I would like to second the call made by some of you ,V8Kid for instance, to somehow nurture for the Locost middy a common building element comparable to that of Ron Champion's Locost. I don't understand how with all these car engineers writing in so many forums we cannot find YET a formal set of drawings. Who is going to amend Champion's drawings and sell them to us amateurs? Thanks.
Hopefully you will....
It sounds like you're wanting to come up with universal plans...
While well intended, I don't think it'll happen, there's just too many of us who want to do it "our way" with the parts we
have on hand. I really can't see one solution being heralded by all.
Most of these small independant car designs that actually happen seem to come from one person, or a group with a strong leader. Once in production
people modify it to their own needs.
I doubt we could even agree on what doner car to use, I mean, what's the budget that can be accepted by everyone... the answer's all over
the place. Then, what world car would be used (so everyone can build it)? Just these two items are real show stoppers since the answers are
different everywhere.
It may a fun exercise, but I just can't see us subborn types agreeing on anything! I mean, look why we're all here, it's because we
don't like any existing cars...
[Edited on 1/1/06 by kb58]
I can't even find a body!
I am planning my next car as a VW GOLF midmount, but need a body to determine wheelbase ect. Then to make up drawings as I go along is no problem.
Once a basis is established surely everybody will start suggesting improvements.
I don't really see the problem with a "universal" set of plans.. look at the Locost.. no two are the same, yet they are usually all based on the same set of plans. Sure, you could design the thing with a particular (commonly found) engine in mind, but people could still change things anyway.. i see no reason why a middy shold be any different in that from a Locost..
How many cheap front engined rear wheel cars are there to use as a basis for a 7 type?
And how many mid/ rear engined cars are there available to use as a basis for a midi?
Reality is that to build a locost midi you much do much more design to adapt a front mounted engine to fit the rear.
So its a more work and engineering on a midi and therefore much less easy to design a generic chassis.
However IMO the biggest challenge will be the body.... it seems with Midi's there is not a generic shape like the 7 that people like.
Although saying this having looked at the La Bella I recon we could be moving towards some real locost midi's.
quote:
Originally posted by andygtt
How many cheap front engined rear wheel cars are there to use as a basis for a 7 type?
And how many mid/ rear engined cars are there available to use as a basis for a midi?
Reality is that to build a locost midi you much do much more design to adapt a front mounted engine to fit the rear.
So its a more work and engineering on a midi and therefore much less easy to design a generic chassis.
However IMO the biggest challenge will be the body.... it seems with Midi's there is not a generic shape like the 7 that people like.
Although saying this having looked at the La Bella I recon we could be moving towards some real locost midi's.
What I meant buy generic mid engine chassis blueprint was a tube frame locost type from which all types of rear mounted engines could be adapted. What Sylva, Meerkat, Onyx call mid engines are not typically mid engines they are rear transaxles (sitting above the rear axle). To me a mid engine is a Porsche spyder, a Matra, a GT40 with the engine hanging somewhere in between the rear and the front wheels. Rear transaxles are perfect but they should not be called mid engine; this confuses the issue. As for the body, I really see no reason why one should entirely depart from the traditional Seven look. Look at Sylva's magnificent specimen from the front you would think that you are looking at an ordinary seven.
In my opinion i think bolting a front front combination of engine and gearbox in the arse end of a car working in the same manor is more a case of
where to put the mounts dependent on the exact engine rather than having to design something bespoke for each specific engine.
im pretty sure that a rover k series in a 214, a 2.0 mondeo zetec and a toyota celica 3s GE engine would all fit and work in near enough the same way
so that their fitment wouldn't be a major issue. Just like its not an issue when building a front engined locost.
The only forseeable poblems would be clutch and throttle cables. and the gearshift cables. these would have to be made to measure but its not a big
price to pay for the engine being in the back.
I think a general chassis design which could be addapted to suit individuals cars and engine choices would be a good starting point and i think there
would be a lot of interest in it.
I think that the bigger problem is the bodywork. If you look at the Meerkat and the la bala, both have locost type frames, but they are going through
lots of work to get the bodywork done, probably as much as it took to get the cars built and running. With the book design the hardest body part to
manufacture is the nose and the scuttle, and those are readily available through suppliers. The rest is just aluminum rivited to the chassis.
Kurt got lucky and started with a mini body and just built his frame to match.
If someone could come up with a simple body then I think it would not only be feasable to design a standard middie frame. Maybe use an existing front
bumper with aluminum sides and rear like the book locost has. I have seen a few middie sevens on the computer, but the elongated rear, ans shortened
nose just doesnt look "right"
quote:
Originally posted by Philippe
What Sylva, Meerkat, Onyx call mid engines are not typically mid engines they are rear transaxles (sitting above the rear axle). To me a mid engine is a Porsche spyder, a Matra, a GT40 with the engine hanging somewhere in between the rear and the front wheels. Rear transaxles are perfect but they should not be called mid engine; this confuses the issue.
quote:
As for the body, I really see no reason why one should entirely depart from the traditional Seven look. Look at Sylva's magnificent specimen from the front you would think that you are looking at an ordinary seven.
Yup, what he said ^. If you define "real" mid-engine cars as the engine ahead of the rear axle, then all the car's noted do in fact
qualify.
I guess I'm including my own "mid-engine" Mini to meet that definition too.
In reply to Dominic.
What is mid engine is of course a matter of appreciation. I take your illustration as legitimate but maintain my point that transaxles have blurred
the lines regarding what the notion of weight distribution in mid engines should be. This is not a "hot button for me". I have seen a
picture of a conventional mid engine Locost with a very long rear engine hood...it looked terrible. I much prefer what Sylva is doing. This is a point
that I would concede: for a true mid engine arrangement to look balanced the whole chassis of the Locost should be lengthened.
Where are you at in your own project. Do you read your mail?
Philippe.
See my design on this thread.
http://www.locostbuilders.co.uk/viewthread.php?tid=30627&page=3
A key part of the design is the use of 4x2 section around the engine bay which frees up this region by being strong enough without any diagonals which
often get in the way of suspension and driveline.
Chassis stiffness is double the book design, the wheel covers are the same all round, there are only two body panels, front bonnet and engine
cover.
It's very similar in concept to the Riot car.
Here we go again!!!. IMHO, it is possible to come up with a 'common' MIDI design - IF you are prepared to make some compromises. As I have found out, stick with Uncle Henry for the donor and away you go. I am getting around the bodywork issue by not having much! But I don't see why a design like mine couldn't have a 'locost' nose cone and end up looking like a Sylva Riot. For what its worth, I would consider selling plans but am still some way off completing my car, before which it would be a brave person to have my plans!!!!
quote:
Originally posted by Philippe
What is mid engine is of course a matter of appreciation. I take your illustration as legitimate but maintain my point that transaxles have blurred the lines regarding what the notion of weight distribution in mid engines should be. This is not a "hot button for me".
quote:
Where are you at in your own project. Do you read your mail?
How did I miss this thread?
Anyway, thanks Dominic...you pretty much said all that I would have said.
Back to the main topic....standardisation is tough...almost everyone says it's a good idea.....but, on the proviso that it mirrors their own
views..
The only way I see of there being an "offical" mid-engined locost is by someone building one and publishing a book or publishing
plans....then if it takes off.......a de facto standard is created.....not unlike what Uncle Ron did.
Until that we are on our own...and IMO, because we prefer to be..
Hmm, just re-read my reply in the cold light of day and it does sound a little short-tempered I'll leave it as is though, since editing it
after the event always seems a little dishonest.
On Alan's point - standardisation is indeed tough and, I believe, made more so because the all-in-one nature of a transverse FWD drivetrain
enforces the inter-relationship of a number of dimensions. With a front engine Locost the relevant dimensions are mostly on separate components
(engine, gearbox, axle) and their inter-relationship is somewhat less critical (and also amenable to some manipulation and adjustment).
There is an example in the design of my rear suspension. I'm re-using the donor struts, converted (cheaply) to adjustable coil-overs. Thus I
only need a simple bottom wishbone. By careful tweaking of chassis member sizes and positions I ended up with a symmetrical wishbone i.e. I can use
the same wishbone on either side. This means I can make one jig instead of two for this critical component and be confident that left and right will
be identical. However, all of this hinges on the particular dimensions of the AE101 Corolla drivetrain I'm using. I think the next model
(AE112) might be the same but am quite confident that none of the other FWD Corolla variants (AE80, AE92, ZZE122) will be. And that's just from
the same manufacturer and one who has a reputation for not changing things much. Adapting a Nissan/Honda/Mitsubishi/Suzuki/whatever strut layout
would require quite a cascade of interconnected changes.
Funnily enough though, I have encountered similar problems lately with the Locost design. I've been exchanging correspondence with a builder who
is using the same Holden Gemini (Chevette to the rest of the world) front suspension uprights as me and he remarked on the difficulty of "getting
it all to line up" on the Locost chassis, including some photos of outriggered wishbone brackets etc. That sent me searching for Cortina upright
dimensions to compare with. The bottom line is that the Gemini upright is of similar height (between balljoints) to the Cortina but the axle line is
about 25mm lower i.e. closer to the bottom balljoint. That, coupled with 15" wheels with a larger rolling radius than the Book Escort 13"
ones, means the chassis end of the wishbones all need to sit about 45-50mm higher than Book (or the clearance under the bottom chassis rails needs to
be 50mm more - great for that "off-road" look! ). Things get tricky then because the book front end has a lot of related angles
(L-assembly, FU1, FU2 etc) that all assume the brackets will go in certain places. I can only assume that the various adapters for using Sierra
uprights closely emulate the Cortina dimensions. Heaven only knows what results builders in the US are getting with S10 or Mustang or Pinto
spindles?! It would certainly explain some of the "interesting" wishbone brackets I've seen in photos.
Expecting the reader of a book to make these sort of design changes is a bit much - particularly when the design is presented as a fait
accompli without any theory or design principals explained. Arguably, presenting that sort of theoretical material is not the role of a "cook
book" type manual anyway. I get the impression that Keith Tanner's new "Cheap Sportscar" book delves into this area a little
(bump steer etc?) but how far do you go? If I publish my design, do I need to provide reams of theory to support any design changes by the reader
(almost impossible) or take the Champion approach and leave 'em to their own devices? I don't find either satisfactory and I don't see
a simple solution. I have some thoughts about a software tool (perhaps a "solver" type Excel spreadsheet) where you could plug in all of
the required donor part dimensions and out would drop an adjusted set of chassis plans. That should be easy to write - not! It took me hours drawing
and re-drawing to get my front suspension the way I want it and many more hours again for the rear end. No easy answers here.
Anyway, enough rambling from me. I'll still probably publish my design in one form or another when it's done but it'll never be
anything like a universal set of mid-engine plans.
Dominic
Exactly, Dominic, well said. This is what I was saying, that everything is connected to everything else. To come up with a design that works for
everyone is impossible. The best approach is to make it generic enough that various drivetrains and uprights can be fitted to it. And use either no
composite or pre-existing Locost part!
[Edited on 1/3/06 by kb58]
Thats one reason i think that the locost is such a good way to go for rwd engines, the bodywork is very simple, and the 2 parts that are complicated
are redily available from suppliers.
To be honest the geko design is probably the best design for a middie that would be easy to build for the masses I think Ive seen yet. I know that
steve is looking at bussiness plans for the labala, but if successful he could publish the book plans for a mid engine car, and make his money selling
bodywork to fit, but then that defeats the biggest selling point of the book 250lb to build the car, which is impossible.
To me it looks like the geko uses mostly book bodywork, and is built around your engine, however if you could extend the rear to fit a wide range of
donors, even if you use book front suspension, and go with a dedion rear and standardize the rear... i dont really know i followed the book dimension
as best i could, but since UK cars dont exist in the uS Ive had to modify my car to suit my donor, out of necessity. i dont really see whay the big
problem would be especially if the larger rear structure takes up a good majority of the stress to the rear, and can still support the engine's
weight.
If anything here doesnt make sence chalk it up to americanisms in action...
oh yeh, and keiths book is on my must read list, it goes into alot more detail on the final assembly than rons does, it pretty much picks up where the
original book leaves off.
[Edited on 3/1/06 by derf]
quote:
To me it looks like the geko uses mostly book bodywork, and is built around your engine, however if you could extend the rear to fit a wide range of donors, even if you use book front suspension, and go with a dedion rear and standardize the rear...
quote:
oh yeh, and keiths book is on my must read list, it goes into alot more detail on the final assembly than rons does, it pretty much picks up where the original book leaves off.
I like the Gheko chassis because it uses a full FWD strut suspension. If there is a std Midi Locost then it must use everything possible from a donor
car. Rear wishbones or de-dion are just too hard to make. So, if using a typical FWD car as a donor, the load pickup points are pretty much the same
for 80% of the likely donors. The chassis should just be the least possible number of tubes that link everything together and provide good strength
and torsional stiffness. The main problem is the front end. Where do you get a wishbone front end from these days? I guess might as well take that
from the original Locost then. or.. (and I don't like this idea really) but several Jap vans have double wishbone front ends, common stud
patterns and removable steering arms. Main disadvantage is that they are designed for about 200mm of ground clearence.
- Brian.
I'd use Miata donor parts for the front suspension, and the preferred FWD parts for the rear. Miata parts because they're widely available,
getting cheap, and are fairly light. Use all of it, the uprights, brakes, and rack.
[Edited on 1/3/06 by kb58]
Perhaps instead of a universal middie car, a universal middie bracket (aka chassis) would be the goal. Engine bay big enough to allow use of most transverse FWD powertrains in both 4's and 6's (someone would inevitably shove an 8 in there), basic boxed front section to allow variations in double wishbone suspensions, and the basic mounting point areas in the rear for McPherson/Chapman links. In the locost way of doing things, people would redo the rear for a DeDeon or SLA, but as long as the primary structure is still there. I like the rear section of cymtriks design as it allows a wide variation of options without cutting into the primary tubes, and a front box is just that. Bodywise it could be made with a wide passenger compartment (either using a backbone structure with a wide center tunnel, or a more twin tube style structure) so as to use the Al sheeting as body work (ala lotus 340R or the like) or someone could go through the rigors (better men than I) of a complete body plug. Naturally a basic suspension layout and parts could be included in the drawing set for those less interested in doing it themselves. But to make a long story short, it would just be a rigid base structure to start from with a lot of latitude build on. Just a thought. If only I could get 2cents each. Cheers!
no thats pretty much what Ive been saying from my 1st post in this thread.
Anywhoo, Mr Geeko, sorry about getting the name wrong (), my insurance is done by Geico so I should have gotten the name right after all the
commercials Ive seen over here
quote:
Yes - a transverse mid-engine layout will have a more rearward mass centre for the drivetrain than a longitudinal one.
I don't think anyone disagrees with the above, but "locost" budgets don't allow for "real" transaxles. Where is this
transaxle going to come from? Where is the expensive adaptor plate coming from?
Since this thread is for a mid-engine Locost, there is only one clear choice, use an existing FWD drivetrain in the back of the car.
This is exactly what I said at the top of the thread, everyone has *their* idea of what makes a Locost midi... and many seem unwilling to bend to a
common view.
Well, as self-appointed dictator, I say the only *realistic* solution is an existing FWD drivetrain. Here's the whole design, use all
Miata parts at the front and the FWD drivetrain, axles, uprights, and brakes at the back. There, Lord Kurt has spoken, so let it be written, so let
it be done. Now stop squabbling and get to work designing it!
[Edited on 1/4/06 by kb58]
Hmmm,
No post from me with render etc last night as I got home and found my PC dead Hopefully it's just the power supply because I can replace that
pretty cheaply. However, work pressures mean that won't happen for a day or two.
Some comments:
Brian (Ratman) - Yes, wishbone front ends are getting rarer. For that matter, undriven front ends are rare (ie RWD rather than FWD/AWD). Van
spindles are a possibility athough everything I see and hear suggests that they're pretty heavy (reflecting their commercial vehicle origins).
The Gemini/Chevette parts are lovely and light and have a nice bolt on caliper mount, making brake upgrades even easier. They are also 20+ years old
and getting rarer, even in Australia. That said, I was given (for free, nada, zip, gratis) three sets, complete with brakes and racks
[MonsterGarage] FREEBIES [/MonsterGarage]
I agree with Kurt (kb58) that the Miata parts are eminently suitable. However, whilst they may be common in North America, the wrecking yards are
definitely not littered with MX-5s here. Japanese parts importers do have them but they're usually pricey (eg $300-$500). And the rack mounts
at an odd angle (I'm told).
The other possibility is modifying strut type uprights, in the same way the Steve Graber, Alan B, and Kurt have all done. Steve and Alan are both
using Mk1 MR2 uprights which are effectively E8/E9 series Corolla parts with the CV/axle replaced with a big bolt to hold the bearings in. It's
not a big step further to do that yourself. Using FWD uprights modified in this way, even by just having the CV cup turned off the spindle in a
lathe, would open up a vast supply of parts.
crbrlfrost - With regard to central tub stiffness (oo'er missus!) - the Gecko has twin top rails on each side of the cockpit, braced back to the
bottom rails and panelled. This effectively makes each side a triangular 'pontoon' structure, adding strength well away from the central
axis where it can be more effective, as well as improving the side impact performance (hopefully that part will never get tested! ). The outward
sloping lower sides are echoed by the upper sides behind the seatback, which slope in at the same angle, adding a bit of visual interest and stopping
it looking too slab-sided there. The little sausage shaped vents break up the big flat part too.
Bill (bpaar) - Thanks for those numbers - they're very interesting. I only have my transverse drivetrain to measure so I wasn't able
to make any real quantitative statements about inline ones. I definitely hadn't thought about how much of one of those transaxles hangs behind
the axle line. Somewhat deflates Phillipe's argument about transverse drivetrains sitting over the axles
Just out of interest, what are you building? The idea of using an Esprit as a 'donor' sounds wild to my Australian sensibilities. I see
Esprit's much less often that I see Ferrari's (and I don't see them very much - maybe once or twice a month).
That's probably enough for now but I'm enthusiastic about how much good discussion this thread is evoking - thanks to Phillipe for kicking
it off.
Dominic (who needs to go shop for a ATX-P4 power supply now)
quote:
Just out of interest, what are you building? The idea of using an Esprit as a 'donor' sounds wild...
Front wishbones... yes Gemini/Chevette. Some kit cars use these here in NZ. Also, these exchange with early Viva parts. And.. in our local "pick-a-part" wreckers I found an Isuzu Piaza (or something) sports version of the Gemini with exchangable parts and ventilated front disks. Also had a disk rear axle and my friend used this to upgrade his Gemini based MG looking kit car. For a midi these are not light weight... but what is? the sacrifice is only a very few kg and it is much easier to get certification on the build for road registration if the suspension components have not been modified. It's hard enough to get a car built that you don't want any unnecessary hassels with "the system".. Cheers, Brian
I didn't mean to imply that the rear box with central tunnel would be ideal unto itself, however, it is still very doable, but a complete redesign of the rear bulkhead area. I personally like the idea of twin sidepods carrying most of the load, but it presents issues such as ingress/egress, doors, arguably dangerous fuel location if used such, etc etc. Just another compromise in my book, only depends on who you're marketting to. As far as uprights go, at least in the states it may be interesting to scrounge up modern light duty truck uprights, since they seem to be the source of most SLA's in this country. With the vastly different roles they market to, perhaps one or a few of the models would be suitable. Otherwise, it may be possible to fabricate/machine relatively simple uprights on the cheap and use a donor spindle (one of the many press fit variety) seeing as they are the more difficult to machine. Or, if using enclosed body work, it would be possible to get away with the ubiqitous honda sla upright, although it limits wheel size and perhaps raises the cowl (not as much as a strut does though). Well, horses for courses. Cheers
It's often possible to use another set of 'normal' FWD front uprights with the driveshaft/CV removed. This has been done since the
60's on mid engine kits based on the mini (GTM etc).
That would open up the Honda Civic which IIRC uses double wishbone suspension assuming the uprights are suitable.
Not sure about the Civic, but the Prelude upright is a huge S-shaped affair. Way too tall IMO. Oh and the calipers weight 15lbs each...
Bit slow getting back with a reply to this one - my home computer is still dead (motherboard and/or CPU) and won't be fixed until this weekend
because of work and other pressures
Re: converting FWD uprights. Although the later Civic's etc have double wishbone fronts Kurt is right on the money when he points out that the
uprights are a VERY odd shape and would look quite strange on the front of a Locost-ish car. The top balljoint, on the variants that I've looked
at at least, is above the tyre. This does make for a very nice KPI and small scrub offset etc but a cycle guard underneath the
balljoint is going to look a litle strange
As well, from memory, the Honda SLA front suspension is arranged in a somewhat non-conventional way too. That is, the wishbones are very different
sizes and the pivot axes aren't 'aligned' with each other. Not very amenable to our purposes I suspect.
I was thinking more along the lines of older Corolla (E8/E9/E10) or, even better, Suzuki's like the Swift. The 4x100 PCD is almost universal on
small FWD's now and the little Suzuki's tend to be more lightly built and, thus, possibly more suited to our purposes. As well, because
these uprights need to fit inside 13" wheels in the native environment, there should be plenty of space to do the Mac strut to ball-joint adapter
shuffle that AlanB & SteveG have done. Brakes should be more than up to the job with lighter overall weight and a much more rearward weight
bias.
In the unlikely even that I find myself with some spare time, I'll have a look at the wreckers and see how big/small and adaptable (or not) the
uprights from Suzuki's and the other small FWD's are.
Dominic
I know this is of little to no use for people outside the EU, but I was wondering if the uprights of the old Fiat Panda could be converted to fit a
wishbone-type suspension?
It would pretty much be the cheapest donor vehicle ever, since people are often giving them out for free when they become too rusty...
And light too, of course!