@vonzace Not really - the only parts we bought were the rose joints. I believe they were about $AU6 each, so $24 for the four. The rest we made ourselves from standard RHS and steel tube which is very cheap, about 6 bucks per metre - but we had a lot of that around anyway left over from another job. Since we just did this for fun and a hobby, we're not counting the labour cost of all the cutting, welding, turning and so on.
@Tactical300 It is angled by design to ensure that the joint has maximum angular travel available to it. Everyone's an expert aren't they? To bend this material needs the strength of two people or an extremely long lever when put in a tube bending jig - short arms like this are never going to bend given the normal forces they'll encounter. I did do the sums you know!
@GRAHAMAUS I'm studying mechanical engineering at Virginia Tech, and I designed Control Arms for our Formula SAE Team (Your accent suggests that you may be in Europe, so you might have heard of Formula Student). So I accomplished what I wanted out of commenting on your post; I learned something about your design. And the title does have some key words in it that will attract the 'experts' (self-proclaimed or not).
@Tactical300 Well, that's cool. It's just the assumption in your original post that the bend in the arm was accidental or indicative of a failure in progress. Seriously, do you think I'd have filmed it if that were the case?
@shredder2468 Yadda-yadda-yadda. So many armchair engineers out there. I built it, it works, works well, does everything it was designed and intended to do. Not perfect? Perhaps, but then I'm just some guy in a garage, not bloody Audi.
@Moopcan It's not - the arm is articulated so those forces cause the arm to move (unless it hits its end stops but in normal use that will not occur). Also, the rose joints used are much larger than that needed for the weight and force carried - i.e. they are very over-specified.
@GRAHAMAUS yes it is, although it may not be bottomed out, the spring still exerts a shear force on the rod end. This being said, it's a go-cart! It won't see forces large enough to cause damage, and if it does you can buy rod ends designed to take some shear.
how did you put the steering into that?.ive been wondering fo ways to have suspension and steering at the ame time..couldnt think of anything? so far!
I'd have moved the pick up points rather then use that odd lookin spindle to get it lower. I'd also make the shock inclination adjustable to change it's effectiveness and spring rate, it looks like there's room enough. With the spindle located like it is just looks weird to me, and it'll stress the upper arm more, which is why I don't like drop spindle mods on "normal" cars. Cross torsions like sprint cars use is an intresting set up too. How does it work anyway, any unexpected quirks?
It looks designed upside down to me, why have the spindle so close to the upper control arm? No sturt or such on the bottom at all?? Time to go back to the drawing board and do this one over again. You call it a double wishbone but it's missing a link on the bottom, or I'm not seeing it.
@505197 The geometry gives it a) a low ground clearance, and b) a zero scrub radius. There is an additional lower strut which we added later that isn't shown here. Originally we thought it wouldn't need one, with longitudinal control provided only by the upper arm, but that turned out not to be strong enough. You can see it in our later video.
@GRAHAMAUS You should see the shit suspensions guys build for outlaw figure eights, you can check the cars out by youtubeing Indy 3 hrs race, or world championships, they're real serious cars not junkers. Talk about scrub, you'd need a yard stick to measure it. I raced in a class where they limited camber for some stupid reason, how come morons always run race tracks? Anyway I just cranked in the caster to the tune of about 13 degrees and had all the camber gain I needed. I like a lot caster
@pyroman675 The kingpin inclination is 14° (more out at the bottom than the top, viewed from the front). The castor angle is 5° (more forward at the bottom than the top, viewed from the side). Hope that clears it up. These are fairly common sorts of values, nothing unusual here.
@vwaudi914 a mailorder company called 'small parts and bearings' supplies this kind of thing, though the rose joints were off the shelf from a local hardware store. The bushings were made by us from Delrin rod.
that is nice looking. also expensive looking. I built my suspension for 40.00. that looks much nicer but your bill hurts ill bet.
vonzace 4 months ago
@vonzace Not really - the only parts we bought were the rose joints. I believe they were about $AU6 each, so $24 for the four. The rest we made ourselves from standard RHS and steel tube which is very cheap, about 6 bucks per metre - but we had a lot of that around anyway left over from another job. Since we just did this for fun and a hobby, we're not counting the labour cost of all the cutting, welding, turning and so on.
GRAHAMAUS 4 months ago
@GRAHAMAUS Cool.
vonzace 6 days ago
What are the dimensions of that 'lower control arm?' Looks like its is slightly bent/already yielded/ will fail in fatigue eventually...
Tactical300 5 months ago
@Tactical300 It is angled by design to ensure that the joint has maximum angular travel available to it. Everyone's an expert aren't they? To bend this material needs the strength of two people or an extremely long lever when put in a tube bending jig - short arms like this are never going to bend given the normal forces they'll encounter. I did do the sums you know!
GRAHAMAUS 5 months ago
@GRAHAMAUS I'm studying mechanical engineering at Virginia Tech, and I designed Control Arms for our Formula SAE Team (Your accent suggests that you may be in Europe, so you might have heard of Formula Student). So I accomplished what I wanted out of commenting on your post; I learned something about your design. And the title does have some key words in it that will attract the 'experts' (self-proclaimed or not).
Tactical300 5 months ago
@Tactical300 Well, that's cool. It's just the assumption in your original post that the bend in the arm was accidental or indicative of a failure in progress. Seriously, do you think I'd have filmed it if that were the case?
GRAHAMAUS 5 months ago
the problem with yours is that your control arms are to short so not going to have much travel.
shredder2468 7 months ago
@shredder2468 Yadda-yadda-yadda. So many armchair engineers out there. I built it, it works, works well, does everything it was designed and intended to do. Not perfect? Perhaps, but then I'm just some guy in a garage, not bloody Audi.
GRAHAMAUS 7 months ago
@shredder2468 They don't need much travel, it's for use on smooth tarmac not off-road.
GRAHAMAUS 5 months ago
@GRAHAMAUS just sayin!
shredder2468 5 months ago
Rod ends are not meant to be loaded in shear + bending
Moopcan 8 months ago
@Moopcan It's not - the arm is articulated so those forces cause the arm to move (unless it hits its end stops but in normal use that will not occur). Also, the rose joints used are much larger than that needed for the weight and force carried - i.e. they are very over-specified.
GRAHAMAUS 8 months ago
@GRAHAMAUS yes it is, although it may not be bottomed out, the spring still exerts a shear force on the rod end. This being said, it's a go-cart! It won't see forces large enough to cause damage, and if it does you can buy rod ends designed to take some shear.
joeslimon 6 months ago
how did you put the steering into that?.ive been wondering fo ways to have suspension and steering at the ame time..couldnt think of anything? so far!
teddyandsalemrules 8 months ago
@teddyandsalemrules The other video shows how the steering works.
GRAHAMAUS 8 months ago
Not sure that using rose joints in bending is the greatest idea.
sccopez 9 months ago
@sccopez ??? This is a very common design, used on loads of classic race cars. Ariel Atom, for instance.
GRAHAMAUS 8 months ago
I'd have moved the pick up points rather then use that odd lookin spindle to get it lower. I'd also make the shock inclination adjustable to change it's effectiveness and spring rate, it looks like there's room enough. With the spindle located like it is just looks weird to me, and it'll stress the upper arm more, which is why I don't like drop spindle mods on "normal" cars. Cross torsions like sprint cars use is an intresting set up too. How does it work anyway, any unexpected quirks?
505197 1 year ago
It looks designed upside down to me, why have the spindle so close to the upper control arm? No sturt or such on the bottom at all?? Time to go back to the drawing board and do this one over again. You call it a double wishbone but it's missing a link on the bottom, or I'm not seeing it.
505197 1 year ago
@505197 The geometry gives it a) a low ground clearance, and b) a zero scrub radius. There is an additional lower strut which we added later that isn't shown here. Originally we thought it wouldn't need one, with longitudinal control provided only by the upper arm, but that turned out not to be strong enough. You can see it in our later video.
GRAHAMAUS 1 year ago
@GRAHAMAUS You should see the shit suspensions guys build for outlaw figure eights, you can check the cars out by youtubeing Indy 3 hrs race, or world championships, they're real serious cars not junkers. Talk about scrub, you'd need a yard stick to measure it. I raced in a class where they limited camber for some stupid reason, how come morons always run race tracks? Anyway I just cranked in the caster to the tune of about 13 degrees and had all the camber gain I needed. I like a lot caster
505197 1 year ago
I have over 8 1/2 inch of travel on mine. Might be a little over kill but it is cool.
91yotapick 1 year ago
so it the king pin at an angle at 14 degrees out ward or in
pyroman675 1 year ago
@pyroman675 The kingpin inclination is 14° (more out at the bottom than the top, viewed from the front). The castor angle is 5° (more forward at the bottom than the top, viewed from the side). Hope that clears it up. These are fairly common sorts of values, nothing unusual here.
GRAHAMAUS 1 year ago
where did you buy the components like balljointa, and the end of the A-arms where the bushings go and the bushings for that matter, regards, Zach
vwaudi914 1 year ago
@vwaudi914 a mailorder company called 'small parts and bearings' supplies this kind of thing, though the rose joints were off the shelf from a local hardware store. The bushings were made by us from Delrin rod.
GRAHAMAUS 1 year ago