While checking the web for unusual car i found this one on another locost forum.... What can i say...beside WoW!!

http://www.cardomain.com/ride/2509637

Loking good and almost completed... what do ya think???

i really like it, gotta take my hate off to him, its impressive.

Looks good, some nice engineering there.

I'd like to see the front wishbones beefed up though, theyre quite long not to be cross braced.

cheers

Chris

i dont see that being locost impressive though

Quality!
Those fabricated uprights are really nice.

Wishbones look sweet to me - the tubes are properly used to carry loads directly from point to point so should only be in tension or compression -ie no bending. Can't see that cross bracing would achieve anything, assuming he's not putting suspension loads into the bottom bone like the locost/westy/caterham design.

I'd agree with that, I was thinking more about torsion, the wheels/ hub are along way out there, a long moment to resist twist.

Maybe they're ok, difficult to tell.

cheers

Chris

they are very long, but from the quality of the welding and the execution of the rest of the project, i think he will have picked a tube size suitable for the job. Unusually for me, i cant pick any faults with it, though im not too keen on the atom approach - i dont like the long bent tubes, though obviously straight ones would ruin the cockpit space.

in fact, the design looks more arty than engineery to me...

[Edited on 22/2/07 by JoelP]

lots of scrub there!
Tig work is nice

Wish he'd offer some comments on the pictures. For example, what are those bolt-on spindles from?

The bolt on bearing set is the least impressive part of the work, it negates the advantage that a fabricated upright might have with wide spaced bearings

Coincidentally he just posted a "hello" on the Locost USA board.

http://locostusa.com/forums/viewtopic.php?t=1503&start=45

Yep! that's it...

One thing is, FWD donor are easyer to find here in north america...rwd donor in quebec are rare and difficult to find.

[Edited on 23/2/07 by CD-5]

quote:

---

Originally posted by rpmagazine
The bolt on bearing set is the least impressive part of the work, it negates the advantage that a fabricated upright might have with wide spaced bearings

---

I agree that it is a lot of work and I have avoided it myself, primarily because I cannot register a vehilce with such components unless they are tested.

Great South African engineering, gotta love it

Looks great

Looks nicely done. However, I think referring to it as "a new concept" is stretching things a bit! It's an obvious tube for tube copy of the Atom.

Still, well executed and should be a lot of fun.

quote:

---

Originally posted by chrisg
Looks good, some nice engineering there.

---

What about the MEV Rocket? http://www.mevltd.co.uk/

It looks close enough for a lawsuit.

[link followed from USA site]
Wow, I never thought I would ever get this kind of response from those that actually do know what they are talking about. Please know That I sincerely appreciate the comments and criticisms from you bunch. You guys and girls are Awesome....

ok enough with the sucking up here...

first let me not patronize anyone here into thinking I'm an Engineer.... I am NOT an engineer, not mechanically anyhow...
Software engineering....well ok maybe I know a thing or two about that...

all I am is someone that likes to play with mechanical stuff. I taught myself how to Weld and work with a lathe and stuff like that. The CADding kind of came from my being into computers and stuff like that, so I've been using AutoCAD since.... well I can't really remember since when....

I've modified Cars and bikes since I was able to ride them, this is however my very first hand at actually building a car from Scratch.....So please be gentle with me
Regards...

Welcome aboard.....you have come to right place...probably the best collection of home-built mid-engined car knowledge on planet earth....

Or the finest collection of nutters, just depends who you ask!

James

Some very fine engineering & an awful lot of hours gone into that I would say!! Congratulations & welcome.

A warm welcome from me too, nice to have another SA on here, and in midengine to boot!

I am also impressed with your workmanship.

Cheers

Fred W B

[Edited on 6/3/07 by Fred W B]

quote:

---

Originally posted by kb58
Wish he'd offer some comments on the pictures. For example, what are those bolt-on spindles from?

---

Hi rotor

To me, you are putting a lot of faith in the weld that connects the rear upright to the lower tube that holds the suspension arm attachment bushes. Or are you still going to add some gussets?

Cheers

Fred W B

I am indeed considering it, yes.

would the stresses at the bottom joint be more than at the top, or is it more a case of leverage being more on the bottom as a result of the cross-bar being there. I personally was a bit more concerned with the cross-bar not being strong enough and maybe bending, but got told by someone in the know, that since both ends of the bar will be pullingpushing simultaneously, it's as if you have only one single rod-end in the middle. granted that for wheel twist, one might want that joint a lot wider. It's the hole idea of having that rod at the bottom, for leverage to keep the wheel looking forward....I think..

You want to be sure that you are not going to get any deflection that would cause movement in the toe in-out plane, as the handling would then be very strange.

Cheers

Fred W B

I am fairly certain that you will see some type of deflection (toe-change) across that lower bush tube under load. Which would be bad. I would possibly start possibly by gusseting it with a triangle shaped sheet steel u-bent along the outer chord and perimeter welded along each side. (Did that make sense?)

Wasn't it Stanisforth that noticed over an inch of deflection on the Terrapin rear suspension when the tire width was increased?

quote:

---

Originally posted by MikeRJ

Everything looks very nicely made except the rear lower wishbones. I don't think the tube welded halfway along one of the wishbone tubes going to the upright is a very nice design at all, it's almost deliberately loading a stressed part in bending. It should also be mounted on a pivot if he is using that arm to adjust toe.

---

I'm afraid I have to join in on the negative comments about the rear lower T-arrangement. It's going to cause toe-in/out under acceleration/braking. Going to make for some odd-feeling handling, at best. At worst, it'll cause the car to experience brake-induced oversteering; the last place you need that to happen.

It needs to be fully boxed, like the excellent job you did on the rest of the assembly.

Well a revised design is allready been sent to the laser-cutter..... a whopping total of R19.87 (that's like just over a pound) Materials included, will get both uprights, nicely boxed.... will have pics shortly....

Jees Rotor, at that pricing can I send you some dwg files?

Port Elizabeth has only one lazer cutting company........minium charge of several hundred rand

Cheers

Fred W B

[Edited on 9/3/07 by Fred W B]

Sure, I can have it priced and then you can decide.

just include the material, the gauge and how many copies there of..... I'll put it into my Template I use for them and lets see how much they will charge...

it's the kind of material that makes it expensive, the cutting itself is cheap....

for instance to make a fueltank from 304 stainless, would cost me just under R980. to do the exact same cut, but from mild steel, cost me no more the 260, same gauge, same everything, just the material...

Lovely.

Do you make the cutouts (I don't know how you call that in english) into the cylinder yourself or are they premanufactured?

How do you get it to the right diameter for the bearings?

Geoff

Exactly!

quote:

---

Originally posted by #Rotor
here is what it should have looked like, yes?

---

well she started up on the 3rd try......
still busy sorting some glitches..... but the motor sounds awesome.....


[Edited on 13/9/07 by #Rotor]

Well, She gave her first steps today.... a whee bit shaky at first, but after a little tweaking on the wheel-alignment and ride height, she got into some respectful shape....

The ECU is on a First-startup map and yet she has the responsiveness that makes all else fade into insignificance.... front brakes are positively potent,

Wow! Nice build

Thank you


[Edited on 13/9/07 by #Rotor]

Really impressed by the standard of workmanship and proffesionalism of your build. And for daring to do a lot of the things most folk on here have got as far as talking about...

The fabricated uprights look superb. Any more info on them? Would love to know how much they ended up weighing and what geometry you went for - KPI, scrub radius etc?

Anyway, respect!

now here she is fully dressed, only thing missing is the windshield....

this is looking more like something to be seen in......


[Edited on 13/9/07 by #Rotor]

Looks good, one thing that stands out is the top wishbone inner location points (loads not fed into chassis but into tube) just one of my pet hates, but then, I am a grumpy old man.

Very impressive.
How do you make the long sweeping curved tubes at the sides?

I like it apart from the scoop over the engine, it's going to create a lot of drag for little effect. If the engine was boxed in I could understand it but a flat deck with mesh in it would do the job.

true that scoop will be a lot of drag, but remember that the Intercooler sits inside that scoop, and it needs all the cool air it can get....

Uphill Racer, you have an interesting point there, yes. And I'm open to any suggestion as to solving it..... though I already have the second car's frame altered around the suspension mainly... to try and solve that problem...

How did you make the curved side tubes?

If I remember correctly Rotor contracted the bending to a metal working company.

Another guy who is scratch building his Atom built something to bend his pipes.
Have a look on the following link.

http://www.locostusa.com/forums/viewtopic.php?t=1503&postdays=0&postorder=asc&start=45

quote:

---

Originally posted by JonBowden
How did you make the curved side tubes?

---

indeed yes... I'm a very lazy person.... that much effort, and I'll just give up....


[Edited on 13/9/07 by #Rotor]

Thanks folks. I haven't had a chance to have a good look but using rollers seems to be the way to go.

I have a few ideas I'd like to make one day. Using curved tubes might solve some issues.

our very first practice.....It was her first taste of racing and she loved it...

here are some of the pictures taken at Zwartkops Int.

She ran very very well, I was most impressed with her manners all round the track. pity about the rod-end failure that ruined an otherwhisely perfect practice.



[Edited on 13/9/07 by #Rotor]

Is it just the front shield or is it the whole car which is lower at his right side?

It looks really good. What was the problem you've written about?
Do you have some engine specs?

Now come on, we're all brothers here, you have to share the bad with the good; it's the only way we learn as a group. If you won't share the video, a detailed explanation, with pictures, is expected!

That aside, was this the car's first outing... because it's really not a good idea to risk two people's lives when finding out if something's going to break, at least for the initial shakedown tests. Don't pull a Mcbearen on me!

[Edited on 5/20/07 by kb58]

we have been driving the car for almost a week, so no not it's very first steps, but first real workout, I was more concerned with roadholding, and engine reliability, than with a failure like this.



[Edited on 13/9/07 by #Rotor]

There HAS to be a large bending load applied to cause this. I'll have to go back and look at your suspension design to see what's going on. This particular part looks like a one-time catastrophic failure, due to the granularity of the material. A stress failure OTOH has tiny beach marks, like tree rings, part way across the shaft.

One sure way this can happen is if the rod-end was forced to move outside it's design range. It jams the shaft against the ball race, then applies massive bending load. After it's all back together, I suggest moving the suspension through its full range of travel (without the shock travel limit pads in place.) There's a very good chance that in a turn, a rod-end was already near its limit of motion, then you hit a bump which forced the rod-end to jam the shaft against the bearing race. Carefully inspect all the broken rod-ends to see if any has a dent in the edge of the bearing race.

Like you say, finding what happened first can be tough if the ensuing damage causes secondary failures. OTOH, if a defective rod-end was installed, yeah, you're pretty much screwed. At least no one was hurt!

BTW, are those aluminum or steel rod-ends?

[Edited on 5/21/07 by kb58]

these are normal steel ones. We are actually now in the process of getting some proper Chromoly rod-ends...... 5 times as strong as these,

I did exactly that, and the joint that failed, could have been flexing the rod-end yes, That is the only explanation I can come up with, for it to have failed.... other than just being a Dud, which with my luck, is also a possibly...

I just realized something else. Not only are you applying heavy suspension loads for the first time (at the track) but with a passenger, it's going to move the suspension toward the ends of its range. Between the high cornering loads, a passenger, and hitting a bump, I'm guess that a rod-end went beyond its limit. Or, like you said, you received a defective part. Are they high quality parts, like $25US apiece? There are some low-priced ones on the market that are really bad.

Oh and it doesn't matter if you get really high quality rod-ends if you run them outside their motion limits, but you already know that.

[Edited on 5/21/07 by kb58]

I would not say they where cheap, but most definitely not extremely expensive,

obviously one should not flex a rod-end, that will make even the most expensive ones snap like a twig, no..... I just want to eliminate as much potential for product failure.

Hi Rotor

Nice to see the car on the move. Re the rod ends, Some discussion here

atom rod ends

Cheers

Fred W B

Thanks for the link, Fred, very interesting.

If the rod-end is used purely to push and pull, as it should, I can't understand how that can happen. OTOH, if there's any bending load, that's a different story. Maybe, and it's a big maybe, if the rod-end's not lined up perfectly with the forces involved, that could do it. What I mean is, if the threaded portion of the rod isn't lined up with the centerline of the tube, then bending loads will affect it right at the end of the stop-nut, which is what happened. Hmmmm.

[Edited on 5/21/07 by kb58]

Looks like a cast rod end housing to me. Even some of the industrial stuff (ie cheap) that we get from China is machined from round stock.

Looks like a classic brittle failure to me....as kb says no evidence of beach marks to suggest fatigue.

That, along with the observation of no significant impact, would lead me to suggest poor material...either cast iron (which it does have a look of) or improper heat treatment..insufficient temper and therefore too brittle.

Just IMO of course.

Alan B

[Edited on 22/5/07 by Alan B]

here I am building the new A-arms for the Rod-ends we are going to be using now, which will be Chromoly 1/2" and won't fit the existing thread.



[Edited on 13/9/07 by #Rotor]

quote:

---

Originally posted by Alan B
Looks like a classic brittle failure to me....as kb says no evidence of beach marks to suggest fatigue.

That, along with the observation of no significant impact, would lead me to suggest poor material...either cast iron (which it does have a look of) or improper heat treatment..insufficient temper and therefore too brittle.

Just IMO of course.

Alan B

[Edited on 22/5/07 by Alan B]

---

what would the fracture look like if the spherical part of the rod end was bottomed out and then the rod end was subjected to a further twisting load along its length? i.e. transition from acceleration to braking etc


Steve

the more I think about these rod-end, the more I seem to start to realize, these where mighty expensive cheap shit...... pardon my French.

and by expensive, I am actually importing some Chromoly rod-ends, from the states at about 80% the cost of what I paid for these locally.... I can go for the Kevlar lined Heims, with the same Chromoly body, but it's not the lining that is my problem, so I went for the normal ones in stead. Will Probably have them Kevlar ones as an BLING option, for those customers.

bin busy though, got done with all the suspension arms.... here is the rear arms, nicely welded up.

[Edited on 13/9/07 by #Rotor]

Intersting on the rod-ends are those the same as spherical bearings? (the names confuse me because english is not native to me)

the kit I'm currently looking into specifies enourmously expensive SKF Ampep series ones that cost 55pounds each, but the manufacturer of the kit stated that he would dare to drive another car without these specific ones fitted?

any lead to the question Why?

grtz Thomas

edit: nice welding btw looks strong.

[Edited on 28/5/07 by thomas4age]

quote:

---

Originally posted by thomas4age
Intersting on the rod-ends are those the same as spherical bearings? (the names confuse me because english is not native to me)

the kit I'm currently looking into specifies enourmously expensive SKF Ampep series ones that cost 55pounds each, but the manufacturer of the kit stated that he would dare to drive another car without these specific ones fitted?

any lead to the question Why?

grtz Thomas

edit: nice welding btw looks strong.

[Edited on 28/5/07 by thomas4age]

---

Are they instead of brakes?

ive long loved the idea of moveable aerofoils - no drag on the straights and extra grip and braking into the corners. Great idea!

How well do you think the ecu will control it? Will it be able to sense forces or just work out what to do from engine inputs?

I don't know yet, The ECU has a couple of PWM GPO channels, hopefully I will be able to rig it up to work, else I will just build a little servo driver for it, that will probably sense speed and brakes, and then from that alter the pitch accordingly, for instance, apply full tilt the moment you touch the brakes, then gradually pull the wing back down, as the speed increases, or something like that....

Theres several ways it could be done, from manual via a lever to getting a simple chip linked to a G meter. Might be an idea to link in a rear spoiler too though, to maintain balance.

Try hooking it up to a pair of triple axis accelerometers. That combined with a speed sensor on each wheel will give the computer more than enough information to work out when to apply force.

hell yeah.... I can even have them individaully controlled.... like up the inside side wing when turning........

I hope you're using a decent control motor to move the wing up and down. The hold torque will have to be enormous if you plan to control the movement by turning the axle.

Geoff

I'll probably have the servo connected to a worm-gear, that screws into a arm, attached to the shaft, so the servo won't actually have to hold the torque from the wing itself, it will just have to hold the worm-gear from turning...

quote:

---

Originally posted by ..::Nightfire::..
Are they instead of brakes?

---

allrighty, got me a bunch of heims in the mail today....
and they look purdy

[Edited on 13/9/07 by #Rotor]