R26.R R26 better lower control arms - chapter 2

Discussion in 'Suspension, Brakes, Wheels & Tyres section' started by bulardas, Mar 17, 2015.

  1. After a long painstaking process of designing and redesigning the lower arms a good couple of times, we got to the pre-production stage of the parts. Next, we are going to make a fast prototyping part and test the fitment and, if everything works as planned, to start making a couple of sets.

    The arms are designed to have 2 extra degrees of caster (so simillar with Meg III RS) and the possibility to adjust camber in a decent way. The weight of one arm should be 2.1kg without the bushes and ball-joint. They will be made out of mild-steel with powder coating on top.
    The rear bush is made out of rubber but is a better version that the original one, somehow similar with the Vibratechnics one, just that the price is lower. The ball-joint is original Renault part made for a heavier car, so it should be at least as good as the original. The small bush is the original one. The Powerflex one can be added if anyone likes the squeal of polyurethane under the car.

    Please tell me if you have anything to add to my design.
    Thank you,

    S.

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    Filo likes this.
  2. Subscribed to this
     
  3. Also subscribed, do you have a ball park figure in mind as to how much you will be charging for these?
     
  4. -Jamie-

    -Jamie- RSM Moderator

    Those look very well thought out and designed. Good effort and the serious MK2 RS owners should be all over these
     
  5. Quite some work there. You milling these from one piece?
     
  6. I know I'm not very fast, but I try to be very good. Or good at least. I don't have any price yet, I'm expecting from a couple of shops to see. I try to keep the price as low as possible, so more people will be attracted by this. When I have a price, I will make it available.

    Thank you Jamie and I hope this will be the case. My car will definitely have them. Now if there will be other, I will manage to pay my electricity bills for the time used my PC to do the 10 different iterations.

    Yes, they will be made from one piece with a welded part where the small bush is. In the next days I hope I will be able to come up with the results from the FEA work (Finite Element Analysis).

    S.
     
  7. -Jamie-

    -Jamie- RSM Moderator

    I take it the castor is built in to the spec of the arm and the camber is adjustable via the slotted holes?
     
  8. from looking at machining work i needed doing cant see much change from 500-1k tbh
     
  9. Well if they are they're far too expensive IMHO.

    I commission machine parts through small scale engineering companies at work, and looking at these, from 5mm mild steel, I would be looking at not more than £250, from a drawing, for a couple off. Given that the OP only wants to pay his PC electric bill (!), add £50 for the R&D work - £300 tops. Any more and who'll buy them?
     
  10. Gray

    Gray RSM Moderator

    subscribed.

    This is getting interesting!
     
  11. -Jamie-

    -Jamie- RSM Moderator

    Other than spending big money on a decent set of coilovers with adjustable topmounts what other way is there to change the camber/castor on these? I would happily spend anything upto £4/500 if i owned a MK2
     
  12. AST do adjustable top mounts for standard suspension
     
  13. I see people are already speaking about the cost and for what price the arms can be produced. And somehow along this lines, my arms are already too expensive, even if I didn't said any price.
    If you ask me (me = a guy trying to get better parts for this small community) this kind of behaviour is not useful for anybody. My plan is not getting rich from selling 10 metal parts, my plan is to find some money to pay for my future projects and parts and this way, we all win. Or at least we get faster cars in a way of another.

    First of all, if there was any decent option, I would bought it for myself a long time ago and had good long nights reading rather than CAD designing.
    Second, there are a lot of people buying original arms from Renault (around 300£ if not a little more) every time a ball-joint goes bad. And they top-up that price with some Vibratechnics or Powerflex bushes for another 150-200£. At the end of 500£ they still have some crappy arms that go rusty after 2 weeks and bend like pancakes when you turn the wheel for lock to lock. Maybe you should calculate starting from here. How much money over the 500£ option you already have, would you pay to have a better designed part? If you look it like this, 700£ is not a lot of money.
    My part is fully serviceable, comes with uprated bushes from the beginning and with the camber adjustment. And it will be far away from 700£.

    But if my arm is still expensive, anyone is free to make it's own version and to get the engineering for free, rather than paying for my work.

    S.


    And speaking of money, people are paying happily for 120-130£ just for 2 bushes.
     
  14. the standard arms are fully serviceable you can change all the bushes and the ball joint fyi
     
  15. Yes. The castor is build-in to spec and the camber is adjustable via slotted holes.

    S.
     
  16. I know what your saying Jamie, and I meant £300 each as a finished product.

    That should really cover the manufacturing cost for very small scale production. The problem is, to make it viable the costs need to be be way higher due to to development work, prototyping etc, and an implied warranty that surely must be given. What if these fail and pitch somebody into a ditch? I'm not in anyway saying they will, but to be able to sell these in the UK, one must need to perform due diligence with the testing to be sure. This all costs big time.

    As a hobbiest making something for themselves/friends this is fine, but it doesn't work as a business model. Sorry if this has put a downer on things guys but just MHO.
     
  17. I don't know yet the price for a set. But if they are going to cost more then 600£, I would not even offer them for sale, because I know that nobody will even consider buying them, I will make a one off set for my car and delete the CADPart from my PC. But something makes me think, this will not be the case.

    S.
     
  18. How do you work out the stresses and forces on the arm to make sure its as strong if not stronger than OEM /the thickness and material needed ,how did you make sure the pick up points are the same as OEM did you make a jig,im not knocking your design or what you are saying im just curious as what you are doing isnt something you do over night as you have said , cheers
     
  19. wow awesome bit of kit bulardas, very impressed

    subscribed.
     
  20. I didn't realise this...

    None the less I'm keen to see the finished product... And if they are stronger than OEM and have the updated bushes etc. I'm having a set :smile: the steering arms are not hugely different from what you get on a std megane (from looking at images) I mean they don't look thicker or machined in a different way of you know what I mean... Where are these look purposeful and it sounds like buldaras is getting them stress tested etc...

    Let's wait and see the finished product / results / testing before the price wars commence.. Remember these aren't being manufactured in the UK where this sort of work is a lot pricier..
     
  21. Bulardas any update on this?
     
  22. We are working on the Finite Element Analysis and we realised we can modify some areas for lower weight. Also, we are looking into the possibility to make them from billet aluminium, rather than steel.
    Work in progress

    S.
     
  23. Keep us posted mate, top work :cool:
     
  24. I'm an aerospace engineer by profession.

    If you undergoing stress analysis through FEA, how did you measure the actual stress forces and measure the angles and directions of original forces?

    What factor of safety are you using?

    What software are you using to draw them and carryout FEA?

    Will they be lighter than the original arms?
     
  25. Blimey mate are you a CAA auditor lol
     
  26. I wish I knew what he was on about... Google here I come lol
     
  27. Yes. I do lecture CAA courses, part 66 stuff.
     
  28. To be honest, with no implied criticism to the original poster, I wouldn't touch this at all.

    Drawing wishbones and doing some simplistic FEA with arbitrary values of stress, is a typical second year university assignment for anyone doing a automotive/Motorsport degree with a CAD unit.

    Taking it to production and reliably testing it (including fatigue testing) is something completely different.

    The original arms are acceptable. The original poster has not said what he is trying to achieve with his design? Torsional stiffness? Less bending? Lighter weight? Less corrosion prone?

    If you really want to stiffen the arms, take an original, and carefully weld ribs and braces to it ensuring the arm isn't subjected to any excessive localised heat (which outs massive stress into local areas and creates micro fractures).

    Even just re welding any seams will strengthen it.
     
  29. double post somehow...
     
    Last edited: Apr 20, 2015
  30. Hello L-1011,

    I will try to answer a couple of your questions. First of all and the most important, you don't have to touch it if you don't feel the need, which is evident from my point of view. I will start by telling that tuning is usually an area where you try new different things to improve in different areas of the car (usually yours). As you may know, this beautiful car has it's roots in a family hauler where everything is cost driven more then anything. Same thing happens with the lower arms of our car. Is the same part with an extra hole for the anti-rotation link and different ball-joint. No one cared too much about torsional strength and rigidity on this particular arm. But, Renault sells this arm with a hefty sum of money and there is no other options besides this. How do I know? Just check Megane III RS and Clio III RS lower arm and you will realise that Renault accepts they made a mistake with our arms.

    Now, let's say you want to track your car and you want a couple of things (which you can also find in some of my first posts here, where I explain why I'm doing it):
    - no more flexing of the arm
    - tougher rubber bushes, that makes no noise like polyurethane and you are also not a big fan paying 120£ to Vibratechnics
    - you want to be able to set-up your camber without going for coil-overs and also you don't want to pay 350£ for some original shock adjustable mounts
    - you want 2 extra degrees of castor
    - and you have anyway to change your arm because let's say is bended.
    - you don't mind being different and getting out of the crowd
    With this list in hand, I had no other option that start building myself a new set of arms. The only reason I posted this here, is that maybe there is another person in the same position like me and he is interested in what I'm doing.

    I started with the idea of welding some ribs, but if you look at the arm and realise where it is bending, you will see that you cannot do to much by welding things. It was a waaay easier solution for me, but got aborded because it was not delivering.

    The testing is made in SolidWorks and then checked in Abaqus to see how is dealing with static loads. Also, we are doing some cinematic simulation using ADAMS.
    We have the original arm CAD part, so we can use it to calculate delta in terms of torsional stiffness and also we can see exactly where it is concentrating the loads.

    So, I will repeat myself. Nobody has to use my part when it will be finished. If you just offered your concerns about this with no future ideas of buying my arms, then it doesn't help to much and you are saved. But if you have any intentions, I HAPPILY accept any constructive ideas, concerns or anything that can help making a better product.

    I just hate when nobody does anything for this community, everyone is just changing hub-bearings and when someone really wants to do something, everybody starts throwing rocks at it!...maybe this community deserve the lack of quality tuning parts!

    In case there is someone with some genuine interest in this, you should know that I'm still pushing this project. I try to find the best place to produce it in order to keep final price in check. And I will continue updating this place, when I have news.

    S.
     
  31. As an long experience enginer i will give you a free advice how to improve these by at least 20% by a small weight increse.
    Just dont mill out the full depth but instead leave 1mm thickness.

    If you want me i can run fea analysis for free if you give me your loads etc as i dont have time to do full research of loads that would emerge on a specific car .

    I work with Wartsila, RR, Marine institute, NTNU etc..

    If interested send me a PM :wink:
     
  32. Crikey if this isn't community spirit I don't know what is! Top work guys!
     
  33. Don't ya just love Naff insulting replies like this to someone who is just trying something new and sharing his attempts with the community here and to reply like this before the said item is finished completely is not just rude but just plain arrogant .

    To be honest, with no implied criticism to the owner of this replie, I wouldn't bother reading his comment at all.
    L-1011 firstly don't underestimate the knowledge and testing facilities that this forum can off people, well done MilosB for your support and help to Bulardas , I would also like to add being an aerospace engineer also that if Bulardos wishes to have this part once finished NDT TESTED then I am more than willing to help with this as I can offer ultrasonic, magnetic-particle, liquid penetrant, radiographic,eddy-current testing,and low coherence interferometry. before and after fatigue and stress testing.

    As for being a Lecturer L-1011 as I have also for 7yrs, ive seen good practical and academic Lecturers and also Lecturers who teach from a book and plan it just the night before who know very little about the subject, I have a feeling I know which one you slot into, again no criticism intended.

    I would just like to say Bulardas thank you for sharing your project here and I look forward to seeing and reading more my friend and I will wait til the finished article before I pass judgement.
    I salute your bravery mate...
     
    Last edited: Apr 21, 2015
  34. Subscribed. I'm in aerospace and I love change so great work so far and I look forward to seeing what you end up with. If the product is good I'll have some :smile:
     
  35. How many of you guys work in aerospace??? Lol bit jealous... Can you guys not get titanium tubing and knock up some exhausts on the cheap lol
     
  36. What you mean like this lol
    uploadfromtaptalk1429622493835.jpg uploadfromtaptalk1429622509855.jpg
     
  37. Oooooops not me best pics lol soz charlie lol
     
  38. Duuuuude get welding an exhaust lol .. I'd be terrible working in aerospace... Just be making contraptions for myself
     
  39. At the risk of being shot down, I'll reply to this. Not least to thank Bulardas for getting back to me with regard the questions I posed.

    Bulardas, I apologise if I've been dismissive with my reply and after re-reading it (easily done after all the re qoutes and follow up comments) I was overly critical of your project.

    I understand what you are trying to achieve and hope you it works out or at the very least you learn lots along the way.

    The point I was trying to make (which others have previously made but not been challenged on) is that I'm not sure of the real value of the return on investment. From that perspective alone I wouldn't be buying your arms. However if I was racing these cars or at least spending some serious time on the track, it would be worth considering. This is indeed your market.

    Best of luck and I'll be following your thread from the point of view of interest.
     
  40. Well said L-1011, a good response, we've all been there tired a bit groggy or not concentrating and things come accross differantly to all people.
    I dont think this is a money making excercise by buldras just a guy who wants something that isn't already available. People spend silly money on silly mods, I'm one of the worst offenders buying crap that I don't 'NEED'.

    I look forward to how this pans out. I'm always up for new ideas on how to spend my tiny pay packet.
     

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