Material of wishbone

[bishoY]

I`d like to ask .. what r the materials of double wishbone ? and the specifications for each ?
thanks

[bishoY]

I`d like to ask .. what r the materials of double wishbone ? and the specifications for each ?
thanks

[CameronBeaton]

Most teams use bamboo and then cover them in foil to make them look like aluminium. I probably should be telling you this but you seem nice http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Canuck Racing]

Mm-hm. Lot of them fancy teams been switchin' to that new plastic stuff. Seems cheap to me. Probly made in China or somethin.

[NickFavazzo]

I have seen lots of that black stripy looking stuff you can get for your skyline being used, it is being used on skylines so it must be fast.

[OspreysGoSWOOP]

paperclips woven with carbon fiber work really well.

[MegaDeath]

We have been using the hair from a Unicorns tail.... Crazy strong, and unbelievably light!!!

[Tallboy]

+1 on the bamboo. We use it to upsell our car as being environmentally friendly.

[vikram.]

i don't know if you will come back and check this forum,and ya i know you might not have read the introduction ,(if you are new here) you should have read that might have helped,or atleast have some basic awareness about the world around you , and a simple answer based on your simple question ,go for steel http://fsae.com/groupee_common/emoticons/icon_smile.gif

[ed_pratt]

We just use actual wishbones. I find the ones from an ostrich work best as turkeys are just too small.

[Ivar Revolve]

Well, the material we have chosen is far the best, yet unknown to most of the designers out there.
It woven hair from virgins of the utopian woods in Mongolia, hardened in sap from a redwood tree that has survived atlest 4 forest fires.
Dont forget to use a drop of sweat from abominable sea ??cucumbers or the mix will get too elastic.

[CameronBeaton]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Tallboy:
+1 on the bamboo. We use it to upsell our car as being environmentally friendly. </div></BLOCKQUOTE>

I´m not sure if your serious, but I was thinking as I was writing it 'this could work, not the best solution but it might be ok'

[Mbirt]

Has TU Graz been running bamboo or ostrich wishbones?

[Jan_Dressler]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mbirt:
Has TU Graz been running bamboo or ostrich wishbones? </div></BLOCKQUOTE>
Sorry, I can't tell... http://fsae.com/groupee_common/emoticons/icon_frown.gif
Last time I've seen it, it was all covered by that black stripy looking stuff vinyl, like you glue on the hood of your Skyline...
But I think they use kangaroo bones, which might be the reason why There Are No Kangaroos In Austria http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Xeilos]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jan_Dressler:
But I think they use kangaroo bones, which might be the reason why There Are No Kangaroos In Austria http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

+1

[Rex Chan]

Because I'm bored, I'll answer you question:

Mild steel or cromoly. Machine ends for press fitting of spherical bearings; then weld onto tubes. You'll have to do some engineering to work out how big (OD) to make your tubes, and how thick it should be. Should be related to forces being transferred to the chassis from the tyre&gt;wheel&gt;upright.

We have used cromoly for the past 2 years (2010/2011), because we can't get mild steel that small OD. We also use much thicker wall thickness than is required, again due to lack of choice.

In 2009, they used carbon fibre tubing glued onto machined aluminium bit, which had bearings glued into them. We didn't do it right, so the glue didn;t work very well. The bearings started to move around, the the tubes became unglued. They are however, noticeably lighter than the steel ones. I still wouldn't do it, cos steel is much cheaper, faster (less machining), and idiot proof. PLus, we can drive it pretty much anywhere without worrying about breaking them.

[swong46]

Quick question, how come you don't see square tubing being used when it has less bending stress per input force?

[ed_pratt]

swong46,

I'm sure someone else will answer at some point but firstly, you shouldn't really be getting bending in your wishbones.
Ok, real world, FSAE scenario, bad manufacturing and questionable design may result in some bending forces, but essentially they are supposed to be in tension or compression only.
Which brings us to the second point, if we are more concerned about buckling then there is less of a difference between the two. Which means we choose on a secondary point, drag.

ed

[swong46]

Thanks for the reply Ed.
Looking at the Euler buckling equation, square tube is still stronger.

I thought it was drag as well but when I analyzed the drag of a square tube A-Arm at 50mph, the drag increased by only ~0.01 lb per arm.

[vikram.]

different structure different advantages, if you will consider buckling square will take more buckling then circular
torsion, circular will take more torsion for same thickness
same with the case of shear square will take more shear than circular
bending, square can take approx 1.7 time the bending stress than circular.
the difference comes in weight.

[shark.ashwa]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by vikram.:
different structure different advantages, if you will consider buckling square will take more buckling then circular
torsion, circular will take more torsion for same thickness
same with the case of shear square will take more shear than circular
bending, square can take approx 1.7 time the bending stress than circular.
the difference comes in weight. </div></BLOCKQUOTE>

I see only square and circular tubes being compared. What about elliptical tubings?
Major diameter in the plane of the control arm.

[swong46]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by vikram.:
different structure different advantages, if you will consider buckling square will take more buckling then circular
torsion, circular will take more torsion for same thickness
same with the case of shear square will take more shear than circular
bending, square can take approx 1.7 time the bending stress than circular.
the difference comes in weight. </div></BLOCKQUOTE>

Sure about the torsion advantage but even when you find a smaller square tube that is the same cross sectional weight of a larger round tube, square tube is still more advantageous in the other aspects.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by shark.ashwa:
I see only square and circular tubes being compared. What about elliptical tubings?
Major diameter in the plane of the control arm. </div></BLOCKQUOTE>

I only considered square because of its readibility.

[Whis]

Actually, most FSAE A-arms using sphericals (all 3 a-arm pickup points) will buckle (Usually, the primary failure mode is buckling) in plane with the A-arm. The reason for this is that the under braking especially the a-arm legs are not under equal loading, usually one is loaded in compression and the other is loaded in tension. This results in negative strain in one leg and positive in the other. Since the legs are joined by a spherical retainer with a web between legs at the outboard pickup point, the a-arms are loaded in a slight amount of bending because of said strain. The max stress is on the leading a trailing edge of the a-arm tubes then causing the a arm to fail in plane. It's something to think about when you size your FOS's because it is not a true pinned joint.

Whis

[Ahmad Rezq]

Old topic but I'am just wondering
when mounting the Push,Pull,Damper on on of your arms usually the lower.
in this case obviously the lower arm will carry bending so the square section tube will take the advantage over the circular section tube.
but almost all teams that mount push,pull,damper on the lower wishbone use circular section tube.
still there is some reason for that i don't know ?

[jd74914]

Round tube is less expensive in small sizes [in 4130 steel], it comes in a larger variety of all sizes, and is also easier to work with if you are making threaded inserts for the ends since they only require a turning operation.

Generally people don't worry as much about bending since the damper attachment point is usually very close to the ball joint.