right on the CG, so fuel load doesn't effect weight distribution as much. It also avoids running fuel lines down the center tunnel.

There was always the wondering about what would happen if I hit something in the front. Would the gas tank end up in the passenger compartment? A true fuel cell was used to lessen any nastiness but in the new car I'm going to run an ordinary steel tank. The thinking is that it's far better protected behind the seats and ahead of the engine than at the front. It's much more likely that the front will get crunched rather then the rear, but it's no excuse for not protecting it as much as possible.

[Edited on 10/1/08 by kb58]

Ninehigh - 3/10/08 at 02:41 PM

Yeah the more I think about it the more I'm thinking it's a good idea to stick it behind the engine with some good heat shielding. The front can have the surprising bonus of some "boot" space hehe